Convection volume, β2-microglobulin and α1-microglobulin reduction ratios, and body composition in predilution online haemodiafiltration

AIM

The effect of convection volume (CV) in patients on predilution online haemodiafiltration (Pre-OL-HDF) was evaluated.

METHODS

We conducted a retrospective, cross-sectional study in 126 patients on Pre-OL-HDF. Dialysis conditions, laboratory data, and same day post-dialysis body composition measurements using bioimpedance spectroscopy were assessed. Patients were divided into two groups according to their CV: ≥ median value and < median value. Linear regression analyses for reduction ratios (RRs) of β2-microglobulin and α1-microglobulin, and body composition, were conducted.

RESULTS

Age, dialysis vintage, and CVs of the study patients were 64 ± 12 years, 81 (48-154) months, and 43.2 (38.5-55.9) L/session, respectively. The higher CV (≥ 43 L/session) group (n=66) had significantly higher RRs of β2-microglobulin and α1-microglobulin, lean tissue index, body cell mass index, total body water (TBW), extracellular water (ECW), and intracellular water (ICW) compared with the lower CV (< 43 L/session) group (n = 60; P < 0.01). Serum albumin and fat tissue index were not significantly different between the groups. CV/ECW, CV/TBW, and CV/ICW but not un-adjusted CV, were significant determinants for β2-microglobulin and α1-microglobulin RRs (P < 0.05). Lean tissue and body cell mass indexes, but not the fat tissue index, showed significant associations with CV, and RRs of β2-microglobulin and α1-microglobulin (P < 0.05).

CONCLUSIONS

Among patients on Pre-OL-HDF, higher values in the lean tissue index and body cell mass index were observed in those with higher CV versus lower CV, and CV adjusted to body water may be useful to prescribe individualized conditions for Pre-OL-HDF. This article is protected by copyright. All rights reserved.

Utility of CHA2DS2-VASc Score to Predict Mid-Term Clinical Outcomes in Hemodialysis Patients

BACKGROUND

The CHA2DS2-VASc score has been widely used to predict stroke in patients with atrial fibrillation (AF). Recently, it was reported that the CHA2DS2-VASc score helps predict cardiovascular disease (CVD) or all-cause mortality in patients with or without AF. However, few reports have examined the association between this score and mortality in hemodialysis (HD) patients.

METHODS

We analyzed 557 consecutive patients who initiated HD at our facilities between February 2005 and October 2017. The CHA2DS2-VASc score was calculated at the time of initiation of HD. Patients were then categorized into three groups according to their CHA2DS2-VASc scores: 0-1 (low), 2-3 (intermediate), and 4-9 (high). Multivariate Cox proportional hazards analysis was used to assess independent risk factors for 3-year all-cause mortality.

RESULTS

During the 3-year follow-up period, 153 (27.5%) patients died (cardiovascular death: n = 88). According to multivariate analysis, serum albumin (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.43-0.85, p = 0.003), creatinine (HR 0.91, 95% CI 0.84-0.99, p = 0.049), and CHA2DS2-VASc score (HR 1.33, 95% CI 1.20-1.46, p < 0.001) were associated with 3-year all-cause mortality. Compared with patients in the low CHA2DS2-VASc score group, those in the intermediate- and high-score groups had a higher risk for all-cause and CVD mortality (all-cause mortality: HR 1.77, 95% CI 1.23-2.55, p = 0.002 and HR 2.94, 95% CI 1.90-4.53, p < 0.001, respectively; CVD mortality: HR 1.82, 95% CI 1.27-2.59, p = 0.001 and HR 2.85, 95% CI 1.88-4.31, p < 0.001, respectively).

CONCLUSION

The CHA2DS2-VASc score is a valuable predictor of 3-year all-cause and CVD mortality in incident HD patients.

A Combination of Iohexol Treatment and Ionizing Radiation Exposure Enhances Kidney Injury in Contrast-Induced Nephropathy by Increasing DNA Damage

Contrast media has been shown to induce nephropathy (i.e., contrast-induced nephropathy) after various types of radiological examinations. The molecular mechanism of contrast-induced nephropathy has been unclear. In this study, we investigated the mechanism of contrast-induced nephropathy by examining the effects of combined treatment of contrast medium and ionizing radiation on kidney cells in vitro and kidney tissue in vivo. In human renal tubular epithelium cells, immunofluorescence analysis revealed that iohexol increased the numbers of radiation-induced γH2AX nuclear foci. The numbers of γH2AX nuclear foci remained high at 24 h, suggesting that some radiation-induced double-strand breaks remain unrepaired in the presence of iohexol. We established a mouse model of contrast-induced nephropathy, then showed that iohexol and ionizing radiation synergistically reduced renal function and induced double-strand breaks. Importantly, iohexol induced significant macrophage accumulation and oxidative DNA damage in the kidneys of contrast-induced nephropathy model mice in the absence of ionizing radiation; these effects were amplified by ionizing radiation. The results suggest that underlying inflammation and oxidative DNA damage caused by iohexol contribute to the enhancement of radiation-induced double-strand breaks, leading to contrast-induced nephropathy.

Penile calciphylaxis in patients with end-stage kidney disease undergoing dialysis: invasive treatment and pain management

INTRODUCTION

Penile calciphylaxis is rarely reported in dialysis patients.

METHODS

We experienced cases of dialysis patients who had penile calciphylaxis between 2003 and 2020.

RESULTS

Seven patients undergoing dialysis were treated for penile necrosis (hemodialysis [HD], 5; peritoneal dialysis [PD], 1; hybrid therapy comprising PD and HD, 1). Their mean age was 62.8 years and their mean dialysis vintage 116.1 months. All had severe penile pain and were clinically diagnosed with calciphylaxis. Four received partial penectomy and three received percutaneous transluminal angioplasty (PTA) due to rapid aggravation. The number of analgesia types and the critical-care pain observation tool score significantly decreased after invasive treatment (both, P = 0.008). The 90-day and 1-year survival rates after onset were 85.7% and 57.1%, respectively.

CONCLUSION

In dialysis patients, penile calciphylaxis has poor prognosis; however, invasive treatments for pain management are effective. PTA may be beneficial in dialysis patients in poor condition. This article is protected by copyright. All rights reserved.

Klotho overexpression protects against renal aging along with suppression of transforming growth factor-β1 signaling pathways

Klotho is an antiaging protein reported to suppress transforming growth factor-β1 (TGF-β1) signaling. Aging kidneys are characterized by interstitial fibrosis, accumulation of cell cycle-arrested cells, and increased levels of oxidative stress. TGF-β1 signaling is involved in these processes. In this study, we investigated whether klotho overexpression improves these features in the kidneys of aging mice and examined the inhibitory effect of klotho on signaling molecules related to transforming growth of TGF-β1. Klotho transgenic (KLTG) and wild-type (WT) mice were used, and 8-wk-old and 24-mo-old mice were defined as young and aging, respectively. We found that klotho expression was decreased in aging WT mice, but it was maintained in aging KLTG mice. Klotho overexpression improved the survival of 24-mo-old mice. Although the serum Ca²⁺ level was significantly lower in aging KLTG mice than in aging WT mice, the serum phosphate level did not differ between these mice. Klotho overexpression attenuated the increases in blood pressure, serum blood urea nitrogen level, and serum creatinine level in aging mice. Interstitial fibrosis, accumulation of cell cycle-arrested cells, and oxidative stress did not differ between young KLTG and WT mice, but they were significantly suppressed in aging KLTG mice compared with aging WT mice. Furthermore, the expression of TGF-β1-related signaling molecules was increased in aging WT mice, whereas it was inhibited in aging KLTG mice. These data suggest that klotho overexpression protects against kidney aging along with suppression of TGF-β1 signaling pathways.NEW & NOTEWORTHY Klotho is considered as an antiaging protein, and its overexpression may be a candidate therapy for protection against kidney damage with advanced aging. Although multiple factors are involved in the aging process, we showed that klotho overexpression inhibited interstitial fibrosis, accumulation of cell cycle-arrested cells, and increased levels of oxidative stress in the kidneys of aging mice, suppressing transforming growth factor-β1-related signaling pathways. The present data showed that klotho overexpression protects against age-associated kidney damage.

Klotho deficiency intensifies hypoxia-induced expression of IFN-α/β through upregulation of RIG-I in kidneys

Hypoxia is a common pathway to the progression of end-stage kidney disease. Retinoic acid-inducible gene I (RIG-I) encodes an RNA helicase that recognizes viruses including SARS-CoV2, which is responsible for the production of interferon (IFN)-α/β to prevent the spread of viral infection. Recently, RIG-I activation was found under hypoxic conditions, and klotho deficiency was shown to intensify the activation of RIG-I in mouse brains. However, the roles of these functions in renal inflammation remain elusive. Here, for in vitro study, the expression of RIG-I and IFN-α/β was examined in normal rat kidney (NRK)-52E cells incubated under hypoxic conditions (1% O₂). Next, siRNA targeting RIG-I or scramble siRNA was transfected into NRK52E cells to examine the expression of RIG-I and IFN-α/β under hypoxic conditions. We also investigated the expression levels of RIG-I and IFN-α/β in 33 human kidney biopsy samples diagnosed with IgA nephropathy. For in vivo study, we induced renal hypoxia by clamping the renal artery for 10 min in wild-type mice (WT mice) and Klotho-knockout mice (Kl^−/− mice). Incubation under hypoxic conditions increased the expression of RIG-I and IFN-α/β in NRK52E cells. Their upregulation was inhibited in NRK52E cells transfected with siRNA targeting RIG-I. In patients with IgA nephropathy, immunohistochemical staining of renal biopsy samples revealed that the expression of RIG-I was correlated with that of IFN-α/β (r = 0.57, P<0.001, and r = 0.81, P<0.001, respectively). The expression levels of RIG-I and IFN-α/β were upregulated in kidneys of hypoxic WT mice and further upregulation was observed in hypoxic Kl^−/− mice. These findings suggest that hypoxia induces the expression of IFN-α/β through the upregulation of RIG-I, and that klotho deficiency intensifies this hypoxia-induced expression in kidneys.

Serum-free medium and hypoxic preconditioning synergistically enhance the therapeutic effects of mesenchymal stem cells on experimental renal fibrosis

Background

Mesenchymal stem cells (MSCs) repair injured tissue in a paracrine manner. To enhance their therapeutic properties, preconditioning with various factors has been researched. We have previously showed that MSCs cultured in serum-free medium (SF-MSCs) promote their immunosuppressive ability, thereby enhancing their anti-fibrotic effect. Here, we examined whether serum-free medium and hypoxic preconditioning synergistically enhance the therapeutic effects of MSCs on renal fibrosis in rats with ischemia–reperfusion injury (IRI).

Methods

SF-MSCs were incubated under 1% O₂ conditions (hypo-SF-MSCs) or 21% O₂ conditions (normo-SF-MSCs) for 24 h before collection. After IRI procedure, hypo-SF-MSCs or normo-SF-MSCs were injected through the abdominal aorta. At 7 or 21 days post-injection, the rats were killed and their kidneys were collected to evaluate inflammation and fibrosis. In in vitro experiments, we investigated whether hypo-SF-MSCs enhanced secretion of anti-fibrotic humoral factors using transforming growth factor (TGF)-β1-stimulated HK-2 cells incubated with conditioned medium from hypo-SF-MSCs or normo-SF-MSCs.

Results

Normo-SF-MSCs showed attenuation of senescence, which increased their proliferative capacity. Although no significant difference in cellular senescence was found between normo-SF-MSCs and hypo-SF-MSCs, hypo-SF-MSCs further increased their proliferative capacity compared with normo-SF-MSCs. Additionally, administration of hypo-SF-MSCs more strongly ameliorated renal fibrosis than that of normo-SF-MSCs. Moreover, although hypo-SF-MSCs strongly attenuated infiltration of inflammatory cells compared with the control rats, which were treated with PBS, this attenuation was almost equal between normo-SF-MSCs and hypo-SF-MSCs. In vitro experiments revealed that hypo-SF-MSCs more significantly inhibited transforming growth factor (TGF)-β/Smad signaling compared with normo-SF-MSCs. Moreover, hypoxic preconditioning increased hepatocyte growth factor (HGF) secretion even under serum-free conditions, whereas knockdown of HGF in hypo-SF-MSCs attenuated inhibition of TGF-β/Smad signaling.

Conclusions

These results indicate that administration of ex vivo-expanded, hypoxia-preconditioned SF-MSCs may be a useful cell therapy to prevent renal fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02548-7.

Annual dialysis data report of the 2018 JSDT Renal Data Registry: dementia, performance status, and exercise habits

According to the annual survey of the Japanese Society for Dialysis Therapy Renal Data Registry (JRDR) conducted at the end of 2018, there were a total of 339,841 patients receiving dialysis (hereinafter, dialysis patients) in Japan. The survey included questions regarding the presence/absence of dementia, the performance status (PS), and the exercise habits of individual patients. The survey revealed that 10.8% of all dialysis patients had dementia (1.8% in the age group of less than 65 years, 6.8% in the age group of 65–74 years, and 22.7% in the age group of 75 years or older). These prevalences of dementia were approximately equal to those estimated from the survey conducted in 2010. Regarding PS, the percentage of patients with lower activity levels tended to be relatively high among patients who were less than 15 years old and those who were 60 years old or older. Concerning the exercise habits of dialysis patients, the percentage of patients who were classified as “not at all or hardly” in response to the question about exercise habit was the highest (60–80%) of all the exercise habit classifications in each of the age groups analyzed.

Effectiveness of a treatment algorithm for hemodialysis-associated pruritus in terms of changes in medications

Background

Hemodialysis-associated pruritus (HAP) is a serious complication that occurs in 60–80% of hemodialysis patients, which not only decreases quality of life but also worsens prognosis. We have developed a treatment algorithm to take a comprehensive cause-specific approach to HAP and used it at our facility since June 2009. In this treatment algorithm, moisturizers and topical steroids are used depending on skin condition and severity of pruritus; administration of nalfurafine hydrochloride is considered in treatment-resistant cases. If pruritus improves, we attempt to taper topical steroids by switching to lower potency or by dose reduction or discontinuation. Here, we examined the effectiveness of the treatment algorithm over 9 years in terms of changes in medications.

Methods

Subjects were hemodialysis patients who received treatment for HAP at our facility: 89 in May 2009 before introduction of the algorithm, and 131 in April 2013, 164 in October 2014, 190 in October 2015, 181 in October 2016, 215 in October 2017, and 224 patients in October 2018 after its introduction. A questionnaire survey was conducted on the presence of pruritus, severity (using a visual analogue scale [VAS] and Shiratori severity scores), frequency, and insomnia due to pruritus. Changes in medications were investigated using medical records and compared.

Results

The proportion of patients with pruritus decreased significantly from 96.6% in 2009 to 66.8% in 2018 (p < 0.001). Median VAS score significantly decreased from 53.0 mm in 2009 to 24.5 mm in 2018 (p < 0.001), and the proportion of patients with insomnia due to pruritus also significantly decreased from 25.8% in 2009 to 2.2% in 2018 (p < 0.001). The proportion of patients who used moisturizers significantly increased from 34.8 to 89.7% (p < 0.001). The proportion of patients receiving topical steroids decreased from 47.2 to 35.7%, but the difference was not significant (p = 0.085).

Conclusions

The treatment algorithm was shown to be useful for improving HAP, but future challenges were identified, including promoting use of lower potency topical steroids or discontinuation. Further prospective studies are required to confirm the role of each treatment intervention in a comprehensive cause-specific approach to HAP.

Mesenchymal stem cells cultured in serum-free medium ameliorate experimental peritoneal fibrosis

BACKGROUND

Mesenchymal stem cells (MSCs) provide potential treatments for peritoneal fibrosis. However, MSCs cultured in media containing serum bring risks of infection and other problems. In this study, we compared the effect of human MSCs in serum-free medium (SF-MSCs) on peritoneal fibrosis with that of MSCs cultured in medium containing 10% fetal bovine serum (10%MSCs).

METHODS

Peritoneal fibrosis was induced by intraperitoneally injecting 0.1% chlorhexidine gluconate (CG). SF-MSCs or 10%MSCs were intraperitoneally administered 30 min after the CG injection. Ten days after the CG and MSC injections, we performed histological analyses and peritoneal equilibrium testing. In the in vitro experiments, we used transforming growth factor (TGF)-β1-stimulated human peritoneal mesothelial cells incubated in conditioned medium from MSCs to examine whether the SF-MSCs showed enhanced ability to produce antifibrotic humoral factors.

RESULTS

Histological staining showed that the SF-MSCs significantly suppressed CG-induced cell accumulation and thickening compared with that of the 10%MSCs. Additionally, the SF-MSCs significantly inhibited mesenchymal cell expression, extracellular matrix protein deposition and inflammatory cell infiltration. Peritoneal equilibration testing showed that compared with administering 10%MSCs, administering SF-MSCs significantly reduced the functional impairments of the peritoneal membrane. The in vitro experiments showed that although the conditioned medium from MSCs suppressed TGF-β1 signaling, the suppression did not significantly differ between the SF-MSCs and 10%MSCs.

CONCLUSIONS

Serum-free culture conditions can enhance the antifibrotic abilities of MSCs by suppressing inflammation. Administering ex vivo expanded SF-MSCs may be a potential therapy for preventing peritoneal fibrotic progression.

Iron, coronary artery calcification, and mortality in patients undergoing hemodialysis

Objective

A high coronary artery calcification score (CACS) may be associated with high mortality in patients undergoing hemodialysis (HD). Recently, effects of iron on vascular smooth muscle cell calcification have been described. We aimed to investigate the relationships between iron, CACS, and mortality in HD patients.

Methods

We studied 173 consecutive patients who were undergoing maintenance HD. Laboratory data and Agatston’s CACS were obtained at baseline for two groups of patients: those with CACS ≥400 (n = 109) and those with CACS <400 (n = 64). Logistic regression analyses for CACS ≥400 and Cox proportional hazard analyses for mortality were conducted.

Results

The median (interquartile range) age and duration of dialysis of the participants were 67 (60–75) years and 73 (37–138) months, respectively. Serum iron (Fe) and transferrin saturation (TSAT) levels were significantly lower in participants with CACS ≥400 than in those with CACS <400, although the serum ferritin concentration did not differ between the groups. TSAT ≥21% was significantly associated with CACS ≥400 (odds ratio 0.46, p<0.05). TSAT ≥17%, Fe ≥63 µg/dL, and ferritin ≥200 ng/mL appear to protect against 5-year all-cause mortality in HD patients, independent of conventional risk factors of all-cause mortality (p < 0.05).

Conclusion

We have identified associations between iron, CACS, and mortality in HD patients. Lower TSAT was found to be an independent predictor of CACS ≥400, and iron deficiency (low TSAT, iron, or ferritin) was a significant predictor of 5-year all-cause mortality in HD patients.

Low-Vacuum Scanning Electron Microscopy to Assess Histopathological Resolution of Class V Lupus Nephritis: A Case Report

Lupus nephritis (LN) is most frequently associated with poor outcomes in patients with systemic lupus erythematosus (SLE). LN manifests as histopathological changes in the kidney caused by immune complex formation and deposition. In particular, immunoglobulin G (IgG) deposits are frequently observed by immunofluorescence staining, which helps to establish the diagnosis of LN. In this case report, we describe a 57-year-old woman with SLE who had been undergoing treatment on an outpatient basis for 11 years. Her first and second renal biopsies revealed class V LN with a coarsely granular pattern of IgG deposition in the peripheral capillary walls. However, her third renal biopsy showed no IgG deposition, which indicated histopathological resolution of her class V LN. We used low-vacuum scanning electron microscopy (LV-SEM) to examine the three-dimensional structural alterations in her glomerular basement membranes. In this report, we describe findings that indicated resorption of epithelial deposits, that is, resolution of LN. The results of repeated kidney biopsies confirmed by LV-SEM suggested the possibility of a state unrelated to LN.

The histopathological spectrum of kidney biopsies in patients with thymoma and myasthenia gravis: a report of 24 biopsies from a single institution

Background

Nephropathy in patients with thymic diseases such as thymoma and myasthenia gravis (MG) is rare and has been described mostly as isolated case reports. Here we evaluate a series of kidney biopsies from patients with thymoma and/or MG from a single institution in order to better define the spectrum and relative frequencies of thymic disease–associated nephropathies.

Methods

We conducted a retrospective case series study of 32 462 native kidney biopsies from January 2005 through December 2019 at Cedars-Sinai Medical Center, Los Angeles, CA, USA.

Results

Twenty-four biopsy specimens (0.07%) from patients with a history of thymoma and/or MG were identified. Two patients had repeat biopsies. The most common pathologic diagnosis that could be immunologically attributed to thymic disease was minimal change disease (MCD; 45%), followed by tubulointerstitial nephritis (TIN; 14%), immune complex (IC)-mediated glomerulonephritis (9%), membranous nephropathy (5%) and immunoglobulin A (IgA) nephropathy (5%). Interestingly, 50% of the MCD and 67% of TIN cases concomitantly showed mild IgG-dominant IC deposition in mesangial areas and/or in tubular basement membranes. In the two patients with repeat biopsies, mild mesangial IC deposition developed in the MCD patient but disappeared in the TIN patient with the second biopsy. Pathologic diagnoses unlikely related to the underlying thymic disease were diabetic glomerulosclerosis (9%), acute tubular necrosis (9%) and monoclonal Ig deposition disease (5%).

Conclusions

Thymic disease is associated with a wide spectrum of kidney diseases affecting the glomerular and tubulointerstitial compartments, often with low-grade IC deposition. These findings suggest a role of immunologic dysregulation in the pathogenesis of thymic disease–associated nephropathy.

Eighteen-year follow-up cohort study on hepatitis B and C virus infections related long-term prognosis among hemodialysis patients in Hiroshima

This study aimed to investigate the prevalence trend of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and their genotype distribution among hemodialysis patients, determining their long-term prognosis and the risk factors to the mortality. This cohort study used both the medical data and the blood samples of hemodialysis patients at nine dialysis centers in Hiroshima from 1999 to 2017. Hepatitis B surface antigen (HBsAg) and anti-HCV were screened and then amplification was done to positive sera by polymerase chain reaction for genotyping. Data were employed for multiple regressions to determine the associated risk factors. A total of 3968 patients were subdivided into three groups: who started hemodialysis before 1990, during 1991 to 2001, and after 2002. The periodic prevalence of HBsAg decreased from 2.8% to 1.3% and that of anti-HCV from 33.3% to 9.5% in the three groups. By multiple regressions, the adjusted hazard ratio of diabetes mellitus (DM) ranges from 1.59 to 2.12 and that of HCV RNA positivity ranges from 1.18 to 1.48 (P < .05). Heart failure is the primary cause of death in all groups. Genotype C2 is predominant for HBV and genotype 1b is predominant for HCV. The decreasing trend of both HBV and HCV was found in the cohort. DM and HCV RNA were the significant risk factors leading to poor prognosis among hemodialysis patients. The similar genotype distribution of both HBV and HCV was found as general population. This alarmed to provide early diagnosis, prompt, and adequate treatment to HCV infection among hemodialysis patients.

Association and predictive value of geriatric nutritional risk index, body composition, or bone mineral density in haemodialysis patients

AIM

Assess the association and predictive value of geriatric nutritional risk index (GNRI), body composition, and bone mineral density (BMD) in haemodialysis (HD) patients.

METHODS

Laboratory data, body composition parameters measured via body composition monitor, and radius, lumbar spine, femoral neck BMD measured using dual energy X-ray absorptiometry were assessed in all subjects on HD or online haemodiafiltration (HDF) at baseline. Regression analysis for GNRI, Cox proportional hazard analyses and comparison of multiple receiver operating characteristic (ROC) curves were performed.

RESULTS

Among all 264 patients, age was 65 ± 12 years and dialysis vintage was 79 (39-144) months. GNRI tertile (T)1, T2, and T3 were 88 (85-91), 94 (93-95), and 98 (97-101), respectively. Patients in GNRI T1 had lower fat tissue index (FTI), lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD, but higher overhydration/extracellular fluid than patients in GNRI T2 or T3 (P < .05). GNRI was significantly associated with FTI, lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD (P < .01). GNRI was a significant predictor of 2-year all-cause mortality (HR 0.92, P < .05). Area under the ROC curve for all-cause mortality using traditional risk factors (age, sex, diabetes mellitus, cardiovascular disease, use of vasopressors for dialysis-related hypotension, and C-reactive protein) was 0.67 and changed by adding GNRI (0.78, P < .05), FTI (0.75), or femoral neck BMD (0.66), respectively.

CONCLUSION

Associations between GNRI, body composition, and BMD were confirmed in HD patients. Combining GNRI with traditional risk factors improved mortality prediction in HD patients.

Clinical characteristics of inflammatory bowel disease patients with immunoglobulin A nephropathy

Background/Aims

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract. Some patients with this condition have been reported to present with immunoglobulin A nephropathy (IgAN), a renal complication that can cause end-stage renal failure, but the frequency of this comorbidity has not been described. Thus, the aim of this study was to investigate the frequency of IgAN in patients with IBD.

Methods

This study included 620 patients with IBD (338 with ulcerative colitis [UC] and 282 with Crohn’s disease [CD]) from the Hiroshima University Hospital outpatient department. IgAN cases were identified from medical interviews, blood examinations (serum immunoglobulin A), and urinalyses (occult blood, proteinuria). Definitive IgAN cases were diagnosed by renal biopsies, while those detected through the clinical course and test results, but not clinically recommended for renal biopsy, were defined as suspected IgAN.

Results

We analyzed 427 cases meeting the inclusion criteria (220 with UC and 207 with CD). The incidence of IgAN across all patients with IBD was 3.0%. The frequency of IgAN was significantly higher in patients with CD (11/207, 5.3%) than in those with UC (2/220, 0.9%) (P< 0.01). Moreover, a significant correlation was found between CD patients with ileostomy or colostomy and a diagnosis of IgAN.

Conclusions

Patients with IBD present a high incidence of IgAN, especially those with CD who have undergone ileostomy or colostomy.

Chronic kidney disease caused by maternally inherited diabetes and deafness: a case report

Maternally inherited diabetes and deafness (MIDD) is a mitochondrial genetic disorder with variable clinical presentations, which can delay its diagnosis. Herein, we report the case of a 57-year-old Japanese man with MIDD who developed chronic kidney disease. He developed proteinuria long before his diabetes and deafness; at the age of 36 years, a renal biopsy showed minor glomerular abnormality and electron microscopy showed mild mitochondrial degeneration in the distal tubular epithelial cells. Twenty years later, a second renal biopsy showed nephrosclerosis with interstitial fibrosis and arteriolar hyaline thickening, despite the absence of hypertension and relatively good glycemic control. Granular swollen epithelial cells were found in the medullary collecting duct epithelium. Electron microscopy showed accumulating mitochondria in podocytes and tubular cells, leading to the diagnosis of MIDD. A muscle biopsy also showed ragged-red fibers, despite the absence of muscle weakness. Mitochondrial DNA analysis revealed an m.3243A > G mutation, and taurine supplementation was initiated. Our findings suggest that mitochondrial dysfunction is mainly associated with progressive renal damage.

Different risk factors are associated with vascular access patency after construction and percutaneous transluminal angioplasty in patients starting hemodialysis

BACKGROUND

The objective of this multicenter, prospective observational study was to determine the factors related to patency rates after construction of vascular access (VA) and the first percutaneous transluminal angioplasty (PTA).

METHODS

The 24-month primary and secondary patency rates after construction of a radiocephalic arteriovenous fistula (RC-AVF) and arteriovenous graft (AVG) were evaluated using the Kaplan-Meier method and log-rank test. The 12-month post-PTA patency rate was also investigated. A Cox proportional hazard model was used to identify clinical parameters associated with the primary patency rate and the post-PTA patency rate.

RESULTS

A total of 611 patients were enrolled in the study. The primary patency rate after VA construction was lower in hemodialysis (HD) patients with an AVG than in those with an AVF. Aging (hazard ratio [HR], 1.02 per 1 year; p < 0.001), female sex (HR, 1.41; p = 0.03), diabetes mellitus (HR, 1.37; p = 0.03), low serum albumin (HR, 0.76 per 1-g/dL decrease; p = 0.02), and use of an erythropoietin-stimulating agent (HR, 1.62; p = 0.02) were risk factors for VA problems. The post-PTA patency rate was associated with aging (HR, 1.02; p < 0.001), diabetes mellitus (HR, 1.49; p = 0.02), polycystic kidney disease (HR, 2.14; p = 0.01), temporary catheter use for initiation of HD (HR, 1.60; p = 0.02), and period from VA construction to use (HR, 0.99; p = 0.04).

CONCLUSION

Although a poor patency rate is commonly associated with advanced age and diabetes, different risk factors affect patency between VA construction and the first PTA.

A classic variant of Fabry disease in a family with the M296I late-onset variant

Fabry disease is an X-linked recessive disease of glycosphingolipid metabolism caused by deficiency or reduced activity of α-galactosidase A. Fabry disease phenotypes are known to consist of a classic variant and a late-onset variant. In patients with Fabry disease, the phenotype is generally considered to be defined (at least partially) by the genotype. However, patients with the classic variant have been encountered in families with mutations that are expected to produce the late-onset variant. Here, we describe a 4-year-old boy with a classic variant of Fabry disease in a family with the M296I late-onset variant. The patient's grandfather, mother, and aunt experienced late-onset disease, characteristic of the M296I variant. Conversely, the patient experienced typical disease symptoms in childhood. He had symptoms of hypohidrosis and associated heat accumulation. He cried at night due to the occurrence of severe acroparaesthesia. This symptom became more pronounced in warmer climates. Although the patient's family had a late-onset variant mutation of Fabry disease, we determined that the patient's symptoms were similar to those of classic Fabry disease. Therefore, the patient began enzyme replacement therapy, which alleviated his symptoms. Notably, enzyme replacement therapy led to rapid improvement of the patient's subjective symptoms. Thus, we presumed that the patient's symptoms supported a diagnosis of classic Fabry disease. These findings suggest that childhood symptoms may occur in patients with Fabry disease, even in families with late-onset variant mutations. The genotype-phenotype correlation in Fabry disease remains controversial.

A case report of adult-onset COQ8B nephropathy presenting focal segmental glomerulosclerosis with granular swollen podocytes

Background

Primary coenzyme Q10 (CoQ10) deficiency of genetic origin is one of a few treatable focal segmental glomerulosclerosis (FSGS). Renal morphologic evidence for COQ8B mutation and CoQ10 deficiencies of other gene mutations is assessed using electron microscopy with marked increase of abnormal-shaped mitochondria in podocytes. However, light microscopic morphologic features of deficiencies other than FSGS have not been reported.

Case presentation

A 30-year-old woman was admitted to our hospital because proteinuria was found during four consecutive medical checkups. She had no medical history or family history of proteinuria and severe renal dysfunction. The swollen podocytes were stained to the same extent as mitochondria-rich proximal tubular cells under both Masson’s trichrome and hematoxylin-eosin staining, whereas no mitochondrial abnormalities were detected under the first electron microscopic views. As proteinuria and estimated glomerular filtration rate (eGFR) deteriorated after pregnancy, we reevaluated the additional electron microscopic views and detected mitochondrial abnormalities. Genetic testing revealed COQ8B mutation (c.532C > T, p.R178W); therefore, we diagnosed COQ8B nephropathy. CoQ10 supplementation improved proteinuria and stopped eGFR reduction.

Conclusions

This is the first report of granular swollen podocytes due to mitochondrial diseases detected under light microscopy. We propose that this finding can be the clue for the diagnosis of both COQ8B nephropathy and the other CoQ10 deficiencies.

Vascular access management after percutaneous transluminal angioplasty using a calcium alginate sheet: a randomized controlled trial

BACKGROUND

Management of vascular access (VA) is essential in hemodialysis (HD) patients. However, VA often fails and percutaneous transluminal angioplasty (PTA) is required. Conventional hemostasis at the puncture site is associated with complications. This study aimed to analyze the efficacy and safety of a hemostatic wound dressing made of calcium alginate at the puncture site of VA after PTA and evaluate other factors affecting hemostasis.

METHODS

After PTA for VA, 200 HD patients were randomized to a calcium alginate sheet (CA) group (n = 100) or a no drug-eluting sheet (control) group (n = 100). We recorded time to hemostasis at the puncture site every 5 min, noting any complications.

RESULTS

In the CA group, rates of hemostatic achievement at 5, 10, 15 and >15 min were 57, 25, 8 and 10%, respectively. In the control group, the rates were 39, 28, 14 and 19%, respectively. Rates of hemostatic achievement at 5 min were significantly higher in the CA group (P = 0.01). In logistic regression analysis, factors affecting hemostasis within 5 min were use of the CA sheet [odds ratio (OR) 2.33; 95% confidence interval (CI) 1.26-4.37], platelet count ≤100 000/μL (OR 0.19; 95% CI 0.04-0.69), number of antithrombotic tablets used per day ≥1 tablet (OR 0.50; 95% CI 0.26-0.94) and upper arm VA (OR 0.16; 95% CI 0.03-0.55).

CONCLUSIONS

A CA sheet can safely reduce time to hemostasis at the puncture site after PTA, and should be considered for treating patients with a bleeding tendency.

Hypoxia-preconditioned mesenchymal stem cells prevent renal fibrosis and inflammation in ischemia-reperfusion rats

Background

Mesenchymal stem cells (MSCs) have been reported to promote the regeneration of injured tissue via their paracrine abilities, which are enhanced by hypoxic preconditioning. In this study, we examined the therapeutic efficacy of hypoxia-preconditioned MSCs on renal fibrosis and inflammation in rats with ischemia-reperfusion injury (IRI).

Methods

MSCs derived from rats and humans were incubated in 1% O₂ conditions (1%O₂ MSCs) for 24 h. After IRI, 1%O₂ MSCs or MSCs cultured under normoxic conditions (21%O₂ MSCs) were injected through the abdominal aorta. At 7 or 21 days post-injection, the rats were sacrificed and their kidneys were analyzed. In in vitro experiments, we examined whether 1%O₂ MSCs enhanced the ability to produce anti-fibrotic humoral factors using transforming growth factor (TGF)-β1-stimulated HK-2 cells incubated with conditioned medium from MSCs.

Results

Administration of rat 1%O₂ MSCs (1%O₂ rMSCs) attenuated renal fibrosis and inflammation more significantly than rat 21%O₂ MSCs. Notably, human 1%O₂ MSCs (1%O₂ hMSCs) also attenuated renal fibrosis to the same extent as 1%O₂ rMSCs. Flow cytometry showed that 1%O₂ hMSCs did not change human leukocyte antigen expression. Further in vitro experiments revealed that conditioned medium from 1%O₂ MSCs further suppressed TGF-β1-induced fibrotic changes in HK-2 cells compared with 21%O₂ MSCs. Hypoxic preconditioning enhanced vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) secretion. Interestingly, VEGF knockdown in 1%O₂ MSCs attenuated HGF secretion and the inhibition of TGF-β1-induced fibrotic changes in HK-2 cells. In addition, VEGF knockdown in 1%O₂ hMSCs reduced the anti-fibrotic effect in IRI rats.

Conclusions

Our results indicate that hypoxia-preconditioned MSCs are useful as an allogeneic transplantation cell therapy to prevent renal fibrosis and inflammation.

TGF-β1 Induced by High Glucose is Controlled by Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker on Cultured Human Peritoneal Mesothelial Cells

Background

Loss of peritoneal function is a major complication associated with long-term peritoneal dialysis. Observed changes include loss and degeneration of the mesothelium, submesothelial thickening, alterations in the structure and number of blood vessels, and reduplication of the vascular basement membrane. Exposure to high glucose concentrations in peritoneal dialysis solutions is known to cause injury to cultured human peritoneal mesothelial cells (HPMC) as a result of overexpression of transforming growth factor beta 1 (TGF-β1). Previous studies have demonstrated that angiotensin II (AII) increases expression of TGF-β1 in a number of different cell types; although this has not been demonstrated in HPMC.

Objective

To clarify possible mechanisms involved in peritoneal fibrosis, we investigated whether HPMC expressed AII-forming pathway mRNA and whether increases in AII induced by high glucose contribute to the production of TGF-β1. We also examined the effects of the angiotensin-converting enzyme inhibitor (ACEI) perindoprilat and the AII receptor blocker (ARB) candesartan on expression of TGF-β1 and proliferation of HPMC.

Methods

Expression of mRNA for the AII-forming pathway and TGF-β1 in HPMC was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Levels of AII and TGF-β1 following 48 hours of incubation of the cells in a range of glucose concentrations were measured by enzyme immunoassay and enzyme linked immunosorbent assay respectively. The effect of glucose on cell proliferation was examined using the water-soluble tetrazolium salt WST-1 and [3H]-thymidine uptake. We also investigated the effect of ACEI and ARB on the expression of TGF-β1 and the proliferation of HPMC incubated at high glucose for 48 hours.

Results

AII-forming pathway mRNA was detected in HPMC, with expression of angiotensinogen, angiotensin-converting enzyme (ACE), AII type 1 receptor, and TGF-β1 mRNA increasing following exposure to glucose according to glucose concentration. High glucose was also shown to increase the production of AII and TGF-β1 and decrease the proliferation of HPMC. In contrast, we found that both the ACEI and the ARB attenuated the increase in TGF-β1 production and reduced cell proliferation caused by exposure to high glucose. These effects were greater with a combination of the two drugs.

Conclusion

The present study provides evidence that ( 1 ) HPMC express mRNA for the AII-forming pathway; ( 2 ) ACEI and ARB inhibit the TGF-β1 production induced by high glucose; ( 3 ) the AII-forming pathway is one mechanism by which high glucose causes production of TGF-β1. In addition to having antihypertensive and renal-protective effects, combination therapy with an ACEI and an ARB may also be effective in preventing loss of peritoneal function and decreasing peritoneal fibrosis.