Predictive equation for assessing appendicular lean soft tissue mass using bioelectric impedance analysis in older adults: Effect of body fat distribution.

BACKGROUND: Low muscle mass is associated with sarcopenia and increased mortality. Muscle mass, especially that of the limbs, is commonly estimated by dual-energy X-ray absorptiometry (DXA) or bioimpedance analysis (BIA). However, BIA-based predictive equations for estimating lean appendicular soft tissue mass (ALST) do not take into account body fat distribution, an important factor influencing DXA and BIA measurements. OBJECTIVES: To develop and cross-validate a BIA-based equation for estimating ALST with DXA as criterion, and to compare our new formula to three previously published models. METHODS: One-hundred eighty-four older adults (140 women and 44 men) (age 71.5 ±â€¯7.3 years, body mass index 27.9 ±â€¯5.3 kg/m2) were recruited. Participants were randomly split into validation (n = 118) and cross-validation groups (n = 66). Bioelectrical resistance was obtained with a phase-sensitive 50 kHz BIA device. RESULTS: A BIA-based model was developed for appendicular lean soft tissue mass [ALST (kg) = 5.982 + (0.188 × S2 / resistance) + (0.014 × waist circumference) + (0.046 × Wt) + (3.881 × sex) - (0.053 × age), where sex is 0 if female or 1 if male, Wt is weight (kg), and S is stature (cm) (R2 = 0.86, SEE = 1.35 kg)]. Cross validation revealed r2 of 0.91 and no mean bias. Two of three previously published models showed a trend to significantly overestimate ALST in our sample (p < 0.01). CONCLUSIONS: The new equation can be considered valid, with no observed bias and trend, thus affording practical means to quantify ALST mass in older adults.

Leucine metabolites do not induce changes in phase angle, bioimpedance vector analysis patterns, and strength in resistance trained men.

We aimed to assess the effects of off-the-shelf leucine metabolite supplements on phase angle (PhA), bioimpedance vector analysis (BIVA) patterns and strength during an 8-week resistance training protocol. Fifty-three male participants were allocated into 4 groups: α-hydroxyisocaproic acid (n = 12, age = 30.9 ± 9.3 years), ß-hydroxy-ß-methylbutyrate free acid (n = 12, age = 31.0 ± 9.3 years), calcium ß-hydroxy-ß-methylbutyrate (n = 15, age = 32.1 ± 5.2 years) or placebo (n = 14, age = 28.9 ± 6.6 years). Bioimpedance parameters and 1-repetition maximum (1RM) for back squat and bench press were assessed at baseline and at the end of weeks 4 and 8. Additionally, fat-free mass and fat mass were evaluated by dual-energy X-ray absorptiometry. No statistically group by time interactions were found, even adjusting for age. PhA and vector did not change over the training period, while time-dependent increases were observed for 1RM back squat and 1RM bench press. A direct association was observed between PhA and 1RM bench press changes (whole sample), while PhA and strength were correlated throughout the study, even when adjusting for fat-free mass and percentage of fat mass. Leucine metabolites have no effect on PhA, BIVA patterns or strength during an 8-week resistance training program, in resistance trained subjects. The trial was registered at ClincicalTrials.gov: NCT03511092. Novelty: Supplementation with leucine metabolites is not a supplementation strategy that improves bioelectrical phase angle, cellular health, and strength after an 8-week resistance training program. When consuming a high protein diet, none of the α-hydroxyisocaproic acid, ß-hydroxy-ß-methylbutyrate free acid, and calcium ß-hydroxy-ß-methylbutyrate metabolites resulted in an ergogenic effect in resistance trained men.

Ethnic differences in body image perception in patients with type 2 diabetes.

BACKGROUND: The present study compared the prevalence of obesity, fat distribution, body image perception and lifestyle among diabetic African and Albanian immigrants living in Italy, as well as diabetic Italians, aiming to identify health risks and their possible causes. METHODS: The study sample consisted of 200 diabetic subjects living in Italy. A questionnaire regarding socio-demographic and lifestyle information was administered to participants, and anthropometric measurements and body image perception were assessed. Proper perception of weight status and the degree of dissatisfaction in body image perception were valued. RESULTS: Italians showed a higher health risk, both with regard to anthropometric characteristics and lifestyle, whereas African immigrants showed a lower one. All of the male groups underestimated their weight and Albanians were the most dissatisfied. Women perceived their current body image as heavier than their desired body image, showing a dissatisfaction toward their weight. Subjects of both sexes belonging to the overweight and obese categories generally underestimated themselves; this was particularly true in obese Africans. People with a higher body mass index were more likely to be dissatisfied than those with a lower one. Body image dissatisfaction increased when people estimated themselves as being overweight. Among lifestyle habits, being an ex-smoker increased body image dissatisfaction. CONCLUSIONS: The underestimation of weight detected in the present study requires attention. Nevertheless, the high percentage of overweight/obese people, coupled with the higher frequency of people dissatisfied with their high weight, suggests an awareness of the problem that could be more effective for weight loss.

Coenzyme Q10 distribution in blood is altered in patients with fibromyalgia.

OBJECTIVE: Coenzyme Q10 (CoQ(10)) is an essential electron carrier in the mitochondrial respiratory chain and a strong antioxidant. Signs and symptoms associated with muscular alteration and mitochondrial dysfunction, including oxidative stress, have been observed in patients with fibromyalgia (FM). The aim was to study CoQ(10) levels in plasma and mononuclear cells, and oxidative stress in FM patients. METHODS: We studied CoQ(10) level by HPLC in plasma and peripheral mononuclear cells obtained from patients with FM and healthy control subjects. Oxidative stress markers were analyzed in both plasma and mononuclear cells from FM patients. RESULTS: Higher level of oxidative stress markers in plasma was observed respect to control subjects. CoQ(10) level in plasma samples from FM patients was doubled compared to healthy controls and in blood mononuclear cells isolated from 37 FM patients was found to be about 40% lower. Higher levels of ROS production was observed in mononuclear cells from FM patients compared to control, and a significant decrease was induced by the presence of CoQ(10). CONCLUSION: The distribution of CoQ(10) in blood components was altered in FM patients. Also, our results confirm the oxidative stress background of this disease probably due to a defect on the distribution and metabolism of CoQ(10) in cells and tissues. The protection caused in mononuclear cells by CoQ(10) would indicate the benefit of its supplementation in FM patients.

Forced expression of the Ikaros 6 isoform in human placental blood CD34(+) cells impairs their ability to differentiate toward the B-lymphoid lineage.

Studies in mice suggest that the Ikaros (Ik) gene encodes several isoforms and is a critical regulator of hematolymphoid differentiation. Little is known on the role of Ikaros in human stem cell differentiation. Herein, the biological consequences of the forced expression of Ikaros 6 (Ik6) in human placental blood CD34(+) progenitors are evaluated. Ik6 is one of the isoforms produced from the Ikaros premessenger RNA by alternative splicing and is thought to behave as a dominant negative isoform of the gene product because it lacks the DNA binding domain present in transcriptionally active isoforms. The results demonstrate that human cord blood CD34(+) cells that express high levels of Ik6 as a result of retrovirally mediated gene transfer have a reduced capacity to produce lymphoid B cells in 2 independent assays: (1) in vitro reinitiation of human hematopoiesis during coculture with the MS-5 murine stromal cell line and (2) xenotransplantation in nonobese diabetic-severe combined immunodeficient mice. These results suggest that Ikaros plays an important role in stem cell commitment in humans and that the balance between the different isoforms is a key element of this regulatory system; they support the hypothesis that posttranscriptional events can participate in the control of human hematopoietic differentiation.