Guadalupe Tirma González-Mateo

Background and hypothesis: End-stage renal disease patients require peritoneal dialysis (PD) as a life-saving therapy; however, they continue to experience systemic inflammation and increased cardiovascular pathology. These complications can be exacerbated by exposure to PD solutions (PDS) containing glucose. This highlights the clinical unmet need for novel osmotic agents to replace glucose. Here, we tested troxerutin, a Food and Drug Administration–approved drug, as a potential osmotic agent. Methods: To evaluate troxerutin osmotic and non-toxic effects, in vitro and in vivo experiments were carried out using artificial membranes, mice and cultured human mesothelial cells (MCs). The local and systemic consequences of chronic peritoneal exposure to PDS associated to renal insufficiency were investigated in a preclinical model. 5/6 nephrectomized C57BL/6J mice were daily exposed to glucose- or troxerutin-PDS for 60 days, then evaluating tissue damage, proinflammatory markers and cardiac damage. Results: In vitro and in vivo studies revealed that troxerutin exhibits similar osmotic and ultrafiltration capacities to glucose, but with colloidal properties. Moreover, only glucose, but not troxerutin, reduced MC viability, induced mesothelial-to-mesenchymal transition, and increased damage markers (such as interleukin-6 and vascular endothelial growth factor A). In the preclinical model, long-term treatment with glucose-PDS, but not troxerutin-PDS, significantly increased peritoneal membrane thickening, tissue proinflammatory markers (evaluated in peritoneum, kidney, heart and aorta) and cardiovascular damage (cardiac hypertrophy and fibrosis) in mice. These preclinical data clearly demonstrate the wide deleterious effects of chronic peritoneal exposure to glucose-containing PDS in mice with kidney insufficiency and that the replacement of glucose with troxerutin notably reduces these effects. Conclusion: Troxerutin emerges as a more biocompatible alternative to glucose as an osmotic agent for PD therapy, exhibiting no adverse local or systemic side effects in preclinical studies. This research presents a novel approach to reduce cardiovascular complications of PD in end-stage kidney disease.

Chronic wounds significantly impact health, diminishing the quality of life for patients and caregivers. These conditions demand substantial financial and time resources from medical teams and are often complicated by comorbidities. The following chapter raises awareness of social costs concerning chronic wounds while reviewing the most recent knowledge and strategies regarding the clinical approach to improve healing outcomes and treatment adherence. Here, traditional and innovative chronic wound management techniques are examined, including wound bed care, dressings, antibiotic therapy, and advanced debridement methods. Special focus is given to debridement due to its critical role in wound healing and functional recovery. Collagenase, a widely used enzymatic debridement agent, selectively degrades denatured collagen while preserving healthy tissue, promoting effective wound cleaning and healing. Exposing healthy tissue enhances the efficacy of complementary treatments and accelerates recovery. Therefore, targeted debridement methods are pivotal in chronic wound management, improving healing and patient outcomes. Identifying critical barriers such as wound stalling, infection, and ischemia, as well as understanding factors that influence adherence and implementing patient-specific interventions, is equally vital. Innovations in wound care formulations designed to enhance comfort, reduce infection risk, and promote faster healing are essential for improving both adherence and quality of life in chronic wound patients.

Peritoneal dialysis (PD) is a widely used kidney replacement therapy for end-stage kidney disease (ESKD) patients. However, long-term exposure to PD fluids (PDF) can lead to peritoneal membrane (PM) damage, causing ultrafiltration failure and thus PD discontinuation. Investigating the molecular mechanisms underlying this damage is crucial for identifying new therapeutic targets to mitigate peritoneal deterioration in PD patients. Therefore, in this work we study the role of STING in peritoneal inflammation and fibrosis. To this aim, we performed different preclinical mouse models of peritoneal inflammation, fibrosis, and adhesions. In a chlorhexidine gluconate (CHX)-induced inflammation model, we found changes in the peritoneal transcriptomic profile, and cytosolic DNA-sensing signaling was one of the most enriched KEGG pathways. STING, as a conspicuous member of this pathway, was upregulated in CHX-and PDF-exposed mice, and in peritoneal biopsies from PD patients. STING genetic deficiency diminished peritoneal inflammation, by downregulating inflammatory gene expression, preventing NF-κB pathway activation, and decreasing cell infiltration, in early (10 days) and advanced (30 days) stages of the CHX model. STING absence also decreased PM thickness and fibrosis in the advanced CHX model, reduced adhesion scores in a post-surgical intra-abdominal adhesion model, and decreased inflammation in an S. epidermidis -induced peritonitis model. Furthermore, pharmacological inhibition of STING with C-176 decreased inflammation and macrophage-mediated mesothelial-to-mesenchymal transition in cultured mesothelial cells, and reduced CHX-induced PM thickness and inflammation in mice. Altogether, these findings highlight STING as a key mediator of peritoneal damage and suggest it may be a novel therapeutic target for preventing PD-associated peritoneal deterioration.

Chronic kidney disease (CKD) incidence is growing worldwide, with a significant percentage of CKD patients reaching end-stage renal disease (ESRD) and requiring kidney replacement therapies (KRT). Peritoneal dialysis (PD) is a convenient KRT presenting benefices as home therapy. In PD patients, the peritoneum is chronically exposed to PD fluids containing supraphysiologic concentrations of glucose or other osmotic agents, leading to the activation of cellular and molecular processes of damage, including inflammation and fibrosis. Importantly, peritonitis episodes enhance peritoneum inflammation status and accelerate peritoneal injury. Here, we review the role of immune cells in the damage of the peritoneal membrane (PM) by repeated exposure to PD fluids during KRT as well as by bacterial or viral infections. We also discuss the anti-inflammatory properties of current clinical treatments of CKD patients in KRT and their potential effect on preserving PM integrity. Finally, given the current importance of coronavirus disease 2019 (COVID-19) disease, we also analyze here the implications of this disease in CKD and KRT.

Background: Peritoneal dialysis (PD) is a renal replacement technique that requires repeated exposure of the peritoneum to hyperosmolar PD fluids (PDFs). Unfortunately, it promotes alterations of the peritoneal membrane (PM) that affects its functionality, including mesothelial-mesenchymal transition (MMT) of mesothelial cells (MCs), inflammation, angiogenesis, and fibrosis. Glucose is the most used osmotic agent, but it is known to be at least partially responsible, together with its degradation products (GDP), for those changes. Therefore, there is a need for more biocompatible osmotic agents to better maintain the PM. Herein we evaluated the biocompatibility of Steviol glycosides (SG)-based fluids.Methods: The ultrafiltration and transport capacities of SG-containing and glucose-based fluids were analyzed using artificial membranes and an in vivo mouse model, respectively. To investigate the biocompatibility of the fluids, Met-5A and human omental peritoneal MCs (HOMCs) were exposed in vitro to different types of glucose-based PDFs (conventional 4.25% glucose solution with high-GDP level and biocompatible 2.3% glucose solution with low-GDP level), SG-based fluids or treated with TGF-β1. Mice submitted to surgery of intraperitoneal catheter insertion were treated for 40 days with SG- or glucose-based fluids. Peritoneal tissues were collected to determine thickness, MMT, angiogenesis, as well as peritoneal washings to analyze inflammation.Results: Dialysis membrane experiments demonstrated that SG-based fluids at 1.5%, 1%, and 0.75% had a similar trend in weight gain, based on curve slope, as glucose-based fluids. Analyzing transport capacity in vivo, 1% and 0.75% SG-based fluid-exposed nephrectomized mice extracted a similar amount of urea as the glucose 2.3% group. In vitro, PDF with high-glucose (4.25%) and high-GDP content induced mesenchymal markers and angiogenic factors (Snail1, Fibronectin, VEGF-A, FGF-2) and downregulates the epithelial marker E-Cadherin. In contrast, exposition to low-glucose-based fluids with low-GDP content or SG-based fluids showed higher viability and had less MMT. In vivo, SG-based fluids preserved MC monolayer, induced less PM thickness, angiogenesis, leukocyte infiltration, inflammatory cytokines release, and MMT compared with glucose-based fluids.Conclusion: SG showed better biocompatibility as an osmotic agent than glucose in vitro and in vivo, therefore, it could alternatively substitute glucose in PDF.

Background: The blockade of the progression or onset of pathological events is essential for the homeostasis of an organism. Some common pathological mechanisms involving a wide range of diseases are the uncontrolled inflammatory reactions that promote fibrosis, oxidative reactions, and other alterations. Natural plant compounds (NPCs) are bioactive elements obtained from natural sources that can regulate physiological processes. Inflammation is recognized as an important factor in the development and evolution of chronic renal damage. Consequently, any compound able to modulate inflammation or inflammation-related processes can be thought of as a renal protective agent and/or a potential treatment tool for controlling renal damage. The objective of this research was to review the beneficial effects of bioactive natural compounds on kidney damage to reveal their efficacy as demonstrated in clinical studies. Methods: This systematic review is based on relevant studies focused on the impact of NPCs with therapeutic potential for kidney disease treatment in humans. Results: Clinical studies have evaluated NPCs as a different way to treat or prevent renal damage and appear to show some benefits in improving OS, inflammation, and antioxidant capacity, therefore making them promising therapeutic tools to reduce or prevent the onset and progression of KD pathogenesis. Conclusions: This review shows the promising clinical properties of NPC in KD therapy. However, more robust clinical trials are needed to establish their safety and therapeutic effects in the area of renal damage.

Lithium added to peritoneal dialysis fluid protects mesothelial cells and attenuates peritoneal fibrosis and angiogenesis by reducing αB-crystallin.

Understanding and targeting the molecular basis of peritoneal solute and protein transport is essential to improve peritoneal dialysis (PD) efficacy and patient outcome. Supplementation of PD fluids (PDF) with alanyl-glutamine (AlaGln) increased small solute transport and reduced peritoneal protein loss in a recent clinical trial. Transepithelial resistance and 10 kDa and 70 kDa dextran transport were measured in primary human endothelial cells (HUVEC) exposed to conventional acidic, glucose degradation products (GDP) containing PDF (CPDF) and to low GDP containing PDF (LPDF) with and without AlaGln. Zonula occludens-1 (ZO-1) and claudin-5 were quantified by Western blot and immunofluorescence and in mice exposed to saline and CPDF for 7 weeks by digital imaging analyses. Spatial clustering of ZO-1 molecules was assessed by single molecule localization microscopy. AlaGln increased transepithelial resistance, and in CPDF exposed HUVEC decreased dextran transport rates and preserved claudin-5 and ZO-1 abundance. Endothelial clustering of membrane bound ZO-1 was higher in CPDF supplemented with AlaGln. In mice, arteriolar endothelial claudin-5 was reduced in CPDF, but restored with AlaGln, while mesothelial claudin-5 abundance was unchanged. AlaGln supplementation seals the peritoneal endothelial barrier, and when supplemented to conventional PD fluid increases claudin-5 and ZO-1 abundance and clustering of ZO-1 in the endothelial cell membrane.

Epithelial-to-mesenchymal transition (EMT) is a self-regulated physiological process required for tissue repair that, in non-controled conditions may lead to fibrosis, angiogenesis, loss of normal organ function or cancer. Although several molecular pathways involved in EMT regulation have been described, this process does not have any specific treatment. This article introduces a systematic review of effective natural plant compounds and their extract that modulates the pathological EMT or its deleterious effects, through acting on different cellular signal transduction pathways both in vivo and in vitro. Thereby, cryptotanshinone, resveratrol, oxymatrine, ligustrazine, osthole, codonolactone, betanin, tannic acid, gentiopicroside, curcumin, genistein, paeoniflorin, gambogic acid and Cinnamomum cassia extracts inhibit EMT acting on transforming growth factor-β (TGF-β)/Smads signaling pathways. Gedunin, carnosol, celastrol, black rice anthocyanins, Duchesnea indica, cordycepin and Celastrus orbiculatus extract downregulate vimectin, fibronectin and N-cadherin. Sulforaphane, luteolin, celastrol, curcumin, arctigenin inhibit β-catenin signaling pathways. Salvianolic acid-A and plumbagin block oxidative stress, while honokiol, gallic acid, piperlongumine, brusatol and paeoniflorin inhibit EMT transcription factors such as SNAIL, TWIST and ZEB. Plectranthoic acid, resveratrol, genistein, baicalin, polyphyllin I, cairicoside E, luteolin, berberine, nimbolide, curcumin, withaferin-A, jatrophone, ginsenoside-Rb1, honokiol, parthenolide, phoyunnanin-E, epicatechin-3-gallate, gigantol, eupatolide, baicalin and baicalein and nitidine chloride inhibit EMT acting on other signaling pathways (SIRT1, p38 MAPK, NFAT1, SMAD, IL-6, STAT3, AQP5, notch 1, PI3K/Akt, Wnt/β-catenin, NF-κB, FAK/AKT, Hh). Despite the huge amount of preclinical data regarding EMT modulation by the natural compounds of plant, clinical translation is poor. Additionally, this review highlights some relevant examples of clinical trials using natural plant compounds to modulate EMT and its deleterious effects. Overall, this opens up new therapeutic alternatives in cancer, inflammatory and fibrosing diseases through the control of EMT process.