Discrimination between postinfectious IgA-dominant glomerulonephritis and idiopathic IgA nephropathy

Background: A unique form of postinfectious glomerulonephritis (PIGN) with IgA-dominant deposition mimicking IgA nephropathy has been increasingly reported. Methods: We compared the clinical and histological features of 12 patients with postinfectious IgA-dominant glomerulonephritis to 134 patients with idiopathic IgA nephropathy. Results: In addition to hypocomplementemia and subepithelial hump-shaped deposits characteristic of PIGN, patients with postinfectious IgA-dominant glomerulonephritis had older age (62.3 ± 16.9 vs. 37.9 ± 16.3 years; p < 0.001) and more frequently presented with acute renal failure (83.3% vs. 10.4%; p < 0.001) than patients with idiopathic IgA nephropathy. Moreover, glomerular changes including endocapillary proliferation, neutrophil infiltration, and capillary loops deposits by immunofluorescence were more commonly present in postinfectious IgA-dominant glomerulonephritis group (p < 0.001). Conclusions: PIGN could be characterized by glomerular IgA-dominant deposition resembling idiopathic IgA nephropathy. It is essential to differentiate postinfectious IgA-dominant glomerulonephritis from idiopathic IgA nephropathy because of the different treatments and prognosis of the two diseases.     

The Spectrum of Adult Postinfectious Glomerulonephritis in the New Millennium

Background. Postinfectious glomerulonephritis is rare in adults. The characteristics of the disease now differ from what were described decades ago. The goal of this study is to illustrate the clinicopathological spectrum of the disease in the modern era. Methods. Between July 2000 and June 2008, 20 adult cases of postinfectious glomerulonephritis were identified at a medical center in Taiwan. The patients' records were retrospectively reviewed with respect to clinical presentation, microbiology, serology, morphology of renal biopsy, and clinical course. Results. There were 14 males and 6 females. The mean age was 61 years. All patients developed acute renal failure, and the majority (65%) required dialysis support during the disease course. Hypocomplementemia was present in 60% of patients. The most frequently identified infectious agent was Staphylococcus (60%). Histological characteristics showed two distinct patterns of glomerulonephritis: diffuse endocapillary proliferative glomerulonephritis (65%) and focal mesangial proliferative glomerulonephritis (35%). There were no significant differences in the clinical presentation and outcome between the two groups. However, glomerular neutrophil infiltration was more commonly present in diffuse endocapillary proliferative pattern (p = 0.017). The percentage of patients with focal mesangial proliferative pattern significantly increased over time (p < 0.001). At the last follow-up, 6 patients (30%) had died, 6 (30%) were in complete remission, 4 (20%) had partial remission with renal insufficiency, and 4 (20%) were on chronic dialysis. Conclusions. Our data suggested that Staphylococcus had become the leading pathogen in adult postinfectious glomerulonephritis over the past 10 years. Furthermore, atypical histological feature with focal mesangial proliferative pattern was increasingly identified over time. The prognosis was still guarded, carrying a considerable mortality rate and risk for developing chronic renal failure.     

The Relationship between the VEGF Levels and VEGF mRNA Expression and Clinical Course in Different Glomerulonephritis

In this study, serum and urinary VEGF levels and VEGF expression in PBMNC were correlated with daily proteinuria, renal function tests, and renal histopathologic findings in untreated patients with different glomerulonephritis and with the course of renal function and proteinuria for one year. Forty-five untreated patients with different glomerulonephritis and 11 healthy persons comprised the study and control groups, respectively. VEGF mRNA expression was detected by RT- PCR in peripheral blood mononuclear cells (PBMNC), and VEGF levels were measured by ELISA in serum and urine samples simultaneously. Male/female ratio was 24/21 and mean ages were 34.49 ± 14.98. Serum and urinary VEGF levels, VEGF expressions in PBMNC, and the ratios of urine VEGF/urine creatinine were found to be similar in patients and controls. There were important correlations between urinary VEGF levels and baseline serum Cr (p = 0.035) and ESR (p = 0.022). There was also a marginal correlation between urinary VEGF levels and baseline CCr (p = 0.072). There was no correlation between serum and urinary VEGF levels and PBMNC mRNA expression and pathological findings such as with or without glomerular sclerosis, tubulointerstitial fibrosis (TIF), periglomerular fibrosis, and mesangial cell proliferation in renal biopsy. Serum and urinary VEGF levels or VEGF expression in PBMNC in patients with renal amyloidosis or proliferative or nonproliferative glomerulonephritis were similar with that of healthy controls and each other. Serum and urinary VEGF levels and PBMNC VEGF mRNA expression in untreated patients with different glomerulonephritis and controls were similar. We found only one important correlation, that between urinary VEGF levels and baseline serum creatinine levels in patients with different glomerulonephritis. Urinary VEGF can be an important pathogenesis of glomerular disease or a simple proteinuria. Serum and urinary VEGF levels and PBMNC VEGFmRNA did not change by periglomerular sclerosis, periglomerular fibrosis, or tubulointerstitial fibrosis on renal biopsy. PBMNC VEGF mRNA expression decreased in patients undergoing remission. In addition to the important correlation between urinary VEGF and serum creatinine, we also found an important correlation between erythrocyte sedimentation rate and urinary VEGF. This finding was interesting because we could not find a similar conclusion in other studies.     

Cellular apoptosis and proliferation in experimental renal fibrosis

Background: The progression of chronic renal failure (CRF) is associated with the progressive deletion of renal cells along with the fibrosis of the kidney. We have studied the role of programmed cell death (apoptosis) in the progression of experimental CRF and renal scarring. Methods: The sub-total (5/6th) nephrectomy (SNx) model of CRF was studied in adult male Wistar rats, with renal tissue collected from experimental and control animals on days 7, 15, 30, 60, 90, and 120 post SNx (n-6 per group). These were examined for morphological signs of apoptosis by light and electron microscopy. Further, we stained the nuclear chromatin by the acridine orange fluorescent method and detected signs of DNA cleavage by endonucleases via the principal of TUNEL staining (ApopTag™). Rates of cellular proliferation were measured simultaneously by immunohistochemical staining for the proliferating cell nuclear antigen (PCNA). In addition, cell division was monitored by counting of morphologically mitotic motifs detectable by light microscopy. Results: Progressive renal insufficiency associated with glomerulosclerosis and tubulointerstitial fibrosis took place in the majority of SNx rats. In these animals, we noted a marked and progressive increase in the number of apoptotic glomerular, tubular as well as interstitial cells. The most significant apoptotic changes were seen in the tubules of remnant kidneys peaking at day 120 post-SNx. At this stage, the increase in apoptosis compared to controls was 10.33±2.67 (M±SEM) fold for glomerular cells (P⩽0.006), 26.20±4.56 fold for tubular cells (P<0.0001) and 4.66±0.81 fold for interstitial cells (P⩽0.01). Parallel changes in the number of PSNA positive renal cells were observed. Maximal PCNA staining was seen at day 120 when the increase with respect to controls was 14.00±4.93 fold (P⩽0.05) for glomerular cells, 60.01±12.20 fold (P⩽0.05) for tubular cells and 28.59±4.45 fold ((P⩽0.05) for interstitial cells. As expected the number of cells undergoing division and detectable by conventional light microscopy was lower at any time point to those expressing PCNA. We also observed a close correlation between the severity of tubular atrophy and tubulointerstitial fibrosis with the rate of tubular apoptosis (r=0.970, R²=0.941, P⩽0.001). Conclusions: We have shown a time-dependent increase in apoptosis and PCNA antigen positive staining in the sub-total nephrectomy model of chronic renal failure correlating with the progression of renal fibrosis. PCNA staining did not match analysis for mitosis and was considered to overestimate the number or proliferating cells in the tissue. With this reservation in mind and taking into account the relative time-frames in vivo of apoptosis and proliferation; apoptosis potentially outweighs proliferation by a factor of 2-8-fold, when examined over the same time period. Consequently, even small changes in the finite numbers of apoptotic cells become highly significant. Our results have shown the definite role of apoptosis within progression of renal damage and highlighted how it may contribute to the progression of tubular atrophy and play a role in the pathogenesis of tubulo-interstitial scarring.     

Beneficial in vitro effect of N-acetyl-cysteine on oxidative stress and apoptosis

Chronic renal failure (CRF) is usually accompanied by abnormalities of both humoral and cellular immune response. The aim of the study was to investigate the influence of N-acetyl-cysteine (NAC) on intracellular oxidative stress and apoptosis rate of T lymphocytes in children with CRF. Twenty-two children (aged 4–16, mean 7.4) with CRF treated with dialysis were enrolled in the study. Intracellular reactive oxygen species (ROS) production was quantified by mean rhodamine 123 (RHO) fluorescence intensity with flow cytometry. Annexin V FITC was used for identifying apoptotic cells. Mean fluorescence intensity (MFI), which reflected intracellular oxidative stress in T lymphocytes, was increased in patients with CRF compared with the controls (CD3+: 31.58±11.58 vs 22.55±4.97, p =0.043; CD3+CD4+: 32.50±8.59 vs 27.75±12.76, NS; CD3+CD8+: 32.10±11.85 vs 20.77±4.89, p =0.012). Apoptotic T lymphocytes occurred more frequently in patients with CRF treated with hemodialysis (HD) (11.36±6.96%) than in the controls (6.14%±3.36%; p =0.025). After 24 h incubation with NAC MFI and apoptosis rate decreased significantly in all subpopulations of lymphocytes. NAC, as a strong antioxidant, has a favorable effect on intracellular oxidative stress and apoptosis rate of T lymphocytes in patients with CRF. A decreased apoptosis rate may have positive effect on functional abnormalities of T cells already found in patients with CRF.     

Diagnostic Value of the Aminopeptidase N,N-Acetyl-β-D-Glucosaminidase and Dipeptidylpeptidase IV in Evaluating Tubular Dysfunction in Patients with Glomerulopathies

Aim. The aim of the present study was to investigate the value of the urine cell glycoprotein 1 (PC-1), aminopeptidase N (APN), N-acetyl-β-D-glucosaminidase (NAGA), and dipeptidylpeptidase IV (DPP IV) in the evaluation of tubular damage in patients with primary glomerulonephritis, diabetic nephropathy, and lupus nephritis. Subjects and Methods. PC-1, APN, NAGA, and DPP IV activities were determined in serum, urine, and lymphocytes of 178 subjects, including 10 patients with membranous nephropathy, 38 with IgA nephropathy, 29 with lupus nephritis, 51 with diabetic nephropathy, and 50 control subjects. Results. Urinary PC-1 excretion in IgA nephropathy group was significantly higher (p < 0.05) than in controls. Urinary NAGA excretion was markedly (p < 0.01) higher in membranous nephropathy group, and APN excretion in diabetic nephropathy group was significantly higher (p < 0.01) than in healthy controls. Urinary APN activity was significantly (p < 0.01) higher in both type 1 and type 2 diabetic patients with microalbuminuria, as well as urinary NAGA and DPP IV activities in type 2 diabetics with microalbuminuria (p < 0.01 and p < 0.05, respectively) compared to controls. Serum PC-1 and APN activities were significantly higher than the control level in membranous nephropathy group, as well as serum PC-1 and DPP IV activities in IgA nephropathy patients (p < 0.05). However, significantly lower serum DPP IV and APN activity was observed in type 2 diabetics with microalbuminuria compared to controls (p < 0.05). Conclusion. Damage of tubules in primary glomerulonephritis, lupus nephritis, and diabetic nephropathy is accompanied by a release of several tubular enzymes, with possible diagnostic and prognostic significance. Increased serum PC-1, APN, and DPP IV activities could be also of diagnostic significance.     

Adrenomedullin and total nitrite levels in children with Henoch-Schönlein purpura

Nitric oxide (NO) is synthesized from endothelium and has an important role in the control of vascular tonus. Adrenomedullin (AM) is a potent vasodilator, and cytoprotective peptide is produced not only in adrenal medulla, but also in the vascular smooth muscle and endothelial cells. To investigate the endothelial synthesis of AM and NO, and endothelial injury in Henoch-Schönlein purpura (HSP), we measured their levels in 16 children with HSP, who were evaluated during the acute and remission phases, and compared with 12 healthy controls. Plasma AM levels (pmol/ml) were significantly higher in acute phase children (46.87±11.49) than in those in remission (35.59±12.39, p<0.01) and controls (30.70±9.12, p<0.001). Similarly, plasma total nitrite levels (mol/l) were higher in acute phase patients (47.50±12.30) than in those in remission (35.94±10.08, p<0.005) and controls (34.56±11.51, p<0.05). Urinary excretion of AM (pmol/mg creatinine) was higher in acute phase patients (53.85±23.22) than in remission patients (29.97±9.33, p<0.01) and controls (37.43±15.78, p<0.05). Patients had increased urinary nitrite excretion (mol/mg creatinine) in acute phase (2.39±1.18) compared to those in remission (1.53±0.90, p<0.05) and controls (1.05±0.61, p<0.005). There was no significant difference between remission phase and controls in AM and nitrite levels (p>0.05). This study concluded that AM and NO may have a role in the immunoinflammatory process of HSP, especially in the active stage, although whether this perpetuates, or protects against, further vascular injury is not clear. Further studies are needed to clearly establish the roles of AM and NO in the pathogenesis of HSP.     

Reversible acute renal failure from gross haematuria due to glomerulonephritis: not only in IgA nephropathy and not associated with intratubular obstruction

Seven patients with acute renal failure due to gross haematuriacaused by glomerulonephritis are described. Gross haematurialasting 4–40 days led to acute impairment of renal functionof variable severity (peak plasma creatinine 1.3–12 mg/dl)and duration. While partial recovery of renal function occurredin all patients within few days, complete remission was observedonly some months later. Three patients had IgA nephropathy (2the primary form and 1 nephritis secondary to Schönlein-Henochpurpura), two patients had acute postinfectious glomerulonephritis,andtwo others had focal necrotizing (pauci-immune) glomerulonephritis.The glomerular changes seen in renal biopsy were not enoughto explain per se the renal function impairment. Tubular changes,however, were severe and consisted of tubular necrosis, erythrocytecasts, erythrocyte phagocytosis by tubular cells, accompaniedby interstitial damage (oedema, red-cell extravasation, andinflammatory infiltrates). Study of the renal biopsies by immunofluorescencerevealed retrodiffusion of Tamm-Horsfall protein into the glomerularBowman’s space, a sign of obstructed tubular flow in anycase. It is concluded that acute renal failure due to grosshaematuria in glomerulonephritic patients may not occur onlyin IgA nephropathy, as reported so far, and is not associatedwith intratubular obstruction.     

Bone mass and mineral metabolism in Klinefelter's syndrome

A reduced bone mineral density (BMD) is frequently observed in hypogonadal males; however, very little is known on bone and mineral metabolism in Klinefelter's syndrome (KS). In this study 32 XXY KS patients and 24 healthy age-matched male controls were examined. Serum total and free testosterone (TT and FT) were significantly lower in patients than in controls (TT in KS, 15.1±7.8 nmol/l; controls, 30.4±9.1;p<0.001. FT in KS, 81.8±24.9 pmol/l; controls, 135.7±16.4;p<0.001). 17-Estradiol was slightly higher in KS patients (KS, 49.0±27.1 pg/ml; controls, 39.3±16.4 pg/ml), but the difference was not significant. BMD, measured at the spine (L2–4) and at the proximal epiphysis of the left femur, was similar in patients and in the control group (spine: KS, 1.016±0.142; controls, 1.085±0.144 g/cm2;p=not significant. Femoral neck: KS, 0.926±0.149; controls, 0.926±0.122 g/cm2;p=not significant). Bone GLA protein (BGP) was significantly higher in the KS group (12.7±4.8 vs 8.9±5.2 ng/ml;p<0.02), while serum calcium, serum phosphate, calciotrophic hormones and the fasting urinary hydroxyproline/creatinine ratio (OHP/Creat) were similar in the two groups. A positive relationship between FT and both spine and femoral BMD was found in KS patients. Furthermore, OHP/Creat ratio was inversely related to BMD at the femur, and positively related to BGP in KS patients, but not in normal subjects. These findings suggest that (1) KS patients have normal bone mass, most probably because the hypogonadism is moderate; and (2) patients with lower bone mass appear to have higher bone turnover.     

Differences in new-onset IgA nephropathy between young adults and the elderly

Background: The goal of this study was to define the clinical and histological differences in new-onset IgA nephropathy between young adults and the elderly. Methods: We retrospectively examined renal biopsy findings, clinical features at presentation and outcomes in 82 young adults (mean age 30.3 ± 10.2 years) and 17 elderly patients (mean age 71.9 ± 4.5 years) with IgA nephropathy whose renal biopsies were taken within 1 year from the onset of renal manifestations. Results: The elderly group more frequently had hypertension (p < 0.001), acute renal failure (p < 0.001), and nephrotic range proteinuria (p = 0.001) at presentation than the young adults group. On histology, a higher percentage of globally sclerotic glomeruli (p < 0.001) was present in the elderly group. In patients presenting with acute renal failure, the elderly group more frequently had an intercurrent disease (p = 0.02), mostly infection, and a higher mortality rate (p = 0.033). On histology, the young adults group had a higher percentage of glomeruli affected by crescents (p = 0.027); in contrast, the elderly group more commonly had acute tubular injury (p = 0.02). Conclusions: The elderly patients affected by IgA nephropathy had more severe renal manifestations at presentation (acute renal failure in 52.9% and nephrotic syndrome in 41.2% of patients). In cases of acute renal failure, the elderly patients had more predominant tubular rather than glomerular injury. Moreover, the considerable mortality rate (44.4%) might be associated with the intercurrent disease, mostly infection, which was more commonly present in the elderly patients.     

Rapidly Progressive Renal Failure in Type 2 Diabetes in the Tropical Environment: A Clinico-Pathological Study

Background. Rapid decline of renal function in a diabetic suggests the presence of a nondiabetic kidney disease (NDKD). We designed a prospective study to evaluate the factors associated with a rapid decline in renal function in patients with type 2 diabetes. Methods. Over a 2 and a half year period, all patients with type 2 diabetes who presented with documented doubling of serum creatinine in less than 4 weeks or recently diagnosed advanced renal failure were identified. Patients with prerenal causes, urinary tract obstruction, or systemic disease causing renal failure were not included. Renal histology was studied in all cases. Results. A total of 26 patients satisfied the inclusion criteria. Over 75% had serum creatinine > 4 mg/dL at presentation and 62% were dialysis dependent. Renal histology showed mixed lesions of diabetic nephropathy (DN) and NDKD in 11 cases, only DN in nine, and pure NDKD in six. Diffuse proliferative glomerulonephritis (DPGN) was the commonest NDKD (27% cases), all on a background of DN. History of preceding cutaneous or pharyngeal infection was available in five cases. The proportion of postinfectious glomerulonephritis in diabetics with rapidly progressive renal failure was over six times that of the nondiabetic adult RPRF population during the study period. Four patients had acute interstitial nephritis and three showed crescentic glomerulonephritis. Other lesions included amyloidosis, atheroembolic disease, and renal papillary necrosis (one each). The frequency of microscopic hematuria and retinopathy was similar in those with pure DN and NDKD. Four out of seven cases with DPGN showed partial recovery whereas the other three remained unchanged. Conclusions. About two-thirds of patients with type 2 diabetes presenting with rapid decline of renal function in a tropical environment show NDKD. The high incidence of postinfectious glomerulonephritis in this group is possibly related to the high prevalence of skin and soft tissue infections; and could contribute to progressive kidney disease.     

A Biomarker for Detecting Early Tubulointerstitial Disease and Ischemia in Glomerulonephropathy

Present diagnostic tests such as serum creatinine determination and creatinine clearance are unable to reflect early tubulointerstitial disease. Because a kidney biopsy cannot be performed in every single patient, tubular epithelial function (namely, the fractional excretion of magnesium; FE Mg) that correlates directly with the degree of tubulointerstitial fibrosis would serve this purpose. FE Mg is normal in acute post-streptococcal glomerulonephritis and mesangial proliferative nephrosis with intact tubulointerstitial structure, and is abnormally elevated in nephrosis with focal segmental glomerulosclerosis (FSGS) and in chronic kidney diseases in which kidney biopsies have been obtained. FE Mg is useful in the screening of tubulointerstitial disease in patients when indication for kidney biopsy in not fulfilled, such as diabetic patients or patients with microscopic proteinuria, hematuria, and hypertension. Altered FE Mg is usually associated with a reduction in peritubular capillary flow. There is a linear correlation between FE Mg and peritubular capillary flow, which supports the chronic ischemic injury inducing altered tubular function and tubulointerstitial fibrosis.     

Endothelin Receptors in the Kidney of Patients with Proteinuric and Non-Proteinuric Nephropathies

Background. Endothelin-1 (ET-1), which acts via the specific receptors ET-A and ET-B, has been implicated in the development of renal scarring. The activation of the endothelin system was observed in experimental models of glomerular diseases and was attributed to the toxic action of proteinuria on the tubular epithelial cells. The aim of this study was to investigate whether the endothelin system in the kidney is altered in glomerular diseases and possibly related to proteinuria. Methods. Thirty-seven patients with different types of glomerulonephritis and 14 controls were included. Patients presented either nephrotic syndrome (n=25) or mild proteinuria (<1g/24h, n=12). The expression of ET-A and ET-B receptors in the renal tissue was examined immunohistochemically. At the time of biopsy, urinary ET-1 was determined. Results. Both receptors were mainly localized within tubular epithelial cells, and their expression was significantly higher in patients with glomerulonephritis compared to controls. The expression of ET-B was higher in nephrotic compared to non-nephrotic patients, while no difference was observed in the expression of ET-A receptors. A significant positive correlation of the degree of proteinuria with the excreted ET-1 (r= 0.487, p<0.05) and the extent of immunostaining for ET-B receptors (r=0.420, p<0.05) was observed. The expression of ET-B receptors and the excretion of ET-1 decreased significantly in patients with remission of nephrotic syndrome after therapy. Conclusion. This study provides evidence that the endothelin system is activated in human glomerular disease, confirming data from experimental studies. Proteinuria seems to be related to the activation of endothelin system, though further investigation is necessary to clarify this issue.     

Protective effect of a platelet-activating factor antagonist (WEB-2086) in postischemic renal failure

The purpose of this study was to evaluate the renoprotective effect of a specific platelet-activating factor antagonist (WEB-2086) in an experimental model of normothermic renal ischemia. Twenty New Zealand white rabbits were studied for 2 days before and 24 hours after a 60-minute period of renal ischemia induced by bilateral clamping of the renal arteries. The animals were divided into two groups: a control group (group A; n=10) and a treated group (group B; n=10). In group A the urinary flow rate decreased significantly (from 0.098±0.008 ml/min to 0.029±0.005 ml/min) (p<0.001) and there was a significant reduction in creatinine clearance (from 11.4±1.2 ml/min to 3.4±1.1 ml/min) (p<0.001). In group B no significant changes were observed, although the urinary flow rate increased even in the postischemic period (from 0.09±0.008 ml/min to 0.11±0.02 ml/min). Microcirculatory cortical flow showed a postischemic reduction in both groups, although it was most significant in the control group (group A=43.7%, group B=71.5%;p<0.001). Histologic study showed mild damage with patchy tubular necrosis in both groups, although this injury was less severe in the treated group. The results suggest that the preoperative administration of WEB-2086 produces a potent diuretic effect with significant attenuation of postischemic acute renal failure.Presented at the Seventeenth World Congress of the International Union of Angiology, London, England, April 3–7, 1995 (IUA Prize).Supported by a grant from the National Institutes of Health (INS) (FIS 95/0837), Madrid, Spain.     

Renal tubular dysfunction in fetal alcohol syndrome

Renal function was evaluated in six patients with fetal alcohol syndrome (FAS) and eight control subjects before and after fluid restriction and acute acid loading. Baseline serum electrolytes, creatinine clearance, fractional sodium excretion, tubular reabsorption of phosphate, urine and blood pH and osmolalities, plasma renin activity, and plasma aldosterone level were normal in all subjects, but fractional potassium excretion (FE_K) was lower in FAS patients than in control subjects (P<0.001). Despita equivalent plasma osmolalities (295±3 vs 293±2 mosmol/kg,P=0.2), the maximum urinary osmolality after 12 h of water deprivation in patients with FAS was significantly lower compared with controls (560±107 vs 965±77 mosmol/kg;P<0.001) and increased to only 578±101 mosmol/kg after vasopressin administration. After ammonium chloride loading, minimum urine pH was significantly higher in patients than in controls (5.7±0.17 vs 4.81±0.19;P<0.001). Net acid excretion and FE_K were also lower in patients than in controls (102±11 vs 139.6±11.3 Eq/min per 1.73 m² and 23.5±1.3 vs 29±1.6%, respectively;P<0.001). The data indicate a subclinical renal tubular defect in urine concentration and acidification in patients with FAS.     

A biomarker for detecting early tubulointerstitial disease and ischemia in glomerulonephropathy

Present diagnostic tests such as serum creatinine determination and creatinine clearance are unable to reflect early tubulointerstitial disease. Because a kidney biopsy cannot be performed in every single patient, tubular epithelial function (namely, the fractional excretion of magnesium; FE Mg) that correlates directly with the degree of tubulointerstitial fibrosis would serve this purpose. FE Mg is normal in acute post-streptococcal glomerulonephritis and mesangial proliferative nephrosis with intact tubulointerstitial structure, and is abnormally elevated in nephrosis with focal segmental glomerulosclerosis (FSGS) and in chronic kidney diseases in which kidney biopsies have been obtained. FE Mg is useful in the screening of tubulointerstitial disease in patients when indication for kidney biopsy in not fulfilled, such as diabetic patients or patients with microscopic proteinuria, hematuria, and hypertension. Altered FE Mg is usually associated with a reduction in peritubular capillary flow. There is a linear correlation between FE Mg and peritubular capillary flow, which supports the chronic ischemic injury inducing altered tubular function and tubulointerstitial fibrosis.     

Apoptosis and antioxidant defense in the nephrotic syndrome

Nephrotic syndrome (NS) is accompanied, and probably caused by, abnormalities in T lymphocyte function. The aim of this study was to investigate the antioxidant status of children with NS and its influence on the apoptosis of T cells. Fifty-seven children with NS were studied, aged 4–16 years (mean 7.4 years), 34 with a first episode (group I) and 23 in remission (>6 months) of NS (group II). The control group comprised 26 healthy children matched for age. Annexin V-FITC was used as a sensitive probe for identifying cells undergoing apoptosis. We found that apoptotic T lymphocytes occurred more frequently in patients with a first episode of NS than in children in remission and in the controls. In group I, total antioxidant status (TAS, plasma) was significantly reduced compared with controls (0.77±0.14 vs. 1.18±0.42 mmol/l, P<0.001). In group I children, glutathione reductase (GR, red blood cells) and glutathione peroxidase (GPX, red blood cells) activity was lower than in controls (GR 8.10±2.40 vs.10.55±3.81 U/g Hb, P<0.001) (GPX 28.65±6.99 vs. 33.84±13.11 U/g Hb, P=0.010). TAS levels and GR activity in group II were also lower than in the controls. A negative correlation between GR activity and the apoptosis rate of T lymphocytes was found. We conclude that in patients with NS, reduced antioxidant defense may contribute to an increase in the apoptosis rate of circulating lymphocytes.     

Expression of Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 in Acute Rejection of Human Renal Allografts

Background

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is expressed on various cell types and mediates homophilic cell adhesion. CEACAM1 plays an important role in cell morphogenesis and angiogenesis. Furthermore, CEACAM1 regulates adhesive activity of immune-competent cells, suggesting an additional role in inflammatory processes.

Methods

Therefore, in the present study the expression of CEACAM1 was analysed retrospectively in renal biopsies from kidney transplant recipients (stable graft [Ctr; n = 18], acute vascular rejection [AVR; n = 14], acute tubulointerstitial rejection [AIR; n = 9], and combined vascular and interstitial rejection [AVIR; n = 7]). Expression patterns of CEACAM1 were determined using immunohistochemistry and quantitative morphometry.

Results

All biopsy specimens from patients with stable grafts showed low CEACAM1 levels, suggesting a constitutive expression in renal transplants. In patients with acute rejection, CEACAM1 was markedly up-regulated. AVR revealed the highest tubular CEACAM1 levels (4.9 ± 0.5% [AVR] vs 2.2 ± 0.3% [Ctr] of tubular area; P < .05), whereas interstitial rejections showed the highest glomerular expressions (4.5 ± 0.5% [AIR] vs 0.9 ± 0.1% [Ctr] of glomerular area; P < .05).

Conclusions

An up-regulated expression of CEACAM1 in tubular and/or glomerular cells is an indicator of acute inflammatory processes in biopsy specimens from patients with acute renal allograft rejections and, therefore, might be used as a new clinical marker.     

Clinical and pathological analysis of renal biopsies of elderly patients in Northeast China: a single-center study

PurposeTo identify the clinical characteristics, histopathological features, and prognosis of kidney disease in a large cohort of elderly patients from Northeast China.MethodsWe retrospectively analyzed the renal disease spectrum in 7,122 patients who underwent renal biopsies at the Second Hospital of Jilin University from 2006 to 2020. Patients were grouped according to age: below 60 years (non-elderly group, n = 5923) and at least 60 years (elderly group, n = 1199). The clinical and pathological characteristics of renal biopsy patients in the groups were analyzed using the t-test and chi-square test.ResultsCompared with the non-elderly group, the elderly group had significantly fewer patients with primary glomerulonephritis, but more patients with tubulointerstitial disorders (p < .05). The incidence of IgA nephropathy, mesangial proliferative glomerulonephritis, and lupus nephritis was significantly lower in elderly patients than in non-elderly patients. The incidence of membranous nephropathy, membranoproliferative glomerulonephritis, diabetic nephropathy, hypertensive nephropathy, systemic vasculitis-associated renal damage, and amyloid nephropathy was significantly higher in elderly patients than in non-elderly patients (p < .05). The incidence of perinephric hematoma (≥4 cm²) in elderly patients with renal biopsy was lower than that in non-elderly patients. We noted that 79.9% of primary glomerulonephritis patients who received immunosuppressive therapy showed a remission rate of 83.5%.ConclusionThe spectrum of kidney disease in the elderly is different from that in the younger population.     

Intraaortic balloon pumping improves hemodynamics and right ventricular efficiency in acute ischemic right ventricular failure

Background

Left ventricular unloading has a potentially deleterious effect in right ventricular failure as a result of altered septal interplay. However, a positive effect of an intraaortic balloon pump during right ventricular failure has been suggested. We investigated the impact of intraaortic balloon pumping on hemodynamics and both left and right ventricular function in an experimental model of isolated right ventricular failure.

Methods

Sixteen anesthetized pigs (25 to 34 kg) were used in an in vivo model. Pressure-conductance catheters assessed right and left ventricular pressure-volume relationships. Acute right ventricular failure was induced by right coronary microembolization, and led to severely impaired right ventricular function, reduced cardiac output and arterial pressure, and an increased pulmonary vascular resistance and pulmonary arterial elastance. Animals were then randomized to balloon pump or control groups and evaluated with respect to hemodynamics and ventricular function after 1 hour.

Results

Intraaortic balloon pumping did not alter right or left ventricular contractility. However, balloon pump-treated animals had significantly improved cardiac output (+18% ± 18% versus −6% ± 7%; p = 0.003) and mean arterial pressure (+36% ± 30% versus −7% ± 14%; p = 0.004) compared with controls. Animals in the balloon pump group had lower pulmonary vascular resistance (795 ± 63 versus 912 ± 259 dynes · sec · cm⁻⁵; p < 0.01) and pulmonary arterial elastance (1.14 ± 0.20 versus 1.69 ± 0.65 mm Hg/mL; p < 0.01), and increased stroke volume (22.3 ± 4.7 versus 17.9 ± 4.7 mL; p = 0.016). Right ventricular efficiency was also improved in the balloon pump group (stroke work per pressure-volume area = 0.60 ± 0.14 versus 0.41 ± 0.12; p < 0.01).

Conclusions

Intraaortic balloon pump support does not alter right or left ventricular function in acute right ventricular failure. However, arterial pressure, cardiac output, and right ventricular efficiency are improved, possibly because of a balloon pump-induced reduction in pulmonary arterial resistance.