Background and Objectives: The worldwide prevalence of chronic kidney disease (CKD) continues to increase, representing a major concern for public health systems. CKD is associated with gut microbiota dysbiosis, which may exacerbate disease progression by increasing the levels of uremic toxins, systemic inflammation, and oxidative stress. Modulation of the gut microbiota through biotic supplementation has been proposed as a potential therapeutic strategy to slow CKD progression and mitigate its complications. This study aimed to evaluate the effect of 10-month synbiotic supplementation on estimated glomerular filtration rate (eGFR), circulating concentrations of indoxyl sulfate (IS), p-cresyl sulfate (p-CS), interleukin-6 (IL-6), and malondialdehyde (MDA) in patients with stage IV–V CKD not receiving dialysis, in comparison to placebo. Materials and Methods: Fifty non-dialysis CKD IV–V patients were assigned (n = 25 each) via matched, non-randomized allocation (age, sex, and primary disease) to synbiotic or placebo. This single-blind, placebo-controlled trial blinded participants and laboratory personnel. The synbiotic group received daily capsules containing Lactobacillus acidophilus La-14 (2 × 10¹¹ CFU/g) + fructooligosaccharides; controls received identical placebo. Adherence was monitored monthly (pill counts, diaries), with < 80% over two visits resulting in withdrawal. The eGFR, IS, p-CS, IL-6, and MDA were measured at baseline and month 10. Results: Forty-two patients (21/arm) completed the study; eight withdrew (4 per arm). At 10 months, the change in eGFR was −1.2 ± 2.5 mL/min/1.73 m² (synbiotic) vs. −3.5 ± 3.0 mL/min/1.73 m² (placebo); between-group difference in change was 2.3 mL/min/1.73 m² (95% CI: 0.5–4.1; p = 0.014; adjusted p = 0.07). IS decreased by −15.4 ± 8.2 ng/L vs. −3.1 ± 6.5 ng/L; between-group difference in change was −12.3 ng/L (95% CI: −17.8 to −6.8; p < 0.001; adjusted p = 0.005). No significant differences were observed for p-CS, IL-6, or MDA after correction. Conclusions: Synbiotic supplementation over a 10-month period resulted in a trend toward decreased serum IS levels in patients with advanced CKD, suggesting potential benefits of microbiota-targeted therapies. However, no significant effects were observed on renal function, inflammatory, or oxidative stress markers. Further large-scale studies are warranted to confirm these findings and explore the long-term impact of synbiotics in CKD management.

Membranous nephropathy (MN) is a disease with an etiology and pathogenesis that are still not fully understood, and it represents a great challenge. It is characterized by a variable course, spontaneous remissions and relapses. The inability to rely entirely on antibodies and the continuous threat of a malignant disease make the differentiation of MN types extremely difficult. Data of twelve patients with membranous nephropathy, ranging in age between 28 and 67 years, are presented; in total, seven men and five women were observed for a period of 2 to 10 years. In all patients, the diagnosis was confirmed through kidney biopsy and laboratory tests, including immunological, histopathological, and immunohistochemical tests. Histopathological and immunohistochemical tests were applied on available material from the thyroid gland in two patients and the gallbladder in two patients with MN. Data of 102 patients with MN and their comorbidities are evaluated in order to establish correlations. These and other data are used to build a hypothetical pathogenetic model that explains the etiology and the likely pattern of disease occurrence. We found a connection between chronic cholecystitis, thyroiditis, hepatitis, and other diseases in the occurrence of MN and disease course. From our practice and cases, we drew the conclusion that chronic inflammation in sites that express PLA2R leads to the formation of antibodies against PLA2R. These antibodies occur as a preformed immune complex or separately and are deposited in the subepithelial space, leading to MN appearance.

The differentiation between primary and secondary forms of membranous nephropathy (MN) is a cornerstone that is necessary for adequate decision making regarding the treatment options and behavior of each specific case. Kidney biopsy and antibody results can be controversial, and a unique biomarker has still not been found. Background and Objectives: We investigated the lack of mannose-binding lectin (MBL) deposition in patients with secondary MNs (sMNs) with the presence of IgG4 deposition in relation to the presence of MBL deposition in patients with primary MNs (pMNs). We also established a connection between the stage of MN and MBL deposition. Materials and Methods: Materials from 72 renal biopsies with proven MN were used for immunohistochemistry staining (IHC) for the phospholipase A2 receptor (PLA2R), immunoglobulin subtype IgG4, and MBL. Patients were separated into one of the following three groups: primary MN (pMN), idiopathic MN (iMN), and secondary MN (sMN). Serum antibodies for PLA2R and thrombospondin type-I-domain-containing 7A (THSD7A) were also used for the precise evaluation of the type of MN, as well as for detecting positivity for PLA2R using IHC. Which stage of MN was present in relation to the deposition of MBL was evaluated. Results: In total, 50 patients were positive for IgG4, 34 with pMN, 12 with iMN, and 4 with sMN. A total of 20 patients were positive for MBL, 14 with pMN and 6 with iMN; no MBL deposits were found in patients with sMN. MBL positivity was predominantly present in the first two stages of MN, with a gradual reduction in the later stages. Conclusions: The activation of the lectin–complement pathway occurs in the early stages of the disease and is associated with the deposition of IgG4; IgG4 deposition is present in sMN, but there is no MBL deposition. IgG4 cannot be used for the differentiation of primary from secondary MNs, but the lack of MBL can be used as a marker for sMN in the early stages of the disease.

Introduction: Membranous nephropathy (MN) is a glomerulonephritis with growing incidence and its pathogenesis still remains unclear, despite discoveries of many new antigens. The understanding of MN pathogenesis has moved from antigen-antibody arena to the complement activation through the lectin pathway. Aim: Confirm the role of lectin complement pathway in the pathogenesis of the disease and reveal the special role of diabetes mellitus (DM) in idiopathic MN (iMN). Materials and methods: Materials from 72 renal biopsies with proven MN are used for immunohistochemistry staining (IHC) for phospholipase A2 receptor (PLA2R), immunoglobulin subtype IgG4 and mannose-binding lectin (MBL). Patients are separated in three groups: primary MN (pMN), iMN and secondary MN (sMN). Relationship between the type of MN and IHC deposition is studied. Patients with diabetes mellitus are presented separately. Patients are divided according to IHC results into triple positive/+/, double positive/+/, positive /+/ and triple negative/-/. Results: Triple /+/ for PLA2R/ IgG4/ MBL, double /+/ for PLA2R/IgG4 and /+/ for PLA2R expression are found only in patients with pMN. Double /+/ cases for IgG4/MBL are found predominantly in patients with iMN. No cases of double /+/ for PLA2R/MBL are found. Patients with DM represent 50% of patients with iMN, and 50% of them are double /+/ for IgG4/MBL. Conclusions: Activation of the lectin complement pathway is essential in MN. The deposition of MBL is always associated with deposition of IgG4 in pMN and iMN. IgG4 in sMN is not associated with MBL deposition. Possible “switch” from diabetic nephropathy (DN) to MN can be discussed since diabetes is associated with abnormal protein glycosylation and increased activation of lectin pathway.

Rhabdomyolysis is one of the leading causes of acute kidney injury (AKI) and is infrequently associated with chronic kidney disease (CKD). CKD appears in diabetes mellitus and arterial hypertension, as a result of other systemic diseases and glomerulonephritis. In this study, we present two cases (one with CKD and one with AKI) that are caused by a genetic defect. A genetic examination was performed in both patients, proving that the patient with CKD has a genetic defect in the RYR1 gene, which is observed in patients with malignant hyperthermia. Meanwhile, the patient with AKI has a homozygous pathogenic variant in SLC2A9, which is associated with urinary urate wasting and is characterized by asymptomatic hypouricemia and AKI after exercise. The first case is chronic rhabdomyolysis, as the patient is an athlete and performs heavy daily exercise. The second case is AKI without prior kidney damage or symptoms. Both patients did not undergo a kidney biopsy. In the first case, changes in daily routine without extreme physical exercise led to the recovery of normal kidney function. The second patient recovered from AKI without sequelae. These two cases are an example of “thinking outside the box” with respect to how genetic diseases and defects can cause kidney damage, both chronic and acute.

Membranous nephropathy is a disease that has been well documented, yet its etiopathogenesis has not been fully clarified and the distinction between its primary and secondary forms has not been completely categorized. The discovery of new antigens and antibodies reveals different percentages of positivity in secondary membranous nephropathy, which is a cause of great confusion and ambiguity not only in diagnosis but also in the choice of a therapeutic approach. The aim of this review is to summarize the literature on newly discovered antigens and antibodies, and to propose a pathogenetic model based on the role of the complement system and its activation pathways. In this model, antigens are categorized based on the type of immunoglobulin deposits and the putative complement pathways that they activate, which can help to differentiate primary from secondary membranous nephropathy. The model also reflects how the deposition of foreign antigens in the basement membrane can activate both the lectin and classical complement pathways, which may explain why positive antibodies are observed in both primary and secondary forms of membranous nephropathy.