Urinary type IV collagen excretion is involved in the decline in estimated glomerular filtration rate in the Japanese general population without diabetes: A 5-year observational study

Urinary Markers of Tubular Injury and Renal Fibrosis in Patients with Type 2 Diabetes and Different Phenotypes of Chronic Kidney Disease

This study assessed the urinary excretion of markers and mediators of tubular injury and renal fibrosis in patients with type 2 diabetes (T2D) and non-albuminuric and albuminuric patterns of chronic kidney disease (CKD). One hundred and forty patients with long-term T2D and different patterns of CKD and twenty non-diabetic individuals were included. Urinary retinol-binding protein 4 (RBP-4), glutathione-S-transferase α₁ and π (GST-α₁ and GST-π), transforming growth factor β (TGF-β), type I and type IV collagen (Col1 and Col4), bone morphogenic protein 7 (BMP-7), and hepatocyte growth factor (HGF) were assessed by ELISA. Patients with T2D demonstrated increased urinary excretion of RBP-4, GST-π, Col4, BMP-7, and HGF (all p < 0.05 vs. control). The excretion of RBP-4, GST-π, Col1, and Col4 was increased in patients with elevated albumin-to-creatinine ratio (UACR; all p < 0.05 vs. control), while BMP-7 and HGF were increased innormoalbuminuric patients also (p < 0.05). Urinary RBP-4, GST-α₁, Col1, Col4, and HGF correlated positively with UACR; meanwhile, no correlations with glomerular filtration rate were found. The results demonstrate that elevated urinary excretions of the markers of tubular injury (RBP-4, GST-π) and renal fibrosis (Col1, Col4), as well as HGF, an antifibrotic regulator, are associated with the albuminuric pattern of CKD in subjects with T2D.

Tubular and glomerular biomarkers of renal tissue function in the urine of fetuses with posterior urethral valves

INTRODUCTION

Posterior urethral valve (PUV) is a congenital malformation characterized by a membranous structure located in the prostatic portion of the male posterior urethra that obstructs the urinary flow. Efforts have been made to determine the degree of impairment of fetal kidney function in this condition.

OBJECTIVE

This study aimed to measure the levels of urinary biomarkers of glomerular and tubular functions in fetuses with PUV and to compare with the levels of the same molecules in healthy male premature newborns.

STUDY DESIGN

Urine samples from 43 fetuses with PUVs were collected and compared with urine samples from 40 healthy male newborns of the same gestational age (controls). Tubular and glomerular biomarkers levels were measured in urine samples by MILLIPLEX® assay kits. Levels of the molecules were related to creatinine (Cr) measurements at same urine samples and expressed as pg/mg Cr. Results were analysed with Graphpad Prism version 7.0 and SPSS version 20.0.

RESULTS

Fetuses with PUV showed a significant reduction in urine levels of Epidermal Growth Factor (EGF), Calbindin, Osteoactivin, Molecule Renal Injury 1 (KIM-1 and Factor of trefoil 3 (TFF-3) when compared to controls. On the other hand, urine levels of cystatin C and renin were higher in PUV fetuses. The levels of molecules also differed according to urine osmolality and grade of hydronephrosis.

DISCUSSION

Some urinary excreted molecules may indicate kidney damage in several segments along the nephron, while others may exert important functions. Mechanical and immunological mechanisms related to PUV might significantly modulate the synthesis of cytokines related to glomerular and tubular physiology, leading to alterations in urinary concentrations of those molecules. These biomarkers can be used as future diagnostic and prognostic markers in clinical practice.

CONCLUSION

Early kidney structural and functional impairment influenced the synthesis of glomerular and tubular molecules related to kidney physiological processes in fetuses with PUV.

Diabetic Nephropathy - possibilities of early laboratory diagnostics and course prediction (review of literature)

The medical and social significance of diabetes mellitus is determined by a progressive increase in the incidence of the disease, as well as the development of disabling and reducing the quality of life of macro- and microvascular complications in patients of working age, in particular, with the development of diabetic nephropathy (DN), which develops in one third of patients with type 1 and 2 diabetes. DN is the third leading cause of death after diseases of the cardiovascular system and oncological pathologies. In this regard, the identification of DN at the early stages is an important task both from the standpoint of prevention and a more favorable prognosis of the course of diabetes. This review presents data on the possibilities of early diagnosis of DN using blood and urine biomarkers, as well as information on their diagnostic and prognostic value. The analysis of the interpretation of the indicator of microalbuminuria in type 1 and 2 diabetes was carried out. In addition, the literature data of recent years on the informative value of determining markers of podocyte damage, on the role of oxidative stress products, immune-inflammatory factors, and vascular endothelial growth factor in the process of the onset and development of DN are presented. The possibility of their practical use for the diagnosis of DN in clinical practice is discussed. The literature search for this review was carried out using the databases of the RSCI, CyberLeninka, Scopus, Web of Science, MedLine, PubMed for the period from 2011 to 2021. using the following keywords: diabetes mellitus, diabetic nephropathy, markers of diabetic nephropathy; kidney damage, early diagnosis of diabetic nephropathy.

Extracellular Matrix in Kidney Fibrosis: More Than Just a Scaffold

Kidney fibrosis is the common histological end-point of progressive, chronic kidney diseases (CKDs) regardless of the underlying etiology. The hallmark of renal fibrosis, similar to all other organs, is pathological deposition of extracellular matrix (ECM). Renal ECM is a complex network of collagens, elastin, and several glycoproteins and proteoglycans forming basal membranes and interstitial space. Several ECM functions beyond providing a scaffold and organ stability are being increasingly recognized, for example, in inflammation. ECM composition is determined by the function of each of the histological compartments of the kidney, that is, glomeruli, tubulo-interstitium, and vessels. Renal ECM is a dynamic structure undergoing remodeling, particularly during fibrosis. From a clinical perspective, ECM proteins are directly involved in several rare renal diseases and indirectly in CKD progression during renal fibrosis. ECM proteins could serve as specific non-invasive biomarkers of fibrosis and scaffolds in regenerative medicine. The gold standard and currently only specific means to measure renal fibrosis is renal biopsy, but new diagnostic approaches are appearing. Here, we discuss the localization, function, and remodeling of major renal ECM components in healthy and diseased, fibrotic kidneys and the potential use of ECM in diagnostics of renal fibrosis and in tissue engineering.

Correction: Urinary type IV collagen excretion is involved in the decline in estimated glomerular filtration rate in the Japanese general population without diabetes: A 5-year observational study

[This corrects the article DOI: 10.1371/journal.pone.0195523.].