enalapril and Diabetic-Neuropathies

Cardiac autonomic neuropathy (CAN) and elevated nocturnal blood pressure are independent risk factors for cardiovascular disease in patients with diabetes. Previously, associations between CAN, non-dipping of nocturnal blood pressure and coronary artery calcification have been demonstrated. The present protocol describes a trial to test the efficacy of bedtime dosing of the ACE inhibitor enalapril on night time blood pressure and left ventricular mass in patients with type 1 diabetes.. In a randomised, double-blind, two-way cross-over study, 24 normoalbuminuric patients with type 1 diabetes with CAN will be treated for 12 weeks with either morning or bedtime dosing of 20 mg enalapril, followed by 12 weeks of switched treatment regimen. During each treatment period, two 24 h ambulatory blood pressure measurements will be performed and after each treatment period left ventricular mass will be determined by multisliced CT. Primary end points will be reduction in blood pressure and reduction in left ventricular mass.. The study has been approved by the Danish Medicines Agency, the Scientific-Ethical Committee of the Capital Region of Denmark and the Danish Data Protection Agency. An external monitoring committee (the Good Clinical Practice Unit at Copenhagen University Hospital) will oversee the study. The results of the study will be presented at national and international scientific meetings and publications will be submitted to peer-reviewed journals.. EudraCT (2012- 002136-90).

Topics: Adult; Aged; Antihypertensive Agents; Autonomic Nervous System Diseases; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Cross-Over Studies; Diabetes Mellitus, Type 1; Diabetic Neuropathies; Double-Blind Method; Drug Chronotherapy; Enalapril; Female; Heart Ventricles; Humans; Hypertension; Hypertrophy, Left Ventricular; Male; Middle Aged; Multidetector Computed Tomography; Organ Size; Young Adult

Although several important studies have been performed in hypertensive type 2 diabetic patients, it is not known whether lowering blood pressure in normotensive (BP <140/90 mm Hg) patients offers any beneficial results on vascular complications. The current study evaluated the effect of intensive versus moderate diastolic blood pressure (DBP) control on diabetic vascular complications in 480 normotensive type 2 diabetic patients.. The current study was a prospective, randomized controlled trial in normotensive type 2 diabetic subjects. The subjects were randomized to intensive (10 mm Hg below the baseline DBP) versus moderate (80 to 89 mm Hg) DBP control. Patients in the moderate therapy group were given placebo, while the patients randomized to intensive therapy received either nisoldipine or enalapril in a blinded manner as the initial antihypertensive medication. The primary end point evaluated was the change in creatinine clearance with the secondary endpoints consisting of change in urinary albumin excretion, progression of retinopathy and neuropathy and the incidence of cardiovascular disease.. The mean follow-up was 5.3 years. Mean BP in the intensive group was 128 +/- 0.8/75 +/- 0.3 mm Hg versus 137 +/- 0.7/81 +/- 0.3 mm Hg in the moderate group, P < 0.0001. Although no difference was demonstrated in creatinine clearance (P = 0.43), a lower percentage of patients in the intensive group progressed from normoalbuminuria to microalbuminuria (P = 0.012) and microalbuminuria to overt albuminuria (P = 0.028). The intensive BP control group also demonstrated less progression of diabetic retinopathy (P = 0.019) and a lower incidence of strokes (P = 0.03). The results were the same whether enalapril or nisoldipine was used as the initial antihypertensive agent.. Over a five-year follow-up period, intensive (approximately 128/75 mm Hg) BP control in normotensive type 2 diabetic patients: (1) slowed the progression to incipient and overt diabetic nephropathy; (2) decreased the progression of diabetic retinopathy; and (3) diminished the incidence of stroke.

Topics: Adult; Aged; Albuminuria; Antihypertensive Agents; Blood Pressure; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Disease Progression; Enalapril; Female; Humans; Male; Middle Aged; Nisoldipine; Prospective Studies; Single-Blind Method; Stroke

The Appropriate Blood Pressure Control in Diabetes (ABCD) Trial is a prospective randomized blinded clinical trial that compares the effects of intensive versus moderate blood pressure control on the incidence and progression of type 2 diabetic complications. The current article discusses the results of 5.3 years of follow-up of 470 patients with hypertension and evaluates the effects of intensive and moderate blood pressure therapy using nisoldipine versus enalapril as the initial antihypertensive medication for nephropathy, retinopathy, and neuropathy.. The 470 hypertensive subjects, defined as having a baseline diastolic blood pressure of > or = 90 mmHg, were randomized to intensive blood pressure control (diastolic blood pressure goal of 75 mmHg) versus moderate blood pressure control (diastolic blood pressure goal of 80-89 mmHg).. The mean blood pressure achieved was 132/78 mmHg in the intensive group and 138/86 mmHg in the moderate control group. During the 5-year follow-up period, no difference was observed between intensive versus moderate blood pressure control and those randomized to nisoldipine versus enalapril with regard to the change in creatinine clearance. After the first year of antihypertensive treatment, creatinine clearance stabilized in both the intensive and moderate blood pressure control groups in those patients with baseline normo- or microalbuminuria. In contrast, patients starting with overt albuminuria demonstrated a steady decline in creatinine clearance of 5-6 ml.min-1.1.73 m-2 per year throughout the follow-up period whether they were on intensive or moderate therapy. There was also no difference between the interventions with regard to individuals progressing from normoalbuminuria to microalbuminuria (25% intensive therapy vs. 18% moderate therapy, P = 0.20) or microalbuminuria to overt albuminuria (16% intensive therapy vs. 23% moderate therapy, P = 0.28). Intensive therapy demonstrated a lower overall incidence of deaths, 5.5 vs. 10.7%, P = 0.037. Over a 5-year follow-up period, there was no difference between the intensive and moderate groups with regard to the progression of diabetic retinopathy and neuropathy. In addition, the use of nisoldipine versus enalapril had no differential effect on diabetic retinopathy and neuropathy.. Blood pressure control of 138/86 or 132/78 mmHg with either nisoldipine or enalapril as the initial antihypertensive medication appeared to stabilize renal function in hypertensive type 2 diabetic patients without overt albuminuria over a 5-year period. The more intensive blood pressure control decreased all-cause mortality.

Topics: Adult; Aged; Antihypertensive Agents; Blood Pressure; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Enalapril; Female; Humans; Hypertension; Male; Middle Aged; Nisoldipine; Placebos

The ABCD (Appropriate Blood Pressure Control in Diabetes) Trial is a large, prospective, randomized clinical trial of 950 patients with non-insulin-dependent diabetes mellitus (NIDDM) designed to compare the effects of intensive blood pressure control with moderate control on the prevention and progression of diabetic nephropathy, retinopathy, cardiovascular disease, and neuropathy in NIDDM. The secondary objective is to determine equivalency of the effects of a calcium channel blocker (nisoldipine) and an angiotensin-converting-enzyme inhibitor (enalapril) as a first-line antihypertensive agent in the prevention and/or progression of these diabetic vascular complications. The study consists of two study populations aged 40-74 years, 470 hypertensive patients (diastolic blood pressure of > or = 90.0 mmHg at time of randomization) and 480 normotensive patients (diastolic blood pressure of 80.0 mmHg at time of randomization). The study duration is 5 years and is scheduled to end in May of 1998. Patients are randomized to receive either intensive antihypertensive drug therapy or moderate antihypertensive drug therapy. Patients are also randomized to nisoldipine or enalapril, with open-label medications added if further blood pressure control is necessary. The primary outcome measure is glomerular filtration rate as assessed by 24-h creatinine clearance. Secondary outcome measures are urinary albumin excretion, left ventricular hypertrophy, retinopathy, and neuropathy. Cardiovascular morbidity and mortality will also be evaluated. Given the data showing the impact of hypertension on complications in NIDDM, the ABCD Trial is designed to determine if intensive antihypertensive therapy will be more efficacious than moderate antihypertensive therapy on the outcome of diabetic complications in NIDDM.

Topics: Adult; Aged; Albuminuria; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Calcium Channel Blockers; Cardiovascular Diseases; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Enalapril; Exercise; Female; Glomerular Filtration Rate; Humans; Hypertension; Male; Middle Aged; Nisoldipine; Prospective Studies; Sex Characteristics

This study investigated the efficacy of monotherapy versus combination of menhaden oil, α-lipoic acid, and enalapril on corneal sensation and morphometry and other neuropathy-related endpoints in a rat model of type 2 diabetes.. Male Sprague-Dawley rats (aged 12 weeks) were fed a high-fat diet for 8 weeks followed by 30 mg/kg streptozotocin. After 16 weeks of hyperglycemia, 12-week treatments consisting of menhaden oil, α-lipoic acid, enalapril, or their combination were initiated. Before and after treatments, we performed analyses of multiple neural and vascular endpoints including corneal sensitivity, corneal nerve density, vascular reactivity of epineurial arterioles, motor and sensory nerve conduction velocity, intraepidermal nerve fiber density, and thermal nociception.. Before treatment, all the neural and vascular endpoints in diabetic rats were impaired. Treating diabetic rats with monotherapy was effective in improving neural and vascular deficits with menhaden oil being most efficacious. However, the combination therapy provided the greatest benefit and improved/reversed all nerve and vascular deficits. The effect of combination therapy on corneal relative sensitivity and structure (in mm/mm), primary endpoints for this study, for control, diabetic, and diabetic treated rats was 4.2 ± 1.4 and 7.5 ± 0.5, 12.1 ± 1.3* and 3.8 ± 0.2*, and 6.6 ± 2.3 and 7.3 ± 0.5, respectively (*P < 0.05 compared with control rats; P < 0.05 compared with diabetic rats).. These studies suggest that a combination therapeutic approach may be most effective for treating vascular and neural complications of type 2 diabetes.

Topics: Adiponectin; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Cornea; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Diet, High-Fat; Drug Therapy, Combination; Enalapril; Fish Oils; Hypesthesia; Lipids; Male; Peptidyl-Dipeptidase A; Rats; Rats, Sprague-Dawley; Streptozocin; Thiobarbituric Acid Reactive Substances; Thioctic Acid; Trigeminal Nerve Diseases

We have previously demonstrated that enalapril, α-lipoic acid and menhaden (fish) oil has potential as a treatment for diabetic peripheral neuropathy. In this study we sought to determine the efficacy of these treatments individually or in combination on multiple neuropathic endpoints in a high fat fed low dose streptozotocin treated mouse, a model of type 2 diabetes, following early or late intervention. Four or twelve weeks after the onset of hyperglycemia, diabetic mice were treated with enalapril, α-lipoic acid, menhaden oil or their combination for 12 weeks. Afterwards, endpoints including glucose tolerance, motor and sensory nerve conduction velocity, thermal nociception, and intraepidermal and cornea nerve fiber density was determined. Glucose clearance was impaired in diabetic mice and significantly improved only with combination treatment and early intervention. Diabetes caused steatosis, slowing of motor and sensory nerve conduction velocity, thermal hypoalgesia and reduction in intraepidermal and cornea nerve fiber density. Treating diabetic mice with enalapril, α-lipoic acid or menhaden oil partially protected diabetic mice from these deficits, whereas the combination of these three treatments was more efficacious following early or late intervention. These studies suggest that a combination therapy may be more effective for treating neural complications of type 2 diabetes.

Topics: Acute Disease; Animals; Chronic Disease; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Drug Therapy, Combination; Enalapril; Fish Oils; Hypoglycemic Agents; Male; Mice, Inbred C57BL; Nerve Regeneration; Neuroprotective Agents; Streptozocin; Thioctic Acid; Time Factors

We examined whether reversal of high fat diet, stimulating weight loss, compared to two treatments previously shown to have beneficial effects, could improve glucose utilization and peripheral neuropathy in animal models of obesity and type 2 diabetes. Rats were fed a high fat diet and treated with a low dose of streptozotocin to create models of diet induced obesity or type 2 diabetes, respectively. Afterwards, rats were transferred to a normal diet or treated with enalapril or dietary enrichment with menhaden oil for 12 weeks. Obesity and to a greater extent type 2 diabetes were associated with impaired glucose utilization and peripheral neuropathy. Placing obese rats on a normal diet improved glucose utilization. Steatosis but not peripheral neuropathy was improved after placing obese or diabetic rats on a normal diet. Treating obese and diabetic rats with enalapril or a menhaden oil enriched diet generally improved peripheral neuropathy endpoints. In summary, dietary improvement with weight loss in obese or type 2 diabetic rats was not sufficient to correct peripheral neuropathy. These results further stress the need for discovery of a comprehensive treatment for peripheral neuropathy.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Anti-Obesity Agents; Biomarkers; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Diet, Fat-Restricted; Diet, High-Fat; Dietary Supplements; Disease Models, Animal; Enalapril; Fish Oils; Hypoglycemic Agents; Male; Neuralgia; Non-alcoholic Fatty Liver Disease; Obesity; Rats, Sprague-Dawley; Streptozocin; Weight Loss

We have previously demonstrated that treating diabetic rats with enalapril, an angiotensin converting enzyme (ACE) inhibitor, α-lipoic acid, an antioxidant, or menhaden oil, a natural source of omega-3 fatty acids can partially improve diabetic peripheral neuropathy. In this study we sought to determine the efficacy of combining these three treatments on vascular and neural complications in a high fat fed low dose streptozotocin treated rat, a model of type 2 diabetes. Rats were fed a high fat diet for 8 weeks followed by a 30 mg/kg dose of streptozotocin. Eight weeks after the onset of hyperglycemia diabetic rats were treated with a combination of enalapril, α-lipoic acid and menhaden oil. Diabetic rats not receiving treatment were continued on the high fat diet. Glucose clearance was impaired in diabetic rats and significantly improved with treatment. Diabetes caused steatosis, elevated serum lipid levels, slowing of motor and sensory nerve conduction, thermal hypoalgesia, reduction in intraepidermal nerve fiber profiles, decrease in cornea sub-basal nerve fiber length and corneal sensitivity and impairment in vascular relaxation to acetylcholine and calcitonin gene-related peptide in epineurial arterioles of the sciatic nerve. Treating diabetic rats with the combination of enalapril, α-lipoic acid and menhaden oil reversed all these deficits to near control levels except for motor nerve conduction velocity which was also significantly improved compared to diabetic rats but remained significantly decreased compared to control rats. These studies suggest that a combination therapeutic approach may be most effective for treating vascular and neural complications of type 2 diabetes.

Topics: Animals; Cornea; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Diet, High-Fat; Dose-Response Relationship, Drug; Drug Therapy, Combination; Enalapril; Fish Oils; Glucose Tolerance Test; Male; Neural Conduction; Rats, Sprague-Dawley; Sciatic Nerve; Streptozocin; Thioctic Acid; Vasodilation

We have previously shown that treating streptozotocin-induced diabetic rats, an animal model of type 1 diabetes, with Ilepatril (an inhibitor of neutral endopeptidase and angiotensin converting enzyme (ACE)) improves vascular and neural function. In this study we sought to determine the individual effect of inhibition of neutral endopeptidase and ACE on diabetes-induced vascular and neural dysfunction. After 4 weeks of untreated diabetes, rats were treated for 12 weeks with Ilepatril, Enalapril (ACE inhibitor) or Candoxatril (neutral endopeptidase inhibitor) followed by analysis of neural and vascular function. Diabetes caused slowing of motor and sensory nerve conduction, thermal hypoalgesia, reduction in intraepidermal nerve fiber density in the hindpaw and impairment in vascular relaxation to acetylcholine and calcitonin gene-related peptide in epineural arterioles of the sciatic nerve and to atrial natriuretic peptide and calcitonin gene-related peptide in renal arteries. Inhibition of neutral endopeptidase or ACE improved neural function; however, dual inhibition of neutral endopeptidase and ACE with Ilepatril tended to have the greatest efficacy. Ilepatril and Candoxatril treatment of diabetic rats was more efficacious in improving vascular responsiveness in epineurial arterioles than treatment with Enalapril. Ilepatril, Enalapril or Candoxatril treatment of diabetic rats were all efficacious in renal arteries. These studies suggest that combination therapy may be the most effective approach for treatment of diabetic neural and vascular complications.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Diabetic Neuropathies; Enalapril; Heterocyclic Compounds, 3-Ring; Indans; Male; Neprilysin; Neural Conduction; Propionates; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Streptozocin

Leptin receptor-deficient db/db mice develop human type 2 diabetes mellitus, hypertension, and obesity with disrupted circadian blood pressure (BP) rhythm. Whether leptin is the sole mechanism mediating autonomic imbalance and hypertension is unclear. To explore this notion further, we measured BP by radiotelemetry combined with fast Fourier transformation and assessed autonomic function pharmacologically before and after renin-angiotensin system blockade with enalapril. The resting period BP (117+/-3 versus 108+/-1.0 mm Hg) and heart rate (HR; 488+/-12 versus 436+/-8 bpm) were higher in db/db mice compared with db/+ mice. BP and HR amplitudes were lower in db/db mice compared with db/+ mice. BP response to trimetaphan (-43+/-5 versus -27+/-3 mm Hg) and HR response to metoprolol (-59+/-12 versus -5+/-4 bpm) were greater in db/db mice than in db/+ mice. The HR response to atropine was blunted in db/db mice (59+/-17 versus 144+/-24 bpm), as were baroreflex sensitivity and HR variability. Enalapril improved autonomic regulation in db/db mice. Stimulation of central alpha-2 adrenoreceptors enhanced both parasympathetic HR control and baroreflex sensitivity in db/db mice. We suggest that functional, rather than structural, alpha-2 adrenoceptor changes and the renin-angiotensin system are involved in the increased sympathetic and decreased parasympathetic tones in db/db mice. Our data suggest that db/db mice exhibit features found in humans with type 2 diabetic autonomic neuropathy and could serve as a model for this complication.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Autonomic Nervous System; Blood Pressure; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Disease Models, Animal; Enalapril; Heart; Heart Rate; Hypertension; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Receptors, Leptin

ACE inhibition and/or blocking of the angiotensin II receptor are recognized as first-line treatment for nephropathy and cardiovascular disease in diabetic patients. However, little information is available about the potential benefits of these drugs on diabetic neuropathy. We examined vascular and neural activity in streptozotocin-induced diabetic rats that were treated for 12 weeks with enalapril, an ACE inhibitor, or L-158809, an angiotensin II receptor blocker. A prevention protocol (group 1) as well as three intervention protocols (treatment was initiated after 4, 8, or 12 weeks of diabetes [groups 2, 3, and 4, respectively]) were used. Endoneurial blood flow and motor nerve conduction velocity (MNCV) were impaired in all groups of untreated diabetic rats. In group 1, treatment of diabetic rats with enalapril or L-158809 partially prevented the diabetes-induced decrease in endoneurial blood flow and MNCV. In groups 2-4, intervention with enalapril was more effective in reversing the diabetes-induced impairment in endoneurial blood flow and MNCV than L-158809. The superoxide level in the aorta and epineurial arterioles of diabetic rats was increased. Treatment of diabetic rats with enalapril or L-158809 reduced the superoxide level in the aorta in all groups but was less effective in epineurial arterioles. Acetylcholine and calcitonin gene-related peptide (CGRP) cause vasodilation in epineurial arterioles of the sciatic nerve, which was impaired by diabetes. Treatment of diabetic rats (all groups) with enalapril or L-158809 completely prevented/reversed the diabetes-induced impairment in CGRP-mediated vascular relaxation. Treatment with enalapril or L-158809 was also effective in improving impaired acetylcholine-mediated vasodilation, but the efficacy was diminished from groups 1 to 4. These studies suggest that ACE inhibitors and/or angiotensin II receptor blockers may be effective treatments for diabetes and vascular and neural dysfunction. However, the efficacy of these treatments may be dependent on when the treatment is initiated.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Arteries; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Drug Therapy, Combination; Enalapril; Imidazoles; Male; Muscle Relaxation; Muscle, Smooth, Vascular; Oxidative Stress; Rats; Rats, Sprague-Dawley; Tetrazoles

The pathogenic mechanisms and molecular events involved in the development and progression of diabetic nephropathy (DN) are not completely known. Recent data indicate that diabetes includes an inflammatory component that is related to diabetic complications. Tumor necrosis factor (TNF)-alpha, a cytokine with mainly proinflammatory activity, may be synthesized by renal cells. Our objective was to analyze intrarenal TNF-alpha gene expression and its relationship with urinary albumin excretion (UAE). We also investigated the effect of inhibition of angiotensin-converting enzyme on TNF-alpha expression and UAE.. Streptozotocin-induced diabetic rats received either no treatment or an angiotensin-converting enzyme inhibitor (enalapril). After eight weeks, renal expression of TNF-alpha was evaluated by real-time polymerase chain reaction.. Renal cortical messenger RNA levels of TNF-alpha increased significantly and were twice as high in diabetic rats than in nondiabetic control rats. Enalapril administration nearly completely abolished the increase in TNF-alpha messenger RNA expression to the level observed in control rats. UAE was significantly correlated with urinary levels of TNF-alpha (r=0.68, P<0.05) and with renal TNF-alpha expression (r=0.51, P<0.05).. DN was associated with increased renal expression of TNF-alpha and UAE. Enalapril administration prevented this enhanced expression of TNF-alpha and decreased urinary cytokine excretion and albuminuria. These data provide a novel insight into the pathogenic mechanisms of DN, and support the hypothesis that inflammatory mechanisms may play a significant role in the development and progression of renal injury secondary to diabetes mellitus.

Topics: Albuminuria; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Enalapril; Gene Expression Regulation; Kidney Cortex; Male; Peptidyl-Dipeptidase A; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Necrosis Factor-alpha

1. The influence of angiotensin-converting enzyme (ACE) inhibitor is investigated in enalapril on renal function in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an animal model of spontaneously non-insulin-dependent diabetes (NIDDM). 2. Enalapril (5 mg/kg) or vehicle was administered once daily by gastric gavage to 22-week-old male OLETF rats for 32 weeks. Blood pressure, albuminuria, creatinine clearance, plasma glucose, serum insulin and lipids were determined before and during the treatment. Renal haemodynamics was examined at the end of the treatment. 3. Enalapril lowered blood pressure mildly but significantly. In the vehicle-treated rats, urinary albumin excretion increased from 0.75 +/- 0.16 mg/mg creatinine (Cr) to 8.65 +/- 0.78 mg/mg Cr. Enalapril significantly blunted the development of albuminuria from 0.66 +/- 0.12 mg/mg Cr to 5.19 +/- 0.67 mg/mg Cr (P < 0.008) without significant influence on creatinine clearances. Enalapril also significantly blunted the rise in serum cholesterol and triglyceride prior to the development of massive albuminuria. Enalapril did not affect bodyweight, plasma glucose or insulin levels. Renal haemodynamics assessed by inulin and p-aminohippuric acid clearances were similar in both groups at the end of the treatment. 4. These results reconfirmed that the ACE inhibitor has protective effects on nephropathy in NIDDM. Massive albuminuria was preceded by increase in serum lipids in OLETF rats, which supports the view that hyperlipidaemia exacerbates glomerular injury in chronic renal disease. Enalapril attenuated the rise in serum lipids, suggesting that the beneficial effects of the compound on renal injury in OLETF rats might also be mediated through the action of affecting serum lipids.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Blood Pressure; Body Weight; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Disease Progression; Enalapril; Glucose Tolerance Test; Hyperlipidemias; Kidney; Kidney Function Tests; Lipids; Male; Rats; Rats, Long-Evans

The effects of the angiotensin converting enzyme inhibitor lisinopril on slow and fast twitch muscle contractile properties, nerve conduction and hypoxic resistance, and muscle and nerve capillary density were examined in streptozotocin-diabetic rats. Prolongation of soleus contraction and relaxation were partially prevented by treatment (p less than 0.01). A 22% deficit in fast twitch extensor digitorum longus tetanic tension production was also ameliorated (p less than 0.01). Sciatic motor and sensory conduction velocity, 25% and 12% reduced by diabetes respectively, were 75% normalized by lisinopril (p less than 0.01). There was a 47% increase in resistance to hypoxic conduction block with diabetes (p less than 0.01). Lisinopril treatment resulted in normal hypoxic resistance. Capillarization of nerve and muscle was little affected by diabetes; however, there was a 17% increase in capillary density in sciatic nerve, and a 40% increase in extensor digitorum longus muscle with lisinopril (p less than 0.01). For soleus, a smaller treatment-induced increase in capillary density led to an elevated capillary/muscle fibre ratio (p less than 0.01). These results suggest that lisinopril promoted angiogenesis. It was concluded that the beneficial effect of preventive lisinopril treatment is likely to depend upon a reduction of peripheral vascular resistance and improvement of tissue blood flow, which implicates relative hypoxia as an important factor in the development of myopathy and neuropathy in experimental diabetes.

Topics: Action Potentials; Angiotensin-Converting Enzyme Inhibitors; Animals; Capillaries; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Enalapril; Lisinopril; Male; Muscle Contraction; Muscles; Neovascularization, Pathologic; Neural Conduction; Rats; Rats, Inbred Strains; Reference Values; Regression Analysis; Sciatic Nerve