Association between Vitamin D Level and Muscle Strength in Patients Undergoing Hemodialysis.

INTRODUCTION: Identification of the risk factors and treatment of the decrease in muscle mass or strength are important to improve the prognosis of patients undergoing hemodialysis (HD). Previous studies have investigated the association between vitamin D level and muscle mass or strength in patients undergoing HD. However, there are conflicting results regarding this association. OBJECTIVE: To evaluate the association between vitamin D level and muscle mass indices, strength, or physical performance in patients undergoing HD. METHODS: This study was performed in a tertiary medical center. We included patients undergoing HD aged ≥20 years. A total of 84 patients were enrolled. The patients were divided into tertiles based on the 25-hydroxy (25-OH) vitamin D level as follows: lowest tertile (Lowest T, n = 28), middle tertile (Middle T, n = 28), and highest tertile (Highest T, n = 28). We evaluated the association between the tertiles and clinical outcomes including nutritional status, muscle mass, muscle function, handgrip strength (HGS), physical performance, and health-related quality of life (HRQoL) scales. RESULTS: There were no significant differences in the muscle mass indices and nutritional markers according to tertiles of 25-OH vitamin D level. However, 25-OH vitamin D level as a continuous variable or the tertile of 25-OH vitamin D level as a categorical variable was positively associated with HGS. Logistic and linear regression analyses showed a consistent superiority of the Highest T in HGS compared with the Lowest or Middle T. Although the statistical significance was weak, the scores of various physical performance tests and the HRQoL scales were highest in the Highest T among the 3 tertiles. CONCLUSION: The present study demonstrated that serum vitamin D level is associated with HGS in patients undergoing HD regardless of muscle mass indices or nutritional status.

Clinicopathological Characteristics of PIK3CA Mutation and Amplification in Korean Patients with Breast Cancers.

The frequency of PIK3CA mutation and amplification was various and their clinical significances have not been clarified in Korean patients with invasive breast carcinoma (IBC). The study aimed to investigate the clinical and prognostic significances of PIK3CA mutation and amplification in IBC patients. DNA was isolated from paired normal and tumoral tissues in 128 IBC patients and the mutation and expression of PIK3CA gene were analyzed. PIK3CA mutation and expression was detected in 14.3% and 21.9% of IBC patients, respectively. And the level of PIK3CA expression was not different according to the presence of PIK3CA mutation (p = 0.775). PIK3CA mutation and expression were significantly associated with Luminal A type (p = 0.017 and p = 0.011, respectively). However, they did not have any clinical and prognostic values for IBC patients. This result suggested that alterations of PIK3CA pathway contribute to the pathogenesis of specific type of IBC.

Comparison of Muscle Mass Indices Using Computed Tomography or Dual X-Ray Absorptiometry for Predicting Physical Performance in Hemodialysis Patients.

BACKGROUND/AIMS: Our study aims to evaluate the association between thigh muscle cross-sectional area (TMA) using computed tomography (CT), or appendicular skeletal muscle mass (ASM) using dual energy X-ray absorptiometry (DEXA), and physical performance levels in hemodialysis (HD) patients. METHODS: Patients were included if they were on HD for ≥6 months (n = 84). ASM and TMA were adjusted to body weight (BW, kg) or height2 (Ht2, m2). Each participant performed a short physical performance battery test (SPPB), a sit-to-stand for 30 second test (STS30), a 6-minute walk test (6-MWT), a timed up and go test (TUG), and hand grip strength (HGS) test. RESULTS: Correlation coefficients for SPPB, GS, 5STS, STS30, 6-MWT, and TUG were highest in TMA/BW. Results from partial correlation or linear regression analyses displayed similar trends to those derived from Pearson's correlation analyses. An increase in TMA/BW or TMA/Ht2 was associated with a decreased odds ratio of low SPPB, GS, or HGS in multivariate analyses. Indices using DEXA were associated with a decreased odds ratio of a low HGS only in multivariate analysis. CONCLUSION: TMA indices using CT may be more valuable in predicting physical performance or strength in HD patients.

Are ex vivo mesothelial cells representative of the in vivo transition from epithelial-to-mesenchymal cells in peritoneal membrane?

BACKGROUND: We investigated whether ex vivo mesothelial cells found in peritoneal dialysis (PD) effluents were representative of the in vivo epithelial-to-mesenchymal transition (EMT) in peritoneal membrane. METHODS: Thirty-six male Sprague-Dawley rats were equally divided into three groups: Group C (control), no PD; Group D, infused with 4.25% Dianeal and Group P, infused with 4.25% Physioneal. PD infusions (25 mL) were given twice daily for 8 weeks. The in vivo study included morphometric analyses performed on the peritoneal membranes of tissue specimens obtained at the end of the study. The ex vivo study included peritoneal mesothelial cells collected from PD effluent and cultured to confluence. Cells were scored with light microscopy. RESULTS: PD for 8 weeks induced significant EMT. The in vivo expression of EMT markers (α-smooth muscle actin:E-cadherin ratio, matrix metalloproteinase-2 and Snail) was higher in Group D than in Group P. However, ex vivo EMT marker expression was similar in cells derived from Groups D and P. A significant correlation was observed among in vivo EMT markers. Moreover, the ex vivo cell score increased with time on PD. However, changes in the ex vivo cell score did not correlated with changes in the in vivo EMT marker expression. Furthermore, we found no correlation between ex vivo and in vivo cells in the expression of EMT markers. CONCLUSIONS: In this animal study, ex vivo findings did not reflect the in vivo EMT changes in the peritoneum. It may be necessary to improve the current methodology for ex vivo studies.

Comparison of appendicular lean mass indices for predicting physical performance in Korean hemodialysis patients: A cross-sectional study.

ABSTRACT: Few studies have examined the optimal adjustment indices for predicting low muscle strength or physical performance in hemodialysis (HD) patients. Thus, the present study aimed to identify optimal adjustment indices for predicting strength and/or physical performance in HD patients.Our study was performed at an HD center (n = 84). Appendicular lean mass (ALM; kg) was calculated using dual-energy X-ray absorptiometry. ALM were adjusted to body weight, height2 (Ht2), body surface area, or body mass index. Physical performance tests (sit-to-stand test performed 5 times test, sit-to-stand for 30 second test, 6-minute walk test, timed up and go test, gait speed, hand grip strength, average steps per day (AST), and short physical performance battery) were also evaluated. Participants with a below median value for each physical performance test were defined as the low group.The mean participant age was 55.6 ±â€Š12.8 years; 44 (52.4%) were men. The univariate analysis revealed a significant difference in ALM/Ht2 values between the low and normal physical performance group in all physical performance tests except short physical performance battery. The multivariate analysis revealed a significant difference in ALM/Ht2 between the low and normal physical performance groups in hand grip strength, 5 times sit-to-stand test, sit-to-stand for 30-second test, and AST. In women on HD, most indices were not associated with physical performance or strength.We demonstrated that, in men on HD, ALM/Ht2 may be the most valuable among various variables adjusted for ALM for predicting physical performance or strength.

Impact of systemic and local peritoneal inflammation on peritoneal solute transport rate in new peritoneal dialysis patients: a 1-year prospective study.

BACKGROUND: The association between peritoneal solute transport rates (PSTRs) and inflammatory markers in patients on peritoneal dialysis (PD) is still under investigation. We aimed to elucidate their relationship during the first year on PD. METHODS: We performed a prospective observational study with 187 incident PD patients who were treated with either biocompatible solution (BCS) or conventional solution (CS). Peritoneal dialysate effluent (PDE) and blood samples for the markers and the calculation of mass transfer area coefficient of creatinine (MTAC) were performed at 1, 6 and 12 months after commencing PD. RESULTS: Of the 187 enrolled patients, 110 completed a 1-year study protocol. All PDE markers [interleukin-6 (IL-6), transforming growth factor-beta (TGF-beta), TGF-beta-induced gene-h3 (beta ig-h3), vascular endothelial growth factor (VEGF)] except CA125 increased over time, whereas PSTRs, high-sensitivity C-reactive protein (hs-CRP) and serum IL-6 levels did not change. Serum albumin and log PDE appearance rates (ARs) of IL-6, TGF-beta and CA125 predicted MTAC. The Delta value (12-month minus 1-month) of PDE AR of IL-6 was correlated with those of all other PDE markers. Both 12-month IL-6 and Delta IL-6 ARs in PDE were highest in the upper Delta MTAC tertile. PSTRs in the CS group, unlike BCS, had a tendency to increase over time, demonstrating a time-by-group interaction. Solution type and MTAC were not associated with patient and technique survival. CONCLUSIONS: The change in PSTR during the first year of PD is related to PDE IL-6 AR, which may represent intraperitoneal inflammation; however, there does not seem to be a close association between PSTR and the degree of systemic inflammation.

Effect of intradialytic exercise on daily physical activity and sleep quality in maintenance hemodialysis patients.

PURPOSE: Physical inactivity and sleep disturbance are frequently observed and relate to poor clinical outcomes in maintenance hemodialysis patients. We aimed to investigate the effect of intradialytic exercise on daily physical activity and sleep quality, measured by an accelerometer, in maintenance hemodialysis patients. METHODS: This study randomly assigned ambulatory maintenance hemodialysis patients aged ≥ 20 years on dialysis ≥ 6 months, without a hospitalization history for the previous 3 months to 4 groups: aerobic exercise (AE), resistance exercise (RE), combination exercise (CE), and control. A stationary bike was used for AE and a TheraBand®/theraball for RE. A 12-week intradialytic exercise program (3 times/week) was completed in the AE (n = 11), RE (n = 10), and CE (n = 12) groups. The control group (n = 13) received only warm-up stretching. At baseline and 12-week follow-up, daily physical activity and sleep quality were measured with a triaxial accelerometer (wActiSleep-BT; ActiGraph, Pensacola, FL) during a continuous 7-day wear period. RESULTS: We observed a significant increase in metabolic equivalent (MET; kcal/h/kg) in the AE (1.02 ± 0.03 vs 1.04 ± 0.04, P = 0.04) and CE (1.06 ± 0.05 vs 1.09 ± 0.08, P = 0.01) groups at 12 weeks compared with baseline. When comparing between-group changes in MET, there was a significant increase in METs in the CE group (0.03 ± 0.03 vs - 0.01 ± 0.04, P = 0.02) compared with the control group. The total number of sedentary bouts (per week) decreased significantly in the AE (200 ± 37 vs 174 ± 36, P = 0.01), RE (180 ± 31 vs 130 ± 49, P = 0.03), and CE groups (180 ± 45 vs 152 ± 46, P = 0.04) at 12 weeks compared with baseline. The average sleep fragmentation index, indicating poor sleep quality, decreased significantly at 12 weeks compared with baseline in the AE (51.4 ± 8.0 vs 44.5 ± 9.6, P = 0.03) and RE groups (52.3 ± 7.3 vs 40.0 ± 15.4, P = 0.01). CONCLUSIONS: Intradialytic exercise appears to be clinically beneficial in improving daily physical activity and sleep quality in maintenance hemodialysis patients.

Clinical analysis of hemodialysis vascular access: comparision of autogenous arterioveonus fistula & arteriovenous prosthetic graft.

BACKGROUND: Mature autogenous arteriovenous fistulas have better long term patency and require fewer secondary interventions compared to arteriovenous prosthetic graft. Our Study evaluated vascular patency rates and incidence of interventions in autogenous arteriovenous fistulas and grafts. MATERIAL AND METHODS: A total of 166 vascular access operations were performed in 153 patients between December 2002 and November 2009. Thirty seven caeses were excluded due to primary access failure and loss of follow-up. One group of 92 autogenous arterioveous fistulas and the other group of 37 arteriovenous prosthetic grafts were evaluated retrospectively. Primary and secondary patency rates were estimated using the Kaplan-Meier method. RESULTS: The primary patency rate (84%, 67%, 51% vs. 51%, 22%, 9% at 1, 3, 5 year; p=0.0000) and secondary patency rate (96%, 88%, 68% vs. 88%, 65%, 16% at 1. 3, 5 year; p=0.0009) were better in autogenous fistula group than prosthetic graft group. Interventions to maintain secondary patency were required in 23% of the autogenous fistula group (average 0.06 procedures/patient/year) and 65% of prosthetic graft group (average 0.21 procedures/patient/year). So the autogenous fistula group had fewer intervention rate than prosthetic graft group (p=0.01) The risk factor of primary patency was diabetus combined with ischemic heart disease and the secondary patency's risk factor was age. CONCLUSION: Autogenous arteriovenous fistulas showed better performance compared to prosthetic grafts in terms of primary & secondary patency and incidence of interventions.

Association of G-137C IL-18 promoter polymorphism with acute allograft rejection in renal transplant recipients.

BACKGROUND: Interleukin 18 (IL-18) is a potent proinflammatory cytokine, which is postulated to play a role in mechanism of renal allograft rejection and strongly induces interferon (IFN)-gamma production. The aim of this study was to investigate the association of the G-137C IL-18 promoter polymorphism with acute allograft rejection in renal transplant recipients (RTRs). METHODS: A total of 226 RTRs and 148 controls were recruited for association analysis. Genotyping was performed by using a real-time polymerase chain reaction. Patients were separated into two groups, the acute rejection (AR) (n=37) or the no AR group (n=189), depending on their history of AR episodes. IL-18 and IFN-gamma serum levels of 73 randomly selected RTRs were measured by ELISA. RESULTS: No significant differences in genotype and allele frequencies were observed between the RTRs and the controls. Significant differences in genotype frequency and allele frequency between the AR and no AR group were observed. The frequency of the -137GG genotype was significantly increased in patients with AR (P=0.015, odds ratio=3.653). Serum levels of IL-18 and IFN-gamma were significantly elevated in the AR group with compared with the no AR group. In the AR group, patients with the -137GG genotype had significantly higher IL-18 serum levels compared to other genotypes. CONCLUSION: These data demonstrate that the -137GG genotype of the IL-18 gene, encoding higher IL-18 production, seems to be associated with AR and may be a useful marker of AR risk in RTRs.

Coronary-artery calcium scores using electron beam CT in patients with chronic renal failure.

We evaluated the risk of coronary-artery disease in patients with chronic renal failure (CRF) by measuring the coronary-artery calcium scores with electron beam CT (EBCT). A total of 81 CRF patients were divided into three groups; pre-dialysis (group I, n = 35), hemodialysis (group II, n = 31) and peritoneal dialysis (group III, n = 15). The several serum biochemical markers and calcium score levels by EBCT were determined. The Ca x P products were significantly higher in groups II (p < 0.05) and III (p < 0.01) than in group I. The serum calcium levels were significantly higher in group III than in both group I (p < 0.01) and II (p < 0.05). The serum calcium level in 15 patients with a calcium score > 400 was significantly higher than the 66 patients with a score < or =400 (p < 0.01). The calcium score was significantly higher in the 15 patients with cardiovascular complications than in the 66 patients without cardiovascular complications (628.9+/-904.8 vs. 150.4+/-350.9, p < 0.01). EBCT seemed to be a good diagnostic tool for evaluating the risk of coronary-artery disease ''noninvasively'' in CRF patients who are at increased risk of cardiovascular morbidity and mortality.