Proteinuria is a well-established biomarker of chronic kidney disease (CKD) and a risk predictor of associated disease outcomes. Proteinuria is also a driver of CKD progression toward end-stage kidney disease. Toxic effects of filtered proteins on proximal tubular epithelial cells enhance tubular atrophy and interstitial fibrosis. The extent of protein toxicity and the underlying molecular mechanisms responsible for tubular injury during proteinuria remain unclear. Nevertheless, albumin elicits its toxic effects when degraded and reabsorbed by proximal tubular epithelial cells. Overall, healthy kidneys excrete over 1000 individual proteins, which may be potentially harmful to proximal tubular epithelial cells when filtered and/or reabsorbed in excess. Proteinuria can cause kidney damage, inflammation and fibrosis by increasing reactive oxygen species, autophagy dysfunction, lysosomal membrane permeabilization, endoplasmic reticulum stress and complement activation. Here we summarize toxic proteins reported in proteinuria and the current understanding of molecular mechanisms of toxicity of proteins on proximal tubular epithelial cells leading to CKD progression.

Proteinuria poses a substantial risk for the progression of chronic kidney disease (CKD) and its related complications. Kidneys excrete hundreds of individual proteins, some with a potential impact on CKD progression or as a marker of the disease. However, the available data on specific urinary proteins and their relationship with CKD severity remain limited. Therefore, we aimed to investigate the urinary proteome and its association with kidney function in CKD patients and healthy controls. The proteomic analysis of urine samples showed CKD stage-specific differences in the number of detected proteins and the exponentially modified protein abundance index for total protein (p = 0.007). Notably, specific urinary proteins such as B2MG, FETUA, VTDB, and AMBP exhibited robust negative associations with kidney function in CKD patients compared to controls. Also, A1AG2, CD44, CD59, CERU, KNG1, LV39, OSTP, RNAS1, SH3L3, and UROM proteins showed positive associations with kidney function in the entire cohort, while LV39, A1BG, and CERU consistently displayed positive associations in patients compared to controls. This study suggests that specific urinary proteins, which were found to be negatively or positively associated with the kidney function of CKD patients, can serve as markers of dysfunctional or functional kidneys, respectively.

Proteinuria is a risk factor for chronic kidney disease (CKD) progression and associated complications. However, there is insufficient information on individual protein components in urine and the severity of CKD. We aimed to investigate urinary proteomics and its association with proteinuria and kidney function in early-stage CKD and in healthy individuals. A 24 h urine sample of 42 individuals (21-CKD and 21-healthy individuals) was used for mass spectrometry-based proteomics analysis. An exponentially modified protein abundance index (emPAI) was calculated for each protein. Data were analyzed by Mascot software using the SwissProt database and bioinformatics tools. Overall, 298 unique proteins were identified in the cohort; of them, 250 proteins belong to the control group with median (IQR) emPAI 39.1 (19–53) and 142 proteins belong to the CKD group with median (IQR) emPAI 67.8 (49–117). The level of 24 h proteinuria positively correlated with emPAI (r = 0.390, p = 0.011). The emPAI of some urinary proteomics had close positive (ALBU, ZA2G, IGKC) and negative (OSTP, CD59, UROM, KNG1, RNAS1, CD44, AMBP) correlations (r < 0.419, p < 0.001) with 24 h proteinuria levels. Additionally, a few proteins (VTDB, AACT, A1AG2, VTNC, and CD44) significantly correlated with kidney function. In this proteomics study, several urinary proteins correlated with proteinuria and kidney function. Pathway analysis identified subpathways potentially related to early proteinuric CKD, allowing the design of prospective studies that explore their response to therapy and their relationship to long-term outcomes.

Background: Vaccine-preventable diseases such as pertussis, measles, and influenza remain among the most significant medical and socioeconomic issues in Kazakhstan, despite significant vaccination achievements. Thus, here we aimed to analyze the long-term dynamics and provide information on the current epidemiology of pertussis, measles, and influenza in Kazakhstan. Methods: A retrospective analysis of the long-term dynamics of infectious diseases was carried out using the data from the statistical collections for 2010-2020 and the Unified Payment System from 2014 to 2020. Results: During the 2010-2020 years, the long-term dynamics show an unequal distribution of pertussis, measles, and influenza-related morbidity. In comparison with earlier years, registration of infectious disease was the highest in 2019 and 2020. The incidence cases among registered infectious diseases in 2019 were: pertussis-147, measles-13,326, and in 2020: influenza-2,678. High incidence rates have been documented in Pavlodar, North Kazakhstan, Mangystau regions, and the cities of Shymkent and Nur-Sultan. The incidence varies depending on the seasonality: pertussis (summer-autumn), measles (winter-spring), and influenza (mostly in winter). Conclusion: The findings highlight the importance of focusing more on the characteristics of the epidemic process of vaccine-preventable diseases in order to assess the effectiveness of implemented measures and verify new routes in strengthening the epidemiological surveillance system.

Chronic kidney disease is a global public health concern, representing a critical global public health challenge with increasing morbidity and mortality rates. The disease is a long-term condition characterized by the progressive loss of renal function. Early detection of declining kidney health and timely intervention are crucial to slow disease progression and improve prognosis, mitigating complications, including cardiovascular events. Current diagnostic standards are unable to detect early stages of kidney disease, reflecting early signs of glomerular and tubular damage. This creates an urgent need to identify reliable biomarkers for early detection, prognosis and therapeutic monitoring of kidney diseases. Novel biomarkers, including urinary microRNA, exosomal components, proteomic signatures and integrated multi-omics profiles, facilitated by up-to-date technologies offer strong promise for enhancing early diagnosis, risk assessment and monitoring of the disease. We focus on the fundamental biological significance and clinical application of these markers, discussing a critical evaluation of novel methodologies and clinical evidence supporting their potential for earlier and more precise diagnosis. This review summarizes innovative urinary biomarkers and advanced analytical technologies that can provide a more comprehensive and accurate assessment of the kidney status towards early diagnosis, better prognosis and better quality of life for patients with chronic kidney disease.