Hydrogen sulfide prevents arterial medial calcification in rats with diabetic nephropathy

Exogenous hydrogen sulfide prevents SOD2 degradation to safeguard renal function in diabetic kidney disease

Diabetic kidney disease (DKD) is a major contributor to chronic kidney disease. Hydrogen sulfide (H2S) serves as an endogenous gaseous signaling molecule capable of safeguarding renal function within the context of DKD. However, the underlying mechanisms need to be elucidated. This study was undertaken to unveil the mechanisms by which H2S counteracts against DKD. Utilizing mice and human renal tubular epithelial (HK-2) cells, we demonstrated a reduction in cystathionine-γ-lyase/H2S levels within renal tissues of db/db mice and in HK-2 cells subjected to hyperglycemic and hyperlipidemic environments. Notably, we observed that sodium hydrosulfide (NaHS) supplementation could serve as an exogenous source of H2S. Exogenous H2S exhibited the capacity to mitigate the accumulation of reactive oxygen species and attenuate the degradation of superoxide dismutase 2 (SOD2) by Lon protease homolog 1 induced by hyperglycemia and hyperlipidemia, thus affording cellular protection against mitochondrial apoptosis. Consequently, NaHS treatment led to decreased serum levels of blood urea nitrogen and serum creatinine, reflecting alleviated renal damage and thereby preserving renal function in db/db mice. Based on these findings, we propose that exogenous H2S exerts a protective role against DKD by inhibiting SOD2 degradation.

Hydrogen Sulfide and Irisin, Potential Allies in Ensuring Cardiovascular Health

Irisin is a myokine secreted under the influence of physical activity and exposure to low temperatures and through different exogenous stimuli by the cleavage of its precursor, fibronectin type III domain-containing protein 5 (FNDC5). It is mainly known for maintaining of metabolic homeostasis, promoting the browning of white adipose tissue, the thermogenesis process, and glucose homeostasis. Growing experimental evidence suggests the possible central role of irisin in the regulation of cardiometabolic pathophysiological processes. On the other side, hydrogen sulfide (H2S) is well recognized as a pleiotropic gasotransmitter that regulates several homeostatic balances and physiological functions and takes part in the pathogenesis of cardiometabolic diseases. Through the S-persulfidation of cysteine protein residues, H2S is capable of interacting with crucial signaling pathways, exerting beneficial effects in regulating glucose and lipid homeostasis as well. H2S and irisin seem to be intertwined; indeed, recently, H2S was found to regulate irisin secretion by activating the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)/FNDC5/irisin signaling pathway, and they share several mechanisms of action. Their involvement in metabolic diseases is confirmed by the detection of their lower circulating levels in obese and diabetic subjects. Along with the importance of metabolic disorders, these modulators exert favorable effects against cardiovascular diseases, preventing incidents of hypertension, atherosclerosis, heart failure, myocardial infarction, and ischemia-reperfusion injury. This review, for the first time, aims to explore the role of H2S and irisin and their possible crosstalk in cardiovascular diseases, pointing out the main effects exerted through the common molecular pathways involved.

The many roles of cathepsins in restenosis

Drug-eluting stents (DES) and dual antiplatelet regimens have significantly improved the clinical management of ischemic heart disease; however, the drugs loaded with DES in clinical practice are mostly paclitaxel or rapamycin derivatives, which target symptoms of post implantation proliferation and inflammation, leading to delayed re-endothelialization and neo-atherosclerosis. Along with the treatments already in place, there is a need for novel strategies to lessen the negative clinical outcomes of DES delays as well as a need for greater understanding of their pathobiological mechanisms. This review concentrates on the function of cathepsins (Cats) in the inflammatory response and granulation tissue formation that follow Cat-induced damage to the vasculature scaffold, as well as the functions of Cats in intimal hyperplasia, which is characterized by the migration and proliferation of smooth muscle cells, and endothelial denudation, re-endothelialization, and/or neo-endothelialization. Additionally, Cats can alter essential neointima formation and immune response inside scaffolds, and if Cats are properly controlled in vivo, they may improve scaffold biocompatibility. This unique profile of functions could lead to an original concept for a cathepsin-based coronary intervention treatment as an adjunct to stent placement.

Endothelium-Mimicking Bilayer Vascular Grafts with Dual-Releasing of NO/H2S for Anti-Inflammation and Anticalcification

Vascular complications caused by diabetes impair the activities of endothelial nitric oxide synthase (eNOS) and cystathionine γ-lyase (CSE), resulting in decreased physiological levels of nitric oxide (NO) and hydrogen sulfide (H2S). The low bioavailability of NO and H2S hinders the endothelialization of vascular grafts. In this study, endothelium-mimicking bilayer vascular grafts were designed with spatiotemporally controlled dual releases of NO and H2S for in situ endothelialization and angiogenesis. Keratin-based H2S donor was synthesized and electrospun with poly(l-lactide-co-ε-caprolactone) (PLCL) as the outer layer of the graft to release H2S. Hyaluronic acid, one of the major glycosaminoglycans in endothelial glycocalyx, was complexed with Cu ions as the inner layer to mimic glutathione peroxidase (GPx) and maintain long-term physiological NO flux. The synergistic effects of NO and H2S of bilayer grafts selectively promoted the regeneration and migration of human umbilical vascular endothelial cells (HUVECs), while inhibiting the overproliferation of human umbilical artery smooth muscle cells (HUASMCs). Bilayer grafts could effectively prevent vascular calcification, reduce inflammation, and alleviate endothelial dysfunction. The in vivo study in a rat abdominal aorta replacement model for 1 month showed that the graft had a good patency rate and had potential for vascular remodeling in situ.

The roles of gut microbiota and its metabolites in diabetic nephropathy

Diabetic nephropathy (DN) is a severe microvascular complication of diabetes, which increases the risk of renal failure and causes a high global disease burden. Due to the lack of sustainable treatment, DN has become the primary cause of end-stage renal disease worldwide. Gut microbiota and its metabolites exert critical regulatory functions in maintaining host health and are associated with many pathogenesis of aging-related chronic diseases. Currently, the theory gut-kidney axis has opened a novel angle to understand the relationship between gut microbiota and multiple kidney diseases. In recent years, accumulating evidence has revealed that the gut microbiota and their metabolites play an essential role in the pathophysiologic processes of DN through the gut-kidney axis. In this review, we summarize the current investigations of gut microbiota and microbial metabolites involvement in the progression of DN, and further discuss the potential gut microbiota-targeted therapeutic approaches for DN.

Clinical Potential of Hydrogen Sulfide in Peripheral Arterial Disease

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H₂S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H₂S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects.

Hydrogen Sulfide in Diabetic Complications Revisited: The State of the Art, Challenges, and Future Directions

Significance: Diabetes and its related complications are becoming an increasing public health problem that affects hundreds of millions of people globally. Increased disability and mortality rate of diabetic individuals are closely associated with various life-threatening complications, such as atherosclerosis, nephropathy, retinopathy, and cardiomyopathy. Recent Advances: Conventional treatments for diabetes are still limited because of undesirable side effects, including obesity, hypoglycemia, and hepatic and renal toxicity. Studies have shown that hydrogen sulfide (H₂S) plays a critical role in the modulation of glycolipid metabolism, pancreatic β cell functions, and diabetic complications. Critical Issues: Preservation of endogenous H₂S systems and supplementation of H₂S donors are effective in attenuating diabetes-induced complications, thus representing a new avenue to treat diabetes and its associated complications. Future Directions: This review systematically recapitulates and discusses the most recent updates regarding the therapeutic effects of H₂S on diabetes and its various complications, with an emphasis on the molecular mechanisms that underlie H₂S-mediated protection against diabetic complications. Furthermore, current clinical trials of H₂S in diabetic populations are highlighted, and the challenges and solutions to the clinical transformation of H₂S-derived therapies in diabetes are proposed. Finally, future research directions of the pharmacological actions of H₂S in diabetes and its related complications are summarized. Antioxid. Redox Signal. 38, 18-44.

Hydrogen Sulfide Suppresses Skin Fibroblast Proliferation via Oxidative Stress Alleviation and Necroptosis Inhibition

Keloid is a common dermatofibrotic disease with excessive skin fibroblast proliferation. Hydrogen sulfide (H₂S) as the third gasotransmitter improves fibrosis of various organs and tissues. Our study is aimed at investigating the effects and possible mechanisms of H₂S on skin fibroblast proliferation. Scar tissues from six patients with keloid and discarded skin tissue from six normal control patients were collected after surgery, respectively. Plasma H₂S content and skin H₂S production in patients with keloid were measured. Keloid fibroblasts and transforming growth factor-β₁- (TGF-β₁, 10 ng/mL) stimulated normal skin fibroblasts were pretreated with H₂S donor as NaHS (50 μM) for 4 h. Cell migration after scratch was assessed. The expressions of α-smooth muscle actin (α-SMA), proliferating cell nuclear antigen (PCNA), collagen I, and collagen III were detected by immunofluorescence, real-time PCR, and/or Western blot. Intracellular superoxide anion and mitochondrial superoxide were evaluated by dihydroethidium (DHE) and MitoSOX staining, respectively. Mitochondrial membrane potential was detected by JC-1 staining. Apoptotic cells were detected by TDT-mediated dUTP nick end labeling (TUNEL). The expressions of receptor interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL) were measured by Western blot. We found that H₂S production was impaired in both the plasma and skin of patients with keloid. In keloid fibroblasts and TGF-β₁-stimulated normal skin fibroblasts, exogenous H₂S supplementation suppressed the expressions of α-SMA, PCNA, collagen I, and collagen III, reduced intracellular superoxide anion and mitochondrial superoxide, improved the mitochondrial membrane potential, decreased the positive rate of TUNEL staining, and inhibited RIPK1 and RIPK3 expression as well as MLKL phosphorylation. Overall, H₂S suppressed skin fibroblast proliferation via oxidative stress alleviation and necroptosis inhibition.

Advances in pathogenesis and therapeutic strategies for osteoporosis

Osteoporosis, is the most common bone disorder worldwide characterized by low bone mineral density, leaving affected bones vulnerable to fracture. Bone homeostasis depends on the precise balance between bone resorption by osteoclasts and bone matrix formation by mesenchymal lineage osteoblasts, and involves a series of complex and highly regulated steps. Bone homeostasis will be disrupted when the speed of bone resorption is faster than bone formation. Based on various regulatory mechanisms of bone homeostasis, a series of drugs targeting osteoporosis have emerged in clinical practice, including bisphosphonates, selective estrogen receptor modulators, calcitonin, molecular-targeted drugs and so on. However, many drugs have major adverse effects or are unsuitable for long-term use. Therefore, it is very urgent to find more effective therapeutic drugs based on the new pathogenesis of osteoporosis. In this review, we summarize novel mechanisms involved in the pathological process of osteoporosis, including the roles of gut microbiome, autophagy, iron balance and cellular senescence. Based on the above pathological mechanism, we found promising drugs for osteoporosis treatment, such as: probiotics, alpha-ketoglutarate, senolytics and hydrogen sulfide. This new finding may provide an important basis for elucidating the complex pathological mechanisms of osteoporosis and provide promising drugs for clinical osteoporosis treatment.