Structural Lesions on Kidney Biopsy in Youth-Onset and Adult-Onset Type 2 Diabetes

<b>Objective: </b>Type 2 diabetes (T2D) is a leading cause of end stage kidney disease (ESKD) worldwide. Recent studies suggest a more aggressive clinical course of diabetic kidney disease (DKD) in youth-onset than adult-onset T2D. We compared kidney structural lesions in youth- and adult-onset T2D to determine if youth-onset was associated with greater early tissue injury.<b></b> <p><b> </b></p> <p><b>Methods: </b>Quantitative microscopy was performed on kidney tissue obtained from research kidney biopsies in 161 Pima Indians (117 women, 44 men) with T2D. Onset of T2D was established by serial oral glucose tolerance testing and participants were stratified as youth-onset (<25 years) or adult-onset (≥25 years). Associations between clinical and morphometric parameters and age of onset were tested using linear models.<b></b></p> <p><b> </b></p> <p><b>Results: </b>At biopsy, the 52 participants with youth-onset T2D were younger than the 109 with adult-onset T2D (39.1±9.9 <i>vs.</i> 51.4±10.2 years, <i>p</i><0.0001), but their diabetes duration was similar (19.3±8.1 <i>vs.</i> 17.0±7.8 years, <i>p</i>=0.09). Median urine albumin-to-creatinine ratio was higher in the youth-onset group (58 [25^th-75^th percentile, 17-470] <i>vs.</i> 27 [13-73] mg/g, <i>p</i>=0.02). Youth-onset participants had greater glomerular basement membrane (GBM) width (552±128 nm <i>vs.</i> 490±114nm, <i>p</i>=0.002) and mesangial fractional volume (0.31±0.10 <i>vs</i>. 0.27±0.08, <i>p</i>=0.001) than adult-onset participants. Percentage glomerular sclerosis, glomerular volume, mesangial fractional volume, and GBM width were also inversely associated with age of diabetes onset as a continuous variable.<b></b></p> <p><b> </b></p> <p><b>Conclusion: </b>Younger age of T2D onset strongly associates with more severe kidney structural lesions. Studies are underway to elucidate the pathways underlying these associations.</p>

Role of Palatine Tonsil and Epipharyngeal Lymphoid Tissue in the Development of Glomerular Active Lesions (Glomerular vasculitis) in Immunoglobulin A Nephropathy

Hematuria is an essential symptom of immunoglobulin A nephropathy (IgAN). Although the etiology of hematuria in IgAN has not been fully elucidated, it is thought that the rupture of the glomerular basement membranes caused by intra-capillary leukocyte influx, so-called glomerular vasculitis, is the pathological condition responsible for severe hematuria. Glomerular vasculitis are active lesions that exist in the glomeruli of acute phase IgAN and it is important because it is suspected to make the transition to segmental glomerular sclerosis (SGS) as a repair scar lesion in the chronic phase, and the progression of SGS would eventually lead to glomerular obsolescence. Worsening of hematuria concomitant with acute pharyngitis is common in patients with IgAN; therefore, elucidating the relationship between the immune system of Waldeyer’s ring, including the palatine tonsil and epipharyngeal lymphoid tissue, and the glomerular vasculitis may lead to understanding the nature of IgAN. The epipharynx is an immunologically activated site even under normal conditions, and enhanced activation of innate immunity is likely to occur in response to airborne infection. Hyperactivation of innate immunity via upregulation of Toll-like receptors in the interfollicular area of the palatine tonsil and epipharyngeal lymphoid tissue, followed by enhanced fractalkine/CX3CR1 interactions, appears to play an important role in the development of glomerular vasculitis in IgAN. As latent but significant epipharyngitis is present in most patients with IgAN, it is plausible that acute upper respiratory infection may contribute as a trigger for the innate epipharyngeal immune system, which is already upregulated in a chronically inflamed environment. Given that epipharyngitis and its effects on IgAN are not fully understood, we propose that the so-called “epipharynx–kidney axis” may provide an important focus for future research.

Structural Lesions on Kidney Biopsy in Youth-Onset and Adult-Onset Type 2 Diabetes

<b>Objective: </b>Type 2 diabetes (T2D) is a leading cause of end stage kidney disease (ESKD) worldwide. Recent studies suggest a more aggressive clinical course of diabetic kidney disease (DKD) in youth-onset than adult-onset T2D. We compared kidney structural lesions in youth- and adult-onset T2D to determine if youth-onset was associated with greater early tissue injury.<b></b> <p><b> </b></p> <p><b>Methods: </b>Quantitative microscopy was performed on kidney tissue obtained from research kidney biopsies in 161 Pima Indians (117 women, 44 men) with T2D. Onset of T2D was established by serial oral glucose tolerance testing and participants were stratified as youth-onset (<25 years) or adult-onset (≥25 years). Associations between clinical and morphometric parameters and age of onset were tested using linear models.<b></b></p> <p><b> </b></p> <p><b>Results: </b>At biopsy, the 52 participants with youth-onset T2D were younger than the 109 with adult-onset T2D (39.1±9.9 <i>vs.</i> 51.4±10.2 years, <i>p</i><0.0001), but their diabetes duration was similar (19.3±8.1 <i>vs.</i> 17.0±7.8 years, <i>p</i>=0.09). Median urine albumin-to-creatinine ratio was higher in the youth-onset group (58 [25^th-75^th percentile, 17-470] <i>vs.</i> 27 [13-73] mg/g, <i>p</i>=0.02). Youth-onset participants had greater glomerular basement membrane (GBM) width (552±128 nm <i>vs.</i> 490±114nm, <i>p</i>=0.002) and mesangial fractional volume (0.31±0.10 <i>vs</i>. 0.27±0.08, <i>p</i>=0.001) than adult-onset participants. Percentage glomerular sclerosis, glomerular volume, mesangial fractional volume, and GBM width were also inversely associated with age of diabetes onset as a continuous variable.<b></b></p> <p><b> </b></p> <p><b>Conclusion: </b>Younger age of T2D onset strongly associates with more severe kidney structural lesions. Studies are underway to elucidate the pathways underlying these associations.</p>

Therapeutic Response and Long-Term Renal Outcomes in Childhood Idiopathic Steroid-Resistant Nephrotic Syndrome: A Single-Center Study

<b><i>Purpose:</i></b> We aimed to evaluate therapeutic response and long-term renal outcomes of childhood idiopathic steroid-resistant nephrotic syndrome (iSRNS). <b><i>Methods:</i></b> We retrospectively reviewed treatment regimens, especially calcineurin inhibitor (CNI), pathologic diagnoses, and long-term renal outcomes of iSRNS patients for 30 years. <b><i>Results:</i></b> Of 516 patients with idiopathic NS, 52 (10.1%) had iSRNS. Renal biopsies from 48 patients showed minimal change disease (MCD) in 23 (47.9%), focal segmental glomerulosclerosis in 24 (50.0%), and mesangioproliferative glomerulonephritis in 1 (2.1%). The median follow-up period was 66.5 (range, 4–275) months, and 90.4% of them were treated with a CNI. CNI induced remission in 70.2% within 50.4 ± 43.5 days. Of the patients with MCD and focal segmental glomerular sclerosis (FSGS), 86.4% (19/22) and 45.0% (9/20) (<i>p =</i> 0.005) responded to CNI, respectively. Mean time until remission after using CNI was longer with FSGS (90.4 ± 54.0 days) than with MCD (29.6 ± 26.3 days) (<i>p =</i> 0.010). CNI-responsive patients with FSGS or MCD showed preserved renal function, and CNI nonresponsive MCD patients also showed preserved renal function during follow-up. However, end-stage renal disease (ESRD) progressed in 8 out of 11 patients with FSGS nonresponsive to the CNI for an average of 44.9 ± 18.4 months after diagnosis. <b><i>Conclusion:</i></b> Different response rates and times for remission were achieved with the CNI according to the pathology of iSRNS. All MCD patients regardless of CNI response and all CNI-responsive patients with FSGS showed excellent renal outcomes, while almost all FSGS patients nonresponsive to CNI eventually progressed to ESRD.

Effective Treatment of a Post-renal Transplantation Patient with Early Recurrent Focal Segmental Glomerulosclerosis and Concomitant Hemolytic Uremic Syndrome, a Case Report

While recurrence of primary Focal Segmental Glomerular Sclerosis (FSGS) is common post renal transplantation (30%-80%), a concomitant presentation of hemolytic uremic syndrome (HUS) and recurrent FSGS has never been reported. In addition, treatment of recurrent FSGS and HUS post-renal transplantation is challenging; and usually individualized based on center's experience. Here, we reported a case of a pediatric patient with early recurrence of FSGS and concomitant HUS post-renal transplantation. This patient had a complete hematological and renal response following the administration of Eculizumab and Rituximab, respectively. Withdrawal of Tacrolimus as well as plasmapheresis did not improve kidney function. Therefore, we concluded that both Eculizumab and Rituximab could achieve remission in comparable cases when administered at fixed intervals.

Assessment of renal glomerulosclerosis and thickness of the carotid intima-media complex as a means of age estimation in Western European bodies

Introduction The estimation of age-at-death of unidentified cadavers is a central aspect of the identification process. With increasing age, the incidence of glomerulosclerosis and the thickness of the carotid wall have been observed to also increase. This correlation has been demonstrated in various international histological studies. The aim of our study was to assess whether these correlations also apply to a Western European population. Methodology In this retrospective observational study, kidney and common carotid artery samples from 216 cases autopsied at the Institute of Legal Medicine at the Justus-Liebig University in Giessen, Germany, were examined. Only cases with available tissue samples from both body sides were included. Exclusion criteria were poor sample quality and an age younger than 21 years. After histological processing, the tissue samples were assessed and digitally evaluated. Regression and classification analyses were used to investigate the correlation between age-at-death and intima-media thickness and age-at-death and the incidence of renal glomerular sclerosis. Results Of the 216 autopsy cases, 183 were included for evaluation. Analysis of the carotid artery segments showed a strong correlation (Pearson correlation coefficient r = 0.887) between the intima-media-complex thickness and chronological age. Classification of the glomerulosclerotic incidence showed a correlation of 37.7–43.1% with the predicted age group. Discussion Both the intima-media thickness and the proportion of sclerotic glomeruli can be used to estimate age in Western European cadavers. On the basis of these results, both methods are suited to supplement other already established methods for age-at-death estimation in the identification of an unknown cadaver.

Beyond ISN/RPS lupus nephritis classification: adding chronicity index to clinical variables predicts kidney survival

Background. A renewed interest for activity and chronicity indices as predictors of lupus nephritis (LN) outcome has emerged. Revised National Institutes of Health (NIH) activity and chronicity indices have been proposed to classify LN lesions but should be validated by future studies. Aims of this study: i) to detect the histological features associated with the development of Kidney Function Impairment (KFI); ii) to identify the best clinical-histological model to predict KFI at time of kidney biopsy. Methods. LN patients with kidney biopsy containing >10 glomeruli per specimen were admitted to the study. Univariate and multivariate logistic regression and Cox proportional hazards model were used to investigate whether activity and chronicity indices could predict KFI development. Results. Among 203 LN participants followed for 14 years, correlations were found between activity index and its components and clinical-laboratory signs of active LN at baseline. Chronicity index was correlated with serum creatinine. Thus, serum creatinine was significantly and directly correlated with both activity and chronicity indexes. At multivariate analysis glomerular sclerosis (OR:3.0478, CI:1.173-7.91, P=0.022) and fibrous crescents (OR:6.8352, CI:3.218-14.519, P<0.001) associated with either moderate/severe tubular atrophy (OR:3.1697, CI:1.042-9.643, P=0.0421), or with interstitial fibrosis (OR:2.361, CI:1.047-5.322, P=0.0383) predicted KFI. Considering both clinical and histological features, serum creatinine (OR:1.677; 1.311-2.145; P<0.001), arterial hypertension (OR:4.641, CI: 1.902-11.324, P<0.001), glomerular sclerosis (OR:2.123, CI:1.001-4.503, P=0.049), and fibrous crescents (OR:5.182, CI: 2.433-11.037, P<0.001) independently predicted KFI. Older age (P<0.001) and longer delay between clinical onset of LN and kidney biopsy (P<0.001) were significantly correlated with baseline chronicity index. Conclusions. Chronicity index and its components, but not activity index, were significantly associated with an impairment of kidney function. The Cox model showed that serum creatinine, arterial hypertension, chronic glomerular lesions and delay in kidney biopsy predicted KFI. These data reinforce the importance of timely kidney biopsy in LN.

A study on the relationship between morphological lesions of lupus nephritis with demographic and biochemical findings

Introduction: Lupus nephritis is one of the important aspects of systemic lupus erythematosus (SLE). Objectives: This study aimed to investigate possible relationship between pathological lesions of lupus nephritis classes and demographic and biochemical findings among patients. Patients and Methods: This is a cross-sectional study that was conducted on a group of renal biopsy proven lupus nephritis patients using lupus nephritis classification of ISN/RPS 2003. We collected demographic data of all patients including age, gender serum creatinine and 24h proteinuria. Results: Data of 101 patients, of whom 78 (77.23%) were females and mean age of 33.54±13.15 years. The mean serum creatinine and proteinuria were 1.54±0.88 mg/dL 2502.5±1495.05 mg/d. Based on our data, IV-G (class IV, diffuse lupus nephritis-global) lupus nephritis class was the most common (39.6%) followed by class III (23.8%). The mean crescent and sclerotic glomeruli were 1.66±3.32 and 2.27±5.32, respectively. In this study, 24 hours proteinuria, serum creatinine, activity percent, chronicity percent, crescent and glomerular sclerosis between genders showed no significant differences (P>0.05). The correlation between plasma creatinine and activity was directly positive and significant (r=0.381, P=0.001). In addition, a significant correlation between C1q deposits and glomerular sclerosis (P=0.031) was detected. Accordingly, a significant correlation between IgG deposits and lupus nephritis classification (P=0.025) was seen. Conclusion: Lupus nephritis of IV-G and III classes of lupus nephritis were most common among patients and higher IgG deposits were observed in patients with IV-G classification. We found a significant correlation between glomerular sclerosis and C1q deposits that could be an indicator of lupus nephritis activity and severity. However, we recommend further studies in this regard.

Clinicopathological characteristics and prognosis of patients with IgA nephropathy and renal vasculitic lesions

Background We studied patients with IgA nephropathy (IgAN) and compared those with and without renal vasculitic lesions (RVLs). Methods From January 2006 to December 2011, patients with biopsy-proven primary IgAN at our institution were retrospectively examined and assigned to an RVL group or a no-RVL group. RVLs were defined as thromboses in arteries and/or arterioles, necrosis of capillary loops, crescent formation, and fibrinoid necrosis of small blood vessels. The association of RVLs with clinical outcomes was analyzed using multivariate models. The primary composite endpoint was end-stage renal disease or doubling of serum creatinine. Results There were 1570 patients, 50.2% (788) with RVLs and 49.8% (782) without RVLs. The RVL group was younger; had shorter disease course, more severe proteinuria and hematuria, worse renal function; and were prescribed more steroids and/or immunosuppressants. The RVL group had a greater prevalence of global glomerular sclerosis, more crescents, and a higher Oxford classification grade. A total of 501 patients in the RVL group (50.7%) and 487 in the no-RVL group (49.3%) completed follow-up. The RVL group was more likely to reach the composite endpoint after 1, 3, and 5 years (all P < 0.001). Proteinuria, anemia, low eGFR, and global and segmental sclerosis were independent predictors of progression to the composite endpoint in patients with RVLs. Conclusions Almost half of our IgAN patients had RVLs, and these patients were younger and had worse renal function, with more severe proteinuria, hematuria, and severe pathologic lesions. IgAN patients with RVLs had worse renal outcomes than those without RVLs.

Pathomorphological Sequence of Nephron Loss in Diabetic Nephropathy

Following our reports on mesangial sclerosis and vascular proliferation in diabetic nephropathy (DN)(25,34) we now describe the advanced stages of DN terminating in glomerular obsolescence and tubulo-interstitial fibrosis based on a total of 918 biopsies. The structural aberrations emerge from two defects: First, an increased synthesis of glomerular basement membrane (GBM) components by podocytes and endothelial cells leading to an accumulation of GBM material in the mesangium. Second, a defect of glomerular vessels consisting of an increased leakiness and an increased propensity to proliferate. Both defects may lead to glomerular degeneration. The progressing compaction of the accumulated worn-out GBM-material together with the retraction of podocytes out of the tuft and the collapse and hyalinosis of capillaries results in a shrunken tuft that fuses with Bowman's capsule to glomerular sclerosis. The most frequent pathway to glomerular decay starts with local tuft expansions that result in contacts of structurally healthy podocytes to the parietal epithelium initiating the formation of tuft adhesions, which include the penetration of glomerular capillaries into BC. Exudation of plasma from such capillaries into the space between the parietal epithelium and its basement membrane causes the formation of insudative fluid accumulations within BC spreading around the glomerular circumference and, via the glomerulo-tubular junction, onto the tubule. Degeneration of the corresponding tubule develops secondarily to the glomerular damage, either due to cessation of filtration in cases of global sclerosis or due to encroachment of the insudative spaces. The degenerating tubules induce the proliferation of myo-fibroblasts resulting in interstitial fibrosis.