Loss of angiotensin-converting enzyme-2 (Ace2) accelerates diabetic kidney injury

Diabetic nephropathy is one of the most common causes of end-stage renal failure, but the factors responsible for the development of diabetic nephropathy have not been fully elucidated. We examined the effect of deletion of the angiotensin-convert-ing enzyme 2 (Ace2) gene on diabetic kidney injury. Ace2(-/-) mice were crossed with Akita mice (Ins2(WT/C96Y)), a model of type 1 diabetes mellitus, and four groups of mice were studied at 3 months of age: Ace2(+/y)Ins2(WT/WT), Ace2(-/y)Ins2(WT/WT), Ace2(+/y) Ins2(WT/C96Y), and Ace2(-/y)Ins2(WT/C96Y). Ace2(-/y) Ins2(WT/C96Y) mice exhibited a twofold increase in the urinary albumin excretion rate compared with Ace2(+/y)Ins2(WT/C96Y) mice despite similar blood glucose levels. Ace2(-/y)Ins2(WT/C96Y) mice were the only group to exhibit increased mesangial matrix scores and glomerular basement membrane thicknesses compared with Ace2(+/y)Ins2(WT/WT) mice, accompanied by increased fibronectin and alpha-smooth muscle actin immunostaining in the glomeruli of Ace2(-/y) Ins2(WT/C96Y) mice. There were no differences in blood pressure or heart function to account for the exacerbation of kidney injury. Although kidney levels of angiotensin (Ang) II were not increased in the diabetic mice, treatment with an Ang II receptor blocker reduced urinary albumin excretion rate in Ace2(-/y)Ins2(WT/C96Y) mice, suggesting that acceleration of kidney injury in these mice is Ang II-mediated. We conclude that ACE2 plays a protective role in the diabetic kidney, and ACE2 is an important determinant of diabetic nephropathy.     

First Report on Sergentomyia sintoni and Sergentomyia clydei (Diptera: Psychodidae): Their Natural Promastigote Infection and Some Aspects of Biology in Sistan-Baluchistan Province,Southeastern Iran

ObjectiveTo This paper has explained initial survey on two vectors of lizard leishmania promastigote in south-east of Iran.MethodsTotally 333 S. sintoni and 475 S. clydei were collected from rodent burrows by sticky traps in three villages of Chabahar County. Sand flies were dissected in a drop of normal saline.ResultsNatural leptomonad infection rate involved %2.1 S. sintoni and %5 S. clydei. The finding about seasonal variation was showed the highest infection rate in two vectors in the first week of August. The highest population of gravid and semi-gravid of main vectors of Lizard leishmaniasis, S. sintoni and S. clydei, were observed in the last week of September and the lowest were in the last week of July. The examination of accessory glands showed that the maximum population of parous was observed in the last week of September and the last week of July it was at least. This is the first report of leptomonad (promastigote) infection in S. sintoni and S. clydei in Sistan-Baluchistan Province, southeastern Iran.ConclusionsA further study with more focus on biology of Sergentomyia genus is suggested.     

Myocardial extra-cellular matrix and its regulation by metalloproteinases and their inhibitors

Cardiovascular disease poses a major health care burden in the Western world. Following myocardial injuries, ventricular remodelling and dysfunction ensue, which can eventually culminate in heart failure. An important event in left ventricular (LV) remodelling is alteration of the extracellular matrix (ECM) integrity, the structural network that interconnects the myocardial components. The critical role of ECM remodelling in cardiac dilation and heart failure was recognized more than a decade ago, and the molecular factors responsible for this process are now being explored. Abnormal ECM turnover is primarily brought about by an imbalance in the activity of matrix metalloproteinases (MMPs) that degrade ECM components, and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Here we provide an overview of composition of the cardiac ECM, and alterations in ECM regulatory proteins, MMPs and TIMPs, in human heart disease. We also discuss the role of TIMPs, MMPs, and a disintegrin and metalloproteinase (ADAMs) enzymes in cardiac development and function as learned through genetically altered mouse models.     

Molecular components of transient outward potassium current in cultured neonatal rat ventricular myocytes

We have previously reported that K(v1.4), K(v4.2), and K(v4.3) mRNAs are present in adult and neonatal rat ventricular myocytes, and that transient outward potassium current (I(to)) recovers from inactivation with a slow (I(to,s)) and a fast (I(to,f)) time course. This study was designed to determine the molecular correlates of I(to,s) and I(to,f) in cultured neonatal rat ventricular myocytes (NRVM) employing dominant-negative adenoviral infections to manipulate the function of endogenous I(to)-encoding K+ channels. Western blot data from cultured NRVM showed that K(v1.4), K(v4.2), and K(v4.3) channel proteins are present in these myocytes. The biphasic recovery from inactivation of I(to) in control GFP-infected myocytes demonstrated equal contribution of I(to,s) and I(to,f) in NRVM. Infection of cultured NRVM with adenoviruses expressing full-length K(v1.4) or K(v4.2) genes generated currents with recovery from inactivation kinetics similar to native I(to,s) and I(to,f) in GFP-infected myocytes, respectively. Overexpression of dominant-negative truncated K(v1.4) transgene (K(v1.4)N) caused a 51% reduction in I(to), selectively removing the slowly recovering I(to,s). Overexpression of dominant-negative K(v4.2)N reduced I(to) by 53% and eliminated the fast-recovering I(to,f). Our results establish that, in neonatal rat ventricular myocytes, the shaker K(v1) family (probably K(v1.4) and/or K(v1.7)) underlies I(to,s), and that the shal K(v4) family (probably K(v4.2) and K(v4.3)) is responsible for I(to,f).