heme-arginate and Hypertension

Although heme-oxygenase (HO) is cytoprotective, its effects on podocyte regulators like podocalyxin, podocin, CD2-associated protein (CD2AP) in renal dysfunction in N (ω)-nitro-l-arginine-methyl ester (l-NAME) hypertension are largely unclear.. Hypertension was induced in normotensive Sprague Dawley rats by administering l-NAME for 4 weeks. Enzyme immunoassay, enzyme-linked immunosorbent, histology/morphology, spectrophotometry, and western immunoblotting were used. HO was enhanced with heme-arginate (HA) or inhibited with chromium mesoporphyrin (CrMP).. Treatment with heme-arginate reduced several renal histo-pathological lesions including renal arteriolar thickening, glomerular abnormalities, tubular cast, tubular atrophy/fibrosis, and mononuclear cell infiltration in l-NAME-hypertensive rats. Similarly, HA abated the elevated levels of renal extracellular matrix/profibrotic proteins like collagen and fibronectin that deplete nephrin, a fundamental transmembrane protein that forms the scaffoldings of the podocyte slit diaphragm permitting small ions to filter, but not massive excretion of proteins, hence proteinuria. Correspondingly, HA enhanced the aberrant expression of nephrin alongside other important regulators of podocyte like podocalyxin, podocin, and CD2AP, and improved renal function by reducing albuminuria/proteinuria, while increasing creatinine clearance. The renoprotection by HA were accompanied by significant reduction of inflammatory/oxidative mediators including nuclear factor-kappaB, macrophage inflammatory protein-1-alpha, macrophage chemoattractant protein-1, tumor necrosis factor-alpha, interleukin (IL)-6, IL1β, 8-isoprostane, endothelin-1, and aldosterone. These were associated with increased levels of adiponectin, HO-1, HO activity, cyclic guanosine monophosphate, and atrial natriuretic peptide (ANP), whereas the HO inhibitor, CrMP annulled the renoprotection and exacerbated renal dysfunction.. HA improves renal function by attenuating histopathological lesions, suppressing inflammatory/oxidative mediators, abating profibrotic/extracellular matrix proteins, and reducing albuminuria/proteinuria, while concomitantly potentiating the HO-adiponectin-ANP axis, enhancing nephrin, podocin, podocalyxin, CD2AP and increasing creatinine clearance. Our study underscores the benefit of potentiating the HO-adiponectin-ANP against nephropathy.

Topics: Animals; Arginine; Biomarkers; Cytoprotection; Disease Models, Animal; Enzyme Induction; Enzyme Inhibitors; Extracellular Matrix Proteins; Fibrosis; Heme; Heme Oxygenase (Decyclizing); Hypertension; Inflammation Mediators; Kidney; Male; Mesoporphyrins; NG-Nitroarginine Methyl Ester; Oxidative Stress; Podocytes; Rats, Sprague-Dawley; Signal Transduction

Heart failure and related cardiac complications remains a great health challenge. We investigated the effects of upregulating heme-oxygenase (HO) on myocardial histo-pathological lesions, proinflammatory cytokines/chemokines, oxidative mediators and important markers of heart failure such as osteopontin and osteoprotergerin in N(ω)-nitro-l-arginine methyl ester (L-NAME)-induced hypertension. Treatment with the HO-inducer, heme-arginate improved myocardial morphology in L-NAME hypertensive rats by attenuating subendocardial injury, interstitial fibrosis, mononuclear-cell infiltration and cardiomyocyte hypertrophy. These were associated with the reduction of several inflammatory/oxidative mediators including chemokines/cytokines such as macrophage inflammatory protein-1 alpha (MIP-1α), macrophage chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, endothelin-1, 8-isoprostane, nitrotyrosine, and aldosterone. Similarly, heme-arginate abated the elevated levels of extracellular matrix/remodeling proteins including transforming-growth factor beta (TGF-β1) and collagen-IV in the myocardium. These were accompanied by significant reduction of proteins of heart failure such as osteopontin and osteoprotegerin. Interestingly, the cardio-protective effects of heme-arginate were associated with the potentiation of adiponectin, atrial-natriuretic peptide (ANP), HO-1, HO-activity, cyclic gnanosine monophosphate (cGMP) and the total-anti-oxidant capacity, whereas the HO-inhibitor, chromium-mesoporphyrin nullified the effects of heme-arginate, exacerbating inflammatory injury and oxidative insults. We conclude that heme-arginate therapy protects myocardial damage by potentiating the HO-adiponectin-ANP axis, which in turn suppressed the elevated levels of aldosterone, pro-inflammatory chemokines/cytokines, mononuclear-cell infiltration and oxidative stress, with concomitant reduction of extracellular matrix/remodeling proteins and heart failure proteins. These data suggest a cardio-protective role of the HO system against L-NAME-induced hypertension that could be explored in the design of novel strategies against cardiomyopathy.

Topics: Adiponectin; Aldosterone; Animals; Antioxidants; Arginine; Atrial Natriuretic Factor; Biomarkers; Blood Pressure; Cardiomyopathies; Cardiotonic Agents; Chemokine CCL2; Chemokine CCL3; Cyclic GMP; Dinoprost; Endothelin-1; Enzyme Induction; Extracellular Matrix Proteins; Heart Failure; Heme; Heme Oxygenase (Decyclizing); Hypertension; Interleukin-1beta; Interleukin-6; Male; NG-Nitroarginine Methyl Ester; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Tyrosine

Induction of heme-oxygenase (HO) is an important cellular defense mechanism against oxidative and inflammatory insults. We analyzed the effects of the HO inducer, heme-arginate, on the phospholipase C (PLC)/inositol-triphosphate (IP(3)) pathway in the mesenteric arterioles of uninephrectomized (UnX) deoxycorticosterone acetate (DOCA)-salt hypertensive rats, which is a volume-overload model characterized by elevated endothelin (ET-1) and mineralocorticoid-induced oxidative/inflammatory insults. Our study included the following groups: (A) controls [(i) surgery-free Sprague-Dawley (SD) rats, (ii) UnX-Sham, (iii) UnX-Salt (0.9% NaCl+0.2% KCl) and (iv) UnX-DOCA)]; (B) UnX-DOCA-salt hypertensive rats; (C) UnX-DOCA-salt+heme-arginate; (D) UnX-DOCA-salt+heme-arginate+chromium mesoporphyrin (CrMP), the HO inhibitor; (E) UnX-DOCA-salt+CrMP (F); SD+heme-arginate, (G) UnX-DOCA-salt+vehicle dissolving heme-arginate and CrMP and (H) normal-SD+heme-arginate. Quantitative reverse transcriptase PCR, western blot, enzyme immunoassay and spectrophotometric analyses were used. Heme-arginate enhanced mesenteric arteriole HO-1, HO activity, cyclic guanosine monophosphate (cGMP) and anti-oxidants including bilirubin, ferritin, superoxide dismutase with potentiation of the total anti-oxidant capacity. Correspondingly, oxidative/inflammatory mediators such as 8-isoprostane, nuclear-factor kappaB (NF-kappaB) and ET-1 were markedly reduced. Furthermore, heme-arginate suppressed PLC activity, attenuated IP(3) and reduced resting intracellular calcium. The effects of heme-arginate were nullified by the HO inhibitor, with aggravation of oxidative/inflammatory insults. In heme-arginate-treated SD rats, the HO system was potentiated to a lesser magnitude and the suppression of ET-1, PLC, IP(3) and NF-kappaB were less accentuated, suggesting greater selectivity of HO against the ET-1-PLC-IP(3)-NF-kappaB destructive axis in the pathological condition of mineralocorticoid-induced hypertension. Given that ET-1 stimulates PLC and IP(3), which in turn activates NF-kappaB, the concomitant reduction of ET-1, PLC, IP(3) and NF-kappaB alongside the corresponding decline of resting intracellular calcium may account for the reduction of blood pressure and attenuation of oxidative/inflammatory injury by heme-arginate.

Topics: Animals; Arginine; Arterioles; Blood Pressure; Calcium; Cyclic GMP; Desoxycorticosterone; Dinoprost; Endothelin-1; Heme; Heme Oxygenase (Decyclizing); Hypertension; Inositol 1,4,5-Trisphosphate; Intracellular Fluid; Male; Mesenteric Arteries; Mineralocorticoids; NF-kappa B; Organometallic Compounds; Oxidative Stress; Rats; Rats, Sprague-Dawley; Second Messenger Systems; Sodium Chloride, Dietary; Type C Phospholipases; Up-Regulation

We investigated the role of heme oxygenase (HO), adiponectin, and atrial natriuretic peptide (ANP) in uninephrectomized (UnX) deoxycorticosterone-acetate (DOCA)-salt hypertensive rats, a volume-overload model characterized by elevated endothelin-1 (ET-1), mineralocorticoid-induced oxidative/inflammatory insults, fibrosis, hypertrophy, and severe renal histopathological lesions that closely mimic end-stage renal disease (ESRD). HO was enhanced with heme arginate (HA) or blocked with chromium mesoporphyrin (CrMP). Histological, morphological/morphometrical, quantitative reverse transcription-polymerase chain reaction, Western blot, enzyme immunoassay, and spectrophotometric analysis were used. Our experimental design included the following groups of rats: A, controls [surgery-free Sprague-Dawley, UnX-sham, UnX-salt (0.9% NaCl + 0.2% KCl), and UnX-DOCA]; B, UnX-DOCA-salt hypertensive; C, UnX-DOCA-salt + HA; D, UnX-DOCA-salt + HA + CrMP; E, UnX-DOCA-salt + CrMP; F, UnX-DOCA-salt + captopril; G, UnX-DOCA-salt + L-arginine; H, UnX-DOCA-salt + spironolactone; and I, UnX-DOCA-salt + vehicle. HA lowered blood pressure and abated kidney hypertrophy and renal lesions, including glomerulosclerosis, tubular dilation, tubular cast formation, interstitial mononuclear cell infiltration, glomerular hypertrophy, and renal-arteriolar thickening in UnX-DOCA hypertension. Correspondingly, HO activity, adiponectin, adenosine monophosphate-activated protein kinase (AMPK), ANP, cGMP, antioxidants such as bilirubin, ferritin, superoxide dismutase, and catalase, and total antioxidant capacity were increased, whereas ET-1, transforming growth factor beta (TGF-beta), fibronectin, and 8-isoprostane were abated. These were accompanied by reduced proteinuria/albuminuria, but increased creatinine clearance. Interestingly, HA was more renoprotective than sipronolactone, L-arginine, and captopril, whereas the HO blocker CrMP exacerbated oxidative injury, aggravating renal lesions and function. Because 8-isoprostane stimulates ET-1 to potentiate oxidative stress and fibrosis, up-regulating HO-1 enhanced tissue antioxidant status alongside cellular targets such as adiponectin, AMPK, ANP, and cGMP to suppress ET-1, TGF-beta, and fibronectin with a corresponding decline of renal lesions, proteinuria/albuminuria, and thus improved renal function. The potent renoprotection of HA could be explored to combat renal hypertrophy and histopathological lesions characteristic of ESRD.

Topics: Adiponectin; Animals; Arginine; Atrial Natriuretic Factor; Blood Pressure; Blotting, Western; Desoxycorticosterone; Disease Models, Animal; Endothelin-1; Heme; Heme Oxygenase (Decyclizing); Hypertension; Kidney; Kidney Diseases; Male; Mineralocorticoids; Rats; Rats, Sprague-Dawley

In hypertension, elevated levels of oxidative/inflammatory mediators including nuclear factor kappaB (NF-kappaB), activating protein (AP-1), c-Jun-NH2-terminal kinase (JNK), and cell-regulatory proteins such as transforming growth factor beta (TGF-beta), trigger the mobilization of extracellular matrix (ECM) leading to fibrosis, hypertrophy and impairment of cardiac function. Although the heme oxygenase (HO) system is cytoprotective, its effects on cardiac fibrosis and hypertrophy in deoxycorticosterone acetate (DOCA-salt) hypertension are not completely elucidated. Here, we report cardioprotection by the HO inducer, heme arginate against histopathological lesions in DOCA-hypertension. Treatment with heme arginate restored physiological blood pressure, and abated cardiac hypertrophy (3.75 +/- 0.12 vs. 3.19 +/- 0.09 g/kg body wt; n =16, P < 0.01), left-to-right ventricular ratio (6.67 +/- 0.62 vs. 4.39 +/- 0.63; n = 16, P < 0.01), left ventricular mass (2.48 +/- 0.14 vs. 2.01 +/- 0.09 g/kg body wt; n = 16, P < 0.01) and left-ventricular wall thickness (2.82 +/- 0.16 vs. 1.98 +/- 0.14 mm; n = 16, P < 0.01), whereas the HO inhibitor, chromium mesoporphyrin, exacerbated hypertrophy and cardiac lesions. The suppression of cardiac hypertrophy was accompanied by a robust increase in HO-1, HO activity, cyclic guanosine monophosphate (cGMP), ferritin and the total antioxidant capacity, whereas 8-isoprostane, NF-kappaB, JNK, AP-1, TGF-beta, fibronectin and collagen-I were significantly abated. Correspondingly, histopathological parameters that depict progressive cardiac damage, including fibrosis, interstitial/perivascular collagen deposition, scarring, muscle-fiber thickness, muscular hypertrophy and coronary-arteriolar thickening were abated. Our study suggests that upregulating the HO system lowers blood pressure, potentiates the antioxidant status in tissues, suppresses oxidative stress/mediators such as NF-kappaB, AP-1 and cJNK, and suppresses the mobilization of ECM proteins like TGF-beta, collagen and fibronectin, with corresponding reduction of cardiac histopathological lesion and hypertrophy.

Topics: Animals; Arginine; Cardiomegaly; Desoxycorticosterone; Disease Models, Animal; Heart; Heart Diseases; Heme; Heme Oxygenase (Decyclizing); Hypertension; Hypertrophy, Left Ventricular; Male; MAP Kinase Kinase 4; Mesoporphyrins; Myocardium; NF-kappa B; Rats; Rats, Sprague-Dawley; Transcription Factor AP-1; Transforming Growth Factor beta

Four forms of porphyria may present clinically with the acute attack, an episodic, severe, and potentially life-threatening manifestation characterized by abdominal and neurologic symptoms. We describe our experience with 112 consecutive attacks observed and treated in 25 patients with the 2 most common forms of acute porphyria in Cape Town, South Africa; 25 attacks in 10 patients with variegate porphyria and 87 attacks in 14 patients with acute intermittent porphyria. The remaining patient experienced more than 100 sequential, severe, and poorly remitting attacks, which are not included in our analysis. In our population, the relative risk of an acute attack in acute intermittent porphyria compared with that in variegate porphyria was 14.3 (confidence intervals, 6.3-32.7). Patients with variegate porphyria were significantly older (median age at first attack, 30 yr) than those with acute intermittent porphyria (median age at first attack, 23.5 yr; p < 0.0001), and demonstrated an equal sex ratio, whereas the male:female ratio in acute intermittent porphyria was 2:12 (p < 0.0001). There was a significant difference in the incidence of factors precipitating the acute attack. Drug exposure was a frequent precipitant of the acute attack in variegate porphyria, whereas hormonal factors were more important in acute intermittent porphyria (p < 0.00001). Patients with acute intermittent porphyria also showed a trend to earlier and more frequent recurrent acute attacks following the initial admission. Mean urine precursor levels, blood pressure, pulse rate, and heme arginate requirement were all significantly higher in patients with acute intermittent porphyria. No significant difference in the frequency of serious complications or in outcome could be shown. We describe our experience with treatment with heme arginate, and provide evidence that heme arginate results in a prompt and statistically significant improvement in symptoms. The incidence of serious complications and mortality in this series was low, confirming a trend to an increasingly good prognosis for patients with acute porphyria who receive expert treatment.

Topics: Abdominal Pain; Acute Disease; Adult; Age Factors; Arginine; Epidemiologic Methods; Female; Heme; Humans; Hypertension; Male; Porphyria, Acute Intermittent; Porphyria, Variegate; Precipitating Factors; Psychotic Disorders; Remission, Spontaneous; Sex Factors; South Africa; Tachycardia

Perturbation in heme metabolism is known to affect the level and activity of hemoproteins, including cytochrome P450-dependent arachidonic acid metabolism. The latter has been associated with elevation in blood pressure seen in spontaneously hypertensive rats. The effect of heme arginate and its components, arginine and heme, on cytochrome P450 levels and blood pressure in spontaneously hypertensive rats were studied. Administration of heme arginate or heme alone at doses of 9 to 30 mg/kg body wt/day for 4 days resulted in a marked decrease of blood pressure in spontaneously hypertensive rats, whereas blood pressure in rats receiving the vehicle control was not affected. Similarly, L-arginine, but not D-arginine, in a dose-dependent manner decreased blood pressure in spontaneously hypertensive rats. The maximal change in blood pressure was achieved at 100 mg/kg body wt of arginine and was associated with a significant increase in heme oxygenase activity. A higher concentration (500 mg/kg) did not cause an additional decrease in blood pressure but further increased heme oxygenase activity. The arginine-induced heme oxygenase activity was suppressed by Sn-protoporphyrin. Administration of heme to spontaneously hypertensive rats resulted in an accumulation of heme oxygenase mRNA, which was accompanied by an increase in enzyme activity. The increase in heme oxygenase activity was also prevented by Sn-protoporphyrin. It is postulated that heme treatment resulted in an increase in heme oxygenase mRNA, which consequently led to a diminution of cellular heme and depletion of hemoproteins, such as the cytochrome P450 arachidonate metabolizing enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arachidonic Acid; Arginine; Blood Pressure; Cytochrome P-450 CYP2J2; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Dose-Response Relationship, Drug; Enzyme Induction; Heme; Heme Oxygenase (Decyclizing); Hemin; Hypertension; Kidney; Male; Microsomes, Liver; Mixed Function Oxygenases; Oxygenases; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Messenger

Cytochrome P450 content and activities are increased in the kidneys of spontaneously hypertensive rats (SHR) as compared with those of normotensive, Wistar-Kyoto (WKY), control rats during the period of rapid elevation of blood pressure. We studied the effect of heme arginate, a potent inducer of heme oxygenase (EC 1.14.99.3), on microsomal cytochrome P450 levels and activities and blood pressure in SHR at 7 wk of age. Administration of heme arginate (15 mg/kg body weight for 4 d) resulted in a marked decrease in blood pressure from 156.3 +/- 4.7 to 129.8 +/- 4.5 mm Hg (P less than 0.001), whereas blood pressure in SHR receiving the vehicle control was not affected. The blood pressure of age-matched WKY was not affected by heme arginate. Heme oxygenase activity increased in both hepatic and renal microsomes of SHR and WKY by two- to four-fold after treatment with heme arginate. Maximal increase of heme oxygenase mRNA occurred 5-7 h after the last injection of heme arginate and returned to control levels after 24 h. The increase in heme oxygenase activity was associated with a parallel decrease in cytochrome P450 content and in the activity of cytochrome P450 omega/omega-1 arachidonate hydroxylases in kidneys of SHR. It is postulated that heme arginate treatment resulted in induction of heme oxygenase which consequently led to a diminution of cytochrome P450, especially the arachidonate omega/omega-1 hydroxylases leading to a marked decrease in 19-hydroxyeicosatetraenoic acid (HETE) and 20-HETE. The effect of heme arginate on blood pressure may be mediated via these biochemical events inasmuch as both 19-HETE and 20-HETE produced by the kidney may promote hypertension by causing vasoconstriction and sodium retention.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Arginine; Blood Pressure; Blotting, Northern; Cytochrome P-450 Enzyme System; Gene Expression; Heme; Heme Oxygenase (Decyclizing); Hemin; Hypertension; Kidney; Liver; Mixed Function Oxygenases; Rats; Rats, Inbred SHR; Rats, Inbred Strains; Rats, Inbred WKY; RNA, Messenger