Renal sinus fat is associated with intrarenal hemodynamic abnormalities independent of visceral fat in patients with chronic kidney disease

OBJECTIVE

Obesity is a risk factor of chronic kidney disease (CKD), contributing to the rising incidence of cardiometabolic diseases. Renal sinus fat (RSF) is an ectopic fat depot located at the renal cavity that could impair renal function and hemodynamic through compression of renal structures. The major purpose of this study was to explore the relationship between RSF accumulation and renal dysfunction in CKD patients.

METHODS

We evaluated the associations between computed tomography measured RSF volume and key clinical and histologic parameters involved in renal function and hemodynamics in 132 well-characterized CKD patients who underwent renal biopsy (median age: 62 years; 63.6% men).

RESULTS

RSF volume normalized by renal volume (RSF%) positively correlated with obesity-related traits such body mass index and visceral fat volume (VFV) (all P < 0.001) whereas it negatively correlated with estimated glomerular filtration rate (eGFR) (ρ = -0.42, P < 0.001) and 24-h urinary creatinine clearance (CCr) (ρ = -0.34, P < 0.001). Notably, we found robust positive correlations between RSF% and renal resistive index (RRI) measured by the Doppler ultrasound (ρ = 0.40, P < 0.001), and the histological severity of global glomerular sclerosis (ρ = 0.48, P < 0.001) and interstitial fibrosis and tubular atrophy (IFTA) (ρ = 0.35, P < 0.001). In the multivariate linear regression models, after accounting for potential confounders including VFV, RSF% remained significantly associated with CCr (β = -0.26, P < 0.001), RRI (β = 0.17, P = 0.022), global glomerular sclerosis (β = 0.21, P = 0.002), and IFTA (β = 0.17, P = 0.012).

CONCLUSION

RSF accumulation is associated with renal dysfunction and hemodynamic abnormalities independent of visceral adiposity. Our results suggest that RSF may have a potential unique role in the pathogenesis of CKD.

Hemodialysis treatment of vancomycin-induced drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome in a patient undergoing peritoneal dialysis

Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS), is a severe drug-induced hypersensitivity reaction with 10% mortality. To date, there is insufficient evidence regarding the association between DRESS/DIHS and serum levels of vancomycin (VCM). Here, we report the case of a 46-year-old woman undergoing peritoneal dialysis who developed VCM-induced DRESS/DIHS. She was hospitalized for peritonitis with abdominal pain and treated with VCM. On day 10 of hospitalization, her abdominal symptoms improved; however, fever, skin rash, lymphadenopathy, eosinophilia, atypical lymphocytes, and liver and renal dysfunction developed. Based on the clinical course and laboratory findings, we diagnosed the patient with DRESS/DIHS due to VCM. Since her serum VCM concentration was high at 39.8 μg/mL, hemodialysis (HD) was performed to remove VCM, which caused her symptoms to improve. However, serum levels of VCM rebounded and the same symptoms recurred. Therefore, we re-performed HD; no further relapse occurred. This clinical course showed that increased serum VCM levels were associated with DRESS/DIHS onset and severity, suggesting that it is a blood level-dependent disease and that removal of VCM by HD is a potential therapeutic option.

Clinical significance of serum urea-to-creatinine ratio in patients undergoing peritoneal dialysis

INTRODUCTION

We aimed to determine the correlation between the serum urea-to-creatinine ratio and residual kidney function (RKF) in patients undergoing peritoneal dialysis (PD), as well as its predictive value for PD-related outcomes.

METHODS

This study included a cross-sectional study to assess the correlation between serum urea-to-creatinine ratio and RKF in 50 patients on PD and a retrospective cohort study to assess the association between serum urea-to-creatinine ratio and PD-related outcomes in 122 patients who initiated PD.

RESULTS

Serum urea-to-creatinine ratios had significant positive correlations with renal Kt/V and creatinine clearance values (r = 0.60, p < 0.001 and r = 0.61, p < 0.001, respectively). Additionally, serum urea-to-creatinine ratio was significantly associated with a lower risk of transfer to hemodialysis or PD/hemodialysis hybrid therapy (hazard ratio: 0.84, 95% confidence interval: 0.75-0.95).

CONCLUSION

The serum urea-to-creatinine ratio can be an indicator of RKF and a prognostic factor in patients undergoing PD.

Comparison of the effects of angiotensin receptor-neprilysin inhibitors and thiazide diuretic/renin-angiotensin system inhibitor combination therapy in hypertensive patients: a retrospective cohort study

Angiotensin receptor-neprilysin inhibitors (ARNIs) have been approved as antihypertensive agents in Japan, and thiazide diuretics (TZDs) are widely used concomitantly with renin-angiotensin system inhibitors (RASIs) for hypertension. This retrospective study included patients with hypertension who switched from RASI to ARNI therapy (ARNI group) and those who were prescribed TZDs with RASIs (TZD/RASI group). Drug-related changes in the estimated glomerular filtration rate (eGFR), blood pressure (BP), body weight (BW), serum electrolytes, uric acid (UA), and triglyceride levels were compared between the two groups. Overall, 70 participants (31 and 39 in the ARNI and TZD/RASI groups, respectively) were enrolled and observed for a median of 2 months. According to linear mixed models, compared with the TZD/RASI group, the ARNI group exhibited a significant change in mean eGFR of 3.71 mL/min/1.73 m2 [95% confidence interval (CI), 0.57-6.84; P = 0.02] from the time of switching drug to the next outpatient visit. Further, compared with the TZD/RASI group, the ARNI group exhibited significant changes in mean serum UA (-1.27; 95% CI, -1.66 to -0.88), sodium (1.22; 95% CI, 0.12 to -2.32), chloride (2.14; 95% CI, 0.75-3.52), and triglyceride (-52.1; 95% CI, -100.9 to -3.29) levels. Conversely, serum potassium levels, BW, and systolic and diastolic BP did not differ significantly between the two groups (P = 0.69, 0.44, 0.49, and 0.66, respectively). Compared with the combination therapy of TZD and RASI, ARNI therapy causes less renal dysfunction, hyperuricemia, and hypertriglyceridemia with fewer electrolyte abnormalities and no significant difference in antihypertensive effects.

Association Between Renal Sinus Fat and Cardiometabolic and Renin-Angiotensin System Parameters in Primary Aldosteronism

Context

Renal sinus fat (RSF) accumulation is associated with cardiometabolic diseases, such as obesity, diabetes, hypertension, and chronic kidney disease. However, clinical implications of RSF in primary aldosteronism (PA) remain unclear.

Objective

We aimed to investigate relationships between RSF volume and key cardiometabolic and renin-angiotensin system (RAS) parameters in PA patients and clarify the differences in these relationships between unilateral and bilateral subtypes.

Methods

We analyzed data obtained from well-characterized PA patients that involved 45 unilateral (median age: 52 years; 42.2% men) and 92 bilateral patients (51 years; 42.4% men).

Results

RSF volume normalized by renal volume (RSF%) was greater in the unilateral group than in the bilateral group (P < .05). RSF% was greater in men than in women (P < .05). RSF% positively correlated with parameters related to cardiometabolic risk, including age, body mass index, visceral fat volume, creatinine, triglycerides/high-density lipoprotein cholesterol ratio, uric acid, fasting glucose, and C-reactive protein regardless of PA subtypes (all P < .05). Intriguingly, RSF% positively correlated with plasma aldosterone concentration (PAC), aldosterone-to-renin ratio, and intact parathyroid hormone (iPTH) (all P < .05) in bilateral patients but did not correlate with RAS parameters and even showed an opposite trend in unilateral patients. In subgroup analyses by sex, these distinctions became more evident in women. After adjustment for potential confounders, RSF% remained positively correlated with PAC and iPTH in bilateral patients.

Conclusion

Our results indicate that RSF accumulation is involved in cardiometabolic dysfunction associated with PA. However, there were distinct correlations between RSF volume and RAS parameters according to sex and PA subtypes.

Peritoneal dialysis-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii: a case series and literature review

Background

As there is no established standard of care for non-tuberculous mycobacterium (NTM) peritoneal dialysis (PD)-related peritonitis, its treatments have to be case-dependent, which is often difficult. Additionally, several reported cases were accompanied by encapsulated ascites, adhesive ileus, and encapsulating peritoneal sclerosis, suggesting treatment difficulties. We report two cases of PD-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii. To the best of our knowledge, this is the first case series to report PD-related peritonitis caused by Mycobacterium abscessus subsp. bolletii.

Case presentation

The first case is that of a 74-year-old male patient who started PD six years ago for end-stage renal failure due to diabetic nephropathy. In February 2021, he presented with signs of infection at the exit-site and swelling of the tunnel. Mycobacterium abscessus subsp. massilience was detected in the culture of the exit-site exudate; thus, he was diagnosed with tunnel infection (caused by NTM). Subsequently, fever, abdominal pain, and increased cell counts in the PD drainage fluid were observed, and he was judged to have NTM peritonitis. His general condition improved after PD catheter removal in addition to antimicrobial treatment and encapsulated ascites drainage. The second case is that of a 52-year-old man who commenced PD for end-stage renal failure due to nephrosclerosis 12 years ago. In May 2022, he was diagnosed with PD-related peritonitis based on signs of infection at the exit-site, encapsulated ascites on computed tomography, and a cloudy PD drainage fluid. Mycobacterium abscessus subsp. bolletii was detected in the culture of the exit-site exudate, which led to the diagnosis of NTM peritonitis. In addition to antimicrobial treatment, PD catheter removal and encapsulated ascites drainage were performed. The patient also had adhesive bowel obstruction due to peritonitis and required decompression therapy with the insertion of a gastric tube.

Conclusions

PD catheter removal and encapsulated ascites drainage might have improved inflammation and treatment outcomes. Additionally, Mycobacterium abscessus might be prone to forming encapsulated cavities and/or intestinal adhesions; however, further accumulation of cases clarifying “subspecies” of Mycobacterium abscessus is necessary to confirm this hypothesis.

A systematic review and meta-analysis of the clinical impact of stopping renin-angiotensin system inhibitor in patients with chronic kidney disease

Although renin-angiotensin system (RAS) inhibitors reduce the risk of cardiovascular diseases and end-stage kidney disease (ESKD) in chronic kidney disease (CKD) patients, they are often discontinued in clinical practice due to drug-related adverse events. However, limited evidence is available about the clinical impact of RAS inhibitor discontinuation in CKD patients. A comprehensive search of publications investigating the effect of discontinuing RAS inhibitors on clinical outcomes in CKD patients in PubMed, the Cochrane Library, and Web of Science was conducted (inception to November 7, 2022), and potentially relevant studies were searched by hand (through November 30, 2022). Two reviewers independently extracted data according to the PRISMA and MOOSE guidelines and assessed the quality of each study with risk-of-bias tools, RoB2 and ROBINS-I. The pooled hazard ratio (HR) for each outcome was integrated with a random-effect model. A total of 1 randomized clinical trial and 6 observational studies involving 248,963 patients were included in the systematic review. The meta-analysis of observational studies showed that discontinuation of RAS inhibitors was associated with a higher risk of all-cause mortality (HR, 1.41 [95% CI, 1.23-1.62]; I² = 97%), ESKD (1.32 [95% CI, 1.10-1.57]; I² = 94%) and MACE (1.20 [95% CI 1.15-1.25]; I² = 38%), but not with hyperkalemia (0.79 [95% CI 0.55-1.15]; I² = 90%). Overall risk of bias was moderate-to-serious, and quality of evidence (GRADE system) was low-to-very low. The present study suggests that CKD patients would benefit from continuing RAS inhibitors.

Correlation between acylcarnitine/free carnitine ratio and cardiopulmonary exercise test parameters in patients with incident dialysis

Objective: Diminished physical capacity is common and progressive in patients undergoing dialysis, who are also prone to deficiency in carnitine, which plays a pivotal role in maintaining skeletal muscle and cardiac function. The present study aimed to evaluate the association of carnitine profile with exercise parameters in patients with incident dialysis. Design and Methods: This was a single-center cross-sectional study including 87 consecutive patients aged 20-90 years who were initiated on dialysis in Keio University Hospital between December 2019 and December 2022 and fulfilled the eligibility criteria. Exercise parameters were evaluated via cardiopulmonary testing (CPX) using the electronically braked STRENGTH ERGO 8 ergometer, whereas the carnitine profile was assessed by determining serum free carnitine (FC), acylcarnitine (AC) levels and AC/FC ratio. Results: The mean cohort age was 62.1 ± 15.2 years, with male and hemodialysis predominance (70% and 73%, respectively). AC/FC was 0.46 ± 0.15, and CPX revealed peak oxygen consumption (VO₂) of 13.9 ± 3.7 (mL/kg/min) with percent-predicted peak VO₂ of 53.6% ± 14.7% and minute ventilation (VE)/carbon dioxide output (VCO₂) slope of 35.1 ± 8.0. Fully-adjusted multivariate linear regression analysis showed that AC/FC was significantly associated with decreased peak VO₂ (β, -5.43 [95% confidence interval (CI), -10.15 to -0.70]) and percent-predicted peak VO₂ (β, -19.98 [95% CI, -38.43 to -1.52]) and with increased VE/VCO₂ slope (β, 13.76 [95% CI, 3.78-23.75]); FC and AC did not exhibit similar associations with these parameters. Moreover, only AC/FC was associated with a decreased peak work rate (WR), percent-predicted WR, anaerobic threshold, delta VO₂/delta WR, and chronotropic index. Conclusion: In patients on incident dialysis, exercise parameters, including those related to both skeletal muscle and cardiac function, were strongly associated with AC/FC, a marker of carnitine deficiency indicating altered fatty acid metabolism. Further studies are warranted to determine whether carnitine supplementation can improve exercise capacity in patients on incident dialysis.