Glomerular Tissue Research Articles

Hypoxia Inducible Factor-1 Alpha Promotes Mesangial Cell Proliferation in Lupus Nephritis

Background: Evidence has accumulated that hypoxia plays a significant role in the pathogenesis and progression of both acute renal injury and chronic renal disease. However, little was known about the effects of hypoxia on lupus nephritis (LN). In the current study, we investigated the expression of hypoxia inducible factor-1 alpha (HIF-1α) in LN. Methods: Renal biopsies from 22 LN patients and 20 patients with renal carcinoma were obtained. In situ HIF-1α expression was examined by immunohistochemical staining, and the relationship between HIF-1α and clinical/pathological features was analyzed. HIF-1α expression in kidney from both MRL/lpr and C57BL/6 mice was detected by immunohistochemical technology. Dimethyloxaloylglycine (DMOG), an inhibitor of HIF-degrading prolylhydroxylases, was utilized to prevent HIF-1α degradation in mouse mesangial cells (MCs). After DMOG treatment, the proliferation and apoptosis rates of mouse MCs were determined. Results: LN patients showed larger amounts of HIF-1α in both glomerular and tubulointerstitial areas. The levels of intraglomerular HIF-1α were closely associated with renal pathology activity index and clinical manifestations in LN patients. In MRL/lpr mice, intraglomerular HIF-1α-positive cells were also significantly increased. Interestingly, the levels of HIF-1α positively correlated with cell density in glomerulus in both LN patients and MRL/lpr mice. Upon treatment with DMOG, the proliferation of MCs was upregulated, and apoptosis was downregulated. Conclusion: HIF-1α is highly expressed in both glomerular and tubulointerstitial tissues in LN, especially in proliferative LN. HIF-1α may promote MCs growth through the induction of proliferation and inhibition of apoptosis, and hence plays an important role in the pathogenesis of LN. © 2014 S. Karger AG, Basel

Abstract 14859: IL17 Contribute to the Atherosclerotic Development and the Initiation of Chronic Kidney Disease

Introduction: Recent studies suggested that the atherogenic state correlated with progression of chronic kidney disease (CKD). However, it is not known whether sustained status of chronic inflammation in atherosclerosis is closely linked to the development of CKD. Hypothesis: Inflammatory cytokine producing-T cells in the advanced atherosclerosis induced the dysfunction of podocytes. Methods/Results: Eighteen-week-old apolipoprotein E-deficient mice (Control) were fed with high-fat diet for 8W (ApoE) and compared to IL17/ApoE-double deficient mice fed with high-fat diet (DKO). Sudan staining of aorta revealed the atherosclerotic lesion was increased in ApoE compared to Control, and inhibited in DKO. Activated IFNγ + CD4 T cells (Th1) and IL17 + CD4 T cells (Th17) were significantly increased in ApoE compared to DKO by FACS. Immunohistochemistry of aortic sinus showed many Th1 and Th17 were infiltrated in the atherosclerotic plaque in ApoE, however, inflammatory infiltrates were inhibited in DKO. Furthermore, the urinary albumin/creatinine ratio was increased significantly in ApoE compared to DKO. Th1 and Th17 were correlated with the urinary albumin/creatinine ratio, and many Th1 and Th17 were observed in the glomeruli. Next, to investigate whether the inflammatory cytokine induced dysfunction of podocytes were involved in proteinuria, we investigated nephrin, podocin, and phosphorylated nephrin in the kidney by Western blots and immunohistochemistry. The decreased phosphorylated neprin in ApoE were recovered in DKO. Finally, we confirmed that the morphological changed of podocytes in ApoE were improved in DKO by electron microscopy. Conclusion: Recruitments of IFNγ + Th1 and IL17 + Th17 T cells might aggravate atherosclerosis acceleration and induce the initiation of glomerular tissue damage.

Non-diabetic renal diseases in a multi-ethnic New Zealand cohort with type 2 diabetes mellitus: clinical and histopathological features

The aims of this study were to identify non-diabetic renal disease (NDRD), including obesity related glomerulopathy (ORG) in diabetic patients, and compare the findings with those of pure diabetic nephropathy (DN).Ninety-three renal biopsies from diabetic patients were reviewed retrospectively, along with their clinical findings at biopsy and their estimated glomerular filtration rate (eGFR) over 5 years follow-up. DN and focal segmental glomerulosclerosis (FSGS) were diagnosed on blinded histology review, together with assessment of renal compartment histology. Other NDRD were diagnosed on full review.Most patients were obese with poor renal function at biopsy. NDRD occurred in more than two-thirds of biopsies. FSGS and interstitial nephritis were common. Patients with pure FSGS presented earlier, and had favourable histological features and clinical course. Most FSGS patients fulfilled criteria for ORG. Biopsies with interstitial nephritis showed more functional glomerular tissue, and most patients retained good renal function. Adverse prognostic features were DN versus NDRD, nodular grade of DN, low eGFR at biopsy, and severe chronic histological changes.In this population, ORG mechanisms contribute to renal injury. FSGS is frequent, and should be diagnosed separately from any DN. Biopsy to confirm suspicion of interstitial nephritis should be performed even if retinopathy is present.

AB0182 Increased Expression of Hypoxia Inducible Factor-1 Alpha in Lupus Nephritis

BackgroundEvidence has accumulated that hypoxia played a significant role in the pathogenesis and progression of both acute renal injury and chronic renal disease.ObjectivesIn this study, the expression of hypoxia inducible...

Mannose binding lectin deposition in skin of lupus erythematosus patients: A case series

IntroductionMannose binding lectin (MBL) has been linked to predisposition to systemic lupus erythematosus (SLE) and to disease activity. Some studies found deposits of MBL in glomerular tissue of patients with lupus nephritis. There is no research about the deposition of MBL in skin. Materials and methodsSkin biopsies from lesional and non lesional skin of 4 discoid lupus erythematosus (DLE) and 10 SLE patients were submitted to immunofluorescence staining for IgG, IgA, IgM, C3, C4, C1q, C5b-9 and MBL. Charts were reviewed for demographic, clinical and serological data. Patients with SLE had disease activity measured by SLEDAI. ResultsMBL was found only in SLE lesional skin and its presence showed an association trend towards higher disease activity. Deposition of C5b-9 occurred in vessels only in patients with SLE (70%) and in the two patients with kidney involvement. ConclusionsMBL deposition was found in the lesional skin of SLE patients but not in SLE non lesional skin nor in DLE patients, and it seems to be less frequent and less strong than observed in the kidneys biopsies, suggesting that the complement participation in the pathophysiology of SLE process may not be the same in these two clinical manifestations.

MiR-223 downregulation promotes glomerular endothelial cell activation by upregulating importin α4 and α5 in IgA nephropathy

Glomerular endothelial cells (GEnCs) contribute to renal injuries in IgA nephropathy (IgAN). Here we profiled microRNAs (miRNAs) in GEnCs treated with conditioned medium from human mesangial cells in vitro. Levels of miR-223 in GEnCs decreased after incubation with the medium prepared with pIgA from patients with glomerular endothelial proliferation and were also decreased in the glomerular tissues of patients with glomerular endothelial proliferation. Mesangial-derived IL-6 caused miR-223 levels to decrease. The addition of exogenous miR-223 inhibited cell proliferation, ICAM-1 expression, and monocyte adhesion. The NF-κB and STAT3 signaling pathways collaborate during the activation process. MiR-223 mimics inhibited the nuclear localization and DNA binding of p65 and STAT3 but had no effect on the expression of upstream molecules. Instead, importin α4 and α5 (multipurpose nuclear transport receptors), validated as targets of miR-223, were responsible for the nuclear transport of p65 and STAT3. Importin α4 and α5 siRNA inhibited the nuclear localization of p65 and STAT3 and prevented cell proliferation and monocyte adhesion. The level of miR-223 in circulating endothelial cells was decreased and related to the clinical and pathological parameters. Thus, miR-223 downregulation promotes glomerular endothelial cell activation by upregulating importin α4 and α5 in IgAN. Monitoring the level of miR-223 in circulating endothelial cells may provide a noninvasive method for evaluating the severity of IgAN.

Renal Heparan Sulfate Proteoglycans Modulate Fibroblast Growth Factor 2 Signaling in Experimental Chronic Transplant Dysfunction

Depending on the glycan structure, proteoglycans can act as coreceptors for growth factors. We hypothesized that proteoglycans and their growth factor ligands orchestrate tissue remodeling in chronic transplant dysfunction. We have previously shown perlecan to be selectively up-regulated in the glomeruli and arteries in a rat renal transplantation model. Using the same model, here we present quantitative RT-PCR profiling data on proteoglycans and growth factors from laser-microdissected glomeruli, arterial tunicae mediae, and neointimae at 12 weeks after transplantation. In glomeruli and neointimae of allografts, selective induction of the matrix heparan sulfate proteoglycan perlecan was observed, along with massive accumulation of fibroblast growth factor 2 (FGF2). Profiling the heparan sulfate polysaccharide side chains revealed conversion from a non-FGF2-binding heparan sulfate phenotype in control and isografted kidneys toward a FGF2-binding phenotype in allografts. In vitro experiments with perlecan-positive rat mesangial cells showed that FGF2-induced proliferation is dependent on sulfation and can be inhibited by exogenously added heparan sulfate. These findings indicate that matrix proteoglycans such as perlecan serve as functional docking platforms for FGF2 in chronic transplant dysfunction. We speculate that heparin-like glycomimetics could be a promising intervention to retard development of glomerulosclerosis and neointima formation in chronic transplant dysfunction.

The aqueous extract of Lycopus lucidus Turcz ameliorates streptozotocin-induced diabetic renal damage via inhibiting TGF-β1 signaling pathway

Purpose Renal fibrosis characterized by accumulation of extracellular matrix protein results in chronic renal diseases including diabetic nephropathy. Transforming growth factor β1 (TGF-β1) signaling pathway plays a key role in mediating renal fibrosis. Hence, agents that antagonize TGF-β signaling could be candidate for kidney disease therapy. Methods We established renal fibrosis model both in vitro with fibroblast cells treated with rhTGF-β1 and streptozocin(STZ)-induced diabetic nephropathy rats model in vivo and evaluated the effect of the aqueous extract of Lycopus lucidus Turcz, the blood-circulation-promoting Chinese herb, on diabetic nephropathy and investigated the mechanism of action. Results We found that Lycopus suppressed rhTGF-β1-induced Smad2 and ERK1/2 activation, down-regulated the expression of TGF-βRI, TGF-βRII, Smad4 and Smad7 in SV40 MES13 cells without inhibiting cell viability. In vivo, lycopus inhibited Smad2 phosphorylation, reduced mRNA level of TGF-β1, ameliorated expansion of the mesangial area in glomerular tissue and reduced the levels of Scr and BUN of serum and total-SOD (superoxide dismutase) activity in STZ-induced diabetic rats. Conclusion Lycopus is a novel inhibitor of renal fibrosis by blocking TGF-β signaling pathway and possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats.

Deposition of the lectin pathway of complement in renal biopsies of lupus nephritis patients

Lupus nephritis (LN) is one of the most serious manifestations of SLE occurring in 66-90% of these patients. The complement system is part of the innate immunity and modulator of inflammation and the adaptative immune response. Mannan-binding lectin (MBL) and Ficolin-2 (FCN-2) are important members of the lectin pathway of complement activation. Despite the significant participation of complement in the pathogenesis of the LN, there are few reports demonstrating "in situ" deposition of complement components in renal biopsy specimens in this disorder. The present study investigated the deposition of complement components in kidney specimens of LN patients. Renal biopsies of 11 patients with SLE and LN were evaluated for immunofluorescence staining for IgG, IgA, IgM, C3, and C1q. Additionally, MBL, FCN-2 and C5b-9 were researched using monoclonal antibodies. All the biopsies were positive for IgG, C3, and C1q, eight were positive IgM and five had IgA deposition in glomerular tissue. The terminal complex of complement C5b9 was positive in all cases, MBL in nine (82%) cases; seven (63.6%) of them presenting concomitantly FCN-2 deposition. Patients presenting MBL deposition had higher mean of urinary proteins (9.0 g/day) than patients with negative MBL deposition (mean of 2.3g/day). In this study, we demonstrated in situ the participation of complement in the renal injury, including MBL and FCN-2 of the lectin pathway; also the strong role of C5b-9 in the pathogenesis of LN.

Rituximab regulates the expression of the Raf kinase inhibitor protein via NF-κB in renal tissue of rats with diabetic nephropathy

This study aimed to investigate the expression levels of the Raf kinase inhibitor protein (RKIP) and NF-κB in renal tissues of diabetic nephropathy (DN) rats, and to determine the underlying molecular targets of rituximab (RTX), with the goal of developing new clinical treatment selection for DN. Sprague-Dawley rats were randomly divided into a normal group (N), a DN group (M), and an RTX treatment group (D). Blood glucose and 24-h urine protein levels of rats were determined. The expression levels of RKIP and NF-κB in glomerular tissues were determined by immunohistochemistry staining and Western blotting. Comparisons between the M and N groups revealed that the concentrations of blood glucose and 24-h urine protein were significantly increased by DN (P < 0.01), and the expression levels of RKIP and NF-κB were significantly decreased and increased (P < 0.05), respectively. In the D group, the expression levels of RKIP and NF-κB were, respectively, upregulated and downregulated by RTX, and the concentrations of 24-h urine protein were also decreased by RTX. These results suggest that expression levels of RKIP might be regulated by RTX via NF-κB. This pathway could play an important role in the development and pathogenesis of DN. Therefore, RTX could be selected for clinical treatment of DN.

당뇨병 동물모델에서 여정엽(女貞葉) 추출물의 항당뇨 및 항염증 효과

Objectives : In this study, we investigated the anti-diabetic and anti-inflammatory effects of water extract from leaves of Ligustrum japonicum (WLJ) in db/db mouse. Methods : The db/db mice were treated orally with WLJ (300 mg/kg/day) for 10 weeks to examine the long-term effects on hyperglycemia and glomerular tissue as well as biochemical and functional abnormalities in the kidney. Results : WLJ treatment markedly reduced plasma levels of glucose, triglyceride, creatinine, and systolic blood pressure in diabetic db/db mouse. Treatment of WLJ significantly increased plasma level of high density lipoprotein (HDL)-cholesterol. We also found that overexpressions of vascular cellular adhesion molecule (VCAM)-1 and endothelin (ET)-1 were observed in aortic tissue of db/db mouse, whereas, WLJ suppressed both expression of VCAM-1 and ET-1 in aorta. In renal tissue, overexpressions of ICAM-1 and TGF-<TEX>${\beta}1$</TEX> were found in untreated db/db mouse, however, significantly decreased those levels by WLJ treatment. The insulin immunoreactivity of the pancreatic islets remarkably increased in WLJ treated db/db mouse compared with untreated db/db mouse. Taken together, WLJ treatment ameliorated hyperglycemia and hyperlipidemia via improvement of insulin secretion and lipid metabolism, respectively. Furthermore, WLJ treatment also ameliorated hypertension via inhibition of inflammatory process in vascular and renal tissues. Conclusions : Ligustrum japonicum has an anti-diabetic and anti-inflammatory effects in db/db mouse. Thus, these results suggested a beneficial effect of Ligustrum japonicum in treatment with diabetes and diabetic vasculopathy.

Not Only Melatonin but also Caffeic Acid Phenethyl Ester Protects Kidneys against Aging-related Oxidative Damage in Sprague Dawley Rats

Microscopic features and antioxidant status of kidneys of young, old, and caffeic acid phenethyl ester (CAPE) and melatonin administered old Sprague Dawley rats were evaluated. Aging-related tubular and glomerular changes were evident. The most prominent tubular alterations were massive vacuole formation, mitochondrial degeneration, and lysosome accumulation. Mean tissue malondialdehyde (MDA) level was increased, mean tissue superoxide dismutase (SOD), catalase (CAT) (p < .001), and glutathione peroxidase (GPx) activities (p < .05), and total glutathione (GSH) level were decreased in old animals. Melatonin significantly reduced tissue MDA levels (p < .005), but increased tissue SOD (p < .001), CAT, and GPx activities (p < .05), and GSH levels (p < .005) in old animals. CAPE also significantly reduced tissue MDA levels (p < .005), but increased tissue SOD (p < .05), CAT (p < .005), GPx activities, and GSH levels (p < .001) in old rats. Mean tissue MDA levels of melatonin and CAPE-administered rats were even lower than those of young rats (p < .05). In conclusion, tubular and glomerular structures and tissue antioxidant enzyme activities were very well preserved in CAPE and melatonin-administered rats.

Neutrophil serine proteases mediate inflammatory cell recruitment by glomerular endothelium and progression towards dysfunction

Neutrophil recruitment into glomerular tissues and reduced capillary wall integrity has been implicated in the development of vasculitic glomerulonephritis (VGN). This study investigated the stages and mechanisms through which neutrophil serine proteases (SPs), proteinase 3 (PR3) or elastase contribute to endothelial dysfunction. Protease-induced damage to endothelium and adhesion molecule upregulation was measured by viability assays and ELISA. Neutrophil/platelet adhesion to human glomerular and umbilical vein endothelium was assessed using in vitro adhesion assays. PR3 and elastase (1 µg/mL, 2 h) significantly induced neutrophil adhesion to endothelial cells (EnC) whilst PR3 also enhanced platelet-EnC interactions. This neutrophil adhesion was associated with enhanced P-selectin expression and required CXCL8 receptor involvement, and could be inhibited by blocking the P-selectin ligand PSGL-1. SPs induced damage in a time- and dose-dependent fashion, decreasing cell monolayer integrity followed by cell membrane integrity, inducing caspase-3 activation and p21 cleavage. However, SPs caused significant EnC damage with increasing concentrations and prolonged exposures. Neutrophil SPs induce a pro-adhesive phenotype in glomerular endothelium primarily by inducing neutrophil and platelet adhesion that transits to dysfunction after high/prolonged exposures. Dysregulated release of these enzymes within glomeruli may contribute to injury during diseases such as VGN.

Effect of cadmium chloride and ascorbic acid exposure on the vital organs of freshwater Cyprinid, Labeo rohita

The present study was carried out to evaluate the impact of sub lethal concentrations of heavy metal, cadmium chloride (CdCl 2 .H 2 O), ascorbic acid (vitamin C) and their combination on Labeo rohita . The effect was investigated on the basis of histopathological examinations of control and experimental groups exposed to heavy metal. The acute semi statistical toxicity test for L. rohita revealed 96 h LC 50 value 22.92 mg L -1 for cadmium chloride (CdCl 2 .H 2 O). 215 fingerlings of L. rohita were exposed to three different experimental conditions for 96 h: 11.46 mg L -1 CdCl 2 .H 2 O, or 450 mg Kg -1 ascorbic acid or combination of both these doses. No alterations were observed in gill sections upon comparison between treated and untreated groups. Congestion in sinusoids, fatty change, an increase in Kupffer cells and intrahepatic lymphocytes was observed in CdCl 2 .H 2 O treated group. In kidney sections of heavy metal treated group, degeneration of the glomerular tissue, occlusion in tubular lumen and necrosis were observed. Similar changes but in less severe form, as described above, were observed in the fish exposed to combination of CdCl 2 .H 2 O and ascorbic indicating that ascorbic acid do detoxify the effect of heavy metal to some extant. Our results indicate that cadmium chloride (CdCl 2 .H 2 O), if present in fresh water bodies, may act as strong toxic agent for L. rohita . Keywords: Labeo rohita , cadmium chloride (CdCl 2 .H 2 O), ascorbic acid, histopathology

A Phytochemical Approach to Experimental Metabolic Syndrome-Associated Renal Damage and Oxidative Stress

The aim of this study was to evaluate the effect of DTS-phytocompound on oxidant-antioxidant balance and protein damage in the kidneys of rats administered high doses of fructose. Adult male Wistar rats were divided into four groups. Group A received a control diet, whereas groups B and C were fed a high-fructose diet (60 g/100 g), the latter with additional DTS (50 mg/kg per day) for 60 days. Lipo- and nitro-peroxidation together with α-smooth muscle actin (α-SMA) expression in the glomerular and interstitial tissue of the kidneys were measured after 60 days. Fructose-fed rats showed significantly higher lipoperoxidation, 2,4-dinitrophenol and 3-nitrotyrosine protein adducts, and upregulation of α-SMA in the kidney. DTS significantly decreased such redox unbalance in renal tissue, while partially downregulating α-SMA (p<0.01). These data suggest the potential clinical benefit of DTS in protecting the kidneys from metabolic syndrome-associated changes; gender-related analysis is under way.

Protective role for CCR5 in murine lupus nephritis

Leukocyte infiltration is a characteristic feature of human and experimental lupus nephritis and is closely correlated with loss of renal function. The chemokine receptor CCR5 is expressed on monocyte and T cell subsets and is thought to play an important role in recruiting these cells into inflamed organs. To investigate the functional role of CCR5 in lupus nephritis, CCR5-deficient mice were backcrossed onto the lupus-prone MRL-Fas(lpr) (MRL/lpr) genetic background. Unexpectedly, CCR5(-/-) MRL/lpr mice developed an aggravated course of lupus nephritis in terms of glomerular tissue injury and albuminuria. Deterioration of the nephritis was associated with an overall increase in mononuclear cell infiltration into the kidney, whereas renal leukocyte subtype balance, systemic T cell response, and autoantibody formation were unaffected by CCR5 deficiency. Renal and systemic protein levels of the CCR5 ligand CCL3, which can also attract leukocytes via its alternate receptor CCR1, were significantly increased in nephritic CCR5(-/-) MRL/lpr mice. Further studies revealed that the systemic increase in the CCR5/CCR1 ligand is also observed in nonimmune CCR5(-/-) C57BL/6 mice and that this increase was due to a reduced clearance, rather than an overproduction, of CCL3. Taken together, our data support the hypothesis that CCR5-dependent consumption of its own ligands may act as a negative feedback loop to restrain local chemokine levels within inflamed tissues, thereby limiting inflammatory cell influx.

Morphometric Analysis of Nonsclerosed Glomeruli Size and Connective Tissue Content during the Aging Process

Number of sclerotic glomeruli increases during the aging process. Consequently, majority of remained nonsclerosed glomeruli become hypertrophic and some of them sclerotic, too. The aim of this study was to quantify the size and connective tissue content of nonsclerosed glomeruli and to evaluate the percentage of hypertrophic ones in examined human cases during the aging. Material was right kidney's tissue of 30 cadavers obtained during routine autopsies. Cadavers were without previously diagnosed kidney disease, diabetes, hypertension, or any other systemic disease. Tissue specimens were routinely prepared for histological and morphometric analysis. Images of the histological slices were analyzed and captured under 400x magnification with digital camera. Further they were morphometrically and statistically analyzed with ImageJ and NCSS-PASS software. Multiple and linear regression of obtained morphometric parameters showed significant increase of glomerular connective tissue area and percentage. Cluster analysis showed the presence of two types of glomeruli. Second type was characterized with significantly larger size, connective tissue content, and significantly lower cellularity, in relation to the first type. Such glomeruli might be considered as hypertrophic. First type of glomeruli was predominant in younger cases, while second type of glomeruli was predominant in cases older than 55 years.

MRI to assess renal structure and function

In addition to excellent anatomical depiction, MRI techniques have expanded to study functional aspects of renal physiology, such as renal perfusion, glomerular filtration rate (GFR) or tissue oxygenation. This review will focus on current developments with an emphasis on clinical applicability. The method of GFR determination is largely heterogeneous and still has weaknesses. However, the technique of employing liver disappearance curves has been shown to be accurate in healthy persons and patients with chronic kidney disease. In potential kidney donors, complete evaluation of kidney anatomy and function can be accomplished in a single-stop investigation. Techniques without contrast media can be utilized to measure renal tissue oxygenation (blood oxygen level-dependent MRI) or perfusion (arterial spin labeling) and could aid in the diagnosis and treatment of ischemic renal diseases, such as renal artery stenosis. Diffusion imaging techniques may provide information on spatially restricted water diffusion and tumor cellularity. Functional MRI opens new horizons in studying renal physiology and pathophysiology in vivo. Although extensively utilized in research, labor-intensive postprocessing and lack of standardization currently limit the clinical applicability of functional MRI. Further studies are necessary to evaluate the clinical value of functional magnetic resonance techniques for early discovery and characterization of kidney disease.

Interstitial fibrosis is associated with increased COL1A2 transcription in AA-injured renal tubular epithelial cells in vivo

Accumulation of type I collagen is a key event in renal interstitial fibrosis. As there is no effective treatment, understanding the site where collagen is transcribed and the factors driving it in response to disease in vivo is critical for designing future therapies. The present research investigated the transcriptional activity of the COL1A2 gene in a mouse model of progressive fibrosis induced by aristolochic acid (aristolochic acid nephropathy, AAN). To achieve this we genetically modified mice to express a reporter gene (LacZ) and CCN2 (connective tissue growth factor) under the transcriptional control of the COL1A2 promoter /enhancer sequences. Using these mice we asked where is collagen actively transcribed and secondly, what is the role of CCN2 in AAN. Here, we report that de-novo transcription of the COL1A2 gene occurred predominantly in damaged tubular epithelial cells during progressive interstitial fibrosis in vivo. The activation of COL1A2 was studied by detection of the reporter gene LacZ and COL1A2 mRNA in interstitial, glomerular, vascular, and tubular epithelial tissue from laser capture microscopy. We also demonstrated that LacZ-positive cells co-express E-Cadherin a marker of epithelial origin which is consistent with an epithelial phenotype which is capable of collagen expression during injury. There was no evidence of detachment of these cells from tubules to become myofibroblasts. Moreover, we showed that the transgenic mice show a modest enhancement of CCN2 expression; however fibrosis induced by AA is the same in transgenics and controls suggesting that CCN2, at this level of expression, is not sufficient to enhance fibrogenesis. Overall our study provides a better understanding into the expression patterns and roles of two major extracellular matrix proteins: type I collagen and CCN2.

Endothelial Factors and Diabetic Nephropathy

The rising incidence and prevalence of chronic kidney disease (CKD) (glomerular filtration rate <60 mL/min per 1.73 m2) is a major public health concern (U.S. Renal Data System 2010, http://www.usrds.org). Hypertension is the second leading cause of end-stage renal disease (ESRD) in the U.S. and is also a major contributor to diabetic renal disease, which is the leading cause of CKD and ESRD (U.S. Renal Data System 2010). The diabetes-related ESRD annual incidence rate has been decreasing since 1996, suggesting that the net increase in diabetes-related ESRD may be secondary to the documented pandemic of type 2 diabetes (1,2). In the general population, CKD predicts death and cardiovascular disease (CVD) events, independently of traditional cardiovascular risk factors such as age, sex, prior CVD, diabetes, hypertension, dyslipidemia, and proteinuria (3). CKD in patients with type 2 diabetes is independently associated with an ∼8–10% annual absolute risk for death and CVD (4). The majority of patients with CKD will die of a CVD event before they reach end-stage renal failure and dialysis treatment (5), and an estimated glomerular filtration rate <60 mL/min is now classified as a major independent risk factor for CVD. Endothelial dysfunction has been implicated as a potential major mechanism for renal chronic microvascular complications both in diabetic and nondiabetic patients with albuminuria. There is a general assumption of a final common biological pathway that results in diabetic kidney disease and renal failure. As shown in Fig. 1, hyperglycemia and hypertension interact at the glomerulus, resulting in glomerular hypertension and, as a consequence, proteinuria, glomerular and interstitial tissue fibrosis (6), progressive decline in glomerular filtration rate, and finally renal failure. Figure 1 Principal mechanisms of diabetic glomerulopathy. Hyperglycemia and hypertension interact at the glomerulus, resulting in glomerular hypertension, progressive glomerular and interstitial tissue fibrosis, and decline …