[The dependence of the progression of chronic glomerulonephritis on the clinical and morphological types of glomerulonephritis and on the tubulointerstitial changes]

Progression of chronic glomerulonephritis (CGN) is strongly associated with morphologic type of the disease, tubulointerstitial changes, some clinical syndromes. The aim of the study was to trace relations between the onset of chronic renal failure within 7 years since the diagnosis (fast progression of CGN--FP CGN), CGN clinical variant according to M. Ia. Ratner et al. classification (1987) and histomorphological changes in the renal biopsy. Unfavorable clinical types (active nephritic types and nephrotic-hypertensive type) proved dominating predictor of FP CGN not only because of close relationship between these type and FP CGN but also due to FP CGN occurrence in morphologically unfavorable morphological types and tubulointerstitial changes in line with concomitant unfavorable clinical types.

Colocalization of collagen overexpression and inflammatory cell infiltration in the two-kidney one-clip rat model from the early days of hypertension onward

In the first 6 days of hypertension, infiltrated mononuclear cells were colocalized with collagen (I) mRNA-overexpressing fibroblasts in the adventitial area of unclipped kidney. The number of adventitial infiltrated mononuclear cells was correlated with adventitial collagen (I) surface expansion. After 22 days of hypertension no collagen (I) mRNA-overexpressing fibroblasts or any increase in collagen area or mononuclear cell infiltration was observed. In the interstitium of unclipped kidney, collagen (I) mRNA overexpression, collagen (I) expansion and mononuclear cell infiltration began later, from the 7th day of hypertension, and kept increasing. In the clipped kidney, after expansion in the first 6 days of hypertension, the adventitial collagen remained stable. These results suggest that in the unclipped kidney fibroblastic activation begins within the first 6 days of hypertension in the adventitial area, but is transient, and fibrosis then spreads in the interstitium. Mononuclear cell infiltration is colocalized and correlated with adventitial and interstitial fibrosis. In the first 6 days, hypertension is not the only cause of fibrosis; the same level of adventitial fibrosis is detected in the nonhypertensive clipped kidney. All observed pathological phenomena could be detected within the first 3 days of hypertension.

[Idiopathic interstitial nephritis induced acute renal failure: clinical and pathological analysis]

OBJECTIVE

To understand idiopathic interstitial nephritis (IIN) and its relationship with acute renal failure as well as its clinical and pathological characteristics for avoiding misdiagnosis and missing diagnosis.

METHOD

A detail clinical and pathological analysis was performed on 7 patients with idiopathic interstitial nephritis.

RESULTS

The major manifestations were acute non-oliguric renal insufficiency combined with mild proteinuria (< 2 g/d), microscopic hematuria and obvious disorder of renal tubular function (for example, glycosuria). Three patients had high gamma-globulinemia and 2 were associated with uveitis. Renal biopsy showed typical tubulointerstial nephritis but glomeruli, and the renal vasculature was almost normal. All patients were treated with prednison. Renal function recovered in 5 patients.

CONCLUSION

When a patient has renal insufficiency especially non-oliguric renal failure with disorder of tubular function without definite causes, IIN should be considered. The diagnosis and treatment should be done immediately.

Thrombospondin 1 precedes and predicts the development of tubulointerstitial fibrosis in glomerular disease in the rat

Tubulointerstitial fibrosis is one of the most important histologic features that predicts progression in kidney disease. Thrombospondin 1 is an extracellular matrix protein that can activate latent TGF-beta, a cytokine implicated in the pathogenesis of tubulointerstitial fibrosis. We examined the expression of thrombospondin 1 in several animal models of glomerulonephritis (anti-Thy1 model, aminonucleoside nephrosis, passive Heymann nephritis) that are associated with tubulointerstitial disease. Thrombospondin 1 mRNA and protein were transiently increased in tubular cells, myofibroblasts and some macrophages in areas of tubulointerstitial injury. Thrombospondin 1 expression always preceded the development of tubulointerstitial fibrosis, and correlated quantitatively and spatially with the later development of interstitial fibrosis. Thrombospondin 1 expression predicted the severity of tubulointerstitial fibrosis better than the degree of macrophage or myofibroblast accumulation. Thrombospondin 1 expression was associated with increased expression and activation of TGF-beta1 and decreased expression of LAP-TGF-beta in areas of tubulointerstitial injury. We conclude that thrombospondin 1 is an early marker predicting the development of tubulointerstitial kidney disease. De novo expression of thrombospondin 1 is associated and colocalized with increased expression of TGF-beta1 and decreased expression of LAP-TGF-beta during the development of tubulointerstitial disease in vivo. These data are consistent with the possibility that thrombospondin 1 may be an endogenous activator of TGF-beta.

Bovine leukemia virus-induced clinical signs and morphological changes of encephalitozoonosis in rabbits

Fourteen three-month-old rabbits spontaneously-infected with the microsporidium Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 were inoculated intravenously with lymphocytes (Ly) from seropositive bovine leukemia virus infected cattle (Ly/BLV) or with fetal lamb kidney cells infected with bovine fetal leukemia (FLK/BLV). Thirteen rabbits were seropositive to BLV at least for a period of three months. Six rabbits died of pulmonary lesions. Chronic inflammatory lesions of encephalitozoonosis were found in six rabbits killed between 454 and 548 days of the observation period. Five animals bore subcutaneous granulomas. Immunohistochemically, E. cuniculi was demonstrated in the inflammatory lesions of rabbits studied. Control animals also spontaneously infected with E. cuniculi did not show clinical signs of encephalitozoonosis. Morphological changes were found incidentally in the form of small glial foci and focal interstitial nephritis in these animals. The combined action of BLV-E. cuniculi on the bodies of rabbits is proposed as a suitable model for the study of encephalitozoonosis in man with human immunodeficiency virus (HIV) infection.

Experimental investigation of preservation injury in animal kidneys after reperfusion with Euro-Collins

The authors evaluated the pathomorphologic alterations of removed and reperfused dog kidneys by means of light and electronmicroscopic examination. In each sample the following reversible signs were found: Hypereosinophilia (HE), Hydropic dystrophy (HD), Nuclear polymorphism (NP), Epithelial desquamation (ED), Brush border lesion (BBL), Single cell necrosis (SCN), Total tubular epithel necrosis (TTEN), Interstitial edema (IE), Perivascular edema (PE). The irreversible signs were: Basement membrane rupture (BMR), Cellular infiltration (CI), Glomerular mesangial matrix expansion (GME) and vascular lesions (VL). The most severe and mostly irreversible alterations occur in the 54-72 hours after harvesting. The authors emphasize the significance of basement membrane rupture, because the impossibility of tubular epithelial regeneration, the cellular infiltration due to its fibrogenic effect, glomerular lesion because it makes decrease the glomerular filtration rate, proceeding juxtaglomerular cell proliferation and hypertension through renin-angiotensin mechanism and vascular lesions causing renovascular hypertension and tubulopathy. The authors believe that reperfusion injury is very important factor in kidney allograft survival. Its mechanism is similar to the normal necrosis pathway, but the timing is delayed. Further investigations are needed to understand what specific alterations may occurred under blood circulation in the host to reveal more exact cause of primary graft failure after transplantation.

Predictive morphological findings in "zero-hour" biopsies of renal allografts

"Zero-hour" biopsies of 65 donors have been performed since 1994. Donor kidneys were categorized into five groups based on the morphological findings in "zero-hour" biopsies. No morphological abnormalities were found in 38% of the cases (group 1). Arteriosclerosis was present in 31% of donor kidneys (group 2). Specific morphological alterations, i.e. acute tubular necrosis [21.5%], tubulointerstitial nephritis [6.2%] or glomerulonephritis [3.1%] were detectable in the cases remained (group 3-5). During an average of 336 posttransplant days clinical and histological follow up was performed (50 rebiopsies). Statistical data of mismatch (1.4-2.0), average of donor/recipient age (35-42 years), cold and warm ischaemic time (1290 and 66 min) were comparable in all groups. According to our observations: 1. higher creatinin was found in grafts with arteriosclerosis (group 2) (p < 0.05), 2. there were more non-viable grafts and longer period of delayed graft function in acute tubular necrosis (group 3), 3 higher creatinin, rejections with the need of rehemodialysis were observed in four cases of tubulointerstitial nephritis (TIN-group 4). Glomerulonephritis (GN-group 5) grafts had only delayed graft function, however these groups were few for statistical evaluation. Biopsy complication in 1/115 cases was found (rebiopsy induced kidney haemorrhage). In conclusion, "zero-hour" biopsies can be useful and safe tools to predict early graft function. Besides "zero-hour" biopsies help the histological interpretation of consecutive graft rebiopsies.

Primary IgA nephropathy. Contrasting morphometric insight into glomerular and interstitial changes in younger and elderly patients

Twelve patients with primary diffuse IgA nephropathy (IgAN) aged under 45 years (IgAN < 45), and eleven patients with this glomerulopathy aged over 45 years (IgAN > 45) for whom both light and electron microscopy as well as immunofluorescence microscopy and full clinical data were available were examined quantitatively and compared with fifteen normal controls. Morphometric investigations were performed by means of a computer image analysis system to characterize quantitatively IgAN in patients over and below 45 years of age as well as to study whether changes in quantitatively analyzed glomeruli could correlate with hematuria, which is thought as the main renal symptom in this glomerulopathy. The study revealed that the mean values of total glomerular cells per total glomerular area, total glomerular cells per unit of glomerular area, mesangium (% of total glomerular area) and relative interstitial volume were in both IgAN < 45 and IgAN > 45 groups increased in comparison with normal controls, most of them significantly. The comparison of these parameters between IgAN < 45 and IgAN > 45 groups showed that the mean values of total glomerular cells per total glomerular area and total glomerular cells per unit of glomerular area were significantly greater in IgAN < 45 group, but relative interstitial volume was significantly increased in IgAN > 45 patients. Moreover, there were significant positive correlations between total glomerular cells per unit of glomerular area and hematuria, but not between glomerular mesangium (% of total glomerular area) and hematuria in both IgAN < 45 and IgAN > 45 groups. In conclusion, we found evident quantitative differences between glomerular and interstitial parameters in younger and elderly patients. Although close relationship was observed between glomerular hypercellularity and the degree of hematuria in both younger and elder patients, this association is not clear and its pathogenesis remains to be shown.

Inhibition of inducible nitric oxide synthase intensifies injury and functional deterioration in autoimmune interstitial nephritis

T lymphocytes are exquisitely sensitive to the antiproliferative effects of nitric oxide. We examined the effects of oral administration of two nitric oxide synthase inhibitors, Nw-nitro-L-arginine methyl ester (L-NAME) and L-N6-(1-iminoethyl)lysine (L-NIL), on the course of T cell-dependent autoimmune interstitial nephritis in Brown Norway rats. Kidneys from rats immunized to produce interstitial nephritis display a net generation of nitric oxide end products. By immunohistochemical staining, the cytokine-inducible nitric oxide synthase (iNOS) is expressed in cortical tubular epithelial cells. Treatment with either inhibitor results in markedly more severe disease following immunization. Animals receiving L-NAME were hypertensive, while those treated with L-NIL, a highly selective inhibitor of iNOS, were not. Evaluation of the expression of IFN-gamma, IL-2, and IL-4 in diseased kidneys by quantitative reverse transcriptase-PCR demonstrated that L-NAME-treated animals displayed significantly augmented levels of IFN-gamma and IL-2 with preserved ratios of IFN-gamma/IL-4 and IL-2/IL-4, while L-NIL-treated animals had augmented levels of IL-2 and IFN-gamma with augmented IFN-gamma/IL-4 and IL-2/IL-4 ratios. Animals treated with L-NAME or L-NIL both had augmented Ag-specific IgG responses. The L-NAME group demonstrated increases in both the IgG2a and IgG1 subtypes, with a constant IgG2a/IgG1 ratio, while the L-NIL group demonstrated an increase in the ratio of the IgG2a/IgG1 response. These Ab and cytokine data suggest that the L-NIL-treated animals had a skewing of their immune response toward a Th1-like response. We conclude that in autoimmune interstitial nephritis, generation of nitric oxide through the iNOS pathway has host-protective effects, and suggest that this may be broadly applicable to T cell-mediated pathologies.

Non-fatal acute renal failure due to wasp stings in children

We report two children who developed acute renal failure after multiple wasp stings. Each case involved intravascular hemolysis which caused acute renal failure, volume overload, hypertension, anemia, hyponatremia, hyperkalemia, and metabolic acidosis. Peritoneal dialysis was required for short periods. The children recovered completely with blood urea nitrogen and creatinine returning to normal within 3 months. One child had a renal biopsy which showed mild tubulointerstitial nephritis. Although there is no specific treatment or antivenom, dialysis and supportive care have proved to be successful.

Tubulointerstitial lesions in non-insulin dependent diabetes mellitus

The clinical features and quantitative renal morphometry, including the index of mesangial expansion (IME), the index of arteriolar hyalinous change (IAHC), the percentage of globally sclerosed glomeruli (%GS), and interstitial volume fraction for total renal cortex (Vv int/T) of 67 Japanese non-insulin dependent diabetes mellitus (NIDDM) patients were examined. For the total subject population, Vv int/T correlated with urine protein, creatinine clearance, blood pressure, IME, IAHC and %GS, but not with duration of NIDDM. No significant difference in interstitial expansion between normo- and microalbuminuric patients was observed, and Vv int/T did not correlate with urine albumin excretion rate in those patients. However, in the area without hyalinized glomeruli and atrophic tubules, we found significant interstitial expansion and thickening of the tubular basement membrane (TBM) in patients without overt proteinuria as compared with those in the age-matched minimal change control group. This study confirmed that interstitial expansion in NIDDM progresses in parallel with glomerular and arteriolar lesions and that the expansion occurs concurrently with TBM thickening before the appearance of proteinuria.

The syndrome of autoimmune interstitial nephritis and membranous nephropathy

A 2-year-old male patient was evaluated for Fanconi syndrome with hypertension and failure to thrive. Renal biopsy revealed autoimmune interstitial nephritis with membranous nephropathy. The patient developed autoimmune hemolytic anemia and intractable diarrhea with villous atrophy of the jejunum. He progressed to end-stage renal disease and was transplanted without recurrent disease. Immune work-up done prior to immunosuppressive therapy showed marked elevation of IgE. Studies of T lymphocyte cytokine production showed normal production of interleukin-4 but depressed levels of interferon-gamma. The simultaneous occurrence of autoimmune interstitial nephritis and membranous nephropathy in a young male represents a unique syndrome. Abnormalities of T lymphocyte subpopulations and their cytokines may be involved in the pathogenesis of this disorder.

Paracetamol induced acute interstitial nephritis superimposed on mesangiocapillary glomerulonephritis

We report the case of a young alcoholic male whose first renal biopsy disclosed mesangiocapillary glomerulonephritis. One month later he took 1.5 g paracetamol to control the fever. Soon he got hospitalized due to toxicoderma, elevated liver and renal function tests. While the liver enzymes returned to normal, uremia developed. A repeated renal biopsy revealed severe interstitial inflammation, tubular atrophy. Haemodialysis was started and he got steroids (1 mg/kg body weight). He showed considerable recovery of renal function in some weeks. The case points to the possibility that paracetamol-even in therapeutic dosage-might result in hepatic and renal damage in alcoholics.

Granulomatous interstitial nephritis and uveitis presenting as salt-losing nephropathy

Salt-wasting nephropathy is a rare syndrome in which renal insufficiency is associated with extracellular volume depletion from marked natriuresis in the absence of adrenal insufficiency or diuretics. We report the clinical course of a 23-year-old woman with renal insufficiency, in association with orthostatic hypotension and salt wasting. A combination of daily infusion of saline, a high-salt diet and oral fludrocortisone did not compensate for her salt loses. Renal biopsy showed noncaseating granulomas and marked interstitial inflammation. Renal function and salt loss improved with prednisone therapy and 6 months after withdrawal of steroids, her renal function remains stable.

Myofibroblast involvement in chronic transplant rejection

BACKGROUND

Chronic rejection remains the major cause of late graft failure. We studied the renal tissue of 10 renal transplant patients with chronic rejection in whom biopsies had been performed at various time points over a 15-year posttransplant period to ascertain whether myofibroblasts (MF) have a role in this process.

METHODS

Biopsies were grouped into five categories with respect to time after vascular anastomosis: 0 (n=10); 1 day to 3 months (n=7); 6-24 months (n=5); 36-72 months (n=7); and >72 months (n=5). A control group consisted of patients who had undergone routine biopsies at 0 (n=10), 3 (n=10), 12 (n=6), 60 (n=5), and >60 months (n=6) with no rejection. MF were identified by morphology and alpha-smooth muscle actin immunostaining. T cells and macrophages (MF) were identified using an antisera to CD3 and CD68, respectively. Collagen III deposition was similarly quantified by immunohistochemistry. Interstitial fractional area was measured by point counting.

RESULTS

At all time points studied beyond time 0, there were significant increases in interstitial fractional area, collagen III staining, MF, and T-cell staining in patients with chronic rejection compared with the controls. Staining for alpha-smooth muscle actin increased with time in conjunction with worsening fibrosis and collagen deposition.

CONCLUSIONS

In this study, MF were a major component of the interstitial infiltrate of the 10 patients with chronic transplant rejection. Abnormal persistence of these cells in the interstitium is one of the events that contributes to pathologic scarring of the kidney.

[Pathogenesis of interstitial kidney fibrosis. Studies in the rat model of unilateral ureteral obstruction]

BACKGROUND

The animal model of unilateral ureteral obstruction (UUO) of the rat is suitable to cause a renal interstitial fibrosis within a few weeks. Prior to the 10th day after UUO, no fibrotic changes were detectable in ureter-ligated kidneys, whereas after day 20 fibrosis was developing strongly.

METHOD

Using cell cultures it was examined whether any in vivo changes in proliferation and function of fibroblasts are also detectable in cell cultures and whether, due to their persistency, they are of fundamental importance for the development of renal interstitial fibrosis.

RESULTS

The comparison of the proliferation in cell cultures established 5 and 21 days after UUO showed that the cultures of the two experimental groups behave similarly. Consequently, the action of acute inflammatory processes on fibroblast proliferation without any existing fibrosis is comparable with that of pronounced fibrosis in the animal model. High concentrations of fetal calf serum in the culture medium cause a stimulation of the cell proliferation as well as a selection of mitotically active differentiation stages of fibroblasts.

CONCLUSION

Obviously, the loss of inhibition of the fibroblast proliferation under the conditions of cell culture causes similar changes to those effected by pathogenic mechanisms in the kidneys of rats with UUO. If the behaviour of fibroblasts in organs is to be assessed using results of cell culture experiments, the stimulating action of the culture conditions and the missing influence of other cells present in the tissue should be considered. These factors make the recognition of remaining differences between cells from normal and damaged kidneys more difficult under the conditions of primary cell cultures.

[The prognostic significance of the morphological type of chronic glomerulonephritis and of the tubulointerstitial changes depending on the clinical type of the disease]

The review of 200 cases of chronic glomerulonephritis (CG) led the authors to the conclusion that there is a statistically significant relationship between rapid progression (RP) of the disease (onset of chronic renal failure within 7 years since the diagnosis) and its morphological type (chi 2 = 37), tubulointerstitial changes (chi 2 = 34; p < 0.0000), clinical disease types according to M. Ia. Ratner, V. V. Serov et al. (chi 2 = 115; p < 0.0000). In both prognostically favourable and unfavorable morphological types RP occurred more frequently in concurrent unfavorable clinical types (chi 2 = 19; p < 0.0001). In prognostically unfavorable morphological types there were, as a rule, unfavorable clinical types, whereas in favorable ones-favorable clinical types. In the presence of tubulointerstitial changes RP occurred primarily in unfavorable clinical types which are encountered in these morphological changes significantly more frequently than in their absence (chi 2 = 48; p < 0.01). RP of CG in prognostically unfavorable morphological types and tubulointerstitial changes depends mainly on accompanying clinical types of CG.

Familial progressive tubulo-interstitial nephropathy and cholestatic liver disease -- a newly recognized entity?

We describe two siblings (female and male) with progressive tubulo-interstitial nephropathy and cholestatic liver disease. The main characteristics were progressive renal failure and elevated liver enzymes (AST, ALT and gamma-GT). Dialysis was started at the age of 1.9 and 6.5 years, respectively. Renal histology disclosed sclerosed glomeruli and atrophic tubules; the interstitium was fibrotic and infiltrated by lymphocytes. Endoscopic retrograde cholangiopancreatography revealed segmental irregularities and narrowing of the intrahepatic bile ducts, consistent with early primary sclerosing cholangitis. Liver histology showed enlarged portal triads, mild proliferation and inflammation of bile ducts, and fibrosis. At 5.9 years the girl underwent a successful renal transplantation whereas the boy is still on dialysis.

CONCLUSION

The association of progressive tubulointerstitial nephropathy and cholestatic liver disease, consistent with early primary sclerosing cholangitis, constitutes a distinct autosomal recessive entity.

Omeprazole-induced interstitial nephritis

Acute renal impairment secondary to interstitial nephritis is a rare complication of omeprazole. We describe a 50-year-old woman who took 20 mg omeprazole twice daily for endoscopically proved ulcerative esophagitis. At the same time, Duke's C colonic cancer was diagnosed and completely resected. Five fluorouracil/folinic acid adjuvant chemotherapy was tolerated without diarrhea or mouth ulceration. Renal function was normal before her first monthly cycle but markedly deteriorated immediately before the second cycle was due. The patient was symptomatic with lethargy, nausea, and mild vomiting, but she was clinically normotensive and only mildly dehydrated. Her serum creatinine concentration increased despite prolonged intravenous hydration, peaking at 4.4 mg/dl 1 week later. Results of a renal ultrasound were normal, and urinary microscopic findings were unremarkable. Renal biopsy showed interstitial nephritis, and renal function improved on cessation of omeprazole, eventually returning to normal. We describe the 12 cases of omeprazole-induced interstitial nephritis reported previously.

Oral feeding of renal tubular antigen abrogates interstitial nephritis and renal failure in Brown Norway rats

We have examined whether oral feeding of antigen can regulate the expression of autoimmune interstitial nephritis induced by antigen-in-adjuvant (RTA/CFA) immunization of Brown Norway rats. Male rats were divided into six experimental groups: Group I, RTA/CFA immunization alone; Groups II, III, and IV were pretreated with 1 mg (Group II), 5 mg (Group III), and 25 mg (Group IV) of oral tubular antigen every other day for ten days, followed by RTA/CFA immunization; Group V was pretreated with a control antigen, followed by RTA/CFA immunization; and Group VI was immunized with CFA alone. Renal histology, inulin clearance, DTH responses to RTA, and IgG antibody responses to RTA were monitored as endpoints of the study. Our results demonstrated that Group III and IV animals had significantly less severe renal injury, as assessed by inulin clearance and extent of renal cortical involvement by mononuclear cells. Group II and IV animals had suppressed DTH responses, and only Group IV animals had significantly depressed antigen-specific IgG serum titers. Group III animals had neither suppressed DTH responses or IgG titers. We conclude that oral administration of tubular antigen can modulate the intensity of interstitial nephritis produced by immunization, but that the regulatory mechanism is not dependent (at all doses of fed antigen) on suppressed DTH reactivity to RTA or suppressed antigen-specific IgG.