Dietary Intake of Proteins and Calories Is Inversely Associated With The Oxidation State of Plasma Thiols in End-Stage Renal Disease Patients.

OBJECTIVES: Oxidative stress contributes to the pathogenesis of protein-energy wasting in maintenance hemodialysis (MHD) patients, but knowledge of specific effectors and mechanisms remains fragmented. Aim of the study was to define whether and how food intake is involved in the causal relationship between oxidative stress and protein-energy wasting. METHODS: Seventy-one adult MHD patients and 24 healthy subjects (control) were studied cross-sectionally with analyses of diet record and of oxidative stress, as measured by a battery of plasma thiols including the protein sulfhydryl (-SH) group (PSH) levels (a marker of total protein-SH reducing capacity), the protein thiolation index (PTI, the ratio between disulfide, i.e., oxidized and reduced -SH groups in proteins), low molecular mass (LMM) thiols, LMM disulfides, and mixed LMM-protein disulfides. In addition, interleukin-6 (IL-6), albumin, C-reactive protein, and neutrophil gelatinase-associated lipocalin (NGAL) were measured as markers of inflammation. RESULTS: The patients showed low energy (22.0 ± 8.4 kcal/kg/day) and adequate protein (1.0 ± 0.4 g/kg/day) intakes, high levels of cystine (CySS; patients vs. CONTROL: 113.5 [90.9-132.8] vs. 68.2 [56.2-75.7] µM), cysteinylated proteins (CySSP; 216.0 [182.8-254.0] vs. 163.5 [150.0-195.5] µM), and high PTI (0.76 [0.61-0.88] vs. 0.43 [0.40-0.54]; P < .001 in all comparisons). In patients, variation of CySSP was explained by a standard regression model (R = 0.775; P = .00001) that included significant contributions of protein intake (ß = -0.361), NGAL (ß = 0.387), age (ß = 0.295), and albumin (ß = 0.457). In the same model, variation of PTI (R = 0.624; P = .01) was explained by protein intake (ß = -0.384) and age (ß = 0.326) and NGAL (ß = 0.311). However, when PSH was entered as dependent variable (R = 0.730; P = .0001), only serum albumin (ß = 0.495) and age (ß = -0.280), but not dietary intake or NGAL, contributed to the model. CONCLUSIONS: In MHD, markers of thiol oxidation including CySSP and PTI show independent association with dietary intake and NGAL, whereas PSH, a marker of thiol-reducing capacity, did not associate with these same variables. The mechanism(s) responsible for inverse association between oxidative stress and food intake in MHD remain undefined.

Comparison of Nutrition Profile and Diet Record Between Veteran and Nonveteran End-Stage Renal Disease Patients Receiving Hemodialysis in Veterans Affairs and Community Clinics in Metropolitan South-Central Texas.

BACKGROUND: U.S. military veterans have high rates of chronic disease and social disadvantage, which are risk factors for protein-energy wasting (PEW). It is not known whether this translates into high prevalence of PEW in veterans with end-stage renal disease. METHODS: We compared the clinical, socioeconomic, and nutrition status and the diet of 33 veteran and 38 nonveteran clinically stable patients receiving maintenance hemodialysis (MHD) in south-central Texas. RESULTS: The whole cohort included 82% Mexican Americans (MAs), 72% type 2 diabetics, and 73% males. The body mass index was 28.9 ± 6.2, while energy intake was 21.5 ± 8.2 kcal/kg/d and protein intake was 1.0 ± 0.4 g/kg/d. Serum albumin (bromocresol purple) was 3.5 ± 0.4 g/dL, transferrin was 171.9 ± 27.8 mg/d, C-reactive protein was 2.9 (1.4-6.5) mg/L, interleukin-6 (IL-6) was 8.3 (4.2-17.9) pg/mL, neutrophil gelatinase-associated lipocalin was 729 (552-1256) ng/mL, and the malnutrition-inflammation score was 8.8 ± 3.0. In group comparison that adjusted for sex and ethnicity, the veterans had better household income, less MAs (60% vs 100%), more males (94% vs 55%), more use of a renin-angiotensin-aldosterone system blockade (66% vs 33%), and lower IL-6 levels (4.4 [3.1-5.8] vs 15.4 [8.3-20.5] pg/mL; P = .01) than nonveterans. In regression analysis, the lower serum IL-6 level in veterans was independently explained by dialysis clinic, sex, and, possibly, household income (intermediate significance). CONCLUSION: In a relatively small cohort of clinically stable MHD patients, the veterans showed equivalent nutrition status and dietary intake and less inflammation than the nonveterans, thus not supporting the possibility that veteran MHD patients may have worse nutrition than the nonveteran counterpart.

Glutathione redox potential is low and glutathionylated and cysteinylated hemoglobin levels are elevated in maintenance hemodialysis patients.

Glutathione (GSH), the most abundant intracellular low molecular mass thiol, protects cells from oxidative damage and regulates their function. Available information is inconsistent regarding levels of GSH and its disulfide (GSSG) in maintenance hemodialysis patients (HD). In addition, very limited data are available in HD about the relationship of GSH and GSSG with other measures of thiol metabolism and with the clinical profile. We tested the hypothesis that erythrocyte GSH/GSSG redox potential (Eh) is lower in HD than in healthy controls (C), and that Eh correlates with posttranslational thiolation of hemoglobin (Hb) and with standard clinical parameters in HD. In cross-sectional comparison of 33 stable HD and 21 C, we found a net loss of reducing capacity in HD as indicated by low erythrocyte GSH/GSSG Eh (-257 ± 5.5 vs -270 ± 5.6 mV, P = 0.002). Glutathionylated Hb (HbSSG) was 46% higher in HD than C (19.3 ± 4.80 vs 13.2 ± 2.79 pmol/mg Hb; P = 0.001) and cysteinylated Hb (HbSSCy) was >3-fold higher in HD than C [38.3 (29.0-63.3) vs 11.5 (9.6-17.2) pmol/mg Hb; P = 0.001]. In multiple regression analysis of the HD cases, statistically significant associations were found between the GSH/GSSG Eh and the blood urea nitrogen (P = 0.001), creatinine (P = 0.015) and normalized protein catabolic rate (P = 0.05), after adjusting for age, race/ethnicity, and etiology of end-stage renal disease. In conclusion, accurate and precise analysis of GSH, GSSG, and mixed disulfides reveals loss of erythrocyte GSH/GSSG Eh, rise of both HbSSG and HbSSCy, and correlation of these thiols with measures of uremia and dietary protein intake.

Maternal acculturation: could it impact oral health practices of mexican-american mothers and their children?

A mother's cultural beliefs can affect her infant's health, but the influence of acculturation of Mexican-American women on their young children's oral health is unknown. The authors hypothesized that maternal acculturation impacts very young children's oral health practices favoring, in particular, the mothers who are more Anglo-oriented. A convenience sample of 204 predominantly Mexican-American women attending the Women, Infants, and Children Clinic in San Antonio, Texas, completed the Knowledge, Attitudes, Beliefs, Social Support, and Self-Efficacy of Oral Health (KASE-OH) and Acculturation Questionnaires. Results indicated that mothers with strong Anglo orientation were more likely educated in the United States, first visited a dentist while in elementary school, and breast-fed their children. Children belonging to Anglo-oriented Mexican-American mothers had stronger oral health practices, were more likely to breast-feed, were exposed to more sugary and acidic drinks, consumed higher levels of candy, had Medicaid coverage, and had stronger supervisions of tooth brushing practices.