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Background Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a rare hereditary disease caused by a variety of genetic mutations. Carriers of a mutation in the responsible genes are at risk of reaching end-stage kidney disease typically in middle age. The frequency of this disease is assumed to be underestimated because of a lack of disease-specific signs. Pathological findings obtained from kidney of uromodulin related ADTKD (ADTKD-UMOD) patients are regarded as non-specific and less-informative for its diagnosis. This research was undertaken to evaluate the significance of kidney biopsy in ADTKD-UMOD patients. Methods Thirteen patients from 10 families with nine identified uromodulin (UMOD) gene mutations who underwent kidney biopsy in the past were studied. Their kidney tissues were stained with anti-UMOD antibody in addition to conventional methods such as PAS staining. When positive, the numbers of tubules with visible UMOD protein accumulations were calculated based on the total numbers of UMOD expressing tubules. Pathological findings such as tubulointerstitial fibrosis, atrophy, inflammation and glomerulosclerosis were also evaluated and analyzed. Results Interstitial fibrosis and tubular atrophy were present in all 13 patients. Most atrophic tubules with thickening and lamellation of tubular basement membranes showed negative UMOD staining. In all but two patients with C94F mutations, massive accumulation of UMOD proteins was observed in the renal endoplasmic reticulum. UMOD accumulations were also detectable by PAS staining as polymorphic unstructured materials in the 11 patients at frequencies of 2.6–53.4%. 80.4% of the UMOD accumulations were surrounded by halos. The detection rate of UMOD accumulations positively correlated with eGFR. Glomerulosclerosis was detected in 11/13 patients, with a frequency of 20.0 to 61.1%, while no cystic dilatations of glomeruli were detected. Conclusions Massively accumulated UMOD proteins in ADTKD-UMOD kidneys are detectable not only by immunostaining using anti-UMOD antibody but also by conventional methods such as PAS staining, although their detection is not easy. These findings can provide important clues to the diagnosis of ADTKD-UMOD. Kidney biopsy in ADTKD-UMOD may be more informative than assumed previously.

Compared with acetate dialysate, bicarbonate dialysate has shown beneficial effects in reducing the morbidity associated with dialysis, but a small amount of acetate in bicarbonate dialysate may evoke hypotension or malaise. Acetate-free citrate hemodialysis (AFHD) may avoid these problems. In 44 hemodialysis patients bicarbonate hemodialysis (BHD) was conducted for three months, followed by a switch to AFHD for three months, and a further switch to bicarbonate hemodialysis (ReBHD). In BHD, AFHD and ReBHD, intra-dialysis hypotension and post-dialysis malaise were determined (hypotension: intra-dialysis systolic blood pressure (SBP) was expressed as a percentage of SBP at the start of hemodialysis, malaise was assessed by a self-reported 0 to 3 scale, 0: absence of malaise, 3: unbearable malaise). Compared with BHD, AFHD patients complained of less malaise but the intra-dialysis blood pressure change did not differ significantly (malaise: BHD 0.73 ± 0.76 vs. AFHD 0.32 ± 0.47, P < 0.0001, end hemodialysis SBP: BHD 93.6 ± 8.9 vs. AFHD 93.8 ± 10.1, P = NS). After switching to ReBHD from AFHD, the malaise score increased (AFHD 0.32 ± 0.47 vs. ReBHD 0.77 ± 0.89, P < 0.0001) and the intra-dialysis blood pressure dropped markedly (end hemodialysis SBP: AFHD 93.8 ± 10.1 vs. ReBHD 87.3 ± 10.5, P < 0.0001). Malaise was very severe in five patients who could not continue ReBHD. After ten days under ReBHD, ReBHD was changed to AFHD again in all patients. Although the exact mechanisms are not known, AFHD may be preferable to BHD to prevent hemodialysis-induced hypotension and malaise.

A 49-year-old man was admitted because of general fatigue, cough and hematuria. During the hospital course, acute renal failure, hemoptysis and dyspnea developed. A percutaneous renal biopsy revealed a diffuse crescentic glomerulonephritis, and direct immunofluorescence showeda linear pattern ofIgG along the glomerular basement membrane. Although serum anti-glomerular basement membrane (anti-GBM) antibody was not detected, Goodpasture's-like syndrome was suspected, and methylprednisolone pulse therapy and plasmapheresis were administered. Concomitantly, extracorporeal membraneoxygenation (ECMO) was instituted because of deterioration in respiratory status due to a severe pulmonary hemorrhage despite maximalventilatory support. Temporarily, the patient improved and ECMO was discontinued. ECMO may be a useful therapeutic support for hypoxia resulting from pulmonary hemorrhage in Goodpasture's syndrome (GPS) and Goodpasture's-like syndrome.

Although antiplatelet medication is used in various situations, including for the prevention of ischemic and thrombotic complications, long-term antiplatelet therapy in hemodialysis patients who are at high risk of bleeding may result in a harmful bleeding tendency. We investigated bleeding events that required the cessation of the use of heparin for hemodialysis in all the hemodialysis patients treated in our clinic. This analysis revealed 111 patients, of whom 52 had been treated with antiplatelet agents (female/male, 15/37; age, 70.4±11.3years; number of days of hemodialysis treatment in our clinic, 1073±696 [31-2144]days; diabetes mellitus [DM]/non-DM, 29/23), and 59 had not been treated with them (female/male, 17/42; age, 66.7±14.0 years; number of days of hemodialysis treatment in our clinic, 917±605 [26-2102]days; DM/non-DM, 21/38). During treatment in our clinic, 21 of the 52 patients undergoing antiplatelet therapy experienced a bleeding event (gastrointestinal bleeding 16, brain stem hemorrhage 2, others 3), while 7 of the 59 patients not receiving them had a bleeding event (gastrointestinal bleeding 7) (P<0.001). Of note, diabetic patients on antiplatelet therapy had the highest incidence of bleeding events (13 of 29 patients; 44.8%), followed by non-diabetic patients on antiplatelet therapy (7 of 23 patients; 30.4%), diabetic patients not receiving antiplatelets (3 of 21 patients; 14.3%), and finally non-diabetic patients not on antiplatelets (4 of 38 patients; 10.5%). Among the patients on antiplatelet therapy, no correlations were apparent between bleeding events and the duration of such therapy or the number of agents. In conclusion, antiplatelet medications can induce bleeding events more frequently in hemodialysis patients, especially in those with DM, than in non-hemodialysis patients, and such agents should be given only under prudent consideration of the associated risks and benefits.

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BackgroundUromodulin kidney disease (UKD) is an inherited kidney disease caused by a uromodulin (UMOD) gene mutation. The UMOD gene encodes the Tamm–Horsfall protein (THP), which is the most abundant protein in healthy human urine. Because of its rarity, the incidence of UKD has not been fully elucidated. The purpose of the present study is to clarify the frequency of UKD among patients who underwent renal biopsy.MethodsImmunostaining for THP was performed for patients <50 years of age with renal insufficiency and hyperuricemia without overt urinalysis abnormality from renal biopsy databases. Serum and urinary THP concentrations were evaluated in available individuals.ResultsFifteen patients were selected for immunostaining from a total of 3787 patients. In three independent patients, abnormal THP accumulation in renal tubular cells was observed. A novel missense A247P UMOD mutation was detected in two of the three patients, including one having a typical family history of familial juvenile hyperuricemic nephropathy. Serum and urinary THP concentrations of all available patients with UMOD A247P mutation were significantly lower than those of controls.ConclusionsIn the present study, UKD was detected in <1 in 1000 subjects who underwent renal biopsies. However, in subjects meeting all of the above criteria, abnormal THP accumulation was detected in 20% (3/15), suggesting that renal biopsy with immunostaining for THP is a good tool for diagnosing UKD. Also, low serum THP concentration detected in the present subjects might be a good diagnostic marker or important in understanding the pathogenesis of UKD.

We conclude that EUA is a useful method for the treatment of massive refractory ascites.