OBJECTIVEClinicopathological characteristics, renal prognosis, and mortality in patients with type 2 diabetes and reduced renal function without overt proteinuria are scarce.
RESEARCH DESIGN AND METHODSWe retrospectively assessed 526 patients with type 2 diabetes and reduced renal function (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m 2 ), who underwent clinical renal biopsy and had follow-up data, from Japan's nationwide multicenter renal biopsy registry. For comparative analyses, we derived oneto-two cohorts of those without proteinuria versus those with proteinuria using propensity score-matching methods addressing the imbalances of age, sex, diabetes duration, and baseline eGFR. The primary end point was progression of chronic kidney disease (CKD) defined as new-onset end-stage renal disease, decrease of eGFR by ‡50%, or doubling of serum creatinine. The secondary end point was all-cause mortality.
RESULTS
Eighty-two patients with nonproteinuria (urine albumin-to-creatinine ratio [UACR]<300 mg/g) had lower systolic blood pressure and less severe pathological lesions compared with 164 propensity score-matched patients with proteinuria (UACR ‡300 mg/g). After a median follow-up of 1.9 years (interquartile range 0.9-5.0 years) from the date of renal biopsy, the 5-year CKD progression-free survival was 86.6% (95% CI 72.5-93.8) for the nonproteinuric group and 30.3% (95% CI 22.4-38.6) for the proteinuric group (log-rank test P < 0.001). The lower renal risk was consistent across all subgroup analyses. The all-cause mortality was also lower in the nonproteinuric group (log-rank test P 5 0.005).
CONCLUSIONSPatients with nonproteinuric diabetic kidney disease had better-controlled blood pressure and fewer typical morphological changes and were at lower risk of CKD progression and all-cause mortality.
Inflammatory abdominal aortic aneurysm (IAA) is associated with autoimmune disease. However, the precise mechanism of IAA remains unclear. There is increasing evidence that IgG4 is involved in the autoimmune mechanism of various idiopathic sclerosing lesions, including sclerosing pancreatitis and retroperitoneal fibrosis. The present study investigated the hypothesis that the IgG4-related autoimmune reaction is involved in the formation of IAA. The study group consisted of 11 cases of IAA (69.2 +/- 8.59y) and 12 age-matched cases of atherosclerotic abdominal aortic aneurysm (AAA, 69.6 +/- 5.94y), which were used in the previous report. A clinicopathologic examination of these lesions was performed, including histology and immunohistochemistry, in relation to the involvement of IgG4-positive plasma cells in the formation of IAA. No difference in the incidence of risk factors for atherosclerosis was observed between the patients with IAA and AAA. Autoimmune diseases were diagnosed in 2 patients with IAA, including rheumatoid arthritis and polyarteritis nodosa. A patient with IAA had pulmonary fibrosis. In contrast, autoimmune diseases were absent in patients with AAA. However, there was no significant difference in the incidence of autoimmune diseases between the patients with IAA and AAA. Lymphocyte and plasma cell infiltration and fibrosis were significantly more intense and extensive in IAA than in AAA. In addition, lymph follicle formation and vasculitis of small veins and arteries were frequently found in the affected lesions of IAA. Immunohistochemically, IAA showed a significant increase in the number of infiltrating IgG4-positive plasma cells and the incidence of a disrupted follicular dendritic cell network in lymph follicles, in comparison with AAA. These findings suggest that IAA may be an aortic lesion reflecting the presence of IgG4-related sclerosing disease, and not a simple inflammatory aneurysm of the aorta.
This nationwide study on kidney biopsy of 600 cases with type 2 diabetes revealed that pathologic findings (presence of nodular lesions, exudative lesions and mesangiolysis) were strong predictors of kidney events in low-risk patients.
Collapsing focal segmental glomerulosclerosis (cFSGS) is a progressive kidney disease characterized by glomerular collapse with epithelial hyperplasia. Here we used a transgenic mouse model of cFSGS with immunotoxin-induced podocyte-specific injury to determine the role for Notch signaling in its pathogenesis. The mice exhibited progressive loss of podocytes and severe proteinuria concomitant with histological features of cFSGS. Hyperplastic epithelium was negative for genetic podocyte tags, but positive for the parietal epithelial cell marker claudin-1, and expressed Notch1, Jagged1, and Hes1 mRNA and protein. Enhanced Notch mRNA expression induced by transforming growth factor-β1 in cultured parietal epithelial cells was associated with mesenchymal markers (α-smooth muscle actin, vimentin, and Snail1). Notch inhibition in vitro suppressed these phenotypic transcripts and Notch-dependent cell migration. Moreover, Notch inhibition in vivo significantly decreased parietal epithelial cell lesions but worsened proteinuria and histopathology in our cFSGS model. Thus, aberrant Notch1-mediated parietal epithelial cell migration with phenotypic changes appears to underlie the pathogenesis of cFSGS. Parietal epithelial cell hyperplasia may also represent an adaptive response to compensate for a disrupted filtration barrier with progressive podocyte loss.
Fibroblastic foci, a major histological feature of usual interstitial pneumonia (UIP), play a critical role in the development of UIP. The mechanisms involved in the formation of these foci, however, including cellular origin, remain unclear. Recent in vitro and animal studies suggested epithelial-mesenchymal transition (EMT) of alveolar epithelial cells during pulmonary fibrogenesis. The aim of the present study was to investigate the presence of EMT in patients with UIP on quantitative immunohistochemistry using pathological tissue sections. The study subjects were 13 patients with UIP pattern among 52 patients with interstitial pneumonia who underwent lung biopsy. Alveolar epithelial cells overlying fibroblastic foci expressed epithelial markers less frequently and mesenchymal markers more frequently compared with those in non-diseased control lung tissues (n= 10). Moreover, double immunostaining showed that some epithelial cells stained for both epithelial and mesenchymal markers. Furthermore, significantly higher numbers of epithelial marker-positive fibroblastic cells were found in fibroblastic foci in UIP as well as in other non-UIP fibrosing diseases than in control lung tissues. The results showed that some epithelial cells overlying fibroblastic foci lose the epithelial phenotype and gain the mesenchymal phenotype, and that some fibroblastic cells in fibroblastic foci originate from epithelial cells. But this EMT may not be specific for UIP.
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