Nestin is a novel marker for renal tubulointerstitial injury in immunoglobulin A nephropathy

Screening impacts of Tilmicosin-induced hepatic and renal toxicity in rats: protection by Rhodiola rosea extract through the involvement of oxidative stress, antioxidants, and inflammatory cytokines biomarkers

Tilmicosin (TIL) is a semisynthetic macrolide antibiotic with a broad spectrum of activity derived from tylosin. TIL is effective in the treatment of bovine and ovine respiratory diseases caused by different microbes. In parallel, Rhodiola rosea (RHO) is a popular herbal remedy because of its anti-inflammatory and antioxidant qualities. The experiment lasted for 12 days. Depending on the experimental group, the animals received either distilled water or RHO root extract dissolved in distilled water for 12 days through a stomach tube, and the single subcutaneous injection on day 6 of the experiment of either 500 μL of 0.9% NaCl or TIL dissolved in 500 μL 0.9% NaCl. Samples and blood were collected for serum analysis, gene expression, and immunohistochemistry screening at liver and kidney levels. TIL injection increased serum levels of hepatic and renal markers (ALP, ALT, AST, TC, TG, creatinine, and urea) with decreased total proteins. In parallel, TIL induced hepatic and renal oxidative stress as there was an increase in malondialdehyde levels, with a decrease in catalase and reduced glutathione activities. Of interest, pre-administration of RHO inhibited TIL-induced increase in hepato-renal markers, decreased oxidative stress, and increased liver and kidney antioxidant activities. Quantitative RT-PCR showed that TIL increased the liver's HSP70 (heat shock protein), NFkB, and TNF-α mRNA expression. Moreover, TIL upregulated the expression of desmin, nestin, and vimentin expression in the kidney. The upregulated genes were decreased significantly in the protective group that received RHO. Serum inflammatory cytokines and genes of inflammatory markers were affected in liver tissues (HSP70, NFkB, and TNF-α) and kidney tissues (desmin, nestin, and vimentin)-TIL-induced hepatic vacuolation and congestion together with glomerular atrophy. The immunoreactivity of PCNA and HMGB1 was examined immunohistochemically. At cellular levels, PCNA was decreased while HMGB1 immunoreactivity was increased in TIL-injected rats, which was improved by pre-administration of RHO. RHO administration protected the altered changes in liver and renal histology. Current findings support the possible use of RHO to shield the liver and kidney from the negative effects of tilmicosin.

The Relationship between Vascular Biomarkers (Serum Endocan and Endothelin-1), NT-proBNP, and Renal Function in Chronic Kidney Disease, IgA Nephropathy: A Cross-Sectional Study

IgA nephropathy (IgAN) is the most common primary glomerular disease. Endothelin-1 (ET-1) is one of the strongest vasoconstrictor materials in the blood. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is associated with renal function and poor outcomes in chronic kidney disease (CKD). Serum endocan is a biomarker associated with proinflammatory cytokines, and the increase in the serum level plays a critical role in inflammatory, proliferative, and neovascularization processes and is associated with poor cardiovascular outcomes in patients with CKD too. Identifying high-risk patients using biomarkers could help to optimize their treatment. Ninety patients with biopsy-confirmed IgAN were included in the study (50 males/40 females, mean age: 54.9 ± 14.4 years). Serum endocan, ET-1, and NT-proBNP were measured by enzyme-linked immunosorbent assay kits. Echocardiography was performed, and carotid-femoral pulse wave velocity (cfPWV) was measured by SphygmoCor in this cross-sectional study. Patients were divided into two groups based on serum endocan median level (cut-off: 44 ug/L). There was significantly higher aorta systolic blood pressure (SBPao) (p = 0.013), NT-proBNP (p = 0.028), albumin/creatinine ratio (p = 0.036), and uric acid (p = 0.045) in the case of the higher endocan group compared to the lower. There was also significantly higher SBPao (p = 0.037) and NT-proBNP (p = 0.038) in the case of higher endothelin-1 (ET-1) levels compared to the lower (cut-off: 231 pg/mL) group by the two-sample t-test. Then, we divided the patients into two groups based on the eGFR (CKD 1-2 vs. CKD 3-5). The levels of serum endocan, NT-proBNP, cfPWV, SBPao, left ventricular mass index (LVMI), uric acid, and albuminuria were significantly higher in the CKD 3-5 group compared to the CKD 1-2 group. The serum endocan and NT-proBNP levels were significantly higher in the diastolic dysfunction group (p = 0.047, p = 0.015). There was a significant increase in serum endocan levels (CKD 1 vs. CKD 5; p = 0.008) with decreasing renal function. In IgAN, vascular biomarkers (endocan, ET-1) may play a role in endothelial dysfunction through vascular damage and elevation of SBPao. Serum endocan, ET-1, and NT-proBNP biomarkers may help to identify IgAN patients at high risk.

Neuronal damage and inflammatory biomarkers are associated with the affective and chronic fatigue-like symptoms due to end-stage renal disease

BACKGROUND

Many biochemical, immunological, and neuropsychiatric changes are associated with end-stage renal disease (ESRD). Neuronal damage biomarkers such as glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL), S100 calcium-binding protein B (S100B), ionized calcium-binding adaptor molecule-1 (IBA1), and myelin basic protein (MBP) are among the less-studied biomarkers of ESRD.

AIM

We examined the associations between these neuro-axis biomarkers, inflammatory biomarkers, e.g., C-reactive protein (CRP), interleukin (IL-6), IL-10, and zinc, copper, and neuropsychiatric symptoms due to ERSD.

METHODS

ELISA techniques were used to measure serum levels of neuronal damage biomarkers in 70 ESRD patients, and 46 healthy controls.

RESULTS

ESRD patients have higher scores of depression, anxiety, fatigue, and physiosomatic symptoms than healthy controls. Aberrations in kidney function tests and the number of dialysis interventions are associated with the severity of depression, anxiety, fibro-fatigue and physiosomatic symptoms, peripheral inflammation, nestin, and NFL. Serum levels of neuronal damage biomarkers (NFL, MBP, and nestin), CRP, and interleukin (IL)-10 are elevated, and serum zinc is decreased in ESRD patients as compared with controls. The neuronal damage biomarkers NFL, nestin, S100B and MBP are associated with the severity of one or more neuropsychiatric symptom domains. Around 50 % of the variance in the neuropsychiatric symptoms is explained by NFL, nestin, S00B, copper, and an inflammatory index.

CONCLUSIONS

The severity of renal dysfunction and/or the number of dialysis interventions may induce peripheral inflammation and, consequently, neurotoxicity to intermediate filament proteins, astrocytes, and the blood-brain barrier, leading to the neuropsychiatric symptoms of ESRD.

Neuronal damage and inflammatory biomarkers are associated with the affective and chronic fatigue-like symptoms due to end-stage renal disease.. [DOI: 10.1101/2023.05.03.23289492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background

Many biochemical, immunological, and neuropsychiatric changes are associated with end-stage renal disease (ESRD). Neuronal damage biomarkers such as glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL), S100 calcium-binding protein B (S100B), ionized calcium-binding adaptor molecule-1 (IBA1), and myelin basic protein (MBP) are among the less-studied biomarkers of ESRD.

Aim

We examined the associations between these neuro-axis biomarkers, inflammatory biomarkers, e.g., C-reactive protein (CRP), interleukin (IL-6), IL-10, and zinc, copper, and neuropsychiatric symptoms due to ERSD.

Methods

ELISA techniques were used to measure serum levels of neuronal damage biomarkers in 70 ESRD patients, and 46 healthy controls.

Results

ESRD patients have higher scores of depression, anxiety, fatigue, and physiosomatic symptoms than healthy controls. Aberrations in kidney function tests and the number of dialysis interventions are associated with the severity of depression, anxiety, fibro-fatigue and physiosomatic symptoms, peripheral inflammation, nestin, and NFL. Serum levels of neuronal damage biomarkers (NFL, MBP, and nestin), CRP, and interleukin (IL)-10 are elevated, and serum zinc is decreased in ESRD patients as compared with controls. The neuronal damage biomarkers NFL, nestin, S100B and MBP are associated with the severity of one or more neuropsychiatric symptom domains. Around 50% of the variance in the neuropsychiatric symptoms is explained by NFL, nestin, S00B, copper, and an inflammatory index.

Conclusions

The severity of renal dysfunction and/or the number of dialysis interventions may induce peripheral inflammation and, consequently, neurotoxicity to intermediate filament proteins, astrocytes, and the blood-brain barrier, leading to the neuropsychiatric symptoms of ESRD.

Age-Associated Loss in Renal Nestin-Positive Progenitor Cells

The decrease in the number of resident progenitor cells with age was shown for several organs. Such a loss is associated with a decline in regenerative capacity and a greater vulnerability of organs to injury. However, experiments evaluating the number of progenitor cells in the kidney during aging have not been performed until recently. Our study tried to address the change in the number of renal progenitor cells with age. Experiments were carried out on young and old transgenic nestin-green fluorescent protein (GFP) reporter mice, since nestin is suggested to be one of the markers of progenitor cells. We found that nestin⁺ cells in kidney tissue were located in the putative niches of resident renal progenitor cells. Evaluation of the amount of nestin⁺ cells in the kidneys of different ages revealed a multifold decrease in the levels of nestin⁺ cells in old mice. In vitro experiments on primary cultures of renal tubular cells showed that all cells including nestin⁺ cells from old mice had a lower proliferation rate. Moreover, the resistance to damaging factors was reduced in cells obtained from old mice. Our data indicate the loss of resident progenitor cells in kidneys and a decrease in renal cells proliferative capacity with aging.

Nestin promotes pulmonary fibrosis via facilitating recycling of TGF-β receptor I

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease that is characterised by aberrant proliferation of activated myofibroblasts and pathological remodelling of the extracellular matrix. Previous studies have revealed that the intermediate filament protein nestin plays key roles in tissue regeneration and wound healing in different organs. Whether nestin plays a critical role in the pathogenesis of IPF needs to be clarified.

Methods

Nestin expression in lung tissues from bleomycin-treated mice and IPF patients was determined. Transfection with nestin short hairpin RNA vectors in vitro that regulated transcription growth factor (TGF)-β/Smad signalling was conducted. Biotinylation assays to observe plasma membrane TβRI, TβRI endocytosis and TβRI recycling after nestin knockdown were performed. Adeno-associated virus serotype (AAV)6-mediated nestin knockdown was assessed in vivo.

Results

We found that nestin expression was increased in a murine pulmonary fibrosis model and IPF patients, and that the upregulated protein primarily localised in lung α-smooth muscle actin-positive myofibroblasts. Mechanistically, we determined that nestin knockdown inhibited TGF-β signalling by suppressing recycling of TβRI to the cell surface and that Rab11 was required for the ability of nestin to promote TβRI recycling. In vivo, we found that intratracheal administration of AAV6-mediated nestin knockdown significantly alleviated pulmonary fibrosis in multiple experimental mice models.

Conclusion

Our findings reveal a pro-fibrotic function of nestin partially through facilitating Rab11-dependent recycling of TβRI and shed new light on pulmonary fibrosis treatment.

Nestin regulates the vesicular trafficking system by promoting Rab11-dependent recycling of TβRI and thereby contributes to the progression of pulmonary fibrosis. Precise targeting of nestin may represent a potential therapeutic strategy for IPF.https://bit.ly/3zO75c3

Moringa oleifera ethanolic extract attenuates tilmicosin-induced renal damage in male rats via suppression of oxidative stress, inflammatory injury, and intermediate filament proteins mRNA expression

Tilmicosin (Til) is a popular macrolide antibiotic, widely used in veterinary practice. The present study was designed to address the efficacy of Moringa oleifera ethanolic extract (MOE) in protecting against Tilmicosin (Til) - induced nephrotoxicity in Sprague Dawley rats. Animals were treated once with Til (75 mg/kg bw, subcutaneously), and/or MOE for 7 days (400 or 800 mg/kg bw, by oral gavage). Til-treatment was associated with significantly increased serum levels of creatinine, urea, sodium, potassium and GGT activity, as well as decreased total protein and albumin concentrations. Renal tissue hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were elevated, while the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes were diminished. The levels of renal tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) and the mRNA expression of intermediate filament protein encoding genes (desmin, nestin and vimentin) in the kidney were up- regulated with histopathological alterations in renal glomeruli, tubules and interstitial tissue. These toxic effects were markedly ameliorated by co-treatment of MOE with Til, in a dose dependent manner. Taken together, these results indicate that MO at 800 mg/kg protects against Til-induced renal injury, likely by its potent antioxidant and anti-inflammatory properties, which make it suitable to be used as a protective supplement with Til therapy.

Nestin protects podocyte from injury in lupus nephritis by mitophagy and oxidative stress

Podocyte injury is the main cause of proteinuria in lupus nephritis (LN). Nestin, an important cytoskeleton protein, is expressed stably in podocytes and is associated with podocyte injury. However, the role of nestin in the pathogenesis of proteinuria in LN remains unclear. The correlations among nestin, nephrin and proteinuria were analyzed in LN patients and MRL/lpr lupus-prone mice. The expression of nestin in mouse podocyte lines (MPCs) and MRL/lpr mice was knocked down to determine the role of nestin in podocyte injury. Inhibitors and RNAi method were used to explore the role of mitophagy and oxidative stress in nestin protection of podocyte from damage. There was a significantly negative correlation between nestin and proteinuria both in LN patients and MRL/lpr mice, whereas the expression of nephrin was positively correlated with nestin. Knockdown of nestin resulted in not only the decrease of nephrin, p-nephrin (Y1217) and mitophagy-associated proteins in cultured podocytes and the podocytes of MRL/lpr mice, but also mitochondrial dysfunction in podocytes stimulated with LN plasma. The expression and phosphorylation of nephrin was significantly decreased by reducing the level of mitophagy or production of reactive oxygen species (ROS) in cultured podocytes. Our findings suggested that nestin regulated the expression of nephrin through mitophagy and oxidative stress to protect the podocytes from injury in LN.

β-Amyrin supplementation ameliorates the toxic effect of glycerol in the kidney of rat model

Acute kidney injury (AKI) is a common life-threatening complication. In this study, β-amyrin is hypothesized to exert a potential nephroprotective effect against glycerol-induced nephrotoxicity in rats. Thirty-two female Sprague-Dawley rats were divided into four groups: normal control, β-amyrin treated (50 mg kg^-1 body weight) for 14 days, glycerol 25% (10 ml kg^-1 BW volume/volume in sterile saline, intramuscular), and β-amyrin + glycerol-treated rats. Assessing kidney function was done through the measurement of serum urea and creatinine (SCr). Real-time quantitative polymerase chain reaction analysis was done to measure the changes in the gap junction protein and intermediate filament proteins (IFPs) messenger RNA (mRNA) levels. Renal tissue histopathology was also observed. Glycerol exhibited significant elevation in the SCr and urea with significant upregulation of connexin43, vimentin, and nestin. The levels of all disrupted parameters were improved by the pre-administration of β-amyrin. The β-amyrin exerts significant improvement of the biochemical parameters with a restoration of the renal tissue histopathological picture. Significant downregulation of the expression levels of the gap junction protein and IFPs mRNA was also seen. Collectively, the administration of β-amyrin showed a promising effect for a protection against glycerol-induced AKI in rats.

Implementation of Proteomics Biomarkers in Nephrology: From Animal Models to Human Application?

Preclinical animal models are extensively used in nephrology. In this review, the utility of performing proteome analysis of kidney tissue or urine in such models and transfer of the results to human application has been assessed. Analysis of the literature identified 68 relevant publications. Pathway analysis of the reported proteins clearly indicated links with known biological processes in kidney disease providing validation of the observed changes in the preclinical models. However, although most studies focused on the identification of early markers of kidney disease or prediction of its progression, none of the identified makers has made it to substantial validation in the clinic or at least in human samples. Especially in renal disease where urine is an abundant source of biomarkers of diseases of the kidney and the urinary tract, it therefore appears that the focus should be on human material based discovery studies. In contrast, the most valid information of proteome analysis of preclinical models in nephrology for translation in human disease resides in studies focusing on drug evaluation, both efficacy for translation to the clinic and for mechanistic insight.

Nestin Improves Preeclampsia-Like Symptoms by Inhibiting Activity of Cyclin-Dependent Kinase 5

BACKGROUND/AIMS

Preeclampsia (PE) is a pregnancy-specific hypertensive disorder that is characterised by a high incidence of hypertension and proteinuria. Podocytes are involved in the formation of a split membrane, which is the last barrier preventing the leakage of protein into the urine. Nestin, a cytoskeleton protein, is expressed stably in podocytes. However, the association between the Nestin concentration in urine and the progression of PE and the role of Nestin in PE remains unclear.

METHODS

In the present study, a mouse podocyte cell line, PE-like animal model and PE patients' urine samples were used. Eilsa kits were used to detect the levels of proteins expression in urine samples from patients and animal models. Western Blotting and immunofluorescence were used to detect proteins expression levels in cell samples and animal tissue samples. Flow cytometry was used to detect the level of apoptosis in cells. Tunel assay was used to detect the levels of apoptosis in animal tissue samples.

RESULTS

Nestin levels were significantly increased in PE patients than in hypertensive patients and healthy subjects, and positively correlated with proteinuria and podocalyxin. Ang II treatment decreased the expression of Nestin and Podocin in a time- and dose- dependent manner in podocytes. Restoration of the Nestin levels could reverse Ang II-induced F-actin degradation and attenuate Ang II-mediated podocyte apoptosis, while knockdown of the Nestin level exhibited the opposite. Moreover, the protective role of Nestin on podocytes is mediated by inhibition of the kinase activity of CDK5. In PE-like animal model induced by L-NAME injection, restoration of Nestin lowered the pressure and proteinuria concentration, attenuated the loss of podocytes, and decreased the expression of p35, p53 and the activity of CDK5 kinase, as compared with the control.

CONCLUSIONS

Our findings suggest that Nestin could improve preeclampsia-like symptoms by inhibiting the activity of CDK5, and Nestin may become a new prognostic factor and a potential therapy target for PE.

Nestin expression is dynamically regulated in cardiomyocytes during embryogenesis

The transcriptional factors implicated in the expression of the intermediate filament protein nestin in cardiomyocytes during embryogenesis remain undefined. In the heart of 9,5-10,5 day embryonic mice, nestin staining was detected in atrial and ventricular cardiomyocytes and a subpopulation co-expressed Tbx5. At later stages of development, nestin immunoreactivity in cardiomyocytes gradually diminished and was absent in the heart of 17,5 day embryonic mice. In the heart of wild type 11,5 day embryonic mice, 54 ± 7% of the trabeculae expressed nestin and the percentage was significantly increased in the hearts of Tbx5^+/- and Gata4^+/- embryos. The cell cycle protein Ki67 and transcriptional coactivator Yap-1 were still prevalent in the nucleus of nestin⁽⁺⁾ -cardiomyocytes identified in the heart of Tbx5^+/- and Gata4^+/- embryonic mice. Phorbol 12,13-dibutyrate treatment of neonatal rat ventricular cardiomyocytes increased Yap-1 phosphorylation and co-administration of the p38 MAPK inhibitor SB203580 led to significant dephosphorylation. Antagonism of dephosphorylated Yap-1 signalling with verteporfin inhibited phorbol 12,13-dibutyrate/SB203580-mediated nestin expression and BrdU incorporation of neonatal cardiomyocytes. Nestin depletion with an AAV9 containing a shRNA directed against the intermediate filament protein significantly reduced the number of neonatal cardiomyocytes that re-entered the cell cycle. These findings demonstrate that Tbx5- and Gata4-dependent events negatively regulate nestin expression in cardiomyocytes during embryogenesis. By contrast, dephosphorylated Yap-1 acting via upregulation of the intermediate filament protein nestin plays a seminal role in the cell cycle re-entry of cardiomyocytes. Based on these data, an analogous role of Yap-1 may be prevalent in the heart of Tbx5^+/- and Gata4^+/- mice.

Nestin expression is upregulated in the fibrotic rat heart and is localized in collagen-expressing mesenchymal cells and interstitial CD31(+)- cells

Renal and lung fibrosis was characterized by the accumulation of collagen-immunoreactive mesenchymal cells expressing the intermediate filament protein nestin. The present study tested the hypothesis that nestin expression was increased in the hypertrophied/fibrotic left ventricle of suprarenal abdominal aorta constricted adult male Sprague-Dawley rats and induced in ventricular fibroblasts by pro-fibrotic peptide growth factors. Nestin protein levels were upregulated in the pressure-overloaded left ventricle and expression positively correlated with the rise of mean arterial pressure. In sham and pressure-overloaded hearts, nestin immunoreactivity was detected in collagen type I(+)-and CD31(+)-cells identified in the interstitium and perivascular region whereas staining was absent in smooth muscle α-actin(+)-cells. A significantly greater number of collagen type I(+)-cells co-expressing nestin was identified in the left ventricle of pressure-overloaded rats. Moreover, an accumulation of nestin(+)-cells lacking collagen, CD31 and smooth muscle α-actin staining was selectively observed at the adventitial region of predominantly large calibre blood vessels in the hypertrophied/fibrotic left ventricle. Angiotensin II and TGF-β1 stimulation of ventricular fibroblasts increased nestin protein levels via phosphatidylinositol 3-kinase- and protein kinase C/SMAD3-dependent pathways, respectively. CD31/eNOS(+)-rat cardiac microvascular endothelial cells synthesized/secreted collagen type I, expressed prolyl 4-hydroxylase and TGF-β1 induced nestin expression. The selective accumulation of adventitial nestin(+)-cells highlighted a novel feature of large vessel remodelling in the pressure-overloaded heart and increased appearance of collagen type I/nestin(+)-cells may reflect an activated phenotype of ventricular fibroblasts. CD31/collagen/nestin(+)-interstitial cells could represent displaced endothelial cells displaying an unmasked mesenchymal phenotype, albeit contribution to the reactive fibrotic response of the pressure-overloaded heart remains unknown.

Renal Medullary and Cortical Correlates in Fibrosis, Epithelial Mass, Microvascularity, and Microanatomy Using Whole Slide Image Analysis Morphometry

Renal tubulointerstitial injury often leads to interstitial fibrosis and tubular atrophy (IF/TA). IF/TA is typically assessed in the renal cortex and can be objectively quantitated with computerized image analysis (IA). However, the human medulla accounts for a substantial proportion of the nephron; therefore, medullary scarring will have important cortical consequences and may parallel overall chronic renal injury. Trichrome, periodic acid-Schiff (PAS), and collagen III immunohistochemistry (IHC) were visually examined and quantitated on scanned whole slide images (WSIs) (N = 67 cases). When tuned to measure fibrosis, IA of trichrome and Trichrome-PAS (T-P) WSIs correlated for all anatomic compartments (among cortex, medulla, and entire tissue, r = 0.84 to 0.89, P all <0.0001); and collagen III deposition correlated between compartments (r = 0.69 to 0.89, P <0.0001 to 0.0002); however, trichrome and T-P measures did not correlate with collagen deposition, suggesting heterogeneous contributions to extracellular matrix deposition. Epithelial cell mass (EPCM) correlated between cortex and medulla when measured with cytokeratin IHC and with the trichrome red portion (r = 0.85 and 0.66, respectively, all P < 0.0001). Visual assessment also correlated between compartments for fibrosis and EPCM. Correlations were found between increasing medullary inner stripe (IS) width and fibrosis in all of the tissue and the medulla by trichrome morphometry (r = 0.56, P < 0.0001, and r = 0.48, P = 0.00008, respectively). Weak correlations were found between increasing IS width and decreasing visual assessment of all tissue EPCM. Microvessel density (MVD) and microvessel area (MVA) measured using a MVD algorithm applied to CD34 IHC correlated significantly between all compartments (r = 0.76 to 0.87 for MVD and 0.71 to 0.87 for MVA, P all < 0.0001). Overall, these findings demonstrate the interrelatedness of the cortex and medulla and the importance of considering the renal parenchyma as a whole.

Plasma endocan level and prognosis of immunoglobulin A nephropathy

Background

Endocan, previously called endothelial cell–specific molecule-1, is a soluble proteoglycan that is secreted from vascular endothelial cells. Elevated plasma endocan levels were shown to be associated with poor cardiovascular outcomes in patients with chronic kidney disease (CKD). We investigated the clinical relevance of plasma and urine endocan levels in patients with immunoglobulin A nephropathy (IgAN).

Methods

Sixty-four patients with IgAN and 20 healthy controls were enrolled in this study. Plasma and urine endocan levels were measured. Clinical parameters, pathologic grades, and renal outcomes were compared among subgroups with different plasma and urine endocan levels.

Results

Both plasma and urine endocan levels were significantly higher in patients with IgAN than in controls. Elevated serum phosphorus and C-reactive protein were independent determinants for plasma endocan, and elevated C-reactive protein was also an independent determinant for urine endocan levels in multivariate analysis. Plasma endocan level was not significantly different across CKD stages, but patients with higher plasma endocan levels showed adverse renal outcome. Urine endocan levels were also elevated in patients with poor renal function. Cox proportional hazard models showed that high plasma endocan was an independent risk factor for CKD progression after adjusting for the well-known predictors of outcome in patients with IgAN.

Conclusion

This study suggested that plasma endocan might be useful as a prognostic factor in patients with IgAN.

Clinicopathological role of kidney injury molecule-1 in immunoglobulin A nephropathy

BACKGROUND

Urinary kidney injury molecule-1 (KIM-1) is an early and sensitive biomarker of acute kidney injury, but it is unclear if it is a biomarker of chronic glomerulonephritis. We evaluated whether urinary KIM-1 levels in patients with immunoglobulin A (IgA) nephropathy can be a marker to reflect clinicopathological severity and predict the prognosis.

METHODS

We measured urinary KIM-1 levels in 40 patients (15 males; mean age 36.6±12.9 years) with IgA nephropathy and 10 healthy people (5 males; mean age 37.3±9.6 years) as controls. The correlation of urinary KIM-1 levels with patients' clinical parameters, histological grades, and follow-up data were analyzed using the modified H. S. Lee grading system and tubulointerstitial change scores.

RESULTS

Urinary KIM-1 levels were higher in patients with IgA nephropathy than healthy controls (P=0.001). Univariate and multivariate regression analyses showed that urinary KIM-1 levels had a direct correlation with H. S. Lee grade and tubulointerstitial inflammation (P=0.004 and P=0.011, respectively).

CONCLUSION

In patients with IgA nephropathy, urinary KIM-1 has a significant correlation with histopathologic severity.

Expression of nestin after renal transplantation in the rat

Chronic allograft injury (CAI) limits the long-term success of renal transplantation. Nestin is a marker of progenitor cells, which probably contribute to its pathogenesis. We hypothesize that nestin is induced by ischemia/reperfusion injury and acute rejection, main risk factors for CAI. Syngeneic renal transplantation was performed in Lewis rats and allogeneic transplantation in the Fischer 344 to Lewis strain combination, which results in reversible acute rejection and in CAI in the long-run. The Dark Agouti to Lewis rat strain combination was used to study fatal acute rejection. In untreated kidneys, nestin immunoreactivity was detected in glomeruli and in very few interstitial or microvascular cells. Syngeneic transplantation induced nestin expression within 4 days, which decreased until day 9 and returned to control levels on day 42. Nestin expression was strong during acute rejection and still detected during the pathogenesis of CAI on day 42. Nestin-positive cells were identified as endothelial cells and interstitial fibroblast-like cells co-expressing alpha-smooth muscle actin. A sub-population of them expressed proliferating cell nuclear antigen. In conclusion, nestin is induced in renal grafts by ischemia/reperfusion injury and acute rejection. It is expressed by proliferating myofibroblasts and endothelial cells and probably contributes to the pathogenesis of CAI.

Identification of nestin as a urinary biomarker for acute kidney injury

OBJECTIVES

Acute kidney injury (AKI) is a common complication in hospitalized patients and the incidence of AKI is rapidly increasing. Despite the advances in treatment of AKI, many patients still progress to end-stage renal disease and depend on dialysis. Therefore, early diagnosis and adequate treatment of AKI could improve prognosis.

METHODS

We established rat models of AKI induced by cisplatin nephrotoxicity and renal ischemia-reperfusion (I/R). Urine samples were collected, labeled with isobaric tags for relative and absolute quantification agents, and then subjected to nano-LC-MS/MS-based proteomic analysis. Results of the proteomic study were confirmed by Western blot. We also performed RNAi to silence nestin and investigate its role in renal I/R injury. We then validated its clinical application by studying urine nestin levels in AKI patients with cardiovascular surgeries.

RESULTS

Our proteomic analysis showed that fetuin-A, nestin, hamartin and T-kininogen were differentially expressed in the urine samples of rats after cisplatin or I/R treatment. Western blot confirmed the differential expression of these proteins in animal models and ELISA confirmed the differential expression of nestin in human urine samples. To explore the expression of nestin in the development of AKI, our results showed that nestin was primarily detected in the glomeruli and barely detected in tubular cells but increased in tubular cells during I/R- and cisplatin-induced AKI. The urine nestin-to-creatinine ratio increased earlier than serum creatinine in AKI patients with postcardiovascular surgeries. The role of nestin in AKI might be related to the p53 signaling pathway.

CONCLUSIONS

Thus, our results demonstrated that urinary nestin could be a urinary biomarker for patients with AKI and its role in AKI might be related to the p53 signaling pathway.

Clinicopathological and immunohistological features in childhood IgA nephropathy: a single-centre experience

Background

IgA nephropathy is a glomerular disease diagnosed by renal biopsy and is characterized by a highly variable course ranging from a completely benign condition to rapidly progressive renal failure. We aimed to evaluate the clinical, histopathological and inflammatory characteristics of children with IgA nephropathy.

Methods

Data of 37 patients with IgA nephropathy diagnosed between the years 1980 and 2008 were retrospectively reviewed. Immunohistochemistry was performed in 24 patients. Expression of CD3, CD4, CD8, CD20, CD68, IL-1β, IL-10, IL-17, TGF-β, TNF-α and the newly proposed tubulointerstitial fibrosis marker nestin were evaluated.

Results

The median age at diagnosis was 10 years. Recurrent macroscopic haematuria (66%) was the most common clinical manifestation, and 35% of the patients had synpharyngitic presentation. A significant correlation was found between proteinuria and increase in mesangial matrix (r = 0.406, P = 0.013). The presence of CD4+ T lymphocytes and CD68+ macrophages were also significantly associated with proteinuria >1 g/day. While cytokines IL-1β, IL-10 and TNF-α were mainly expressed in tubular epithelial cells, TGF-β was evident in glomeruli but they had no correlation to clinical features and severity of the disease. Nestin was detected at the tubules in almost half of the patients with no correlation to proteinuria and tubulointersititial fibrosis.

Conclusions

We found a correlation between proteinuria and mesangial matrix expansion. The presence of CD4+ T-lymphocytes and CD68+ macrophages were also significantly associated with proteinuria >1 g/day. Although there are many evidences, for immunological basis of IgA nephropathy, the immunological markers were not fully expressed in children to evaluate glomerular and tubulointerstitial inflammation, and progression of the disease. Further studies with the extended number of children are needed to shed light on the immunological basis of the disease.

Upregulation of nestin in proximal tubules may participate in cell migration during renal repair

The characteristics of renal tubular progenitor/precursor cells and the role of renal tubule regeneration in the repair of remnant kidneys (RKs) after nephrectomy are not well known. In the present study of a murine model of subtotal nephrectomy, we used immunofluorescence (IF), immunoblot analysis, and in situ hybridization methods to demonstrate that nestin expression was transiently upregulated in tubule cells near the incision edges of RKs. The nestin-positive tubules were immature proximal tubules that colabeled with lotus tetragonolobus agglutinin but not with markers of mature tubules (aquaporin-1, Tamm-Horsfall protein, and aquaporin-2). In addition, many of the nestin-expressing tubule cells were actively proliferative cells, as indicated by colabeling with bromodeoxyuridine. Double-label IF and immunoblot analysis also showed that the upregulation of tubular nestin was associated with enhanced transforming growth factor-β1 (TGF-β1) expression in the incision edge of RKs but not α-smooth muscle actin, which is a marker of fibrosis. In cultured human kidney proximal tubule cells (HKC), immunoblot analysis indicated that TGF-β1 induced nestin expression and loss of E-cadherin expression, suggesting an association of nestin expression and cellular dedifferentiation. Knockdown of nestin expression by a short hairpin RNA-containing plasmid led to decreased migration of HKC cells that were induced by TGF-β1. Taken together, our results suggest that the tubule repair that occurs during the recovery process following nephrectomy may involve TGF-β1-induced nestin expression in immature renal proximal tubule cells and the promotion of renal cell migration.

Nestin+ cells and healing the infarcted heart

Scar formation following an ischemic insult to the heart is referred to as reparative fibrosis and represents an essential physiological response to heal the damaged myocardium. The biological events of reparative fibrosis include inflammation, the deposition of collagen by myofibroblasts, sympathetic innervation, and angiogenesis. Several studies have further reported that scar formation was associated with the recruitment of neural crest-derived cardiac resident nestin(+) cells that display characteristics consistent with a neural progenitor/stem cell phenotype. During the reparative fibrotic response, these nestin(+) cells participate in neural remodeling and represent a novel cellular substrate of angiogenesis. In addition, a subpopulation of nestin(+) cells identified in the normal heart expressed cardiac progenitor transcriptional factors and may directly contribute to myocardial regeneration following ischemic damage. Nestin protein was also detected in endothelial cells of newly formed blood vessels in the scar and may represent a marker of revascularization. Lastly, nestin was induced in a subpopulation of smooth muscle α-actin(+) scar-derived myofibroblasts, and the expression of the intermediate filament protein may provide a proliferative advantage. Collectively, these data demonstrate that diverse populations of nestin(+) cells participate in cardiac wound healing.

Upregulation of nestin protects podocytes from apoptosis induced by puromycin aminonucleoside

BACKGROUND

Nestin is an intermediate filament protein widely used as a marker of stem cells or progenitor cells. Nestin is also highly expressed in the glomerular podocyte, a type of terminally differentiated epithelial cell. Little is known about the significance of nestin in podocytes.

METHODS

Puromycin aminonucleoside (PAN) was injected into the rats to produce a PAN nephrosis model. Transmission electronic microscopy and terminal dUTP nick end-labeling assay were used to examine the podocyte foot process (FP) effacement and apoptosis, respectively. A mouse podocyte cell line was cultured and incubated with PAN. Immunoblot was used to examine the level of nestin expression both in vivo and in vitro. Enhanced green fluorescence protein-tagged plasmids containing nestin shRNA were transfected into the cultured podocytes to silence nestin expression. F-actin arrangement within cultured podocytes was investigated by immunofluorescence, while the apoptosis rate was examined by both Hoechst stain and flow cytometry.

RESULTS

In the PAN-induced rat nephrosis model, podocyte nestin expression was increased in the absence of apparent podocyte apoptosis, even though the FP was significantly effaced. In the cultured mouse podocytes, PAN upregulated nestin expression in a time-dependent manner within 24 h of treatment. Notably, no significant apoptosis occurred, however knocking down nestin expression resulted in a remarkable derangement of actin cytoskeleton and an increase in apoptosis in the cultured podocytes 24 h after being incubated with PAN.

CONCLUSIONS

Upregulation of nestin expression during PAN nephrosis could protect podocytes from apoptosis and that this process is mediated by maintaining the regular arrangement of actin cytoskeleton.

Adult human CD133/1(+) kidney cells isolated from papilla integrate into developing kidney tubules

Approximately 60,000 patients in the United States are waiting for a kidney transplant due to genetic, immunologic and environmentally caused kidney failure. Adult human renal stem cells could offer opportunities for autologous transplant and repair of damaged organs. Current data suggest that there are multiple progenitor types in the kidney with distinct localizations. In the present study, we characterize cells derived from human kidney papilla and show their capacity for tubulogenesis. In situ, nestin(+) and CD133/1(+) cells were found extensively intercalated between tubular epithelia in the loops of Henle of renal papilla, but not of the cortex. Populations of primary cells from the renal cortex and renal papilla were isolated by enzymatic digestion from human kidneys unsuited for transplant and immuno-enriched for CD133/1(+) cells. Isolated CD133/1(+) papillary cells were positive for nestin, as well as several human embryonic stem cell markers (SSEA4, Nanog, SOX2, and OCT4/POU5F1) and could be triggered to adopt tubular epithelial and neuronal-like phenotypes. Isolated papillary cells exhibited morphologic plasticity upon modulation of culture conditions and inhibition of asymmetric cell division. Labeled papillary cells readily associated with cortical tubular epithelia in co-culture and 3-dimensional collagen gel cultures. Heterologous organ culture demonstrated that CD133/1(+) progenitors from the papilla and cortex became integrated into developing kidney tubules. Tubular epithelia did not participate in tubulogenesis. Human renal papilla harbor cells with the hallmarks of adult kidney stem/progenitor cells that can be amplified and phenotypically modulated in culture while retaining the capacity to form new kidney tubules. This article is part of a Special Issue entitled: Polycystic Kidney Disease.