R. Waldherr

Hepatocyte proliferation in primary biliary cirrhosis as assessed by proliferating cell nuclear antigen and Ki-67 antigen labelling

Expression of the proliferating cell nuclear antigen and Ki-67 antigen by hepatocytes was investigated in liver tissue specimens of 29 patients with primary biliary cirrhosis (stage I 13, stage II 6, stage III 5 and stage IV 5 patients) prior to treatment with ursodeoxycholic acid and of five control subjects using immunocytochemical methods. Proliferating cell nuclear antigen and Ki-67 expression were reevaluated in seven patients after 3 years of treatment with ursodeoxycholic acid. Proliferating cell nuclear antigen labelling indices were significantly higher in primary biliary cirrhosis (stage I, 6.4% to 32.4%, median, 10.9%; stage II, 9.6% to 21.6%, median 11.4%; stage III, 5.2% to 12.5%, median, 7.6%; stage IV, 3.8% to 8.9%, median, 5.6%) than in controls (0% to 0.5%, median, 0.1%; p < 0.005). Ki-67 antigen labelling counts were lower than proliferating cell nuclear antigen indices but elevated in all stages of primary biliary cirrhosis (stage I, 0.5% to 3.5%, median 2.0%; stage II, 1.8% to 3.6%, median 2.6%; stage III, 1.3% to 2.5%, median 1.9%; stage IV, 0.4% to 1.7%, median 1.0%) compared with controls (0% to 0.5%, median 0.3%; p < 0.005). After ursodeoxycholic acid treatment, mean proliferating cell nuclear antigen and Ki-67 labelling indices decreased from a median of 9.0% (range, 3.8% to 32.4%) to a median of 7.8% (range, 4.5% to 17.2%; p = 0.045) for proliferating cell nuclear antigen and from a median of 2.5% (range, 0.8% to 3.6%) to a median of 2.1% (range, 0.9% to 3.1%; p = 0.031) for Ki-67 antigen. It is concluded that hepatocyte proliferation is markedly increased in primary biliary cirrhosis, particularly in the early stages of the disease, and that ursodeoxycholic acid treatment reduces proliferative activity in primary biliary cirrhosis.

The renal histopathology in systemic vasculitis: an international survey study of inter- and intra-observer agreement

In order to relate histopathological findings of the kidney in systemic vasculitis to renal outcome, scoring of various morphological parameters is necessary. Therefore, we conducted a standardization study for evaluating renal biopsies from patients with systemic vasculitis. Four experienced renal pathologists from four European centres joined in the study. A scoring protocol was devised that required the observers to score an extensive number of histopathological lesions either quantitatively (as a percentage of the total number of glomeruli) or dichotomously (on a present/absent scale). Twenty renal biopsies were scored individually by all the observers, from which the inter-observer variability was analysed. Ten randomly chosen biopsies were scored again, in order to obtain the intra-observer variability. For inter-observer agreement, the evaluation of the quantitative variables was satisfactory for both rounds (0.55 < or = Kendalls W < or = 0.95 and 0.59 < or = W < or = 0.96, respectively, with all P < 0.05). However, the inter-observer agreement for the dichotomous data was poor (kappa < or = 0.30 in more than half of the parameters in both rounds). Also the data on intra-observer agreement showed more favourable results for the analysis of the quantitative data (Pearsons r > 0.45 in more than 85% of the variables in both rounds) than for the dichotomous scoring system (kappa < or = 0.30 in more than half of the variables). It is concluded that even between experienced renal pathologists discrepancies occur in scoring kidney biopsies. Inter- and intra-observer agreement is greater if a quantitative method for reviewing the biopsies is applied that requires the observers to score the tissue specimens systematically.

The nephronophthisis complex: clinical and genetic aspects.

SummaryFamilial juvenile nephronophthisis (NPH) and medullary cystic disease (MCD) are hereditary forms of early-onset chronic renal failure caused by the bilateral formation of cysts at the corticomedullary junction of the kidney. Polyuria, polydipsia, anemia, and growth retardation precede end-stage renal failure. The absence of edema and hypertension frequently leads to a delay in the diagnosis and commencement of therapy. The condition is a major cause of end-stage renal disease (ESRD) in children, accounting for 10%–25% of these patients. About 300 cases of NPH or MCD have been described. Although they are almost indistinguishable clinically and pathologically, the two conditions are separated by a characteristic age of onset (11.5 years in NPH vs. 28.5 years in MCD) and by the mode of inheritance (autosomal recessive in NPH vs. autosomal dominant in MCD). An association of NPH with retinitis pigmentosa is known as the Senior-Løken syndrome (SLS). Hepatic fibrosis, skeletal defects, and central nervous system abnormalities have been described in association with NPH but are typically absent in MCD. Since the pathology of NPH and MCD is similar, the term “nephronophthisis complex” has been introduced to summarize the related diseases. At present, there are no means of identifying heterozygotes, conducting prenatal diagnosis, or screening children in affected families. The histologic changes of NPH are characteristic but not specific for the disease. Cysts of 1–15 mm in diameter, located primarily at the corticomedullary junction, are seen in 70% of the patients. Light microscopy reveals a chronic sclerosing tubulo-interstitial nephropathy. Characteristic changes on electron microscopy are thickening, splitting, attenuation, and granular disintegration of the tubular basement membrane with abrupt transitions between the alterations. Since the pathophysiology of the disease complex is obscure, a reverse genetics approach is currently being used to localize a gene or several genes for the NPH/MCD complex.

Rapidly progressive glomerulonephritis : analysis of prevalence and clinical course

Over a period of 68 months we observed 33 patients with biopsy-confirmed severe crescentic glomerulonephritis (GN) and another 5 patients who fulfilled the clinical criteria of rapidly progressive glomerulonephritis (RPGN; no biopsy confirmation) in a region comprising approximately 930,000 inhabitants. Additional 7 patients with Wegeners granulomatosis (WG)/microscopic polyarteritis (MP) from the same region were not seen by nephrologists. The calculated annual incidence of crescentic GN/RPGN is 0.7/100,000. Of the 38 patients 13 had classical WG, 7 MP, 3 systemic lupus erythematosus, 5 Schönlein-Henoch purpura, 3 Goodpastures syndrome, 2 IgA glomerulonephritis. Of note is the high prevalence of WG/MP and the relative frequency of Schönlein-Henoch purpura. At the last follow-up, 3 patients were dead (8%), 7 patients were on dialysis (18%), 7 patients had elevated serum creatinine (18%) and 21 patients had normal serum creatinine (55%). We conclude that: (i) RPGN is more frequent than reported; (ii) WG and MP account for more than 50% of cases of RPGN; (iii) renal functional prognosis is good in WG/MP, but less favorable in RPGN of other causes; (iv) severe hypertension is not a feature of RPGN; (v) WG/MP, and not Goodpastures syndrome, is the most common cause of pulmonary hemorrhage in association with RPGN; (vi) death from infection or malignoma is uncommon (not observed in this series); (vii) de novo IgA GN may occur in patients in remission from WG (2 observations).

Abnormalities of CD4+ T cell subpopulations in ANCA-associated vasculitis

In patients with ANCA‐associated vasculitis (AAV), CD25 expression is increased on circulating T cells. Although in animal experiments the role of CD4+ CD25+ T‐regulatory‐cells (Treg) in protection against autoimmunity is well established, the role of these cells in AAV is unknown. To investigate the hypothesis that an increased expression of CD25 on T cells is related to persistent T cell activation and not to disturbances in Treg cells in AAV (34 patients, six of them after renal transplantation), we investigated CD25 expression in different subpopulations of CD4+ cells and FOXP3 mRNA expression by reverse transcription‐polymerase chain reaction (RT‐PCR). In addition, T cell proliferation and cytokine secretion after stimulation with anti‐CD3 and anti‐CD28 and intracellular cytokine production after stimulation with phorbol myristate acetate (PMA)‐ionomycin was determined. Controls were non‐vasculitic renal transplant patients (n = 9) and healthy controls (HC) (n = 13). In AAV the total number of lymphocytes, CD4+ lymphocytes and the percentage of naive T cells are lower than in HC and RTX. An increased percentage of CD25+ cells was found in AAV and AAV/RTX, irrespective of disease activity, but not in HC or RTX. This was confined to the naive (CD4+ CD45RBhigh) population only. FOXP3 mRNA expression in CD4+ T cells did not differ between AAV patients and healthy controls. In vitro T cell proliferation was enhanced in AAV patients compared to HC (P < 0·01). PBMC of AAV patients produced significantly less interleukin (IL)‐10 and interferon (IFN)‐γ after anti‐CD3/CD28 stimulation. The percentage of IL‐10 and IL‐12, but not IFN‐γ, IL‐4 or tumour necrosis factor (TNF)‐α‐producing cells was significantly higher in patients compared to HC. These findings were confined to the memory population of CD4+ cells. We conclude that AAV patients are lymphopenic and have low numbers of CD4+ T cells, which seem to be in a persistent state of activation.

Percutaneous Renal Biopsy in Children: A 27-Year Experience

Background: The introduction of automated biopsy devices and the localization of the kidney by ultrasound were aimed at optimizing efficacy and safety of the percutaneous renal biopsy procedure. We evaluated these technological advances in our renal biopsies performed in children. Methods: We sequentially used the Silverman needle (1969–1974), the TruCut needle (1974–1990), and the automated Biopty device (1990–1996). Fluoroscopy was used to localize the kidney until 1985, ultrasound examination prior to biopsy from 1985 to 1992, and direct ultrasound guidance since 1992. A total of 962 native kidney biopsies and 119 allograft biopsies were performed. Results: In the native kidney biopsies, the introduction of the Biopty device and ultrasound guidance were independently associated with fewer passes required to obtain adequate tissue and more glomeruli per specimen. The rate of biopsies yielding more than 9 glomeruli increased from 69 to 92% (p < 0.05). The number of glomeruli harvested per centimeter core length was inversely related to patient age (p < 0.01). More appropriate cortical tissue was retrieved in renal allograft biopsy specimens with the application of the new techniques. The occurrence of macroscopic hematuria (9.6%) in the native kidney biopsies was not affected by the puncture or localization technique applied, but subcapsular hematomas were documented more often with the Biopty device (42%) than with the TruCut needle (16%), probably due to improved ultrasound equipment. In the whole series 2 patients died, and 3 others required renal surgery and 4 blood transfusions. Conclusions: The automated ultrasound-guided procedure is a feasible and reliable technique for percutaneous renal biopsy in children. It gives a greater yield of diagnostic tissue without increasing the rate of clinical complications.

Targeting complement activation in brain-dead donors improves renal function after transplantation.

Kidneys recovered from brain-dead donors have inferior outcomes after transplantation compared to kidneys from living donors. Since complement activation plays an important role in renal transplant related injury, targeting complement activation in brain-dead donors might improve renal function after transplantation. Brain death (BD) was induced in Fisher rats by inflation of an epidurally placed balloon catheter and ventilated for 6h. BD animals were treated with soluble complement receptor 1 (sCR1) 1h before or 1h after BD. Kidney transplantation was performed and 7 days after transplantation animals were sacrificed. Plasma creatinine and urea were measured at days 0, 1, 3, 5 and 7 after transplantation. Renal function was significantly better at day 1 after transplantation in recipients receiving a sCR1 pre-treated donor kidney compared to recipients of a non-treated donor graft. Also treatment with sCR1, 1h after the diagnosis of BD, resulted in a better renal function after transplantation. Gene expression of IL-6, IL-1beta and TGF-beta were significantly lower in renal allografts recovered from treated donors. This study shows that targeting complement activation, during BD in the donor, leads to an improved renal function after transplantation in the recipient.

Modulation of brain dead induced inflammation by vagus nerve stimulation.

Because the vagus nerve is implicated in control of inflammation, we investigated if brain death (BD) causes impairment of the parasympathetic nervous system, thereby contributing to inflammation. BD was induced in rats. Anaesthetised ventilated rats (NBD) served as control. Heart rate variability (HRV) was assessed by ECG. The vagus nerve was electrically stimulated (BD + STIM) during BD. Intestine, kidney, heart and liver were recovered after 6 hours. Affymetrix chip‐analysis was performed on intestinal RNA. Quantitative PCR was performed on all organs. Serum was collected to assess TNFα concentrations. Renal transplantations were performed to address the influence of vagus nerve stimulation on graft outcome. HRV was significantly lower in BD animals. Vagus nerve stimulation inhibited the increase in serum TNFα concentrations and resulted in down‐regulation of a multiplicity of pro‐inflammatory genes in intestinal tissue. In renal tissue vagal stimulation significantly decreased the expression of E‐selectin, IL1β and ITGA6. Renal function was significantly better in recipients that received a graft from a BD + STIM donor. Our study demonstrates impairment of the parasympathetic nervous system during BD and inhibition of serum TNFα through vagal stimulation. Vagus nerve stimulation variably affected gene expression in donor organs and improved renal function in recipients.

Decreased Glomerular Expression of Agrin in Diabetic Nephropathy and Podocytes, Cultured in High Glucose Medium

Aim: A decrease in glomerular heparan sulfate (HS) proteoglycan (PG), without apparent decrease in HSPG core protein expression, has been reported to occur in diabetic nephropathy (DN). In most studies however, agrin, the major HSPG core protein in the glomerular basement membrane, has not been studied. This prompted us to study the glomerular expression of agrin in parallel to the expression of HS-glycosaminoglycans (GAG) in biopsies of patients with DN. Furthermore, the influence of glucose on agrin production in cultured podocytes and the expression of agrin in fetal kidneys was investigated. Methods: Cryostat sections of renal biopsies from patients with DN (n = 8) and healthy controls (HC, n = 8), were stained for agrin and HS-GAG. Sections of fetal kidneys were double stained for agrin and CD35 or CD31. Stainings were performed by indirect immunofluorescence (IIF). The production of agrin by cultured human podocytes was tested by ELISA and IIF. Results: The expression of agrin, detected by AS46, was significantly reduced in biopsies from patients with DN compared to HC (p < 0.01). Similar findings were observed when monoclonal antibody JM72 was used (p < 0.05). In addition, a significant reduction in the glomerular expression of HS-GAG was detected with JM403 in these patients (p < 0.01). Agrin is expressed in cultured podocytes, the expression hereof was reduced when the cells were cultured in the presence of 25 mM D-glucose (p < 0.01). In biopsies of human fetal kidneys, glomerular expression of agrin coincided with the expression of CD31. In early stages of glomerular differentiation there was a strong staining for agrin and CD31 while CD35 was only slightly positive. Conclusions: Our data argue against a selective dysregulation in HSPG sulfation in DN, but suggest a pivotal role for hyperglycemia in the downregulation of agrin core protein production.

Scleroderma Renal Crisis as a Presenting Feature in the Absence of Skin Involvement

A 56-year-old man was admitted to the nephrology unit with a short (6-week) history of severe hypertension that necessitated renal replacement therapy within 7 days after admission. Renal biopsy showed features of thrombotic microangiopathy in arterioles and small arteries with occluding thrombi. The skin was unremarkable at the time of admission. Progressive skin lesions with scleroderma, telangiectasia, sclerodactyly, and generalized cutaneous sclerosis developed within 4 weeks and the specific skin changes were found on skin biopsy. On admission antinuclear antibody titers were high (1:10, 240) with a nucleolar pattern, and PM-Scl antibodies (1:5, 120) were present. In the present case the diagnosis of scleroderma renal crisis was made in vivo by renal biopsy. Renal and skin biopsies documented that renal lesions may precede the clinically manifest skin lesions of progressive systemic sclerosis.