DXA, bioelectrical impedance, ultrasonography and biometry for the estimation of fat and lean mass in cats during weight loss

Background: Few equations have been developed in veterinary medicine compared to human medicine to predict body composition. The present study was done to evaluate the influence of weight loss on biometry (BIO), bioimpedance analysis (BIA) and ultrasonography (US) in cats, proposing equations to estimate fat (FM) and lean (LM) body mass, as compared to dual energy x-ray absorptiometry (DXA) as the referenced method. For this were used 16 gonadectomized obese cats (8 males and 8 females) in a weight loss program. DXA, BIO, BIA and US were performed in the obese state (T0; obese animals), after 10% of weight loss (T1) and after 20% of weight loss (T2). Stepwise regression was used to analyze the relationship between the dependent variables (FM, LM) determined by DXA and the independent variables obtained by BIO, BIA and US. The better models chosen were evaluated by a simple regression analysis and means predicted vs. determined by DXA were compared to verify the accuracy of the equations. Results: The independent variables determined by BIO, BIA and US that best correlated (p < 0.005) with the dependent variables (FM and LM) were BW (body weight), TC (thoracic circumference), PC (pelvic circumference), R (resistance) and SFLT (subcutaneous fat layer thickness). Using Mallows'Cp statistics, p value and r(2), 19 equations were selected (12 for FM, 7 for LM); however, only 7 equations accurately predicted FM and one LM of cats. Conclusions: The equations with two variables are better to use because they are effective and will be an alternative method to estimate body composition in the clinical routine. For estimated lean mass the equations using body weight associated with biometrics measures can be proposed. For estimated fat mass the equations using body weight associated with bioimpedance analysis can be proposed.

Lean and Fat Mass Loss in Obese Patients Before and After Roux-en-Y Gastric Bypass: A New Application for Ultrasound Technique

This study aims to evaluate the thickness of the femoral quadriceps and biceps brachii and brachialis muscles bilaterally and the adjacent subcutaneous fat in patients undergoing gastric bypass Roux-en-Y before and after surgery, using ultrasound as the diagnostic method of choice. We studied 12 patients undergoing this surgical method preoperatively and during the first, third, and sixth postoperative months. During these periods, patients were evaluated by ultrasound to determine the thickness of subcutaneous adipose tissue and muscle of the upper and lower limbs. Postoperatively, these patients showed a reduction in the thickness of the upper and lower extremities muscle and adipose tissue as compared to their preoperative values. There was a significant difference in the loss of muscle thickness in all postoperative months and in the thickness of fatty tissue in the sixth month after surgery, compared to the preoperative muscle and fatty tissue thickness. Ultrasound can be considered as the diagnostic method of choice when assessment of the fat and lean body mass is required in morbidly obese patients before and after bariatric surgery.

Low fatness, reduced fat intake and adequate plasmatic concentrations of LDL-cholesterol are associated with high bone mineral density in women: a cross-sectional study with control group

Background: Several parameters are associated with high bone mineral density (BMD), such as overweight, black background, intense physical activity (PA), greater calcium intake and some medications. The objectives are to evaluate the prevalence and the main aspects associated with high BMD in healthy women. Methods: After reviewing the database of approximately 21,500 BMD scans performed in the metropolitan area of Sao Paulo, Brazil, from June 2005 to October 2010, high BMD (over 1400 g/cm(2) at lumbar spine and/or above 1200 g/cm2 at femoral neck) was found in 421 exams. Exclusion criteria were age below 30 or above 60 years, black ethnicity, pregnant or obese women, disease and/or medications known to interfere with bone metabolism. A total of 40 women with high BMD were included and matched with 40 healthy women with normal BMD, paired to weight, age, skin color and menopausal status. Medical history, food intake and PA were assessed through validated questionnaires. Body composition was evaluated through a GE-Lunar DPX MD + bone densitometer. Radiography of the thoracic and lumbar spine was carried out to exclude degenerative alterations or fractures. Biochemical parameters included both lipid and hormonal profiles, along with mineral and bone metabolism. Statistical analysis included parametric and nonparametric tests and linear regression models. P < 0.05 was considered significant. Results: The mean age was 50.9 (8.3) years. There was no significant difference between groups in relation to PA, smoking, intake of calcium and vitamin D, as well as laboratory tests, except serum C-telopeptide of type I collagen (s-CTX), which was lower in the high BMD group (p = 0.04). In the final model of multivariate regression, a lower fat intake and body fatness as well a better profile of LDL-cholesterol predicted almost 35% of high BMD in women. (adjusted R2 = 0.347; p < 0.001). In addition, greater amounts of lean mass and higher IGF-1 serum concentrations played a protective role, regardless age and weight. Conclusion: Our results demonstrate the potential deleterious effect of lipid metabolism-related components, including fat intake and body fatness and worse lipid profile, on bone mass and metabolism in healthy women.

Liposuction induces a compensatory increase of visceral fat which is effectively counteracted by physical activity: a randomized trial

Context: Liposuction is suggested to result in long-term body fat regain that could lead to increased cardiometabolic risk. We hypothesized that physical activity could prevent this effect. Objective: Our objective was to investigate the effects of liposuction on body fat distribution and cardiometabolic risk factors in women who were either exercise trained or not after surgery. Design, Setting, and Participants: Thirty-six healthy normal-weight women participated in this 6-month randomized controlled trial at the University of Sao Paulo, Sao Paulo, Brazil. Interventions: Patients underwent a small-volume abdominal liposuction. Two months after surgery, the subjects were randomly allocated into two groups: trained (TR, n = 18, 4-month exercise program) and nontrained (NT, n = 18). Main Outcome Measures: Body fat distribution (assessed by computed tomography) was assessed before the intervention (PRE) and 2 months (POST2), and 6 months (POST6) after surgery. Secondary outcome measures included body composition, metabolic parameters and dietary intake, assessed at PRE, POST2, and POST6, and total energy expenditure, physical capacity, and sc adipocyte size and lipid metabolism-related gene expression, assessed at PRE and POST6. Results: Liposuction was effective in reducing sc abdominal fat (PRE vs. POST2, P = 0.0001). Despite the sustained sc abdominal fat decrement at POST6 (P = 0.0001), the NT group showed a significant 10% increase in visceral fat from PRE to POST6 (P = 0.04; effect size = -0.72) and decreased energy expenditure (P = 0.01; effect size = 0.95) when compared with TR. Dietary intake, adipocyte size, and gene expression were unchanged over time. Conclusion: Abdominal liposuction does not induce regrowth of fat, but it does trigger a compensatory increase of visceral fat, which is effectively counteracted by physical activity. (J Clin Endocrinol Metab 97: 2388-2395, 2012)

Bioelectrical impedance with different equations versus deuterium oxide dilution method for the inference of body composition in healthy older persons

There is no consensus regarding the accuracy of bioimpedance for the determination of body composition in older persons. This study aimed to compare the assessment of lean body mass of healthy older volunteers obtained by the deuterium dilution method (reference) with those obtained by two frequently used bioelectrical impedance formulas and one formula specifically developed for a Latin-American population. A cross-sectional study. Twenty one volunteers were studied, 12 women, with mean age 72 +/- 6.7 years. Urban community, Ribeiro Preto, Brazil. Fat free mass was determined, simultaneously, by the deuterium dilution method and bioelectrical impedance; results were compared. In bioelectrical impedance, body composition was calculated by the formulas of Deuremberg, Lukaski and Bolonchuck and Valencia et al. Lean body mass of the studied volunteers, as determined by bioelectrical impedance was 37.8 +/- 9.2 kg by the application of the Lukaski e Bolonchuk formula, 37.4 +/- 9.3 kg (Deuremberg) and 43.2 +/- 8.9 kg (Valencia et. al.). The results were significantly correlated to those obtained by the deuterium dilution method (41.6 +/- 9.3 Kg), with r=0.963, 0.932 and 0.971, respectively. Lean body mass obtained by the Valencia formula was the most accurate. In this study, lean body mass of older persons obtained by the bioelectrical impedance method showed good correlation with the values obtained by the deuterium dilution method. The formula of Valencia et al., developed for a Latin-American population, showed the best accuracy.

Effects of Two Different Levels of Dietary Protein on Body Composition and Protein Nutritional Status of Growing Rats

This study aimed to investigate the effect of a high-protein diet on growth, body composition, and protein nutritional status of young rats. Newly-weaned Wistar rats, weighing 45-50 g, were distributed in two experimental groups, according to their diets, which contained 12% (G12) or 26% protein (G26), over a period of 3 weeks. The animals were euthanized at the end of this period and the following analyses were performed: chemical composition of the carcass, proteoglycan synthesis, IGF-I concentration (serum, muscle and cartilage), total tissue RNA, protein concentration (muscle and cartilage) and protein synthesis (muscle and cartilage). The high-protein diet was found to result in a higher fat-free mass and lower fat mass in the carcass, with no difference in growth or protein nutritional status.

Body changes: antiretroviral therapy and lipodystrophy syndrome in people living with HIV/aids

Objective: to identify the different types of morphological alterations from lipodystrophy syndrome (LS) in outpatients and relate them to the therapeutic regimen used. Method: a cross-sectional study which recruited 60 patients with HIV and LS and 79 without LS, who consented to interview and data collection from their medical notes. Results: the region most affected by lipoatrophy was the face; by lipohypertrophy, the abdomen, and by the mixed form, the alterations to the abdomen, face, and upper and lower limbs. Conclusion: among the therapeutic regimens, that comprised of zidovudine, lamivudine and efavirenz seemed to protect against LS. Nursing can act in the early identification of the changes, as well as providing guidance and support for patients affected by the changes in their body image.

Elevated tissue omega-3 fatty acid status prevents age-related glucose intolerance in fat-1 transgenic mice

The objective of this study was to investigate the impact of elevated tissue omega-3 (n-3) polyunsaturated fatty acids (PUFA) status on age-related glucose intolerance utilizing the fat-1 transgenic mouse model, which can endogenously synthesize n-3 PUFA from omega-6 (n-6) PUFA. Fat-1 and wild-type mice, maintained on the same dietary regime of a 10% corn oil diet, were tested at two different ages (2months old and 8months old) for various glucose homeostasis parameters and related gene expression. The older wild-type mice exhibited significantly increased levels of blood insulin, fasting blood glucose, liver triglycerides, and glucose intolerance, compared to the younger mice, indicating an age-related impairment of glucose homeostasis. In contrast, these age-related changes in glucose metabolism were largely prevented in the older fat-1 mice. Compared to the older wild-type mice, the older fat-1 mice also displayed a lower capacity for gluconeogenesis, as measured by pyruvate tolerance testing (PTT) and hepatic gene expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6 phosphatase (G6Pase). Furthermore, the older fat-1 mice showed a significant decrease in body weight, epididymal fat mass, inflammatory activity (NFκ-B and p-IκB expression), and hepatic lipogenesis (acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) expression), as well as increased peroxisomal activity (70-kDa peroxisomal membrane protein (PMP70) and acyl-CoA oxidase1 (ACOX1) expression). Altogether, the older fat-1 mice exhibit improved glucose homeostasis in comparison to the older wild-type mice. These findings support the beneficial effects of elevated tissue n-3 fatty acid status in the prevention and treatment of age-related chronic metabolic diseases

Exercise and caloric restriction alter the immune system of mice submitted to a high-fat diet

As the size of adipocytes increases during obesity, the establishment of resident immune cells in adipose tissue becomes an important source of proinflammatory mediators. Exercise and caloric restriction are two important, nonpharmacological tools against body mass increase. To date, their effects on the immune cells of adipose tissue in obese organisms, specifically when a high-fat diet is consumed, have been poorly investigated. Thus, after consuming a high-fat diet, mice were submitted to chronic swimming training or a 30% caloric restriction in order to investigate the effects of both interventions on resident immune cells in adipose tissue. These strategies were able to reduce body mass and resulted in changes in the number of resident immune cells in the adipose tissue and levels of cytokines/chemokines in serum. While exercise increased the number of NK cells in adipose tissue and serum levels of IL-6 and RANTES, caloric restriction increased the CD4+/CD8+ cell ratio and MCP-1 levels. Together, these data demonstrated that exercise and caloric restriction modulate resident immune cells in adipose tissues differently in spite of an equivalent body weight reduction. Additionally, the results also reinforce the idea that a combination of both strategies is better than either individually for combating obesity

Strength training combined with plyometric jumps in adults: sex differences in fat-bone axis adaptations

[EN] Leptin and osteocalcin play a role in the regulation of the fat-bone axis and may be altered by exercise. To determine whether osteocalcin reduces fat mass in humans fed ad libitum and if there is a sex dimorphism in the serum osteocalcin and leptin responses to strength training, we studied 43 male (age 23.9 2.4 yr, mean +/- SD) and 23 female physical education students (age 23.2 +/- 2.7 yr). Subjects were randomly assigned to two groups: training (TG) and control (CG). TG followed a strength combined with plyometric jumps training program during 9 wk, whereas the CG did not train. Physical fitness, body composition (dual-energy X-ray absorptiometry), and serum concentrations of hormones were determined pre- and posttraining. In the whole group of subjects (pretraining), the serum concentration of osteocalcin was positively correlated (r = 0.29-0.42, P < 0.05) with whole body and regional bone mineral content, lean mass, dynamic strength, and serum-free testosterone concentration (r = 0.32). However, osteocalcin was negatively correlated with leptin concentration (r = -0.37), fat mass (r = -0.31), and the percent body fat (r = -0.44). Both sexes experienced similar relative improvements in performance, lean mass (+4-5%), and whole body (+0.78%) and lumbar spine bone mineral content (+1.2-2%) with training. Serum osteocalcin concentration was increased after training by 45 and 27% in men and women, respectively (P < 0.05). Fat mass was not altered by training. Vastus lateralis type II MHC composition at the start of the training program predicted 25% of the osteocalcin increase after training. Serum leptin concentration was reduced with training in women. In summary, while the relative effects of strength training plus plyometric jumps in performance, muscle hypertrophy, and osteogenesis are similar in men and women, serum leptin concentration is reduced only in women. The osteocalcin response to strength training is, in part, modulated by the muscle phenotype (MHC isoform composition). Despite the increase in osteocalcin, fat mass was not reduced.

REGULATION OF WHOLE-BODY ENERGY HOMEOSTASIS WITH GROWTH HORMONE REPLACEMENT THERAPY AND ENDURANCE EXERCISE

We hypothesized that network analysis is useful to expose coordination between whole body and myocellular levels of energy metabolism and can identify entities that underlie skeletal muscle's contribution to growth hormone-stimulated lipid handling and metabolic fitness. We assessed 112 metabolic parameters characterizing metabolic rate and substrate handling in tibialis anterior muscle and vascular compartment at rest, after a meal and exercise with growth hormone replacement therapy (GH-RT) of hypopituitary patients (n = 11). The topology of linear relationships (| r | ≥ 0.7, P ≤ 0.01) and mutual dependencies exposed the organization of metabolic relationships in three entities reflecting basal and exercise-induced metabolic rate, triglyceride handling, and substrate utilization in the pre- and postprandial state, respectively. GH-RT improved aerobic performance (+5%), lean-to-fat mass (+19%), and muscle area of tibialis anterior (+2%) but did not alter its mitochondrial and capillary content. Concomitantly, connectivity was established between myocellular parameters of mitochondrial lipid metabolism and meal-induced triglyceride handling in serum. This was mediated via the recruitment of transcripts of muscle lipid mobilization (LIPE, FABP3, and FABP4) and fatty acid-sensitive transcription factors (PPARA, PPARG) to the metabolic network. The interdependence of gene regulatory elements of muscle lipid metabolism reflected the norm in healthy subjects (n = 12) and distinguished the regulation of the mitochondrial respiration factor COX1 by GH and endurance exercise. Our observations validate the use of network analysis for systems medicine and highlight the notion that an improved stochiometry between muscle and whole body lipid metabolism, rather than alterations of single bottlenecks, contributes to GH-driven elevations in metabolic fitness.

Massive Systemic Fat Embolism Detected by Postmortem Imaging and Biopsy

Postmortem computed tomography (pmCT) and pmCT angiography (pmCTA) provide a minimally invasive method to determine the cause of death. Postmortem image-guided biopsy allows for precise sampling of histological specimens. This case study describes the findings of lethal systemic fat embolism (FE) on whole-body unenhanced pmCT, pmCTA, and image-guided biopsy, with autopsy and histopathologic correlation. Unenhanced pmCT revealed a distinct fat level on top of sedimented layers of corpuscular blood particles and serum in the arterial system and pulmonary trunk. Subsequent pmCTA showed reproducible results, and image-guided biopsy confirmed fatal FE. pm CT/pmCTA combined with image-guided biopsy established the cause of death as right heart failure as a result of systemic fatal FE prior to autopsy. All imaging findings were consistent with traditional autopsy and histological specimens. This unique case demonstrates new imaging findings in massive, fatal FE and highlights that postmortem imaging, supplemented by image-guided biopsy, may detect the cause of death prior to traditional autopsy.

Correlation of fat embolism severity and subcutaneous fatty tissue crushing and bone fractures

Pulmonary fat embolism (PFE) is frequently encountered in blunt trauma. The clinical manifestation ranges from no impairment in light cases to death due to right-sided heart failure or hypoxaemia in severe cases. Occasionally, pulmonary fat embolism can give rise to a fat embolism syndrome (FES), which is marked by multiorgan failure, respiratory disorders, petechiae and often death. It is well known that fractures of long bones can lead to PFE. Several authors have argued that PFE can arise due to mere soft tissue injury in the absence of fractures, a claim other authors disagree upon. In this study, we retrospectively examined 50 victims of blunt trauma with regard to grade and extent of fractures and crushing of subcutaneous fatty tissue and presence and severity of PFE. Our results indicate that PFE can arise due to mere crushing of subcutaneous fat and that the fracture grade correlated well with PFE severity (p = 0.011). The correlation between PFE and the fracture severity (body regions affected by fractures and fracture grade) showed a lesser significant correlation (p = 0.170). The survival time (p = 0.567), the amount of body regions affected by fat crushing (p = 0.336) and the fat crush grade (p = 0.485) did not correlate with the PFE grade, nor did the amount of body regions affected by fractures. These results may have clinical implications for the assessment of a possible FES development, as, if the risk of a PFE is known, preventive steps can be taken.

Plasma PCSK9 concentrations during an oral fat load and after short term high-fat, high-fat high-protein and high-fructose diets

Background PCSK9 (Proprotein Convertase Subtilisin Kexin type 9) is a circulating protein that promotes hypercholesterolemia by decreasing hepatic LDL receptor protein. Under non interventional conditions, its expression is driven by sterol response element binding protein 2 (SREBP2) and follows a diurnal rhythm synchronous with cholesterol synthesis. Plasma PCSK9 is associated to LDL-C and to a lesser extent plasma triglycerides and insulin resistance. We aimed to verify the effect on plasma PCSK9 concentrations of dietary interventions that affect these parameters. Methods We performed nutritional interventions in young healthy male volunteers and offspring of type 2 diabetic (OffT2D) patients that are more prone to develop insulin resistance, including: i) acute post-prandial hyperlipidemic challenge (n=10), ii) 4 days of high-fat (HF) or high-fat/high-protein (HFHP) (n=10), iii) 7 (HFruc1, n=16) or 6 (HFruc2, n=9) days of hypercaloric high-fructose diets. An acute oral fat load was also performed in two patients bearing the R104C-V114A loss-of-function (LOF) PCSK9 mutation. Plasma PCSK9 concentrations were measured by ELISA. For the HFruc1 study, intrahepatocellular (IHCL) and intramyocellular lipids were measured by 1H magnetic resonance spectroscopy. Hepatic and whole-body insulin sensitivity was assessed with a two-step hyperinsulinemic-euglycemic clamp (0.3 and 1.0 mU.kg-1.min-1). Findings HF and HFHP short-term diets, as well as an acute hyperlipidemic oral load, did not significantly change PCSK9 concentrations. In addition, post-prandial plasma triglyceride excursion was not altered in two carriers of PCSK9 LOF mutation compared with non carriers. In contrast, hypercaloric 7-day HFruc1 diet increased plasma PCSK9 concentrations by 28% (p=0.05) in healthy volunteers and by 34% (p=0.001) in OffT2D patients. In another independent study, 6-day HFruc2 diet increased plasma PCSK9 levels by 93% (p<0.0001) in young healthy male volunteers. Spearman’s correlations revealed that plasma PCSK9 concentrations upon 7-day HFruc1 diet were positively associated with plasma triglycerides (r=0.54, p=0.01) and IHCL (r=0.56, p=0.001), and inversely correlated with hepatic (r=0.54, p=0.014) and whole-body (r=−0.59, p=0.0065) insulin sensitivity. Conclusions Plasma PCSK9 concentrations vary minimally in response to a short term high-fat diet and they are not accompanied with changes in cholesterolemia upon high-fructose diet. Short-term high-fructose intake increased plasma PCSK9 levels, independent on cholesterol synthesis, suggesting a regulation independent of SREBP-2. Upon this diet, PCSK9 is associated with insulin resistance, hepatic steatosis and plasma triglycerides.

Whole-body MRI of multiple myeloma: comparison of different MRI sequences in assessment of different growth patterns

PURPOSE: To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM). METHODS AND MATERIALS: WB-MRI using a 1.5T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63+/-12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n=7; intermediate-grade, n=7; high-grade, n=9) and to the staging system of Durie and Salmon PLUS (stage I, n=12; stage II, n=4; stage III, n=7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57+/-13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1+/-CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis. RESULTS: Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1+/-CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1+/-CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1=60%; 2=36%; 3=83%; T2: 1=70%; 2=71%; 3=89%; T1+/-CE/T2: 1=50%; 2=50%; 3=89%) and clinical stage (T1: 1=58%; 2=63%; 3=79%; T2: 1=58%; 2=88%; 3=100%; T1+/-CE/T2: 1=50%; 2=63%; 3=100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers). CONCLUSIONS: T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.