Endothelial cells are important constituents of blood vessels that play critical roles in cardiovascular homeostasis by regulating blood fluidity and fibrinolysis, vascular tone, angiogenesis, monocyte/leukocyte adhesion, and platelet aggregation. The normal vascular endothelium is taken as a gatekeeper of cardiovascular health, whereas abnormality of vascular endothelium is a major contributor to a plethora of cardiovascular ailments, such as atherosclerosis, aging, hypertension, obesity, and diabetes. Endothelial dysfunction is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and proinflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. The occurrence of endothelial dysfunction disrupts the endothelial barrier permeability that is a part of inflammatory response in the development of cardiovascular diseases. As such, abrogation of endothelial cell activation/inflammation is of clinical relevance. Recently, hydrogen sulfide (H 2 S), an entry as a gasotransmitter, exerts diverse biological effects through acting on various targeted signaling pathways. Within the cardiovascular system, the formation of H 2 S is detected in smooth muscle cells, vascular endothelial cells, and cardiomyocytes. Disrupted H 2 S bioavailability is postulated to be a new indicator for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we will summarize recent advances about the roles of H 2 S in endothelial cell homeostasis, especially under pathological conditions, and discuss its putative therapeutic applications in endothelial inflammation-associated cardiovascular disorders.

Hydrogen sulfide (H 2 S) has been proposed as a novel neuromodulator, which plays critical roles in the central nervous system affecting both neurons and glial cells. However, its relationship with neurodegenerative diseases is unexplored. The present study was undertaken to investigate the effects of H 2 S on cell injury induced by rotenone, a commonly used toxin in establishing in vivo and in vitro Parkinson's disease (PD) models, in humanderived dopaminergic neuroblastoma cell line (SH-SY5Y). We report here that sodium hydrosulfide (NaHS), an H 2 S donor, concentration-dependently suppressed rotenone-induced cellular injury and apoptotic cell death. NaHS also prevented rotenone-induced p38-and c-Jun NH 2 -terminal kinase (JNK)-mitogen-activated protein kinase (MAPK) phosphorylation and rotenone-mediated changes in Bcl-2/Bax levels, mitochondrial membrane potential (⌬⌿ m ) dissipation, cytochrome c release, caspase-9/3 activation and poly(ADP-ribose) polymerase cleavage. Furthermore, 5-hydroxydecanoate, a selective blocker of mitochondrial ATP-sensitive potassium (mitoK ATP ) channel, attenuated the protective effects of NaHS against rotenone-induced cell apoptosis. Thus, we demonstrated for the first time that H 2 S inhibited rotenone-induced cell apoptosis via regulation of mitoK ATP channel/ p38-and JNK-MAPK pathway. Our data suggest that H 2 S may have potential therapeutic value for neurodegenerative diseases, such as PD.

No abstract

ADPKD is marked by gradual renal cyst and kidney enlargement and ultimately renal failure. Magnetic resonance-based, height-adjusted total kidney volume (htTKV) over 600 ml/m predicts the development of CKD Stage 3 within 8 years in the Consortium for Radiologic Imaging in Polycystic Kidney Disease cohort. Here we compared simultaneous ultrasound and magnetic resonance imaging to determine if ultrasound and kidney length (KL) predict future CKD Stage 3 over longer periods of follow-up. A total of 241 ADPKD patients, 15–46 years, with creatinine clearance of 70 ml/min and above had iothalamate clearance, magnetic resonance and ultrasound evaluations. Participants underwent an average of five repeat clearance measurements over a mean follow-up of 9.3 years. Ultrasound and magnetic resonance-based TKV and KL were compared using Bland-Altman plots and intra-class correlations. Each measure was tested to predict future CKD Stage 3. Relatively strong intra-class correlations between ultrasound and magnetic resonance were found for both htTKV and KL (0.81 and 0.85, respectively). Ultrasound and magnetic resonance-based htTKV and KL predicted future CKD Stage 3 similarly (AUC of 0.87, 0.88, 0.87 and 0.88 respectively). An ultrasound kidney length over 16.5 cm and htTKV over 650 ml/m had the best cut-point for predicting the development of CKD Stage 3. Thus, kidney length alone is sufficient to stratify the risk of progression to renal insufficiency early in ADPKD using either ultrasound or magnetic resonance imaging.

Aims: Mitochondrion is considered as the major source of intracellular reactive oxygen species (ROS). H 2 S has been reported to be an antioxidant, but its mechanism remains largely elusive. P66Shc is an upstream activator of mitochondrial redox signaling. The aim of this study was to explore whether the antioxidant effect of H 2 S is mediated by p66Shc. Results: Application of exogenous H 2 S with its donor, NaHS, or overexpression of its generating enzyme, cystathionine b-synthase, induced sulfhydration of p66Shc, but inhibited its phosphorylation caused by H 2 O 2 /D-galactose in SH-SY5Y cells or in the mice cortex. H 2 S also decreased mitochondrial ROS production and protected neuronal cells against stress-induced senescence. PKC bII and PP2A are the two key proteins to regulate p66Shc phosphorylation. Although H 2 S failed to affect the activities of these two proteins, it disrupted their association. Cysteine-59 resides in proximity to serine-36, the phosphorylation site of p66Shc. The C59S mutant attenuated the above-described biological function of H 2 S. Innovation: We revealed a novel mechanism for the antioxidant effect of H 2 S and its role in oxidative stress-related diseases. Conclusion: H 2 S inhibits mitochondrial ROS production via the sulfhydration of Cys-59 residue, which in turn, prevents the phosphorylation of p66Shc. Antioxid. Redox Signal. 21, 2531-2542.

Objective: To evaluate whether kidney and cyst volumes can be accurately estimated based on limited area measurements from magnetic resonance (MR) images of patients with autosomal dominant polycystic kidney disease (ADPKD). Materials and Methods: MR coronal images of 178 ADPKD participants from the Consortium for Radiologic Imaging Studies of ADPKD (CRISP) were analyzed. For each MR image slice, we measured kidney and renal cyst areas using stereology and region-based thresholding methods, respectively. The kidney and cyst ‘observed' volumes were calculated by summing up the area measurements of all the slices covering the kidney. To estimate the volume, we selected a coronal mid-slice in each kidney and multiplied its area by the total number of slices (‘PANK2' for kidney and ‘PANC2' for cyst). We then compared the kidney and cyst volumes predicted from PANK2 and PANC2, respectively, to the corresponding observed volumes, using a linear regression analysis. Results: The kidney volume predicted from PANK2 correlated extremely well with the observed kidney volume (R² = 0.994 for the right kidney and 0.991 for the left kidney). The linear regression coefficient multiplier to PANK2 that best fit the kidney volume was 0.637 (95% CI: 0.629-0.644) for the right kidney and 0.624 (95% CI: 0.616-0.633) for the left kidney. The correlation between the cyst volume predicted from PANC2 and the observed cyst volume was also very high (R² = 0.984 for the right kidney and 0.967 for the left kidney). The least squares linear regression coefficient for PANC2 was 0.637 (95% CI: 0.624-0.649) for the right kidney and 0.608 (95% CI: 0.591-0.625) for the left kidney. Conclusion: Kidney and cyst volumes can be closely approximated by multiplying the product of the mid-slice area measurement and the total number of slices in the coronal MR images of ADPKD kidneys by 0.61-0.64. This information will help save processing time needed to estimate total kidney and cyst volumes of ADPKD kidneys.

Diabetic kidney disease develops in approximately 40% of diabetic patients and is a major cause of chronic kidney diseases (CKD) and end stage kidney disease (ESKD) worldwide. Hydrogen sulfide (H2S), the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO), is synthesized in nearly all organs, including the kidney. Though studies on H2S regulation of renal physiology and pathophysiology are still in its infancy, emerging evidence shows that H2S production by renal cells is reduced under disease states and H2S donors ameliorate kidney injury. Specifically, aberrant H2S level is implicated in various renal pathological conditions including diabetic nephropathy. This review presents the roles of H2S in diabetic renal disease and the underlying mechanisms for the protective effects of H2S against diabetic renal damage. H2S may serve as fundamental strategies to treat diabetic kidney disease. These H2S treatment modalities include precursors for H2S synthesis, H2S donors, and natural plant-derived compounds. Despite accumulating evidence from experimental studies suggests the potential role of the H2S signaling pathway in the treatment of diabetic nephropathy, these results need further clinical translation. Expanding understanding of H2S in the kidney may be vital to translate H2S to be a novel therapy for diabetic renal disease.

Diabetic kidney disease is known as a major cause of chronic kidney disease and end stage renal disease. Polysulfides, a class of chemical agents with a chain of sulfur atoms, are found to confer renal protective effects in acute kidney injury. However, whether a polysulfide donor, sodium tetrasulfide (Na 2 S 4 ), confers protective effects against diabetic nephropathy remains unclear. Our results showed that Na 2 S 4 treatment ameliorated renal dysfunctional and histological damage in diabetic kidneys through inhibiting the overproduction of inflammation cytokine and reactive oxygen species (ROS), as well as attenuating renal fibrosis and renal cell apoptosis. Additionally, the upregulated phosphorylation and acetylation levels of p65 nuclear factor κB (p65 NF-κB) and signal transducer and activator of transcription 3 (STAT3) in diabetic nephropathy were abrogated by Na 2 S 4 in a sirtuin-1 (SIRT1)-dependent manner. In renal tubular epithelial cells, Na 2 S 4 directly sulfhydrated SIRT1 at two conserved CXXC domains (Cys371/374; Cys395/398), then induced dephosphorylation and deacetylation of its targeted proteins including p65 NF-κB and STAT3, thereby reducing high glucose (HG)-caused oxidative stress, cell apoptosis, inflammation response and epithelial-to-mesenchymal transition (EMT) progression. Most importantly, inactivation of SIRT1 by a specific inhibitor EX-527, small interfering RNA (siRNA), a de-sulfhydration reagent dithiothreitol (DTT), or mutation of Cys371/374 and Cys395/398 sites at SIRT1 abolished the protective effects of Na 2 S 4 on diabetic kidney insulting. These results reveal that polysulfides may attenuate diabetic renal lesions via inactivation of p65 NF-κB and STAT3 phosphorylation/acetylation through sulfhydrating SIRT1.