Inhibition of EZH2 mitigates peritoneal fibrosis and lipid precipitation in peritoneal mesothelial cells mediated by klotho

Metabolic reprogramming of peritoneal mesothelial cells in peritoneal dialysis-associated fibrosis: therapeutic targets and strategies

Peritoneal dialysis (PD) is considered a life-saving treatment for end-stage renal disease. However, prolonged PD use can lead to the development of peritoneal fibrosis (PF), diminishing its efficacy. Peritoneal mesothelial cells (PMCs) are key initiators of PF when they become damaged. Exposure to high glucose‑based peritoneal dialysis fluids (PDFs) contributes to PF development by directly affecting highly metabolically active PMCs. Recent research indicates that PMCs undergo metabolic reprogramming when exposed to high-glucose PDFs, including enhanced glycolysis, impaired oxidative phosphorylation, abnormal lipid metabolism, and mitochondrial dysfunction. Although this metabolic transition temporarily compensates for the cellular damage and maintains energy levels, its long-term impact on peritoneal tissue is concerning. Multiple studies have identified a close association between this shift in energy metabolism and PF, and may promote the progression of PF through various molecular mechanisms. This review explores recent findings regarding the role and mechanism of PMC metabolic reprogramming in PF progression. Moreover, it provides a summary of potential therapeutic strategies aimed at various metabolic processes, including glucose metabolism, lipid metabolism, and mitochondrial function. The review establishes that targeting metabolic reprogramming in PMCs may be a novel strategy for preventing and treating PD-associated fibrosis.

Dyslipidemia in Peritoneal Dialysis: Implications for Peritoneal Membrane Function and Patient Outcomes

Dyslipidemia is a common metabolic complication in patients undergoing peritoneal dialysis (PD) and has traditionally been viewed primarily in terms of cardiovascular risk. Current guidelines do not recommend initiating lipid-lowering therapy in dialysis patients due to insufficient evidence of its benefits on cardiovascular mortality. However, the impact of dyslipidemia in PD patients may extend beyond cardiovascular concerns, influencing PD-related outcomes such as the peritoneal ultrafiltration rate, residual kidney function, PD technique survival, and overall mortality. This review challenges the traditional perspective by discussing dyslipidemia's potential role in PD-related complications, which may account for the observed link between dyslipidemia and increased all-cause mortality in PD patients. It explores the pathophysiology of dyslipidemia in PD, the molecular mechanisms linking dyslipidemia to peritoneal membrane dysfunction, and summarizes clinical evidence supporting this hypothesis. In addition, this paper examines the potential for therapeutic strategies to manage dyslipidemia to improve peritoneal membrane function and patient outcomes. The review calls for future research to investigate dyslipidemia as a potential contributor to peritoneal membrane dysfunction and to develop targeted interventions for PD patients.

Intercellular communication in peritoneal dialysis

Long-term peritoneal dialysis (PD) causes structural and functional alterations of the peritoneal membrane. Peritoneal deterioration and fibrosis are multicellular and multimolecular processes. Under stimulation by deleterious factors such as non-biocompatibility of PD solution, various cells in the abdominal cavity show differing characteristics, such as the secretion of different cytokines, varying protein expression levels, and transdifferentiation into other cells. In this review, we discuss the role of various cells in the abdominal cavity and their interactions in the pathogenesis of PD. An in-depth understanding of intercellular communication and inter-organ communication in PD will lead to a better understanding of the pathogenesis of this disease, enabling the development of novel therapeutic targets.

High glucose dialysate-induced peritoneal fibrosis: Pathophysiology, underlying mechanisms and potential therapeutic strategies

Peritoneal dialysis is an efficient renal replacement therapy for patients with end-stage kidney disease. However, continuous exposure of the peritoneal membrane to dialysate frequently leads to peritoneal fibrosis, which alters the function of the peritoneal membrane and results in withdrawal from peritoneal dialysis in patients. Among others, high glucose dialysate is considered as a predisposing factor for peritoneal fibrosis in patients on peritoneal dialysis. Glucose-induced inflammation, metabolism disturbance, activation of the renin-angiotensin-aldosterone system, angiogenesis and noninflammation-induced reactive oxygen species are implicated in the pathogenesis of high glucose dialysate-induced peritoneal fibrosis. Specifically, high glucose causes chronic inflammation and recurrent peritonitis, which could cause migration and polarization of inflammatory cells, as well as release of cytokines and fibrosis. High glucose also interferes with lipid metabolism and glycolysis by activating the sterol-regulatory element-binding protein-2/cleavage-activating protein pathway and increasing hypoxia inducible factor-1α expression, leading to angiogenesis and peritoneal fibrosis. Activation of the renin-angiotensin-aldosterone system and Ras-mitogen activated protein kinase signaling pathway is another contributing factor in high glucose dialysate-induced fibrosis. Ultimately, activation of the transforming growth factor-β1/Smad pathway is involved in mesothelial-mesenchymal transition or epithelial-mesenchymal transition, which leads to the development of fibrosis. Although possible intervention strategies for peritoneal dialysate-induced fibrosis by targeting the transforming growth factor-β1/Smad pathway have occasionally been proposed, lack of laboratory evidence renders clinical decision-making difficult. We therefore aim to revisit the upstream pathways of transforming growth factor-beta1/Smad and propose potential therapeutic targets for high glucose-induced peritoneal fibrosis.

Current Insights into Cellular Determinants of Peritoneal Fibrosis in Peritoneal Dialysis: A Narrative Review

Peritoneal fibrosis is the final process of progressive changes in the peritoneal membrane due to chronic inflammation and infection. It is one of the main causes of discontinuation of peritoneal dialysis (PD), apart from peritonitis and cardiovascular complications. Over time, morphological changes occur in the peritoneal membranes of patients who use PD. Of those are mesothelial-to-mesenchymal transition (MMT), neoangiogenesis, sub-mesothelial fibrosis, and hyalinizing vasculopathy. Several key molecules are involved in the complex pathophysiology of peritoneal fibrosis, including advanced glycosylation end products (AGEs), transforming growth factor beta (TGF-β), and vascular endothelial growth factor (VEGF). This narrative review will first discuss the physiology of the peritoneum and PD. Next, the multifaceted pathophysiology of peritoneal fibrosis, including the effects of hyperglycemia and diabetes mellitus on the peritoneal membrane, and the promising biomarkers of peritoneal fibrosis will be reviewed. Finally, the current and future management of peritoneal fibrosis will be discussed, including the potential benefits of new-generation glucose-lowering medications to prevent or slow down the progression of peritoneal fibrosis.

EZH2 serves as a promising therapeutic target for fibrosis

Fibrosis affects the function of many organs and tissues, and its persistent development can lead to tissue sclerosis and cancer, even leading to death further. Recent studies suggested that enhancer of zeste homolog 2 (EZH2), a major regulator of epigenetic repression, played an important role in the occurrence and development of fibrosis through gene silencing or transcriptional activation. As the most studied and powerful pro-fibrotic cytokine closely related to EZH2, TGF-β1 was primarily involved in the regulation of fibrosis along with the typical Smads and non-Smads signaling pathways. In addition, EZH2 inhibitors demonstrated inhibitory effects in several types of fibrosis. This review summarized the relationship underlying the action of EZH2, TGF-β1/Smads, and TGF-β1/non-Smads with fibrosis and described the research progress of EZH2 inhibitors in the treatment of fibrosis.