The clinical spectrum of tubulointerstitial nephritis

Quantitative evaluation of 67Ga-citrate scintigraphy in the management of nephritis

In 67Ga-citrate scintigraphy (Ga-S), visual assessment is used by evaluating renal-uptake comparison with liver and spine and is simple and objective. We adopted the standardized uptake value (SUV) for 67Ga-citrate and proposed two quantitative indices, active nephritis volume (ANV) and total nephritis uptake (TNU). This study clarified the utility of new Ga-S-based quantitative indices in nephritis management. Before SUV measurement, the Becquerel calibration factor of 67Ga-citrate was obtained using a phantom experiment. Seventy patients who underwent SPECT/CT imaging were studied. SUV, ANV, and TNU were calculated using a quantitative analysis software for bone SPECT. SUVmean, ANV, and TNU were analyzed using the (1) threshold method (set 40%) and constant-value method for (2) vertebral SUVmax, and (3) vertebral SUVmean. ROC analysis was used to evaluate SUV, ANV, and TNU diagnostic abilities to distinguish nephritis presence and absence as well as interstitial nephritis (IN) and non-IN. The area under the curve (AUC) for nephritis presence or absence had a good value (0.80) for SUVmean (1), ANV (3), and TNU (3). The AUC for differentiation between IN and non-IN groups had a good value (0.80) for SUVmean (1). Thus, the new Ga-S-based quantitative indices were useful to evaluate nephritis and distinguish IN and non-IN.

Increased Renal Expression of Complement Components in Patients With Liver Diseases: Nonalcoholic Steatohepatitis, Alcohol-Associated, Viral Hepatitis, and Alcohol-Viral Combination

Inflammatory liver diseases, including nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (ALD), hepatitis C virus (HCV), and ALD/HCV, account for nearly 2 million deaths annually. Despite increasing evidence that liver dysfunction impacts renal physiology, there is limited supportive clinical information, due to limited diagnosis of liver disease, complexity in liver disease etiology, and inadequacy of renal function tests. Human kidney biopsies with liver and renal pathology were obtained from patients with nonalcoholic fatty liver disease (NAFLD), NASH, ALD, HCV, and ALD/HCV (n = 5-7). Each liver disease showed renal pathology with at least 50% interstitial nephritis, 50% interstitial fibrosis, and renal dysfunction by estimated glomerular filtration rate (NAFLD 36.7 ± 21.4; NASH 32.7 ± 15.0; ALD 16.0 ± 11.0; HCV 27.6 ± 11.5; ALD/HCV 21.0 ± 11.2 ml/min/1.73 m2). Transcriptomic analysis identified 55 genes with expression changes in a conserved direction in response to liver disease. Considering association with immune regulation, protein levels of alpha-2-macroglobulin, clusterin, complement C1q C chain (C1QC), CD163, and joining chain of multimeric IgA and IgM (JCHAIN) were further quantified by LC-MS/MS. C1QC demonstrated an increase in NASH, ALD, HCV, and ALD/HCV (42.9 ± 16.6; 38.8 ± 18.4; 39.0 ± 13.5; 40.1 ± 20.1 pmol/mg protein) relative to control (19.2 ± 10.4 pmol/mg protein; p ≤ 0.08). Renal expression changes identified in inflammatory liver diseases with interstitial pathology suggest the pathogenesis of liver associated renal dysfunction. This unique cohort overcomes diagnostic discrepancies and sample availability to provide insight for mechanistic investigations on the impact of liver dysfunction on renal physiology.

Brain dysfunction in tubular and tubulointerstitial kidney diseases

Kidney function has two important elements: glomerular filtration and tubular function (secretion and reabsorption). A persistent decrease in glomerular filtration rate (GFR), with or without proteinuria, is diagnostic of chronic kidney disease (CKD). While glomerular injury or disease is a major cause of CKD and usually associated with proteinuria, predominant tubular injury, with or without tubulointerstitial disease, is typically non-proteinuric. CKD has been linked with cognitive impairment, but it is unclear how much this depends on a reduced GFR, altered tubular function or the presence of proteinuria. Since CKD is often accompanied by tubular and interstitial dysfunction, we explore here for the first time the potential role of the tubular and tubulointerstitial compartments in cognitive dysfunction. To help address this issue, we have selected a group of primary tubular diseases with preserved GFR, in which to review the evidence for any association with brain dysfunction. Cognition, mood, neurosensory, and motor disturbances are not well characterized in tubular diseases, possibly because they are subclinical and less prominent than other clinical manifestations. The available literature suggests that brain dysfunction in tubular and tubulointerstitial diseases is usually mild and is more often seen in disorders of water handling. Brain dysfunction may occur when severe electrolyte and water disorders in young children persist over a long period of time before the diagnosis is made. We have chosen as examples to highlight this topic, Bartter and Gitelman syndromes and nephrogenic diabetes insipidus. We discuss current published findings, some unanswered questions, and propose topics for future research.

Spontaneous perirenal urinoma induced by NSAID-associated acute interstitial nephritis

Urinoma, defined as the urine leakage beyond the urinary tract, is commonly induced by blunt trauma or urinary tract obstruction by stone, intra-abdominal malignancy, or retroperitoneal fibrosis. Spontaneous urinoma is rare and parenchymal pathologic change is rarely mentioned when urinoma is found. We present a case of a 28-year-old woman with bilateral flank pain induced by spontaneous urinoma. The lady received chronic analgesics because of migraine. After intravenous ketorolac injection, bilateral perirenal urinoma developed. Renal biopsy showed acute interstitial nephritis associated with nonsteroid anti-inflammatory drug (NSAID). After discontinuing the medication, urinoma subsided, and the patient was discharged with normal serum creatinine. This was the first case of urinoma induced by NSAID-related interstitial nephritis, and pathophysiology and management of spontaneous urinoma are discussed.

Co-localization of LTBP-2 with FGF-2 in fibrotic human keloid and hypertrophic scar

We have recently shown that Latent transforming growth factor-beta-1 binding protein-2 (LTBP-2) has a single high-affinity binding site for fibroblast growth factor-2 (FGF-2) and that LTBP-2 blocks FGF-2 induced cell proliferation. Both proteins showed strong co-localisation within keloid skin from a single patient. In the current study, using confocal microscopy, we have investigated the distribution of the two proteins in normal and fibrotic skin samples including normal scar tissue, hypertrophic scars and keloids from multiple patients. Consistently, little staining for either protein was detected in normal adult skin and normal scar samples but extensive co-localisation of the two proteins was observed in multiple examples of hypertrophic scars and keloids. LTBP-2 and FGF-2 were co-localised to fine fibrous elements within the extracellular matrix identified as elastic fibres by immunostaining with anti-fibrillin-1 and anti-elastin antibodies. Furthermore, qPCR analysis of RNA samples from multiple patients confirmed dramatically increased expression of LTBP-2 and FGF-2, similar TGF-beta 1, in hypertrophic scar compared to normal skin and scar tissue. Overall the results suggest that elevated LTBP-2 may bind and sequester FGF-2 on elastic fibres in fibrotic tissues and modulate FGF-2's influence on the repair and healing processes.

Characteristics and clinical outcome of nonsteroidal anti-inflammatory drug-induced acute hepato-nephrotoxicity among Chinese patients

AIM: To determine the clinicopathological characteristics of nonsteroidal anti-inflammatory drug (NSAID)-induced acute hepato-nephrotoxicity among Chinese patients.

METHODS: We conducted a retrospective chart review of patients using the International Classification of Diseases, Ninth Revision diagnosis code for acute kidney injury (AKI) (584.5 or 584.9) and for acute liver injury (ALI) (570.0 or 573.3) from January 2004 to December 2013. Medical records were reviewed to confirm the diagnosis of AKI and ALI and to quantify NSAID administration.

RESULTS: Seven of 59 patients (11.8%) were identified with acute hepato-nephrotoxicity induced by NSAIDs. Five patients (71.4%) received over the recommended NSAIDs dose. Compared with NSAIDs-associated mere AKI, the risk factors of NSAIDs-induced acute hepato-nephrotoxicity are age older than 60 years (57.1%), a high prevalence of alcohol use (71.4%) and positive hepatitis B virus (HBV) markers (85.7%). Compared with NSAIDs-associated mere ALI, the risk factors of NSAIDs-induced acute hepato-nephrotoxicity are age older than 60 years (57.1%), increased extracellular volume depletion (71.4%), and renin-angiotensin-aldosterone system (RAAS) inhibitor combined use (57.1%). Acute interstitial nephritis and acute tubulointerstitial disease were apparent in three out of six (42.9%) kidney biopsy patients, respectively. Acute hepatitis was found in four out of six (66.7%) liver biopsy patients. Overall complete recovery occurred in four patients within a mean of 118.25 ± 55.42 d.

CONCLUSION: The injury typically occurred after an overdose of NSAIDs. The risk factors include age older than 60 years, alcohol use, positive HBV markers, extracellular volume depletion and RAAS inhibitor combined use.

Renal interstitial fibrosis and Angiotensin inhibition

Tubulointerstitial (TI) fibrosis is a final common pathway to progressive renal injury of all forms of renal disease. However, once renal damage reaches a certain threshold, progression of renal disease is consistent, irreversible, and largely independent of the initial injury. Angiotensin (AT) II is the main effector of the renin angiotensin system (RAS) and effects that may contribute to the onset and progression of renal damage. AT II may also directly contribute to accelerate renal damage by sustaining cell growth, inflammation, and fibrosis. Interventions that inhibit the activity of the RAS are renoprotective and may retard or even halt the progression of chronic nephropathies. Unilateral ureteral obstruction suggested as a well-established experimental model of progressive interstitial expansion and fibrosis. Although technically challenging, some investigators have successfully relieved the obstruction and reported significant reduction in interstitial fibrosis severity. Drugs that modulate the RAS, such as ACE inhibitors and angiotensin type 1 (AT1) receptor antagonists, have demonstrated protective renal effects and can ameliorate fibrosis. However, neither ACE inhibitor nor AT1 receptor blockade completely suppresses progression of renal disease. Dual blockade of the RAS with ACE inhibitors and AT1 receptor blockers may provide renal benefit beyond therapy with either drug alone, due to their potential additive beneficial effect.

Acute Interstitial Nephritis: Etiology, Pathogenesis, Diagnosis, Treatment and Prognosis

Acute interstitial nephritis (AIN) is an important and common cause of acute kidney injury, particularly in hospitalized patients. The classic presentation of AIN includes fever, rash, arthralgias, eosinophilia, and acute kidney injury. While renal biopsy is considered the gold standard for diagnosis, the clinical presentation of fever and rash along with laboratory evidence of peripheral blood eosinophilia, eosinophiluria, and low-grade proteinuria strongly suggest the diagnosis. Histologically, interstitial inflammation with interstitial edema and tubulitis is the hallmark of interstitial nephritis. The most common causative factors are drugs, infections, and certain immune-mediated disorders. Discontinuation of the offending agent is considered the mainstay of therapy while the use of corticosteroids to hasten renal recovery may be beneficial. The role of interstitial nephritis in the pathogenesis of chronic kidney disease and end-stage renal disease is increasingly recognized, further emphasizing the importance of its early diagnosis and timely treatment.

Tubulointerstitial nephritis associated with IgG4-related autoimmune disease

Autoimmune pancreatitis is a chronic fibroinflammatory condition primarily affecting the pancreas. Recent accumulating evidence suggested that autoimmune pancreatitis is a systemic autoimmune disease (immunoglobulin G4 [IgG4]-related autoimmune disease) affecting various organs with dense infiltration of IgG4-positive mononuclear cells. Tubulointerstitial nephritis is still a mysterious disease with an unknown cause. We report 2 cases of tubulointerstitial nephritis associated with autoimmune pancreatitis. In these patients, dense infiltrations of IgG4-positive mononuclear cells were observed in renal interstitium, with high serum IgG4 levels. Furthermore, in patient 1, who had sclerosing cholangitis, serum alkaline phosphatase and serum creatinine levels changed synchronously. Steroid therapy was followed by improved renal function and serum IgG4 levels in both patients. Because tubulointerstitial nephritis associated with IgG4-related autoimmune disease shows a favorable response to steroids and the renal dysfunction and pancreatic dysfunction are reversible, awareness of this entity is necessary for early diagnosis and prompt treatment. In addition, these cases support the hypothesis that IgG4-related autoimmune disease could be one cause of tubulointerstitial nephritis.

Tubulointerstitial immune complex nephritis in a patient with systemic lupus erythematosus: role of peritubular capillaritis with immune complex deposits in the pathogenesis of the tubulointerstitial nephritis

Class IV-G (A/C) diffuse lupus nephritis and tubulointerstitial (TI) nephritis in a 31-year old woman was studied by light, immunofluorescence (IF), and electron microscopy (EM), to determine the pathogenesis of the TI lesions. The light microscopic findings showed peritubular capillaritis in the interstitium, with ruptures in the capillary structure, lysis of the surrounding tubular basement membrane (TBM), extravasated red blood cells (RBCs), the infiltration of neutrophils and mononuclear cells, and edema. The IF study revealed IgG, IgA, IgM, C1q, C3, and C4 depositions along the TBM, on the capillary walls, and in the interstitium proper. The EM study disclosed the deposition of immune complexes in the TBM, the capillary wall, and the interstitium proper. Based on these findings, the TI nephritis in this patient was considered to be due to peritubular capillaritis secondary to the immune complex depositions in the capillary wall of the interstitium.

Renal resistive index early detects chronic tubulointerstitial nephropathy in normo- and hypertensive patients

BACKGROUND

We studied whether the measurement of intrarenal vascular resistance by Doppler ultrasonography, capable of investigating renal interstitial compartment, allows the early detection of chronic tubulointerstitial nephropathy (TIN).

METHODS

30 normotensive and 28 hypertensive (I-II OMS) patients with a clinical history suggestive of chronic TIN and normal renal function were enrolled. 40 healthy volunteers served as controls. Patients were considered TIN-negative or TIN-positive after investigating tubular function by urine concentrating and acidification tests. Renal sonographic parameters and renal resistive index (RRI) were obtained by duplex scanner. Glomerular filtration rate/effective renal plasmatic flow ratio was investigated by sequential renal scintigraphy in TIN-negative and TIN-positive patients; (99m)Tc-DMSA scintigraphy was also performed in TIN-positive patients.

RESULTS

RRI values of TIN-positive normotensive and hypertensive patients were significantly higher (p < 0.01 for both) than those of TIN-negative patients and of controls. RRI values resulted to be linearly related to uricemia (r = 0.88, p < 0.0001) only in normotensive patients. RRI values also resulted to be linearly related to filtration ratio values (r = 0.60, p < 0.0001). (99m)Tc-DMSA scintigraphy confirmed interstitial renal damage (grade 1 and 2).

CONCLUSION

RRI measurement allows the early identification of both normotensive and hypertensive patients with chronic TIN and signs of tubular dysfunction, when renal function is still preserved.

A case of severe hypercalcemia with acute renal failure in sarcoidosis: a diagnostic challenge for the emergency department

We present and discuss the case of a man admitted to our emergency room because of severe hypercalcemia and renal failure with maintained diuresis. We diagnosed a relapse of sarcoidosis, manifesting as hypercalcemia and renal failure, based on a history of lung sarcoidosis. This is a rare complication of sarcoidosis, due to granulomatous production of vitamin D. This mechanism may have been exacerbated by exposure of sunlight. The initial treatment of the patient was directed towards lowering the circulating calcium level through hyperhydration and forced diuresis, with secondary control of granulomatous activity using corticosteroid therapy. The patient was discharged after 7 days with normal levels of serum calcium, urinary calcium excretion and serum creatinine. Recognition of this rare cause of hypercalcemia is a challenge for the emergency physician.

A case of tubulointerstitial nephritis and uveitis syndrome with severe immunologic dysregulation

Idiopathic tubulointerstitial nephritis and uveitis (TINU) syndrome is an uncommon condition, characterized by acute tubulointerstitial nephritis (TIN) with a favorable course and uveitis with a chronic relapsing course. The pathogenesis remains unclear, but a lymphocyte-mediated immune mechanism has been suggested. A 9-year-old boy was evaluated for fatigue and 2 kg of weight loss. Renal glucosuria, elevated urine beta(2)-microglobulin (MG), progressive renal dysfunction, polyclonal hypergammaglobulinemia, various autoantibodies and abnormal lymphocyte phenotypes were found. A renal biopsy revealed acute TIN. After 2 months of treatment with prednisolone, renal function and polyclonal hypergammaglobulinemia were normalized. While tapering prednisolone, anterior uveitis developed, which was improved with topical steroid. But abnormal lymphocyte phenotypes and autoantibodies persisted on low-dose prednisolone. Uveitis became aggravated, and urine beta(2)-MG increased again. The second renal biopsy (7 months later) was normal except for minimal focal interstitial fibrosis. Uveitis was not responsive to systemic steroids, but improved with additional cyclosporin. Abnormal lymphocyte phenotypes improved, and most autoantibodies disappeared. We report a rare case of idiopathic TINU syndrome with severe immunologic dysregulation, which correlated with the clinicopathological and biochemical parameters. The information about lymphocyte phenotypes and autoantibodies may provide more insight into the pathophysiology and the clinical course of uveitis in this rare disorder.

Acute renal failure after treatment with non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are known to have adverse effects on kidney function. Situations with a stimulated renin-angiotensin system such as volume depletion or pre-existing chronic renal failure predispose to acute renal failure (ARF) via inhibition of prostaglandin synthesis by NSAIDs. To date, NSAIDs are frequently used as antipyretic drugs even in situations predisposing to ARF. Within 20 months, seven children presenting with diarrhoea and/or vomiting and fever were treated with therapeutic doses (11.5-32 mg/kg per day) of ibuprofen for 1 to 3 days before developing ARF. Maximum plasma creatinine levels were 180-650 micromol/l. One patient required emergency dialysis for hyperkalaemia, uraemia, and hyperphosphataemia. After cessation of NSAID treatment and rehydration, all patients recovered completely with a normalised creatinine level after 3 to 9 days. Once the acute phase is controlled, long-term outcome is excellent. Interstitial nephritis, another possible adverse effect of NSAIDs, might require steroid treatment and is the major differential diagnosis. Only histological examination can confirm the exact pathomechanism of ARF after NSAID exposure. If immunological events are responsible for the ARF, the recovery period is usually longer.

CONCLUSION

non-steroidal anti-inflammatory drugs are potentially dangerous in situations with even moderate volume depletion.

Apoptosis and oxidative stress induced by ochratoxin A in rat kidney

Ochratoxin A (OTA) is a widespread mycotoxin produced by several species of fungi. OTA induces a tubular-interstitial nephropathy in humans and in animals. It has been implicated as one of the aetiological agents involved in the development of endemic nephropathy. OTA-induced oxidative stress and apoptosis may play key roles in the development of chronic tubulointerstitial nephritis connected to the long-term exposure to this food contaminant. We studied the effects of low doses of OTA on kidney cells. Wistar rats were treated with 120 microg OTA/kg bodyweight daily, for 10, 30 or 60 days. Toxin concentration in kidney was proportional to the time of exposure, and amounted to 547.2, 752.5 and 930.3 ng OTA/g kidney tissue after 10, 30 and 60 days, respectively. OTA treatment caused an increased number of cells undergoing apoptosis in both proximal and distal epithelial kidney cells. The apoptotic cells were visualised using the TUNEL assay and staining with haematoxylin and eosin in situ. The number of apoptotic cells in rats treated for 10, 30 and 60 days increased by 5-, 6.4- and 12.7-fold, respectively, compared with the control cells. However, DNA electrophoresis did not show characteristic fragmentation (DNA laddering). The oxidative stress was evident via increased malondialdehyde formation. The concentration of lipid peroxides showed an increase (36%), but the activity of superoxide dismutase decreased (26%) in 60-day treated rats. In spite of the observed biochemical and morphological changes in the kidney cells, renal functional status was preserved to the end of experiment. This study demonstrates that a combination of morphologic and biochemical markers can be used to monitor early cell death in OTA-induced renal injury. We have shown that the exposure to the relatively low OTA concentrations has activated apoptotic processes and oxidative damage in kidney cells.

Epstein-Barr virus-associated acute renal failure: diagnosis, treatment, and follow-up

We retrospectively reviewed our experience of Epstein-Barr virus (EBV)-associated acute renal failure. Of 165 previously healthy children hospitalized with serologically proven primary EBV infection, 8 had acute renal failure, of whom 5 (group A) did not have virus-associated hemophagocytic syndrome (VAHS), while 3 (group B) did have VAHS. All had complications in four or more organ systems. Two patients in group A had renal biopsies showing acute tubulointerstitial nephritis, and the clinical and laboratory findings in the other 3 group A patients were consistent with acute tubulointerstitial nephritis. Acyclovir was used in 1 patient, but she died of hepatic failure and pulmonary hemorrhage. The other 4 spontaneously recovered renal function after supportive care, including hemodialysis in 1 patient. Our experience does not support the routine use of corticosteroids or antiviral agents in these patients. Children in group B had a relatively normal urinalysis. Renal biopsies were not performed, but their presentations were compatible with acute tubular necrosis. We conclude that EBV should be considered as a possible etiological agent in all children presenting with acute renal failure of unknown cause. The diagnosis depends on a high index of suspicion and careful serological evaluation in atypical cases.

Primary chronic interstitial nephritis in Crohn's disease

BACKGROUND & AIMS

In Crohn's disease, cases of interstitial nephritis with renal failure have been reported in connection with the use of mesalamine.

METHODS

We observed 4 patients with severe interstitial nephritis proven by examination of kidney biopsy specimens. Renal failure was discovered before or simultaneously with the diagnosis of Crohn's disease, and patients were not treated with mesalamine. Impairment of renal function progressed to end-stage renal failure in 3 of the 4 patients.

RESULTS

Our results show that the kidney can be an extraintestinal target of Crohn's disease.

CONCLUSIONS

Several unanswered questions remain concerning the frequency of interstitial nephritis in patients with Crohn's disease, as well as the exact role of mesalamine in the development of chronic interstitial nephritis.

Acute tubulointerstitial nephritis associated with the selective COX-2 enzyme inhibitor, rofecoxib

The nephrotoxic effect of COX-2 selective inhibitors has not yet been established. We report a case of reversible acute renal failure due to acute tubulointerstitial nephritis, confirmed by histology of a renal biopsy sample, associated with taking rofecoxib, a selective cyclo-oxygenase-2 (COX-2) inhibitor.

Amlodipine besylate induced acute interstitial nephritis

Adverse effects of amlodipine besylate, a widely used antihypertensive medication, include peripheral edema, flushing, headache, pruritus, and rash. An adverse renal effect attributable to the medication has hitherto not been reported in the literature. We herein report a case of amlodipine besylate induced acute interstitial nephritis.

Suppression of experimental autoimmune tubulointerstitial nephritis in BALB/c mice by berberine

Berberine (BB) is a protoberberine alkaloid derived from various representatives of the Berberidaceae family. Although used as a therapeutic agent, it has not been applied in the treatment of immune-mediated disorders. In the present study, BB was administered at a daily dose of 10 mg/kg for 3 consecutive days before the induction of tubulointerstitial nephritis (TIN) by injection of bovine tubular basement membrane (TBM) antigen in BALB/c mice. The animals were investigated 2 months after TBM inoculation. The intensity of pathological injuries in animals with TIN+BB decreased significantly, an effect that correlated with the improvement of renal function. Flow cytometric analysis of peripheral blood cells showed that BB caused a decrease in the number of CD3(+), CD4(+), CD8(+), and sIg(+) lymphocytes in comparison with TIN mice. The same tendency was noticed in the lymphocytes from kidney infiltrates of treated animals. The control animals treated only with BB showed a decrease in the number of CD3(+), CD4(+), CD8(+) T-lymphocytes in comparison with control nontreated mice. Our results, thus, indicate that BB has an immunosuppressive effect in the TIN model, which is an analogue of various human kidney autoimmune diseases.