Urinary Biomarkers of Mycotoxin Induced Nephrotoxicity-Current Status and Expected Future Trends.

The intensifying world-wide spread of mycotoxigenic fungal species has increased the possibility of mycotoxin contamination in animal feed and the human food chain. Growing evidence shows the deleterious toxicological effects of mycotoxins from infants to adults, while large population-based screening programs are often missing to identify affected individuals. The kidney functions as the major excretory system, which makes it particularly vulnerable to nephrotoxic injury.

Evaluation of Urinary Biomarkers of Proximal Tubular Injury, Inflammation, and Fibrosis in Patients With Albuminuric and Nonalbuminuric Diabetic Kidney Disease.

Introduction: Albuminuric and nonalbuminuric pathways contribute to diabetic kidney disease. Proximal tubule and inflammation play important roles in these processes. Urinary biomarker(s) to detect early kidney damage and predict progression are needed.

Time-resolved fluorescence immunoassay for urine retinol-binding protein is more sensitive than polyclonal and monoclonal assays.

Background: Retinol-binding protein4 (RBP) assays using polyclonal antibodies (pRBP) have major problems of non-linearity of dilution and a very small useable dynamic range. Our objective was to develop a specific assay with a wider dynamic range to detect tubular proteinuria.

Methods: mRBP (monoclonal capture and second antibody with colorimetric detection) and fluoroimmunoassays for RBP (fRBP) (polyclonal capture and monoclonal second antibody with fluorescence detection) were developed and compared with pRBP.

High glucose-induced Smad3 linker phosphorylation and CCN2 expression are inhibited by dapagliflozin in a diabetic tubule epithelial cell model.

Background: In the kidney glucose is freely filtered by the glomerulus and, mainly, reabsorbed by sodium glucose cotransporter 2 (SGLT2) expressed in the early proximal tubule. Human proximal tubule epithelial cells (PTECs) undergo pathological and fibrotic changes seen in diabetic kidney disease (DKD) in response to elevated glucose. We developed a specific in vitro model of DKD using primary human PTECs with exposure to high D-glucose and TGF-β1 and propose a role for SGLT2 inhibition in regulating fibrosis.

Systematic Review and Meta-analysis of COVID-19 and Kidney Transplant Recipients, the South West London Kidney Transplant Network Experience.

Introduction: There is paucity of literature comparing outcomes of kidney transplant patients with COVID-19 to that of dialysis and waitlisted patients. This report describes our data, provides comparative analysis, together with a meta-analysis of published studies, and describes our protocols to restart the transplant program.

Methods: Data were analyzed on kidney transplant, dialysis, and waitlisted patients tested positive for SARS-CoV-2 (nasopharyngeal swab polymerase chain reaction [PCR] test) between March 1, 2020, and June 30, 2020, together with a meta-analysis of 16 studies.

First presentation of LPIN1 acute rhabdomyolysis in adolescence and adulthood.

LPIN1 mutations are a known common cause of autosomal recessive, recurrent and life-threatening acute rhabdomyolysis of childhood-onset. The first episode of rhabdomyolysis usually happens in nearly all cases before the age of 5 and death is observed in 1/3 of patients. Here we present two cases of acute rhabdomyolysis with a milder phenotype caused by LPIN1 mutation presenting in adolescence (11 years old) and adulthood (40 years old) after Parvovirus infection and metabolic stress, respectively.

COVID-19 infection in kidney transplant recipients.

By 21 March 2020 infections related to the novel coronavirus SARS-CoV-2 had affected people from 177 countries and caused 11,252 reported deaths worldwide. Little is known about risk, presentation and outcomes of SARS-CoV-2 (COVID-19) infection in kidney transplantation recipients, who may be at high-risk due to long-term immunosuppression, comorbidity and residual chronic kidney disease. Whilst COVID-19 is predominantly a respiratory disease, in severe cases it can cause kidney and multi-organ failure.

Pfeifer-Weber-Christian disease and successful treatment with mycophenolate mofetil: a case report.

Inflammatory conditions manifest with a broad spectrum of signs and symptoms. Panniculitis is such a condition affecting the subcutaneous fat and presents as tender erythematous nodules. It is also associated with a systemic response and has been described in the literature as early as in 1892 by Pfeifer and in the 1920s by Weber and Christian.

Metformin attenuates the effect of Staphylococcus aureus on airway tight junctions by increasing PKCζ-mediated phosphorylation of occludin.

Airway epithelial tight junction (TJ) proteins form a resistive barrier to the external environment, however, during respiratory bacterial infection TJs become disrupted compromising barrier function. This promotes glucose flux/accumulation into the lumen which acts as a nutrient source for bacterial growth. Metformin used for the treatment of diabetes increases transepithelial resistance (TEER) and partially prevents the effect of bacteria but the mechanisms of action are unclear.

A novel COL4A1 frameshift mutation in familial kidney disease: the importance of the C-terminal NC1 domain of type IV collagen.

Background: Hereditary microscopic haematuria often segregates with mutations of COL4A3, COL4A4 or COL4A5 but in half of families a gene is not identified. We investigated a Cypriot family with autosomal dominant microscopic haematuria with renal failure and kidney cysts.

Methods: We used genome-wide linkage analysis, whole exome sequencing and cosegregation analyses.

The urinary proteome and metabonome differ from normal in adults with mitochondrial disease.

We studied the extent and nature of renal involvement in a cohort of 117 adult patients with mitochondrial disease, by measuring urinary retinol-binding protein (RBP) and albumin; established markers of tubular and glomerular dysfunction, respectively. Seventy-five patients had the m.3243A>G mutation and the most frequent phenotypes within the entire cohort were 14 with MELAS, 33 with MIDD, and 17 with MERRF.

The Regulation of TGFβ1 Induced Fibronectin EDA Exon Alternative Splicing in Human Renal Proximal Tubule Epithelial Cells.

The EDA+ splice variant of fibronectin (Fn) is an early and important component of the extracellular matrix in renal fibrosis. In this work, we investigate cellular mechanisms of EDA+Fn production in human primary proximal tubule epithelial cells (PTECs). TGFβ1-induced EDA+Fn production was assessed by immunocytochemistry, PCR, and Western blotting.

Erk5 is a mediator to TGFβ1-induced loss of phenotype and function in human podocytes.

Background: Podocytes are highly specialized cells integral to the normal functioning kidney, however, in diabetic nephropathy injury occurs leading to a compromised phenotype and podocyte dysfunction which critically produces podocyte loss with subsequent renal impairment. TGFβ1 holds a major role in the development of diabetic nephropathy. Erk5 is an atypical mitogen-activated protein (MAP) kinase involved in pathways modulating cell survival, proliferation, differentiation, and motility.

Smad mediated regulation of inhibitor of DNA binding 2 and its role in phenotypic maintenance of human renal proximal tubule epithelial cells.

The basic-Helix-Loop-Helix family (bHLH) of transcriptional factors plays a major role in regulating cellular proliferation, differentiation and phenotype maintenance. The downregulation of one of the members of bHLH family protein, inhibitor of DNA binding 2 (Id2) has been shown to induce de-differentiation of epithelial cells. Opposing regulators of epithelial/mesenchymal phenotype in renal proximal tubule epithelial cells (PTEC), TGFβ1 and BMP7 also have counter-regulatory effects in models of renal fibrosis.

Differential regulation of E-cadherin and alpha-smooth muscle actin by BMP 7 in human renal proximal tubule epithelial cells and its implication in renal fibrosis.

Chronic kidney diseases are characterized by progressive tubulointerstitial fibrosis, and TGFbeta1 plays a crucial role in its development. Bone morphogenic protein 7 (BMP 7), another member of the TGF superfamily, antagonized the profibrotic effects of TGFbeta1, including epithelial mesenchymal transition and E-cadherin loss, in the previous studies from animal models. We investigated the effect of BMP 7 on TGFbeta1-mediated E-cadherin loss in two different transformed human adult proximal tubule epithelia.

Albumin induces interleukin-6 release from primary human proximal tubule epithelial cells.

Background: Proximal tubule epithelial cells (PTECs) release proinflammatory and profibrogenic mediators when exposed to serum albumin that may contribute to progression of kidney disease. Interleukin 6 (IL-6) may influence renal fibrosis by modulating transforming growth factor beta1 (TGFbeta1) signalling. PTECs have been demonstrated to produce IL-6 in response to albumin treatment, but the mechanism has not been investigated.

TGF-beta activates ERK5 in human renal epithelial cells.

The role of the MAP kinase, extracellular signal-regulated kinase 5 (ERK5) remains unknown, however it is involved in cell differentiation and survival as highlighted by the embryonic lethality of the ERK5 knockout. ERK5 can be activated by growth factors and other extracellular signals. TGF-beta, a powerful controller of epithelial cell phenotype, is known to activate the MAP kinase, ERK1/2 however its effect on ERK5 remains unknown.

BMP-7 and proximal tubule epithelial cells: activation of multiple signaling pathways reveals a novel anti-fibrotic mechanism.

Purpose: Bone morphogenic protein-7 (BMP-7) is a member of the transforming growth factor beta (TGFbeta) superfamily involved in organogenesis. Recent work suggests that BMP-7 can reverse the fibrotic effects of TGFbeta but the underlying mechanism is unknown. We sought to determine BMP-7 signaling and its modulation of TGFbeta induced fibrotic outcomes in adult human proximal tubule epithelial cells (PTECs).

Role played by disabled-2 in albumin induced MAP Kinase signalling.

Albumin has been shown to activate the mitogen activated protein kinase (MAPK) pathway in proximal tubular cells (PTECs) of the kidney. Megalin, the putative receptor for albumin has potential signalling properties. However, the mechanisms by which megalin signals are unclear.

The TGFbeta1-induced fibronectin in human renal proximal tubular epithelial cells is p38 MAP kinase dependent and Smad independent.

Background/aim: Transforming growth factor beta 1 (TGFbeta1) is a fibrokine implicated in the progression of renal fibrosis. Following TGFbeta1 receptor activation, a number of signalling pathways are stimulated. This study investigates the role of p38 mitogen-activated protein (MAP) kinase and Smad pathways in the TGFbeta1-induced fibronectin (FN) production.

The role played by endocytosis in albumin-induced secretion of TGF-beta1 by proximal tubular epithelial cells.

Proteinuria predicts the decline of renal function in chronic kidney disease. Reducing albuminuria has been shown to be associated with a reduction in this rate of decline. Proximal tubular epithelial cells (PTECs), when exposed to albumin produce matrix proteins, proinflammatory and profibrotic cytokines like TGF-beta(1).

Development of an outpatient finger-prick glomerular filtration rate procedure suitable for epidemiological studies.

Development of an outpatient finger-prick glomerular filtration rate (GFR) procedure suitable for epidemiological studies. In clinical practice, reference GFR procedures are rarely used; in large-scale research studies, a great deal of effort and experience is required to obtain them, which is a considerable disincentive to using GFR as an end point. The major problem for both clinical staff and the subject is the length of time that the procedure takes, requiring continuous attendance in the outpatient clinic or its vicinity.

The differential role of Smad2 and Smad3 in the regulation of pro-fibrotic TGFbeta1 responses in human proximal-tubule epithelial cells.

In chronic renal diseases, progressive loss of renal function correlates with advancing tubulo-interstitial fibrosis. TGFbeta1-Smad (transforming growth factor-beta1-Sma and Mad protein) signalling plays an important role in the development of renal tubulo-interstitial fibrosis. Secretion of CTGF (connective-tissue growth factor; CCN2) by PTECs (proximal-tubule epithelial cells) and EMT (epithelial-mesenchymal transdifferentiation) of PTECs to myofibroblasts in response to TGFbeta are critical Smad-dependent events in the development of tubulo-interstitial fibrosis.

Systematic review on urine albumin testing for early detection of diabetic complications.

Objectives: To determine whether microalbuminuria is an independent prognostic factor for the development of diabetic complications and whether improved glycaemic or blood pressure control has a greater influence on the development of diabetic complications in those with microalbuminuria than in those with normoalbuminuria.

Data Sources: Electronic databases up until January 2002.

Review Methods: A protocol for peer review by an external expert panel was prepared that included selection criteria for data extraction and required two independent reviewers to undertake article selection and review.

TGF-beta1-induced connective tissue growth factor (CCN2) expression in human renal proximal tubule epithelial cells requires Ras/MEK/ERK and Smad signalling.

Background: Connective tissue growth factor (CTGF, CCN2) plays a fundamental role in the development of tissue fibrosis by stimulating matrix deposition and mediating many of the pro-fibrotic effects of transforming growth factor (TGF)-beta. CCN2 induction by TGF-beta in renal proximal tubule epithelial cells (PTECs) is likely to play an important role in the development of tubulointerstitial fibrosis. In this study, we investigated the induction of CCN2 by TGF-beta1 and the possible mechanisms of this induction in human PTECs.