Sarcopenia, the progressive loss of muscle mass and strength, is a common complication in patients with chronic kidney disease (CKD). This condition arises from a combination of factors including reduced physical activity, insufficient protein intake, hyperphosphatemia, chronic inflammation, and uremia itself; however, the underlying molecular mechanisms remain poorly understood. Proteolysis in skeletal muscle is primarily controlled by the ubiquitin–proteasome system, autophagy–lysosome system, and calpains (CAPNs) cysteine proteases, which degrade structural proteins and mediate cell signaling. This study aims to investigate the role of CAPNs in CKD-associated muscle deterioration. CKD was induced in mice through an adenine-rich diet for 2, 4 and 6 weeks. The involvement of CAPNs in CKD-related sarcopenia was assessed using mice that overexpressed the CAPNs endogenous inhibitor, calpastatin (CAST). Gastrocnemius muscle strength, structural integrity, and function were evaluated. Mice with CKD showed elevated CAPNs, particularly CAPN2, expression and activity in the gastrocnemius, in parallel with significant muscle deterioration, including strength loss, structural damage, and impaired muscle performance. Overexpression of CAST prevented muscle strength loss, improved muscle function and structure without affecting renal function, and reversed fibrosis, inflammation and adipogenesis expression markers. Targeting CAPN2 could be a promising therapeutic strategy to mitigate muscle damage and improve physical performance in CKD patients.

Drugs providing antihypertensive and protective cardiovascular actions are of clinical interest in controlling cardiovascular events and slowing the progression of kidney disease. We studied the effect of a hybrid compound, GGN1231 (derived from losartan in which a powerful antioxidant was attached), on the prevention of cardiovascular damage, cardiac hypertrophy, and fibrosis in a rat model of severe chronic renal failure (CRF). CRF by a 7/8 nephrectomy was carried out in male Wistar rats fed with a diet rich in phosphorous (0.9%) and normal calcium (0.6%) for a period of 12 weeks until sacrifice. In week 8, rats were randomized in five groups receiving different drugs including dihydrocaffeic acid as antioxidant (Aox), losartan (Los), dihydrocaffeic acid+losartan (Aox+Los) and GGN1231 as follows: Group 1 (CRF+vehicle group), Group 2 (CRF+Aox group), Group 3 (CRF+Los group), Group 4 (CRF+Aox+Los group), and Group 5 (CRF+GGN1231 group). Group 5, the CRF+GGN1231 group, displayed reduced proteinuria, aortic TNF-α, blood pressure, LV wall thickness, diameter of the cardiomyocytes, ATR1, cardiac TNF-α and fibrosis, cardiac collagen I, and TGF-β1 expression. A non-significant 20% reduction in the mortality was also observed. This study showed the possible advantages of GGN1231, which could help in the management of cardiovascular and inflammatory processes. Further research is needed to confirm and even expand the positive aspects of this compound.

Cardiovascular diseases are a major cause of morbidity and mortality in chronic kidney disease (CKD) patients. Integrin-linked kinase (ILK) regulates integrin–extracellular matrix interactions and vascular integrity. This study investigated the role of ILK in CKD-associated vascular alterations. An adenine-supplemented diet induced a progressive CKD in wild-type (WT) and conditional ILK knock-down (cKD-ILK) mice. Aortic tissue was collected for histology and RT-qPCR analysis. Moreover, aortas were incubated ex vivo with the uremic toxins p-cresyl sulfate and indoxyl sulfate. In vitro, human aortic vascular smooth muscle cells were exposed to uremic toxins, and the effect of siRNA-mediated ILK silencing was tested. Aortas of adenine-fed WT mice showed a progressive increase in ILK expression, morphological alterations, and increased fibrosis, which was not observed in cKD-ILK aortas, compared to control mice. Statistically significant correlations between vascular content of ILK and fibrosis markers were observed. Ex vivo, uremic toxins increased ILK and fibrosis protein expression in WT aortas but not in cKD-ILK. In vitro, uremic toxins increased ILK activity and fibrosis markers, like collagen, while ILK-deleted cells prevented collagen increase. ILK depletion prevents CKD-associated vascular fibrosis, suggesting ILK as a potential therapeutic target to prevent arterial alterations in renal patients.