SC. Hydrogen sulfide ameliorates hyperhomocysteinemia-associated chronic renal failure. Am J Physiol

BackgroundWe have previously reported the role of anti-angiogenic factors in inducing the transition from compensatory cardiac hypertrophy to heart failure and the significance of MMP-9 and TIMP-3 in promoting this process during pressure overload hemodynamic stress. Several studies reported the evidence of cardiac autophagy, involving removal of cellular organelles like mitochondria (mitophagy), peroxisomes etc., in the pathogenesis of heart failure. However, little is known regarding the therapeutic role of mitochondrial division inhibitor (Mdivi) in the pressure overload induced heart failure. We hypothesize that treatment with mitochondrial division inhibitor (Mdivi) inhibits abnormal mitophagy in a pressure overload heart and thus ameliorates heart failure condition.Materials and MethodsTo verify this, ascending aortic banding was done in wild type mice to create pressure overload induced heart failure and then treated with Mdivi and compared with vehicle treated controls.ResultsExpression of MMP-2, vascular endothelial growth factor, CD31, was increased, while expression of anti angiogenic factors like endostatin and angiostatin along with MMP-9, TIMP-3 was reduced in Mdivi treated AB 8 weeks mice compared to vehicle treated controls. Expression of mitophagy markers like LC3 and p62 was decreased in Mdivi treated mice compared to controls. Cardiac functional status assessed by echocardiography showed improvement and there is also a decrease in the deposition of fibrosis in Mdivi treated mice compared to controls.ConclusionAbove results suggest that Mdivi inhibits the abnormal cardiac mitophagy response during sustained pressure overload stress and propose the novel therapeutic role of Mdivi in ameliorating heart failure.

High levels of homocysteine (Hcy), known as hyperhomocysteinemia (HHcy) are associated with neurovascular diseases. H2S, a metabolite of Hcy, has a potent anti-oxidant and anti-inflammatory activity; however, the effect of H2S has not been explored in Hcy (IC) induced neurodegeneration and neurovascular dysfunction in mice. Therefore, the present study was designed to explore the neuroprotective role of H2S on Hcy induced neurodegeneration and neurovascular dysfunction. To test this hypothesis we employed wild type (WT) males ages 8–10 weeks, WT+ artificial cerebrospinal fluid (aCSF), WT+ Hcy (0.5μmol/μl) intracerebral injection (I.C., one time only prior to NaHS treatment), WT+Hcy +NaHS (sodium hydrogen sulfide, precursor of H2S, 30 μmol/kg, body weight). NaHS was injected intra-peritoneally (I.P.) once daily for the period of 7 days after the Hcy (IC) injection. Hcy treatment significantly increased MDA, nitrite level, acetylcholinestrase activity, TNFα, IL1β, GFAP, iNOS, eNOS and decreased glutathione level indicating oxidative-nitrosative stress and neuroinflammation as compared to control and aCSF treated groups. Further, increased expression of NSE, S100B and decreased expression of (PSD95, SAP97) synaptic protein indicated neurodegeneration. Brain sections of Hcy treated mice showed damage in the cortical area and periventricular cells. TUNEL positive cells and Fluro Jade-C staining indicated apoptosis and neurodegeneration. The increased expression of MMP9, MMP2 and decreased expression of TIMP-1, TIMP-2, tight junction proteins (ZO1, Occuldin) in Hcy treated group indicate neurovascular remodeling. Interestingly, NaHS treatment significantly attenuated Hcy induced oxidative stress, memory deficit, neurodegeneration, neuroinflammation and cerebrovascular remodeling. The results indicate that H2S is effective in providing protection against neurodegeneration and neurovascular dysfunction.

Elevated blood level of Fibrinogen (Fg) is commonly associated with vascular dysfunction. We tested the hypothesis that at pathologically high levels, Fg increases cerebrovascular permeability by activating matrix metalloproteinases (MMPs). Fibrinogen (4 mg/mL blood concentration) or equal volume of phosphate-buffered saline (PBS) was infused into male wild-type (WT; C57BL/6J) or MMP-9 gene knockout (MMP9À/À) mice. Pial venular leakage of fluorescein isothiocyanate-bovine serum albumin to Fg or PBS alone and to topically applied histamine (10 À5 mol/L) were assessed. Intravital fluorescence microscopy and image analysis were used to assess cerebrovascular protein leakage. Pial venular macromolecular leakage increased more after Fg infusion than after infusion of PBS in both (WT and MMP9À/À) mice but was more pronounced in WT compared with MMP9À/À mice. Expression of vascular endothelial cadherin (VE-cadherin) was less and plasmalemmal vesicle-associated protein-1 (PV-1) was greater in Fg-infused than in PBS-infused both mice groups. However, in MMP9À/À mice, VE-cadherin expression was greater and PV-1 expression was less than in WT mice. These data indicate that at higher levels, Fg compromises microvascular integrity through activation of MMP-9 and downregulation of VE-cadherin and upregulation of PV-1. Our results suggest that elevated blood level of Fg could have a significant role in cerebrovascular dysfunction and remodeling.

In patients with EHPVO and obstructive jaundice, primary biliary tract surgery has significant morbidity and mortality. Endoscopic management should be the preferred modality. In patients with endoscopic failure, a staged procedure (portosystemic shunt followed by biliary surgery) should be preferred. Strictures alone may resolve after a portosystemic shunt. Endoscopic stenting may be required as an adjunct.

Hydrogen sulfide (H2S) has recently been identified as a regulator of various physiological events, including vasodilation, angiogenesis, antiapoptotic, and cellular signaling. Endogenously, H2S is produced as a metabolite of homocysteine (Hcy) by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST). Although Hcy is recognized as vascular risk factor at an elevated level [hyperhomocysteinemia (HHcy)] and contributes to vascular injury leading to renovascular dysfunction, the exact mechanism is unclear. The goal of the current study was to investigate whether conversion of Hcy to H2S improves renovascular function. Ex vivo renal artery culture with CBS, CSE, and 3MST triple gene therapy generated more H2S in the presence of Hcy, and these arteries were more responsive to endothelial-dependent vasodilation compared with nontransfected arteries treated with high Hcy. Cross section of triple gene-delivered renal arteries immunostaining suggested increased expression of CD31 and VEGF and diminished expression of the antiangiogenic factor endostatin. In vitro endothelial cell culture demonstrated increased mitophagy during high levels of Hcy and was mitigated by triple gene delivery. Also, dephosphorylated Akt and phosphorylated FoxO3 in HHcy were reversed by H2S or triple gene delivery. Upregulated matrix metalloproteinases-13 and downregulated tissue inhibitor of metalloproteinase-1 in HHcy were normalized by overexpression of triple genes. Together, these results suggest that H2S plays a key role in renovasculopathy during HHcy and is mediated through Akt/FoxO3 pathways. We conclude that conversion of Hcy to H2S by CBS, CSE, or 3MST triple gene therapy improves renovascular function in HHcy.

Mishra PK, Tyagi N, Sen U, Givvimani S, Tyagi SC. H2S ameliorates oxidative and proteolytic stresses and protects the heart against adverse remodeling in chronic heart failure. Am J Physiol Heart Circ Physiol 298: H451-H456, 2010. First published November 20, 2009; doi:10.1152/ajpheart.00682.2009.-Reactive oxygen and nitrogen species (ROS and RNS, respectively) generate nitrotyrosine and activate latent resident myocardial matrix metalloproteinases (MMPs). Although in chronic heart failure (CHF) there is robust increase in ROS, RNS, and MMP activation, recent data suggest that hydrogen sulfide (H 2S, a strong antioxidant gas) is cardioprotective. However, the role of H 2S in mitigating oxidative and proteolytic stresses in cardiac remodeling/apoptosis in CHF was unclear. To test the hypothesis that H 2S ameliorated cardiac apoptosis and fibrosis by decreasing oxidative and proteolytic stresses, arteriovenous fistula (AVF) was created in wild-type (C57BL/6J) mice. The hearts were analyzed at 0, 2, and 6 wk after AVF. To reverse the remodeling, AVF mice were treated with NaHS (an H 2S donor, 30 mol/l in drinking water) at 8 and 10 wk. The levels of MMPs were measured by gelatin-gel zymography. The levels of nitrotyrosine, tissue inhibitors of metalloproteinase (TIMPs), ␤ 1-integrin, and a disintegrin and metalloproteinase-12 (ADAM-12) were analyzed by Western blots. The levels of pericapillary and interstitial fibrosis were identified by Masson trichrome stains. The levels of apoptosis were measured by identifying the TdT-mediated dUTP nick end labeling (TUNEL)-positive cells and caspase-3 levels. The results suggested robust nitrotyrosine and MMP activation at 2 and 6 wk of AVF. The treatment with H 2S donor mitigated nitrotyrosine generation and MMP activation (i.e., oxidative and proteolytic stresses). The levels of TIMP-1 and TIMP-3 were increased and TIMP-4 decreased in AVF hearts. The treatment with H 2S donor reversed this change in TIMPs levels. The levels of ADAM-12, apoptosis, and fibrosis were robust and integrin were decreased in AVF hearts. The treatment with H 2S donor attenuated the fibrosis, apoptosis, and decrease in integrin. fibrosis; extracellular matrix; ADAM; integrin; matrix metalloproteinase; tissue inhibitor of metalloproteinase; left ventricle hypertrophy; collagen; TUNEL; apoptosis; homocysteine ALTHOUGH IN GASTROINTESTINAL and nervous systems hydrogen sulfide (H 2 S) plays a crucial role as a signaling molecule (12, 24), recent studies established that H 2 S is a cardioprotective gas (4, 21, 27). However, its role in regulating the ECM remodeling and apoptosis is still nebulous. Considering the tremendous therapeutic potential, H 2 S gas has attracted the attention of biomedical research (2,5,9,10,12). It is a strong antioxidant and is generated endogenously by two important enzymes involved in sulfur-containing amino acid [cysteine and homocysteine (Hcy)] metabolism, namely cystathionine ␤-synthase (CBS) and cystathionine ␥-lyase (CGL) (26). Paradoxically, it is interesting that hyperh...

Although matrix metalloproteinase (MMPs) and tissue inhibitor of metalloproteinase (TIMPs) play vital role in tumor angiogenesis and TIMP-3 caused apoptosis, their role in cardiac angiogenesis is unknown. Interestingly, a disruption of coordinated cardiac hypertrophy and angiogenesis contributed to the transition to heart failure, however, the proteolytic and anti-angiogenic mechanisms of transition from compensatory hypertrophy to decompensatory heart failure were unclear. We hypothesized that after an aortic stenosis MMP-2 released angiogenic factors during compensatory hypertrophy and MMP-9/TIMP-3 released antiangiogenic factors causing decompensatory heart failure. To verify this hypothesis, wild type (WT) mice were studied 3 and 8 wks after aortic stenosis, created by banding the ascending aorta in WT and MMP-9−/− (MMP-9KO) mice. Cardiac function (echo, PV loops) was decreased at 8 wks after stenosis. The levels of MMP-2 (western blot) increased at 3 wks and returned to control level at 8 wks, MMP-9 increased only at 8 wks. TIMP-2 and −4 decreased at 3 and even more at 8 wks. The angiogenic VEGF increased at 3 wks and decreased at 8 wks, the antiangiogenic endostatin and angiostatin increased only at 8 wks. CD-31 positive endothelial cells were more intensely labeled at 3 wks than in sham operated or in 8 wks banded mice. Vascularization, as estimated by x-ray angiography, was increased at 3 wks and decreased at 8 wks post-banding. Although vast majority of studies were performed on control WT mice only, interestingly, MMP9-KO mice seemed to have increased vascular density 8 wks after banding. These results suggested that there was increase in MMP-2, decrease in TIMP-2 and −4, increase in angiogenic factors and vascularization in compensatory hearts. However, in decompensatory hearts there was increase in MMP-9, TIMP-3, endostatin, angiostatin and vascular rarefaction.