Cathepsins, a family of lysosomal proteases, play critical roles in maintaining cellular homeostasis through protein degradation and modulation of immune responses. In the central nervous system (CNS), their functions extend beyond classical proteolysis, influencing neuroinflammation, synaptic remodeling, and neurodegeneration. Emerging evidence underscores the crucial role of microglial cathepsins in the pathophysiology of several neurological disorders. This review synthesizes current knowledge on the involvement of cathepsins in a spectrum of CNS diseases, including Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, epilepsy, Huntington’s disease, and ischemic stroke. We highlight how specific cathepsins contribute to disease progression by modulating key pathological processes such as α-synuclein and amyloid-β clearance, tau degradation, lysosomal dysfunction, neuroinflammation, and demyelination. Notably, several cathepsins demonstrate both neuroprotective and pathogenic roles depending on disease context and expression levels. Additionally, the balance between cathepsins and their endogenous inhibitors, such as cystatins, emerges as a critical factor in CNS pathology. While cathepsins represent promising biomarkers and therapeutic targets, significant gaps remain in our understanding of their mechanistic roles across diseases. Future studies focusing on their regulation, substrate specificity, and interplay with genetic and epigenetic factors may yield novel strategies for early diagnosis and disease-modifying treatments in neurology.

Background: Chronic antibody-mediated rejection (cAMR) constitutes a serious challenge in the long-term success of organ transplantation. It is associated with donor-specific antibodies (DSAs) which activate a complement pathway in response to the presence of human leukocyte antigens (HLAs) on the graft, which results in chronic inflammation and leads to graft dysfunction. One of the recent promising methods of cAMR treatment is a recombinant humanized anti-interleukin-6 receptor (IL-6R) monoclonal antibody referred to as Tocilizumab (TCZ). The aim of the presented systematic review is to explore the existing knowledge regarding the effect of tocilizumab treatment on cAMR and to perform a meta-analysis of the available data. Methods: A systematic review was performed using the PRISMA 2020 Checklist and Flow diagram. A systematic review protocol was registered in PROSPERO: CRD42024510996. The bias assessment was obtained with Methodical Index for Non-Randomized Studies (MINORS), whereas meta-analysis was performed using MedCalc. Results: Five clinical trials with a total number of 105 patients were included in our review. The mean loss of eGFR in time was −0.141 mL/min/1.73 m² (95% CI: −0.409 to 0.126; p = 0.298) and was found to be statistically insignificant. The heterogeneity was low and was equal to I² = 0.00%. The authors demonstrated a reduction in DSA titer by TCZ (−0.266 MFI (95% CI: −0.861 to 0.329; p = 0.377)). In the majority of studies, eGFR stabilization was associated with a reduction in DSAs. Conclusions: TCZ pharmacotherapy insignificantly reduced DSA titer and eGFR. Despite promising outcomes of potential eGFR stabilization, there is a need for large randomized controlled trials comparing standard management of cAMR and tocilizumab treatment.

Background: C3 glomerulopathies (C3G), including dense deposit disease (DDD) and C3 glomerulonephritis (C3GN), are rare kidney disorders driven by dysregulation of the alternative complement pathway. Eculizumab, a terminal complement inhibitor targeting C5, has emerged as a potential therapeutic option in these conditions. This systematic review evaluated the efficacy and safety of eculizumab in patients with C3G or DDD. Methods: Literature searches in PubMed and Cochrane databases identified case reports and case series reporting eculizumab use. Results: Only eight studies involving ten patients met the inclusion criteria. Eculizumab stabilized renal function and reduced proteinuria in most cases, especially when C5b-9 deposition was present. Histopathological improvements were variable, and recurrence after discontinuation occurred in some patients. Responses were limited in cases with alternative mechanisms of C5 activation. Conclusions: Eculizumab offers clinical benefit in select C3G and DDD patients but does not address the underlying cause of complement dysregulation. The need for long-term therapy, incomplete histologic resolution, and risk of relapse underscore the necessity of larger trials and the development of personalized treatment strategies.

Migraine is a complex neurovascular disorder with a multifactorial pathophysiology involving genetic, metabolic, and environmental factors. Increasing evidence indicates that oxidative stress plays a key role in the development of migraine; however, it is unclear whether oxidative imbalance acts primarily as a causal factor or occurs as a consequence of migraine-related processes. Oxidative stress, defined as an imbalance between reactive oxygen species production and antioxidant defense mechanisms, contributes to neuronal hyperexcitability, mitochondrial dysfunction, and neuroinflammation—key mechanisms underlying migraine pathogenesis. Studies have shown elevated markers of oxidative damage and altered antioxidant enzyme activity in migraine patients. Simultaneously, metabolic and inflammatory changes associated with migraine may further exacerbate oxidative imbalance, suggesting a bidirectional relationship. Furthermore, genetic factors such as SOD2, GPX1, and CAT significantly influence susceptibility to oxidative stress and migraine. The CALCA gene, encoding CGRP, links oxidative stress mechanisms with neurogenic inflammation and activation of the trigeminovascular system. This article reviews the current evidence regarding the role of oxidative stress in migraine and discusses its relationship to molecular and genetic mechanisms. Particular attention is given to genes involved in oxidative pathways, mitochondrial function, and inflammatory responses, which may help explain individual susceptibility and variability in clinical presentation.

Hyperparathyroidism is a serious complication of chronic kidney disease (CKD) and can occur in patients not on renal replacement therapy, during dialysis therapy, or after kidney transplantation. The disease leads to an increased risk of cardiovascular events, bone loss, and fractures. Cinacalcet is a widely used drug, but its effectiveness in treating hyperparathyroidism in selected stages of chronic kidney disease remains unclear. This critical review aims to integrate findings from meta-analyses and clinical trials to assess optimal therapeutic strategies in patients suffering from CKD, who are non-dialysis-dependent, dialysis-dependent, and after kidney transplantation. The authors reviewed eligible studies, including meta-analyses, randomized controlled trials, and observational studies assessing biochemical outcomes, cardiovascular, bone, and survival outcomes with cinacalcet. Cinacalcet effectively reduced serum parathyroid hormone (PTH), calcium, and phosphorus across all CKD stages, particularly in hemodialysis patients. Combination therapy with vitamin D analogs enhanced biochemical control without increasing adverse events, although mild, transient hypocalcemia and gastrointestinal symptoms were common. In kidney transplant recipients, parathyroidectomy achieved greater normalization of PTH and calcium. Cinacalcet has been shown to reduce mortality in patients on hemodialysis and peritoneal dialysis.