isoleucyl-prolyl-proline and Hypertension

The lactotripeptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP) have been shown to decrease systolic blood pressure (SBP) in several populations, but the size of the effect varies among studies. We performed a meta-analysis including all published studies to evaluate the SBP-lowering effect of IPP/VPP in Japanese subjects more comprehensively.. Eligible randomized controlled trials were searched for within four bibliographic databases, including two Japanese ones. Eighteen studies (including a total of 1194 subjects) were included in the meta-analysis. A random effect model using the restricted maximum likelihood (REML) estimator was used for the analysis. The analysis showed that consumption of IPP/VPP induced a significant reduction in SBP as compared with placebo in Japanese subjects, with an estimated effect of -5.63 mm Hg (95% CI, -6.87 to -4.39, P<0.0001) and no evidence of publication bias. A significant heterogeneity between series was evident, which could be explained by a significant influence of the baseline blood pressure status of the subjects, the effect of IPP/VPP on SBP being stronger in hypertensive subjects (-8.35 mm Hg, P<0.0001) than in non-hypertensive subjects (-3.42mm Hg, P<0.0001). Furthermore, the effect of IPP/VPP on SBP remained significant when limiting the analysis to series that tested the usual doses of IPP/VPP consumed daily (below 5 mg/d), with estimated effects of -6.01 mm Hg in the overall population and -3.32 mm Hg in non-hypertensive subjects.. Results from this meta-analysis show that IPP/VPP lactotripeptides can significantly reduce office SBP in Japanese subjects with or without overt hypertension, and for doses that can potentially be consumed as an everyday supplement. This suggests that these peptides could play a role in controlling blood pressure in Japanese subjects. The systematic review protocol was published on the PROSPERO register (CRD42014014322).

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Humans; Hypertension; Japan; Middle Aged; Oligopeptides; Randomized Controlled Trials as Topic

Lactotripeptides (LTPs, including IPP and VPP) have held promise in the framework of lifestyle modification for prevention and control of hypertension - a cardiovascular risk factor, as LTPs are reported to have an inhibitory effect on angiotensin-converting enzyme. While the number of clinical trials to test the efficacy of LTP continues to increase, the results have been inconsistent, especially in the last few years. The purpose of the present meta-analysis is to precisely estimate the pooled mean effect of LTPs on conventional blood pressure (BP) generally and on 24-h ambulatory BP (ABP) particularly, as well as the change of BP in relation to baseline BP, race, and study design, to better reflect the evolving field.. In general analysis of 24 studies with 28 trials on 1919 human subjects, there are small reductions in both systolic BP (SBP) and diastolic BP (DBP) with the pooled mean effects of 1.66 (95% confidence interval (CI): -2.48 and -0.84) and 0.76 mmHg (-1.31 and -0.20) in response to LTP administration. In analysis of 24-h ABP response to LTP intervention, the reductions of SBP and DBP are 1.30 (-2.49 and -0.11) and 0.57 mmHg (-1.49 and 0.35). In subgroup analysis, the anti-hypertensive efficacy appears to be related to baseline BP, ethnic differences, treatment duration and double versus not double-blind design.. The present findings indicate that the BP-lowering effect of LTP is statistically significant, though small in magnitude. More clinical investigations (especially randomized double-blind trials with ABP) are warranted to determine the anti-hypertensive efficacy of LTP conclusively.

Topics: Antihypertensive Agents; Blood Pressure; Humans; Hypertension; Oligopeptides; Randomized Controlled Trials as Topic; Risk Factors

A meta-analysis of possible antihypertensive effects of small doses of bioactive tripeptides isoleucine-proline-proline and valine-proline-proline in commercial milk products or tablets was carried out. A random effects model was used on 19 randomized, placebo-controlled clinical intervention trials (published 1996-October 2010) consisting of about 1500 prehypertensive or mildly hypertensive subjects.The overall blood pressure lowering for systolic blood pressure was -4.0 mmHg (95% CI -5.9 to -2.1 mmHg, P < 0.001) and for diastolic blood pressure -1.9 mmHg (95% CI -3.1 to -0.8 mmHg, P < 0.001). However, a positive effect was not reported in all the studies. The results suggest that rather small daily doses of the lactotripeptides in different functional food products may offer a valuable option as a non-pharmacological treatment of prehypertension or mild hypertension as part of life-style advice.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Confidence Intervals; Dietary Supplements; Humans; Hypertension; Milk Proteins; Oligopeptides; Randomized Controlled Trials as Topic

The milk-derived peptides isoleucine-proline-proline (IPP) and valine-proline- proline (VPP) have been shown to reduce systolic blood pressure (SBP). This decrease is convincingly shown in subjects of Asian origin, but less consistent results have been obtained in European populations.. A meta-analysis was conducted in accord with the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) requirements, to assess the effect of IPP and VPP on SBP in Europeans, and to explore some determinants of this effect.. Ninety-one publications on the effect of IPP and VPP on SBP in Europeans were identified, and 14 trials with 15 sets of data (n = 1,306) met the inclusion criteria for the meta-analysis. A random-effects model (using the restricted maximum likelihood (REML) estimator) was used for the analysis. Although not all individual trials showed a statistically significant effect of IPP or VPP in reducing SBP, the combination of all data for the two peptides yielded a statistically significantly greater effect for IPP/VPP than for placebo. The decrease in SBP with IPP/VPP was 1.28mm Hg (95% CI, -2.09 to -0.48, P = 0.0017) and the decrease in diastolic BP (DBP) was 0.59mm Hg (95% CI, -1.18 to -0.01, P = 0.047). There was no evidence in the meta-analysis of any publication bias or of heterogeneity (P = 0.13). Among other features, a significant effect was seen for age, with each additional year of age reducing the effect on SBP by 0.09mm Hg. This might be related to isolated systolic hypertension, a condition often encountered in the elderly, who may be poorly responsive to first-line treatments for hypertension.. The peptides IPP and VPP are effective in moderately reducing SBP in European subjects, as is known for Asian populations. These two peptides could therefore have a role in controlling blood pressure (BP), a prospect that merits their further study.

Topics: Animals; Antihypertensive Agents; Asian People; Blood Pressure; Humans; Hypertension; Milk; Oligopeptides; Randomized Controlled Trials as Topic; White People

The oral assumption of lactotripeptides Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP) as nutraceuticals or functional foods is supposed to improve blood pressure (BP) control by angiotensin-converting enzyme-inhibition. However, data derived from clinical trials have reached conflicting conclusions. To perform a meta-analysis of placebo-controlled clinical trials evaluating the anti-hypertensive effect of lactotripeptides assumed as nutraceuticals or functional foods. Trials identified using a defined search strategy in PubMed were included in the meta-analysis, and their pooled effect was estimated with a random effects model, weighting for the inverse of the variance. Heterogeneity, publication bias, subgroup and meta-regression analyses were performed. A total of 18 trials have been identified, the clinical data of which have been clearly reported. Pooled effect of peptides was a reduction of -3.73 mm Hg (95% CI: -6.70, -1.76) for systolic blood pressure (SBP) and 1.97 mm Hg (95% CI: -3.85, -0.64) for diastolic blood pressure (DBP). The effect was more evident in Asian patients (SBP = -6.93 mm Hg (95% CI: -10.95, -2.94); DBP=-3.98 mm Hg(95% CI: -5.38, -2.44)) than in Caucasian ones (SBP=-1.17 mm Hg (95% CI: -2.82, 0.72); DBP = -0.52 mm Hg (95% CI: -1.39, 0.13)), and apparently not related to age, baseline BP values, dose of lactotripeptides assumed or length of the treatment. VPP and IPP lactotripeptides assumed as functional foods may significantly reduce SBP particularly in Asian subjects. The relevance of this findings in other ethnicities or associated with different dietary pattern should to be further investigated.

Topics: Adult; Asian People; Blood Pressure; Dietary Supplements; Female; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Randomized Controlled Trials as Topic

Bioactive peptides derived from milk proteins are of particular interest to the food industry due to the potential functional and physiological roles that they demonstrate, particularly in relation to cardiovascular disease (CVD). By 2020 it is estimated that heart disease and stroke will become the leading cause of death and disability worldwide. Acute and chronic cardiovascular events may result from alterations in the activity of the renin-angiotensin aldosterone system and activation of the coagulation cascade and of platelets. Medications that inhibit angiotensin converting enzyme (ACE) are widely prescribed in the treatment and prevention of cardiovascular disease. ACE inhibitory peptides are of particular interest due to the presence of encrypted inhibitory peptide sequences. In particular, Ile-Pro-Pro and Val-Pro-Pro are fore runners in ACE inhibition, and have been incorporated into commercial products. Additionally, studies to identify additional novel peptides with similar bio-activity and the ability to withstand digestion during transit through the gastrointestinal tract are ongoing. The potential sources of such peptides in cheese and other dairy products are discussed. Challenges to the bio-availability of such peptides in the gastro intestinal tract are also reviewed. Activation of platelets and the coagulation cascade play a central role in the progression of cardiovascular disease. Platelets from such patients show spontaneous aggregation and an increased sensitivity to agonists which results in vascular damage and endothelial dysfunction associated with CVD. Peptide sequences exhibiting anti-thrombotic activity have been identified from fermented milk products. Studies on such peptides are reviewed and their effects on platelet function are discussed. Finally the ability of food derived peptides to decrease the formation of blood clots (thrombi) is reviewed. In conclusion, due to the widespread nature of cardiovascular disease, the identification of food derived compounds that exhibit a beneficial effect in such widespread areas of CVD regulation will have strong clinical potential. Due to the perception that food derived products have an acceptable risk profile they have the potential for widespread acceptance by the public. In this review, selected biological effects relating to CVD are discussed with a view to providing essential information to researchers.

Topics: Animals; Blood Platelets; Cardiovascular Diseases; Disease Models, Animal; Humans; Hypertension; Milk; Milk Proteins; Oligopeptides; Peptidyl-Dipeptidase A; Renin-Angiotensin System

The consumption of fermented milk to maintain good health, including the maintance of normal blood pressure, is an ancient tradition in a number of areas of the world (e.g., East Asia, France). Recent studies have suggested that fermented milk has a normotensive effect in hypertensive rats and humans, but no effect on blood pressure in normotensive rats and humans. Two tripeptides, L-valyl-L-prolyl-L-proline (VPP) and L-isoleucyl-L-prolyl-L-proline (IPP), have been identified as possessing significant angiotensin-converting enzyme inhibitory activity and are therefore believed to be the source of the normotensive effects. This document, the second of nine chapters, provides information on these two tripeptides, including physical/chemical properties, molecular weights, chemical structures, normal consumption in the diet, manufacturing information, regulatory approval in Japan, and Japanese consumption of food containing enhanced levels of VPP plus IPP. In addition, the results of studies in rats and humans conducted to evaluate the effect of these substances on blood pressure are presented. The research suggests that in adult normotensive volunteers, consumption of up to 7.92 mg of VPP and 4.52 mg IPP daily for 2 weeks causes neither clinical signs nor biologically meaningful effects on systolic or diastolic blood pressure, pulse rate, or clinical pathology (serum chemistry or hematology). However, when a similar study was performed using mildly and moderately hypertensive adults as subjects and they consumed 2.52 mg of VPP and 1.64 mg of IPP per day, a significant drop in systolic blood pressure was detected for a prolonged time interval. This chapter also introduces the issue of safety testing for these substances and describes the information to be found in the subsequent seven chapters.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Cultured Milk Products; Humans; Hypertension; Oligopeptides

Lactotripeptides (LTPs) have a mild antihypertensive effect in hypertensive subjects. The main aim of our clinical trial was to test if LTPs could have some influence on blood pressure (BP) and related hemodynamic parameters in a sample of outpatients affected by metabolic syndrome.. A randomized, double-blind, placebo-controlled, crossover clinical trial was conducted in a group of 40 nonsmoking volunteers with metabolic syndrome. The treatment periods were 4 weeks long and were separated by a 4-week washout period. The dietary supplementation was made by daily administration of LTPs from casein, 10.2 mg/day, and compared with placebo.. During the LTP treatment, patients experienced a significant mean decrease in systolic BP (SBP; -3.4 ± 4.4 mmHg, P = 0.041), diastolic BP (DBP; -3.1 ± 3.2 mmHg, P = 0.049), and pulse wave velocity (PWV; -0.7 ± 0.3 m/sec, P = 0.001). After LTP treatment, delta SBP, DBP, and PP were all significantly improved (P < 0.01 for all) compared with placebo. PWV also improved significantly after LTP treatment with respect to the end of the treatment with placebo (-0.8 ± 0.4 vs. -0.1 ± 0.3 m/sec, P = 0.009). The square root of the ratio of peak:baseline pulse volume during hyperemia (√V2/V1) improved after LTP treatment only (1.2 ± 0.4 vs. 1.4 ± 0.5, P = 0.04). Through the evaluation of the hemodynamic parameters that were measured by the 24-hr ambulatory monitoring, we observed that SBP, MBP, and the percentage of time with SBP over the normal were significantly reduced only after the LTP treatment (P < 0.05). These parameters were also significantly improved when compared with the ones measured after the placebo treatment (P < 0.05).. In our trial, during LTP treatment, patients affected by metabolic syndrome experienced a mild but significant improvement in office and 24-hr BP, PWV, and endothelial function compared with placebo treatment.

Topics: Adult; Aged; Antihypertensive Agents; Blood Pressure; Cross-Over Studies; Double-Blind Method; Female; Humans; Hypertension; Male; Metabolic Syndrome; Middle Aged; Oligopeptides; Pulse Wave Analysis; Vascular Stiffness

Our aim was to evaluate the predictors of Isoleucine-Proline-Proline/Valine-Proline-Proline (IPP-VPP) lactotripeptides (LTPs) antihypertensive effect in the context of a short-term large double-blind randomized clinical trial involving 164 pharmacologically untreated subjects in primary prevention for cardiovascular disease. When compared with the baseline, office systolic blood pressure (SBP) (-3.42 mm Hg, P < .001) and diastolic blood pressure (DBP) (-2.35 mm Hg, P < .001) significantly decreased, in the LTP-treated patients only. No significant change in predictors during the study of ambulatory blood pressure measurement (ABPM) parameters was observed. A short-term supplementation with LTPs significantly improves the office SBP and DBP, especially in male subjects. The main predictor of LTP antihypertensive effect was the baseline BP.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Cardiovascular Diseases; Caseins; Double-Blind Method; Female; Humans; Hypertension; Male; Middle Aged; Office Visits; Oligopeptides; Predictive Value of Tests; Time Factors; Treatment Outcome

Lactobacillus helveticus LBK-16H-fermented milk products containing tripeptides isoleucine-proline-proline and valine-proline-proline lower blood pressure in hypertensive subjects using office and home blood pressure registration. The present study was aimed to evaluate the effects of two doses of these lactotripeptides on 24-h ambulatory blood pressure and lipidomics profiles in mildly hypertensive subjects.. In a randomized, double-blind, placebo-controlled parallel group study, 89 mildly hypertensive subjects ingested, after a 1-month run-in period, a fermented milk drink with 5 mg per day of lactotripeptides during 3 months, and a milk drink with 50 mg per day of lactotripeptides for the following 3 months, or a placebo milk drink without lactotripeptides. Ambulatory blood pressure (24 h) was recorded at baseline and at the end of the intervention periods. Lipidomics profiles were characterized before and after the 6-month intervention.. After the second intervention period (50 mg per day of lactotripeptides), systolic and diastolic 24-h blood pressures decreased significantly in the peptide, but not in the placebo group. However, the treatment effects -2.6 mm Hg (95% confidence interval (CI): -5.7 to 0.4) in systolic and -1.3 mm Hg (95% CI: -3.4 to 0.8) in diastolic blood pressure did not reach statistic significance. Ingestion of 5 mg per day of lactotripeptides for 3 months did not lower blood pressure. The peptide group was dominated by decrease in multiple phospholipids (PL).. Ingestion of fermented milk with daily dose of 50 mg of lactotripeptides appears to lower elevated blood pressure slightly from the baseline, but not significantly compared with the placebo group and to induce significant decreases in multiple PL.

Topics: Adult; Antihypertensive Agents; Blood Pressure; Cardiovascular Diseases; Cultured Milk Products; Double-Blind Method; Female; Humans; Hypertension; Lactobacillus helveticus; Male; Middle Aged; Oligopeptides; Phospholipids; Risk Factors

A double-blind, placebo-controlled, randomized clinical trial was conducted to evaluate the effects of ingesting an excess of tablets containing casein hydrolysate, incorporating angiotensin I-converting enzyme (ACE) inhibitory peptides such as Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), in subjects with blood pressure ranging from normal to mild hypertension. A total of 48 subjects were given either 5 times more than the effective amount of casein hydrolysate or a placebo in tablet form for 4 weeks. In the active group, systolic blood pressure (SBP) decreased significantly as compared with the placebo group. In stratified analysis, however, this antihypertensive effect was not found in normotensive subjects. In addition, neither an acute or nor an excessive reduction in blood pressure nor clinically important adverse events were observed in this study. These findings suggest that intake of a 5-fold excess of tablets containing casein hydrolysate can lead to a mild improvement in hypertension without side effects.

Topics: Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Pressure; Body Mass Index; Body Weight; Caseins; Double-Blind Method; Female; Humans; Hypertension; Japan; Male; Middle Aged; Oligopeptides; Peptidyl-Dipeptidase A; Placebos; Tablets

Casein-derived tripeptides isoleucine-proline-proline (Ile-Pro-Pro) and valine-proline-proline (Val-Pro-Pro) lower blood pressure (BP) in long-term clinical studies. Their acute effects on BP and vascular function, important for daily dosing scheme, were studied in a placebo-controlled double-blind crossover study using a single oral dose of a fermented milk product containing Ile-Pro-Pro and Val-Pro-Pro as well as plant sterols. Twenty-five subjects with untreated mild hypertension received in random order 250 g of study product (25 mg peptides and 2 g plant sterols) or placebo. Ambulatory BP was monitored for 8 h post-dose and arterial stiffness measured by pulse wave analysis at 2, 4, and 8 h. Blood and urine samples were analyzed for markers of the renin-angiotensin system (RAS) and endothelial function. Baseline adjusted treatment effect for systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial BP was -2.1 mmHg (95% CI: -4.1 to -0.1, p = 0.045), -1.6 mmHg (95% CI: -3.1 to -0.1, p = 0.03), and -1,9 mmHg (95% CI: -3-3 to -0.4, p = 0.0093), respectively, in favor of the active treatment for 8 h post- dose. No significant differences between the treatments were seen in brachial or aortic augmentation index, pulse wave velocity, or markers of RAS. Urinary excretion of cGMP, the second messenger of endothelial nitric oxide, was higher in the active group vs. placebo (p = 0.01). The results indicate that a single dose of a fermented milk product containing Ile-Pro-Pro and Val-Pro-Pro and plant sterols acutely lowers brachial SBP and DBP in mildly hypertensive subjects.

Topics: Administration, Oral; Animals; Antihypertensive Agents; Blood Pressure; Cross-Over Studies; Cultured Milk Products; Cyclic GMP; Dose-Response Relationship, Drug; Double-Blind Method; Female; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Phytosterols; Renin-Angiotensin System; Treatment Outcome

This trial evaluated the effects of casein hydrolysate containing milk-derived peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), on central blood pressure and arterial stiffness.. A randomized, double-blind, placebo-controlled trial was conducted in 70 Japanese subjects aged 50-69 years with untreated stage-I hypertension. They were randomly assigned to two groups, which received either placebo tablets or active tablets containing 3.4 mg of VPP and IPP. At the beginning and end of the 8-week intervention, hemodynamic parameters, including central blood pressure and brachial-ankle pulse wave velocity (baPWV), a marker of arterial stiffness, were measured.. A significant difference in changes in central systolic blood pressure between the groups was observed (active: -11.0±11.0 vs placebo: -4.5±9.6 mmHg, P<0.01). In the active group, reductions in baPWV (-73.9±130.0 vs -8.4±137.1 cm/s, P<0.05), brachial SBP (-10.5±11.5 vs -3.9±9.6 mmHg, P<0.05), and radial mean blood pressure (-7.3±8.9 vs -2.0±7.4 mmHg, P<0.01) were significantly greater as compared with the placebo group.. Casein hydrolysate containing VPP and IPP improves central SBP and baPWV in hypertensive subjects, which suggests VPP and IPP might have beneficial effects on arterial properties.

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Ankle Brachial Index; Antihypertensive Agents; Blood Pressure; Caseins; Double-Blind Method; Female; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Vascular Stiffness

Contrasting data partially support a certain antihypertensive efficacy of lactotripeptides (LTPs) derived from enzymatic treatment of casein hydrolysate. Our aim was to evaluate this effect on a large number of hemodynamic parameters. We conducted a prospective double-blind randomized clinical trial, which included 52 patients affected by high-normal blood pressure (BP) or first-degree hypertension. We investigated the effect of a 6-week treatment with the LTPs isoleucine-proline-proline and valine-proline-proline at 3 mg per day, assumed to be functional food, on office BP, 24-h ambulatory BP monitoring (ABPM) values, stress-induced BP increase and cardiac output-related parameters. In the LTP-treated subjects, we observed a significant reduction in office systolic BP (SBP; -5±8 mm Hg, P=0.013) and a significant improvement in pulse wave velocity (PWV; -0.66±0.81 m s(-1), P=0.001; an instrumental biomarker of vascular rigidity). No effect on 24-h ABPM parameters and BP reaction to stress was observed from treatment with the combined LTPs. LTPs, but not placebo, were associated with a mild but significant change in the stroke volume (SV), SV index (markers of cardiac flow), the acceleration index (ACI) and velocity index (VI) (markers of cardiac contractility). No effect was observed on parameters related to fluid dynamics or vascular resistance. LTPs positively influenced the office SBP, PWV, SV, SV index, ACI and VI in patients with high-normal BP or first-degree hypertension.

Topics: Adult; Aged; Blood Flow Velocity; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Cardiac Output; Caseins; Double-Blind Method; Female; Heart Rate; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Pulsatile Flow; Stress, Physiological

The milk casein-derived biologically active tripeptides, isoleucyl-prolyl-proline (Ile-Pro-Pro) and valyl-prolyl-proline (Val-Pro-Pro), have documented antihypertensive effect probably related to reduced angiotensin formation. It has been suggested that these tripeptides may reduce arterial stiffness and improve endothelial function. Our aim was to evaluate whether the milk-based drink containing Ile-Pro-Pro and Val-Pro-Pro influence arterial stiffness, measured as augmentation index (AIx), and endothelial function in man.. In a double-blind parallel group intervention study, 89 hypertensive subjects received daily peptide milk containing a low dose of tripeptides (5 mg/day) for 12 weeks and a high dose (50 mg/day) for the following 12 weeks, or a placebo milk drink to titrate the dose-response effect. Arterial stiffness was assessed by pulse wave analysis at the beginning and end of each intervention period. Endothelial function was tested by examining pulse wave reflection response to sublingual nitroglycerin and salbutamol inhalation. Blood pressure was measured by using office and 24-h ambulatory blood pressure measurement.. At the end of the second intervention period, AIx decreased significantly in the peptide group compared with the placebo group (peptide group -1.53% (95% confidence interval (CI) -2.95 to -0.12), placebo group 1.20% (95% CI 0.09-2.32), P=0.013). No change in endothelial function index was observed (peptide group 0.02 (95% CI -0.06 to 0.08), placebo group 0.04 (95% CI -0.04 to 0.12), P=0.85). There were no statistically significant differences between the effects of the peptide and placebo treatment on office and 24-h ambulatory blood pressure.. Long-term treatment with Lactobacillus helveticus-fermented milk containing bioactive peptides reduces arterial stiffness expressed as AIx in hypertensive subjects.

Topics: Adult; Animals; Antihypertensive Agents; Blood Pressure; Caseins; Double-Blind Method; Endothelium, Vascular; Female; Fermentation; Food Microbiology; Humans; Hypertension; Lactobacillus helveticus; Male; Middle Aged; Milk; Oligopeptides; Radial Artery

Nearly 70 million Americans have hypertension, and approximately an equal number have prehypertension. The prevalence of both disorders increases with advancing age and obesity. Many at-risk individuals do not have controlled blood pressure (BP). Lifestyle modification for most persons is the first step in a plan to control these conditions. Non-drug treatments offer an appeal to many patients with modest BP elevation. The authors recently evaluated BP response using 24-hour ambulatory BP monitoring and office BP monitoring of lactotripeptides dosed twice daily in 91 previously treated and treatment-naive patients with stage 1 and stage 2 hypertension. In this population, daytime systolic BP, the primary efficacy end point, significantly decreased (-3.6 mm Hg; P=.013), while placebo did not affect systolic BP (0 mm Hg; P=not significant). Treatment-naive patients exhibited a more robust drop in their daytime systolic BP (-7.6 mm Hg; P=.005) compared with placebo (-3.6 mm Hg; P=not significant). Lactotripeptides may be an effective agent in the management of low-risk and low-grade hypertension and prehypertension.

Topics: Adult; Aged; Antihypertensive Agents; Blood Pressure Monitoring, Ambulatory; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Drug Combinations; Female; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Prospective Studies

It is well known that the sour milk containing lactotripeptides has a blood pressure lowering effect. The aim of this study was to evaluate the blood pressure (BP) lowering effect of lactotripeptides by monitoring home blood pressure, 24-h ambulatory measurements (ABPM), and daily urinary salt excretion. A total of 30 volunteers were given 200 ml of sour milk twice a day for 8 weeks after a 1-week run-in period. This preparation contained the lactotripeptides valine-proline-proline 2.66 mg and isoleucine-proline-proline 1.38 mg. The study participants had daily measurements of urinary salt excretion determined by an electric salt sensor and home blood pressure for each week during the run-in period, before the 4-and 8-week time points. 24-h ABPM was measured at the end of each week. Mean systolic blood pressure (SBP) during night sleep including base BP at 4 and 8 weeks were significantly lower than baseline values. Mean SBP and diastolic blood pressure (DBP) during night sleep of the 22 participants who belonged to the criteria of hypertension by 24-h ABPM was significantly decreased at 4 and 8 weeks. The change in 24-h mean SBP significantly correlated with mean urinary salt excretion over the three measurement periods. The 22 hypertensive subjects without taking lactotripeptides did not show significant change of blood pressure during 24 hours at 4 and 8 weeks. Our study confirmed the BP lowering effect of lactotripeptides during night-time sleep and showed that a lower intake of salt may increase the BP lowering effect of lactotripeptides through 24 hours in hypertensive subjects.

Topics: Adult; Aged; Algorithms; Blood Pressure Monitoring, Ambulatory; Circadian Rhythm; Cultured Milk Products; Female; Humans; Hypertension; Male; Middle Aged; Oligopeptides; Sodium; Sodium Chloride, Dietary; Systole; Treatment Outcome

Milk derived peptides have been identified as potential antihypertensive agents. The primary objective was to investigate the effectiveness of IPP-rich milk protein hydrolysates (MPH) on reducing blood pressure (BP) as well as to investigate safety parameters and tolerability. The secondary objective was to confirm or falsify ACE inhibition as the mechanism underlying BP reductions by measuring plasma renin activity and angiotensin I and II.. We conducted a randomized, placebo-controlled, double blind, crossover study including 70 Caucasian subjects with prehypertension or stage 1 hypertension. Study treatments consisted of daily consumption of two capsules MPH1 (each containing 7.5 mg Isoleucine-Proline-Proline; IPP), MPH2 (each containing 6.6 mg Methionine-Alanine-Proline, 2.3 mg Leucine-Proline-Proline, 1.8 mg IPP), or placebo (containing cellulose) for 4 weeks.. In subjects with stage 1 hypertension, MPH1 lowered systolic BP by 3.8 mm Hg (P = 0.0080) and diastolic BP by 2.3 mm Hg (P = 0.0065) compared with placebo. In prehypertensive subjects, the differences in BP between MPH1 and placebo were not significant. MPH2 did not change BP significantly compared with placebo in stage I hypertensive or prehypertensive subjects. Intake of MPHs was well tolerated and safe. No treatment differences in hematology, clinical laboratory parameters or adverse effects were observed. No significant differences between MPHs and placebo were found in plasma renin activity, or angiotensin I and II.. MPH1, containing IPP and no minerals, exerts clinically relevant BP lowering effects in subjects with stage 1 hypertension. It may be included in lifestyle changes aiming to prevent or reduce high BP.. ClinicalTrials.gov NCT00471263.

Topics: Aged; Animals; Antihypertensive Agents; Blood Pressure; Cross-Over Studies; Female; Humans; Hypertension; Male; Middle Aged; Milk; Milk Proteins; Oligopeptides; Prehypertension; Protein Hydrolysates

Contrasting data partially support a certain antihypertensive efficacy of lactotripeptides derived from enzymatic treatment of casein hydrolysate. We carried out a randomized, double-blind, crossover clinical study to investigate the antihypertensive efficacy of a short-term treatment with lactotripeptides in Mediterranean subjects with normal or high-normal blood pressure (BP). We consecutively enrolled 55 untreated subjects (men:women = 30:25), 40.3 ± 9.8 years old, with normal or high-normal BP. After 4 weeks of dietary standardization, they were allocated to treatment with a fruit juice containing 3 mg of added Ile-Pro-Pro/Val-Pro-Pro lactotripeptides or with placebo for 4 weeks. After a 4-week washout period, they were then assigned to the alternative treatment for a further period of 4 weeks. Overall, no significant difference has been observed in office BP comparing baseline data with those posttreatment. Repeating the analysis by basal BP level, a mild but significant reduction in systolic BP (-1.7 ± 2.3 mm Hg; t = 3.5, P = .002) has been observed only in subjects with high-normal BP after treatment with lactotripeptides. With regard to 24-hour BP measurement, after lactotripeptide treatment only, the subjects experienced a significant reduction in diurnal diastolic BP (-1.6 ± 5.4 mm Hg; P = .042), diurnal mean BP (-2.1 ± 5.9 mm Hg; P = .19), and 24-hour (-5.4 ± 14.2 mm Hg; P = .011) and diurnal (-7.1 ± 19.2%; P = .014) diastolic BP value measurements relative to normal values. No modification has been observed in relation to plasma renin activity and aldosteronemia. In conclusion, diurnal diastolic BP is significantly reduced by lactrotripeptide supplementation in untreated Mediterranean subjects with normal or high-normal BP. Office systolic BP is reduced only in subjects with high-normal BP.

Topics: Adult; Aged; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Cardiovascular Diseases; Caseins; Circadian Rhythm; Cross-Over Studies; Dietary Supplements; Double-Blind Method; Female; Hemodynamics; Humans; Hypertension; Male; Mediterranean Region; Middle Aged; Oligopeptides; Severity of Illness Index; Young Adult

Clinical studies have demonstrated a beneficial effect on blood pressure for milk derived material containing isoleucyl-prolyl-proline (IPP) and valine-prolyl-proline (VPP) peptides. The aim of the present study was to evaluate the blood pressure lowering effect of three different IPP and VPP doses in products with a comparable electrolyte and protein composition. The present study was designed as a randomized, double-blind, parallel-group, dose-response trial: 166 subjects (>140/90 mmHg) received placebo during a 2-week run-in, 8-weeks intervention followed by a 2-week washout. Results indicate that materials containing IPP and VPP do lower blood pressure dose-dependently (p < 0.05 for diastolic blood pressure, DBP). The effect on systolic blood pressure (SBP)/DBP over 8 weeks compared with placebo was + 0.1/- 1.3, - 1.5/- 1.4 and - 2.5/- 1.9 mmHg for the low, medium and high dose of peptides, respectively. The percentages of subjects who showed a fall in SBP > 3 mmHg or who attained an SBP below 140 mmHg, were 54% (placebo), 64% (low), 76% (medium) and 71% (high dose) respectively. This effect can only be demonstrated for office pressure and not for home or ambulatory pressure. Furthermore, the results suggest that the magnitude of the fall in blood pressure is a function of baseline blood pressure. We conclude that IPP and VPP may have a modest dose-dependent effect on office blood pressure in mildly hypertensive subjects although this could not be confirmed with ambulatory or home blood pressure measurements.

Topics: Aged; Beverages; Blood Pressure Determination; Blood Pressure Monitoring, Ambulatory; Caseins; Dose-Response Relationship, Drug; Double-Blind Method; Female; Humans; Hypertension; Male; Middle Aged; Office Visits; Oligopeptides; Powders; Reproducibility of Results; Yogurt

Pharmaceutical angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce arterial stiffness; the possible effect of food-derived putative ACE inhibitory peptides on this degenerative process, however, has not been reported. In the present study, casein hydrolysate containing the lactotripeptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), which has been found to have an antihypertensive effect in a number of clinical studies, was investigated for its ability to improve hemodynamic parameters, including central systolic blood pressure (cSBP), in hypertensive subjects. Twelve hypertensive subjects who were not on prescribed medication were monitored for various hemodynamic parameters, including brachial blood pressure (peripheral blood pressure), cSBP, and augmentation index (AI), at the start and then after 3, 6, and 9 weeks of a daily treatment comprising four tablets containing VPP and IPP. Compared with basal levels, treatment with casein hydrolysate for 6 and/or 9 weeks showed a significant reduction in peripheral systolic and diastolic blood pressure, AI, and cSBP, but not in heart rate or pulse pressure. cSBP showed a reduction sooner and greater (-21.8 mm Hg) than did brachial systolic blood pressure (-16.4 mm Hg) during the 9-week treatment. Although small and not placebo-controlled, this study suggests that continuous intake of VPP and IPP might have the potential to improve arterial stiffness as well as cSBP and peripheral brachial blood pressure.

Topics: Adult; Blood Pressure; Caseins; Female; Hemodynamics; Humans; Hypertension; Male; Middle Aged; Oligopeptides

Several placebo-controlled clinical studies suggest that products containing isoleucyl-prolyl-proline and valyl-prolyl-proline are able to lower blood pressure without adverse effects. The most efficient way of producing high concentrations of these lactotripeptides (LTPs) is enzymatic hydrolysis of dairy protein (casein) with the use of a mixture of several enzymes derived from the nongenetically modified organism Aspergillus oryzae, including proteases and peptidases. To date, no large studies of the blood pressure-lowering properties of enzymatically produced LTP (ELTP) powder in European populations have been published.. This study was performed to evaluate the hypothesis that consumption of ELTP in a yogurt beverage for 8 wk significantly lowers blood pressure.. In this multicenter, double-blind, parallel, placebo-controlled trial, office blood pressure was evaluated in 275 Dutch hypertensive subjects. Blood pressures and body weight were measured on several days at baseline and at weeks 4 and 8 of the intervention between 2.5 and 3 h after intake of the test product. Twenty-four-h urine samples were collected at baseline and at the end of the intervention for urinalysis of sodium, potassium, creatinine, and microalbumin excretion.. The results showed that 10.2 mg ELTP/d does not lead to a reduction in systolic blood pressure (P = 0.66) or diastolic blood pressure (P = 0.72) compared with placebo.. This study showed no effect of an ELTP-enriched yogurt beverage on blood pressure in hypertensive subjects in a fairly large study.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Cultured Milk Products; Diastole; Double-Blind Method; Female; Humans; Hypertension; Male; Middle Aged; Netherlands; Oligopeptides; Peptides; Systole; Treatment Failure; Urinalysis; Yogurt

Accumulating evidence shows that deterioration of vascular endothelial function underlies the pathophysiology of cardiovascular diseases following lifestyle-related diseases. Both Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), which are tripeptides derived from proteolytic hydrolysate of milk casein, inhibit angiotensin-converting enzyme (ACE), suggesting that both VPP and IPP may improve vascular endothelial function, because many ACE inhibitors are known to improve endothelial function. We investigated the effects of ACE-inhibitory food component in humans with mild hypertension, since there has been no report on such effects. The study was conducted by the placebo-controlled, double-blind crossover method in 25 male subjects with mild hypertension. After casein hydrolysate containing both VPP and IPP were administered for 1 week, reactive hyperemia of the left upper forearm was measured using plethysmography as an index of vascular endothelial function. Since one subject dropped out, we analyzed the data of 24 subjects. The reactive hyperemia of the left upper forearm was produced by a 5 min occlusion using inflation of a cuff. The maximum blood flow during reactive hyperemia was 20.8+/-6.7 mL/min/100 mL tissue in the placebo group, whereas it increased remarkably to 30.0+/-10.4 mL/min/100 mL tissue in the group administered casein hydrolysate containing both VPP and IPP (p<0.001). There was no change in systemic blood pressure, indicating that the improvement of the vascular endothelial function attributable to VPP and IPP is independent of hemodynamic changes. We conclude that casein hydrolysate containing VPP and IPP improves the vascular endothelial dysfunction in subjects with mild hypertension. The continuous intake of VPP and IPP could help to prevent cardiovascular diseases in hypertensive subjects.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Biomarkers; Blood Pressure; Caseins; Cross-Over Studies; Endothelium, Vascular; Forearm; Humans; Hypertension; Male; Middle Aged; Oligopeptides

Two tripeptides (Val-Pro-Pro and Ile-Pro-Pro) that have inhibitory activities for angiotensin I-converting enzyme are produced in milk fermented with Lactobacillus helveticus. In this study we evaluated the effect and safety of powdered fermented milk with L. helveticus CM4 on subjects with high-normal blood pressure or mild hypertension.. A randomized, placebo-controlled, double-blind study was conducted using 40 subjects with high-normal blood pressure (HN group) and 40 subjects with mild hypertension (MH group). Each subject ingested 6 test tablets (12 g) containing powdered fermented milk with L. helveticus CM4 daily for 4 weeks (test group) or the same amount of placebo tablets for 4 weeks (placebo group).. During treatment, the decrease in systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the test group tended to be greater than in the placebo group for both blood pressure groups. At the end of treatment (week 4), a significant decrease in DBP in the HN group was observed (i.e. 5.0 mm Hg (0.1, 9.9; p = 0.04) compared with the placebo group). There was no significant change in SBP (3.2 mm Hg (95% CI -2.6, 8.9; p = 0.27). In the MH group, SBP decreased by 11.2 mm Hg (4.0, 18.4; p = 0.003) and there was a statistically non-significant decrease in DBP of 6.5 mm Hg (-0.1, 13.0; p = 0.055) compared with the placebo group. No marked changes were observed in other indexes, including pulse rate, body weight and blood serum variables, and no adverse effects attributed to the treatment was found in each group.. Daily ingestion of the tablets containing powdered fermented milk with L. helveticus CM4 in subjects with high-normal blood pressure or mild hypertension reduces elevated blood pressure without any adverse effects.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Consumer Product Safety; Double-Blind Method; Female; Fermentation; Humans; Hypertension; Lactobacillus; Male; Middle Aged; Milk; Oligopeptides; Probiotics

We describe a clinical trial to study the efficacy of a casein hydrolysate, prepared using an Aspergillus oryzae protease, containing the major angiotensin-I-converting enzyme inhibitory peptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) in a single-blind, placebo-controlled study. A total of 131 volunteers with high-normal blood pressure and mild hypertension were randomly divided into four groups (n 32 or 33 in each group). Each volunteer was given two tablets containing four different dosages of VPP and IPP (VPP+IPP: 0, 1.8, 2.5 and 3.6 mg), daily for 6 weeks. A significant decrease in systolic blood pressure was observed at 6 weeks in the active group receiving 1.8 mg (P<0.01) VPP and IPP; in the active groups receiving either 2.5 mg or 3.6 mg, systolic blood pressure was decreased at both 3 weeks (P<0.05 and P<0.05) and 6 weeks (P<0.001 and P<0.0001) compared with systolic blood pressure measured before treatment. Changes in the systolic blood pressure after 6 weeks of treatment in the four groups were --1.7, --6.3, --6.7 and --10.1 mmHg, and these effects were dose dependent. In addition, a significant difference in systolic blood pressure between the placebo group and the VPP and IPP group receiving 3.6 mg was observed (P<0.001) by two-way ANOVA. The antihypertensive effect was greater in mildly hypertensive subjects (n 20 or 21 in each group) than in any of the other subjects. No significant change of diastolic blood pressure was observed for all the test groups, and no differences in diastolic blood pressure in the test sample groups compared with the placebo group were observed during the test period.

Topics: Administration, Oral; Adult; Analysis of Variance; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Aspergillus oryzae; Blood Pressure; Body Mass Index; Body Weight; Caseins; Dietary Supplements; Female; Humans; Hypertension; Male; Oligopeptides; Single-Blind Method

The present study was carried out to evaluate the blood pressure (BP)-lowering effect and the safety aspects of Lactobacillus helveticus LBK-16H fermented milk with high tripeptide doses on hypertensive subjects using 24-h ambulatory measurements (ABPM).. In a randomized, double blinded placebo-controlled parallel group study, 94 hypertensive patients not receiving any drug treatment were given 150 mL twice daily of either L. helveticus LBK-16H fermented milk with a high concentration of tripeptides (Ile-Pro-Pro 7.5 mg/100 g and Val-Pro-Pro 10 mg/100 g) or a control product, for 10 weeks after a 4-week run-in period. Twenty-four-hour ABPM were taken at the beginning and at the end of the intervention period. The average baseline systolic and diastolic BP values were 132.6 +/- 9.9/83.0 +/- 8.0 mm Hg in the L. helveticus group and 130.3 +/- 9.6 /80.2 +/- 7.0 mm Hg in the control group.. There was a mean difference of -4.1 +/- 0.9 mm Hg in systolic (P = .001) and a -1.8 +/- 0.7 mm Hg in diastolic BP (P = .048) between the L. helveticus group and the control group. There was no difference in the sum of the adverse events (P = .820).. Lactobacillus helveticus LBK-16H fermented milk containing bioactive peptides, in daily use, does have a BP-lowering effect in hypertensive subjects and is thus a potential for the dietary treatment of hypertension.

Topics: Analysis of Variance; Animals; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Circadian Rhythm; Double-Blind Method; Female; Fermentation; Humans; Hypertension; Lactobacillus helveticus; Male; Milk; Milk Proteins; Office Visits; Oligopeptides

Angiotensin-converting enzyme (ACE) is important in the regulation of blood pressure (BP). Two tripeptides that inhibit ACE, isoleucyl-prolyl-proline (Ile-Pro-Pro) and valyl-prolyl-proline (Val-Pro-Pro), have been isolated from certain sour milks. The aim of the study reported was to evaluate the effect on BP in subjects with mild hypertension of a new sour milk containing tripeptides. The initial number of subjects was 60 (36 men, 24 women). Among the criteria for inclusion in the study were systolic BP (SBP) between 140 and 180 mmHg and/or diastolic BP (DPB) between 90 and 110 mmHg, without antihypertensive drug therapy. There were two study periods with a washout period between. All subjects were given 1.5 dl per day of a placebo (regular sour milk) or of the active product, a milk that had been fermented with Lactobacillus helveticus bacteria and contained 2.4-2.7 mg of Ile-Pro-Pro and 2.4-2.7 mg of Val-Pro-Pro per 1.5 dl. In the first phase, SBP fell 16 mmHg from baseline in the active group, 2 mmHg more than in the placebo group (P=0.0668) and no difference in DBP (P=0.92). There was a statistically significant downward trend both in SBP and DBP (P=0.0001). During the second phase, SBP fell 11 mmHg in the active group (P=0.008). The reduction in SBP was significantly larger in active than placebo group (P=0.012). In the crossover analysis combining both phases, SBP fell on average 2.6+/-15.9 mmHg more on the active product compared with the placebo product, but this difference was not statistically significant (P=0.3111). The difference in DBP, 1.0+/-8.3 mmHg between the two test products was not significant either (P=0.4431). In conclusion, the ingestion of sour milk fermented by L. helveticus bacteria and that containing ACE inhibitory tripeptides seems to lower BP modestly.

Topics: Analysis of Variance; Cross-Over Studies; Female; Fermentation; Finland; Humans; Hypertension; Lactobacillus; Male; Middle Aged; Milk Proteins; Oligopeptides

The tripeptides, Ile-Pro-Pro (IPP) and Leu-Lys-Pro (LKP), inhibit angiotensin-converting enzyme (ACE) resulting in lowered blood pressure. Our hypothesis was that the medium chain fatty acid permeation enhancer, sodium caprate (C

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Caco-2 Cells; Decanoic Acids; Dipeptides; Disease Models, Animal; Humans; Hypertension; Intestinal Absorption; Intestinal Mucosa; Jejunum; Male; Oligopeptides; Peptide Transporter 1; Rats; Rats, Inbred SHR; Rats, Wistar

Bradykinin is the main player of the kallikrein-kinin system. Bradykinin-induced vasodilatation is age-dependent; this is believed to be associated with the level of expression of the two bradykinin receptors (BR1 and BR2) in the vasculature. The aim of this study was to clarify bradykinin-induced vascular reactivity of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY) after 6 weeks' consumption of a drink containing bioactive tripeptides (Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro). Two age groups were used: young (10 weeks at the end of experiment) and old (24 weeks). Blood pressure was monitored weekly by the tail-cuff method. After six weeks, vascular reactivity was assessed in vitro in mesenteric artery rings focusing on bradykinin induced activity. Blood pressure was lowered in old SHR after 6 weeks' tripeptide consumption compared to water drinking controls (P < 0.05). Blood pressure was lowered by peptide consumption also in old WKY (P < 0.05) but tripeptide consumption exerted no effect on the blood pressure of young animals. Old SHR suffered from endothelial and smooth muscle dysfunction which was not improved by these tripeptides. Interestingly, bradykinin caused vasoconstriction even in young SHR; this was blocked by a non-selective cyclooxygenase (COX) inhibitor but not by a B1 and B2 receptor antagonist. The expressions of mRNA of COX-1 and COX-2 in aorta were slightly upregulated in old SHR. ACE-1 activity in aorta and protein level in kidney, but not ACE-1 mRNA expression was upregulated in old animals (P < 0.05). To conclude, long-term feeding with a drink containing tripeptides lowers or prevents the age-associated increase in blood pressure in hypertensive and normotensive animals. ACE-1 activity, protein level but not mRNA expression are elevated in old animals. We also demonstrated that the vascular inflammation and dysfunction present in aged hypertensive animals cause bradykinin to induce vasoconstriction; this is not prevented by tripeptide feeding but involves the prostaglandin pathway.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Aorta; Blood Pressure; Bradykinin; Captopril; Cyclooxygenase 1; Hypertension; Kidney; Membrane Proteins; Mesenteric Arteries; Oligopeptides; Peptidyl-Dipeptidase A; Rats, Inbred SHR; Rats, Inbred WKY; Vasoconstriction; Vasodilator Agents

The bioactive peptides Ile-Pro-Pro (IPP) and Val-Pro-Pro (VPP) are believed to improve blood pressure and arterial function. To gain a better understanding of the mechanisms underlying the action of these peptides, we investigated their effects upon autonomic neurotransmission and blood pressure in spontaneously hypertensive rats (SHR). Both IPP and VPP caused a significant reduction in cutaneous arterial sympathetic nerve activity (CASNA) and reduced mean arterial pressure (MAP); however, both of these effects were eliminated following sub-diaphragmatic vagotomy. On the other hand, captopril, an angiotensin-converting enzyme inhibitor, reduced MAP without changing CASNA, and maintained this hypotensive effect following vagotomy. Moreover, the effects of IPP and VPP upon CASNA were observed following gastric administration but not by duodenal administration. These results suggest that IPP and VPP reduce CASNA via the stomach and afferent vagus nerve, thus causing reductions in MAP in SHR.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Autonomic Nervous System; Blood Pressure; Captopril; Chromosomal Proteins, Non-Histone; DNA Helicases; Drosophila Proteins; Hypertension; Oligopeptides; Rats, Inbred SHR; Synaptic Transmission; Transcription Factors; Vagotomy

Topics: Angiotensin I; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Bradykinin; Captopril; Humans; Hypertension; Mesenteric Arteries; Oligopeptides; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Rats; Rats, Wistar; Receptor, Bradykinin B1; Receptor, Bradykinin B2; Receptors, G-Protein-Coupled; Vasodilation

Somatic angiotensin-converting enzyme (ACE) contains two active sites, the C- and N-domain, from which the C-domain is supposed to play a major role in blood pressure regulation and is therefore a promising pharmacological target to reduce blood pressure without side-effects. We report for the first time that tryptophan-containing dipeptides such as Ile-Trp or Val-Trp, which were recently found in food protein hydrolysates, are selective and competitive inhibitors for the C-domain with a selectivity factor of 40 and 70, respectively. Structure-activity studies showed that an N-terminal aliphatic amino acid and a tryptophan moiety in the P2' position are favourable structures for C-domain inhibition in dipeptides. In contrast, the lactotripeptides Ile-Pro-Pro and Val-Pro-Pro, which were widely used as ingredients for hypotensive food, showed a slight selectivity for the N-domain. Hence, tryptophan containing dipeptides are interesting ingredients for functional foods as a natural prevention for hypertension with reduced side effects due to its selective inhibition of the C-domain.

Topics: Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Body Mass Index; Catalytic Domain; Dipeptides; Humans; Hypertension; Oligopeptides; Peptidyl-Dipeptidase A; Protein Hydrolysates; Structure-Activity Relationship; Tryptophan

Hypertension is a major global health issue which elevates the risk of a large world population to chronic life-threatening diseases. The inhibition of angiotensin-converting enzyme (ACE) is an effective target to manage essential hypertension. In this study, the fermentation properties (titratable acidity, free amino nitrogen, and fermentation time) and ACE-inhibitory (ACEI) activity of fermented milks produced by 259 Lactobacillus helveticus strains previously isolated from traditional Chinese and Mongolian fermented foods were determined. Among them, 37 strains had an ACEI activity of over 50%. The concentrations of the antihypertensive peptides, Ile-Pro-Pro and Val-Pro-Pro, were further determined by ultra performance liquid chromatography with quadrupole-time-of-flight mass spectrometry. The change of ACEI activity of the fermented milks of 3 strains exhibiting the highest ACEI activity upon gastrointestinal protease treatment was assayed. Fermented milks produced by strain H9 (IMAU60208) had the highest in vitro ACEI activity (86.4 ± 1.5%), relatively short fermentation time (7.5 h), and detectable Val-Pro-Pro (2.409 ± 0.229 µM) and Ile-Pro-Pro (1.612 ± 0.114 µM) concentrations. Compared with the control, a single oral dose of H9-fermented milk significantly attenuated the systolic, diastolic, and mean blood pressure of spontaneously hypertensive rats (SHR) by 15 to 18 mmHg during the 6 to 12 h after treatment. The long-term daily H9-fermented milk intake over 7 wk exerted significant antihypertensive effect to SHR, but not normotensive rats, and the systolic and diastolic blood pressure were significantly lower, by 12 and 10 mmHg, respectively, compared with the control receiving saline. The feeding of H9-fermented milk to SHR resulted in a significantly higher weight gain at wk 7 compared with groups receiving saline, commercial yogurt, and captopril. Our study identified a novel probiotic L. helveticus strain originated from kurut sampled from Tibet (China), which is a valuable resource for future development of functional foods for hypertension management.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; China; Dairy Products; Diet; Fermentation; Hypertension; Lactobacillus helveticus; Male; Milk; Oligopeptides; Probiotics; Rats; Rats, Inbred SHR; Tibet; Yogurt

Lactobacillus helveticus H9 was isolated from traditionally fermented yak milk in Tibet (China) with the ability to produce the antihypertensive peptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) during milk fermentation. To understand the changes in the protein expression of L. helveticus H9, proteome analysis was performed at 3 different growth stages, lag phase (pH 6.1), log phase (pH 5.1), and stationary phase (pH 4.5) using 2-dimensional electrophoresis (2-DE). Further analysis showed that 257 differential protein spots were found and 214 protein spots were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The cellular functions of the differentially expressed proteins were complex. Interestingly, the proteolytic system-related proteins aminopeptidase N (PepN), aminopeptidase E (PepE), endopeptidase O2 (PepO2), and oligopeptide transport system permease protein (OppC) were observed only on the maps of pH 5.1 and pH 4.5, which was consistent with the presence of angiotensin I-converting enzyme (ACE)-inhibitory peptides VPP and IPP during these 2 growth stages (log phase and stationary phase). These results, combined with a previous study of gene expression of the proteolytic system, led us to conclude that the Opp transport system, pepE, and pepO2 are likely related to the production of ACE-inhibitory peptides.

Topics: Animals; Bacterial Proteins; Cattle; Electrophoresis, Gel, Two-Dimensional; Endopeptidases; Female; Fermentation; Hypertension; Lactobacillus helveticus; Membrane Transport Proteins; Milk; Oligopeptides; Peptides; Peptidyl-Dipeptidase A; Proteolysis; Proteome; Proteomics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tibet

The antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, were successfully detected in the aorta of spontaneously hypertensive rats after orally administering these peptides by a guanidine-thiocyanate treatment to prevent proteolysis. Cy3-labeled versions of both peptides were localized in the endothelial cells of arterial vessels in the rats. The accumulation of both peptides in the endothelial cells suggested in vivo inhibitory activity of the angiotensin I-converting enzyme.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Arteries; Blood Pressure; Carbocyanines; Endothelial Cells; Guanidines; Hypertension; Isotope Labeling; Male; Microscopy, Fluorescence; Oligopeptides; Peptidyl-Dipeptidase A; Rats; Rats, Inbred SHR; Thiocyanates

Milk casein-derived bioactive tripeptides isoleucine-proline-proline (Ile-Pro-Pro) and valine-proline-proline (Val-Pro-Pro) lower blood pressure in animal models of hypertension and humans. In some studies, their angiotensin-converting enzyme (ACE)-inhibitory effect has been demonstrated. Besides classical ACE-angiotensin II-AT(1)-receptor pathway (ACE-Ang II- AT(1)), the significance of ACE2-angiotensin-(1-7)-Mas-receptor (ACE2-Ang-(1-7)-Mas) axis in the blood pressure regulation has now been acknowledged. The present study was aimed to further evaluate the renin-angiotensin system (RAS)-related vascular effects of Ile-Pro-Pro in vitro using rat mesenteric arteries.. Superior mesenteric arteries of spontaneously hypertensive rat (SHR) were isolated, cut into rings and mounted in standard organ bath chambers. Endothelium-intact arterial rings were incubated in Krebs solution either with Ile-Pro-Pro, proline-proline (Pro-Pro), isoleucine (Ile), proline (Pro) or captopril for 6h at +37°C and vascular reactivity was measured.. In the presence of AT(1)-antagonist valsartan, Ang II induced vasodilatation, which was more pronounced in the arteries incubated with Ile-Pro-Pro (P<0.05) compared to the other compounds. Ang-(1-7)-induced vasodilatation was augmented by Ile-Pro-Pro or Pro (P<0.001 vs. control). Mas-receptor antagonist A-779 did not alter the responses. Ile-Pro-Pro and Pro augmented also bradykinin-induced relaxations (P<0.001 vs. control). Control arteries and arteries incubated with captopril showed only slight relaxations at higher bradykinin concentrations.. Casein-derived tripeptide Ile-Pro-Pro and amino acid Pro enhance the vasodilatory effect of Ang-(1-7) and bradykinin. The role of ACE2-Ang-(1-7)-Mas axis in the modulation of vascular tone by these compounds seems probable.

Topics: Angiotensin I; Animals; Blood Pressure; Bradykinin; Captopril; Hypertension; Male; Mesenteric Arteries; Oligopeptides; Peptide Fragments; Rats; Vasodilator Agents

Milk casein-derived angiotensin-converting enzyme (ACE)-inhibitory tripeptides isoleucine-proline-proline (Ile-Pro-Pro) and valine-proline-proline (Val-Pro-Pro) have been shown to have antihypertensive effects in human subjects and to attenuate the development of hypertension in experimental models. The aim of the present study was to investigate the effect of a fermented milk product containing Ile-Pro-Pro and Val-Pro-Pro and plant sterols on already established hypertension, endothelial dysfunction and aortic gene expression. Male spontaneously hypertensive rats (SHR) with baseline systolic blood pressure (SBP) of 195 mmHg were given either active milk (tripeptides and plant sterols), milk or water ad libitum for 6 weeks. SBP was measured weekly by the tail-cuff method. The endothelial function of mesenteric arteries was investigated at the end of the study. Aortas were collected for DNA microarray study (Affymetrix Rat Gene 1.0 ST Array). The main finding was that active milk decreased SBP by 16 mmHg compared with water (178 (SEM 3) v. 195 (SEM 3) mmHg; P < 0.001). Milk also had an antihypertensive effect. Active milk improved mesenteric artery endothelial dysfunction by NO-dependent and endothelium-derived hyperpolarising factor-dependent mechanisms. Treatment with active milk caused mild changes in aortic gene expression; twenty-seven genes were up-regulated and eighty-two down-regulated. Using the criteria for fold change (fc) < 0.833 or > 1.2 and P < 0.05, the most affected (down-regulated) signalling pathways were hedgehog, chemokine and leucocyte transendothelial migration pathways. ACE expression was also slightly decreased (fc 0.86; P = 0.047). In conclusion, long-term treatment with fermented milk enriched with tripeptides and plant sterols decreases SBP, improves endothelial dysfunction and affects signalling pathways related to inflammatory responses in SHR.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Caseins; Cultured Milk Products; Endothelium, Vascular; Gene Expression; Hypertension; Male; Nitric Oxide; Oligonucleotide Array Sequence Analysis; Oligopeptides; Peptidyl-Dipeptidase A; Phytosterols; Phytotherapy; Plant Extracts; Rats; Rats, Inbred Strains; Signal Transduction

The bradykinin potentiating peptides (BPPs) are oligopeptides found in different animal venoms. BPPs isolated from Bothrops jararaca venom were the first natural inhibitors described for somatic angiotensin I-converting enzyme (ACE). They were used in the structural modeling for captopril development, a classical ACE inhibitor widely used to treat human hypertension.. We evaluated the effect of BPP-5a on cardiovascular parameters of conscious Wistar (WTs) and spontaneously hypertensive rats (SHRs).. In SHR, BPP-5a showed potent cardiovascular effects, at doses ranging from 0.47 to 710 nmol/kg. The maximal changes in mean arterial pressure (MAP) and heart rate (HR) were found at the dose of 2.37 nmol/kg (Δ MAP: -38 ± 4 mmHg, p < 0.01; Δ HR: -71 ± 17 bpm, p < 0.05). Reductions in MAP and HR occurred throughout 6 hours of post-injection period. In contrast to active site-directed ACE inhibitors, no ACE inhibition, evaluated by the Ang I pressor effect, or bradykinin potentiation was observed during the antihypertensive effect of the pentapeptide. In vitro assays showed no effects of BPP-5a upon argininosuccinate synthetase and B(1), B(2), AT(1), AT(2) or Mas receptors. Ex vivo assays showed that BPP-5a induced endothelium-dependent vasorelaxation in isolated aortic rings of SHRs and WTs.. Although the BPP-5a is considered an ACE inhibitor, our results indicate that its antihypertensive effect is exerted via a unique target, a nitric-oxide-dependent mechanism.

Topics: Amino Acid Motifs; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Bradykinin; Endothelium, Vascular; Heart Rate; Hypertension; Male; Mice; Mice, Inbred C57BL; Nitric Oxide; Oligopeptides; Protein Subunits; Rats; Rats, Inbred SHR; Vasodilation; Venoms; Viper Venoms

Many antihypertensive effects of angiotensin-I-converting enzyme (ACE) inhibitory peptides have been studied in spontaneously hypertensive rats (SHRs) and human, however, the mild actions of these peptides expressed by these consecutive uptakes are still not clear. Here, to understand the in vivo antihypertensive effects of well-characterized two peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), DNA microarray was used to analyze gene expression in SHRs fed these peptides for 5 days. By using an Affymetrix analyzer, gene profiling was performed in a target organ, the aorta, of SHRs after repeated administration of VPP and IPP for 5 days. The changes in gene expression were relatively mild; therefore, among the analyzed genes associated with blood pressure, those that showed changes over +/- 5% as compared to the control group were categorized as the renin angiotensin aldosterone system, vascular function, arachidonic acid system, blood coagulation system, and cytokines and growth factors. Significant and marked differences were detected for the endothelial nitric oxide synthase (eNOS) gene (1.89-fold, P<0.05) and the connexin 40 (gap junction 40) gene (2.81-fold, P<0.05). Administration of VPP and IPP led to a slight increase in the expression of the cyclooxigenase (COX-1) gene and a decrease in the expression of both the nuclear factor kappa B subunit (NF-kappaB) gene for vascular function and the peroxisome proliferator activator receptor gamma (PPARgamma) gene. Taken together, these results suggest that VPP and IPP function as ACE inhibitors in the aorta, where they may have a preventive role in cardiovascular function.

Topics: Administration, Oral; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Aorta, Abdominal; Arachidonic Acid; Blood Coagulation; Blood Pressure; Blood Vessels; Cytokines; Endothelium; Gene Expression Regulation; Hypertension; Intercellular Signaling Peptides and Proteins; Male; Oligonucleotide Array Sequence Analysis; Oligopeptides; Peptidyl-Dipeptidase A; Polymerase Chain Reaction; Rats; Renin-Angiotensin System

The effect of chronic treatment with fermented milk products containing bioactive tripeptides and plant sterols on blood pressure and vascular function was investigated in spontaneously hypertensive rats (SHR). Six-weeks old male SHR (n=36) were randomized into 4 groups by body weight and blood pressure to receive either Lactobacillus helveticus fermented standard milk product (containing tripeptides Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro), test product with enzymatically produced tripeptides without or with plant sterols or control product without the active constituents for 8 weeks. Systolic blood pressure (SBP) was measured weekly using the tail-cuff method. Thoracic aorta and mesenteric artery were excised for vascular response measurements. At the end, SBP values vs. control product group were: standard product group -14 mmHg (P<0.05), test product group -12 mmHg and test product +sterols group -7 mmHg. The average daily tripeptide dose was 2.8-5.2 mg/kg. Total serum cholesterol in the test product +sterols group tended to be lower than in the test product group (P=0.10) whereas serum plant sterol (campesterol, sitosterol) concentrations were higher (P<0.001). In conclusion, bioactive tripeptide-containing milk products attenuated the blood pressure development in SHR. The plant sterols did not improve this effect. Vascular responses did not markedly differ between the groups, except that endothelium-derived hyperpolarizing factor (EDHF) -related aortic relaxation was demonstrated in the test product +sterols group.

Topics: Acetylcholinesterase; Animals; Antihypertensive Agents; Arteries; Blood Pressure; Caseins; Cholesterol; Cultured Milk Products; Hypertension; Lactobacillus helveticus; Male; Oligopeptides; Phytosterols; Random Allocation; Rats; Rats, Inbred SHR; Time Factors