Specific features of ex‐obese patients significantly influence the functional cell properties of adipose‐derived stromal cells

Adipose‐derived stromal cells (ADSC) are increasingly used in clinical applications due to their regenerative capabilities. However, ADSC therapies show variable results. This study analysed the effects of specific factors of ex‐obese patients on ADSC functions. ADSC were harvested from abdominal tissues (N = 20) after massive weight loss. Patients were grouped according to age, sex, current and maximum body mass index (BMI), BMI difference, weight loss method, smoking and infection at the surgical site. ADSC surface markers, viability, migration, transmigration, sprouting, differentiation potential, cytokine secretion, telomere length and mtDNA copy number were analysed. All ADSC expressed CD73, CD90, CD105, while functional properties differed significantly among patients. A high BMI difference due to massive weight loss was negatively correlated with ADSC proliferation, migration and transmigration, while age, sex or weight loss method had a smaller effect. ADSC from female and younger donors and individuals after weight loss by increase of exercise and diet change had a higher activity. Telomere length, mtDNA copy number, differentiation potential and the secretome did not correlate with patient factors or cell function. Therefore, we suggest that factors such as age, sex, increase of exercise and especially weight loss should be considered for patient selection and planning of regenerative therapies.     

Body image and quality of life in post massive weight loss body contouring patients

Objective: Because post‐bariatric surgery patients undergo massive weight loss, the resulting skin excess can lead to both functional problems and profound dissatisfaction with appearance. Correcting skin excess could improve all these corollaries, including body image. Presently, few data are available documenting body image and weight‐related quality of life in this population. Research Methods and Procedures: Eighteen patients who underwent both bariatric surgery and body contouring completed our study. Both established surveys and new surveys designed specifically for the study were used to assess body perception and ideals, quality of life, and mood. Patients were surveyed at the following time‐points: pre‐body contouring (after massive weight loss) and both 3 and 6 month post‐body contouring. Statistical testing was performed using Student's t test and ANOVA. Results: The mean age of the patients was 46 ± 10 years (standard deviation). Quality of life improved after obesity surgery and was significantly enhanced after body contouring. Three months after body contouring, subjects ascribed thinner silhouettes to both current appearance and ideal body image. Body image also improved with body contouring surgery. Mood remained stable over 6 months. Discussion: Body contouring after surgical weight loss improved both quality‐of‐life measurements and body image. Initial body dissatisfaction did not correlate with mood. Body contouring improved body image but produced dissatisfaction with other parts of the body, suggesting that as patients become closer to their ideal, these ideals may shift. We further developed several new assessment methods that may prove useful in understanding these post‐surgical weight loss patients.     

Dynamics of Change in Total and Regional Body Composition After Gastric Bypass in Obese Patients

Little is known on patterns of change over time in body composition, especially lean body mass (LBM), during massive weight loss after Roux‐en‐Y gastric bypass (RYGB) in obese patients. We performed sequential measurements of total and regional body composition in patients after RYGB, and we compared a subsample of patients after surgery to a nonsurgical control group of similar age and body fatness. We used dual‐energy X‐ray absorptiometry (DXA) before and at 3, 6, and 12 months after RYGB in 42 obese women (before surgery: age 39.5 ± 11.6 years; BMI 44.6 ± 6.1 kg/m²; mean ± s.d.) and in 48 control obese women referred for nonsurgical weight management, before weight loss. During 1‐year follow‐up after RYGB, there was a continuous decrease in body weight (?36.0 ± 12.5 kg at 1 year), total fat mass (FM) (?26.0 ± 9.1 kg), as well as in trunk and appendicular FM. In contrast, the decrease in total LBM (?9.8 ± 4.8 kg at 1 year), as well as in trunk and appendicular LBM, plateaued after 3–6 months. Rates of loss in weight, FM, and LBM were highest during the first 3‐month period after RYGB (6.4 ± 1.8, 4.1 ± 1.7, and 2.3 ± 1.2 kg/month, respectively), then decreased continuously for FM but plateaued for LBM. There was no evidence of a decrease in total, trunk, or appendicular LBM in weight‐reduced subjects compared to the control group. In conclusion, follow‐up of these obese women revealed a differential pattern of change in FM and LBM after RYGB. Despite an important loss in LBM, especially during the 3–6 months of initial period, LBM appears to be spared thereafter.     

Correcting the saddlebag deformity in the massive weight loss patient

Skin redundancy of the trunk and thigh is treated by a circumferential abdominoplasty and a lower body lift. Despite preservation and tight approximation of the subcutaneous facial system, the authors have failed to adequately correct severe saddlebag deformity and midthigh laxity in the massive weight loss patient. The technique used in the last nine of the senior author's 43 lower body lifts was modified by fully abducting each operated thigh on a side utility table, before closure in the prone position. This maneuver permits an increase in width of skin excision and causes the lateral thigh skin to be taut upon leg adduction. This is a retrospective review of the senior surgeon's experience over a 3-year period. Postoperative follow-up of the nine-patient cohort ranged from 8 to 12 months. A standardized set of six-view preoperative and postoperative photographs was available for each patient. A regional grading system was developed to assign points for deformity seen in preoperative and postoperative photographs. To compare the effect of the new technique on the correction of hip/lateral thigh deformities, the authors used this same grading system to analyze 10 other lower body lift patients treated by the same surgeon without full thigh abduction who had six sets of standardized photographs. A deformity severity score was determined for each anatomic region by four trained observers blinded to the surgical technique. The nonparametric Mann-Whitney U test using exact p values was used to compare preoperative and percentage change in deformity severity score from preoperative to postoperative scores relative to preoperative scores for each anatomical region among subjects in each treatment group. The nonparametric Wilcoxon signed rank test using exact p values was used to evaluate the change in deformity severity score from preoperative to postoperative values. The change in technique resulted in an observable symmetrical correction of the severe saddlebag deformity and better contour to the distal lateral thighs. All evaluated patients were satisfied with the lateral thigh skin contour. The grading system revealed that patients treated with or without intraoperative thigh abduction had similar preoperative deformity severity scores for each anatomic region (p > 0.05). Postoperatively, all subjects showed improvement in scores for all treated regions. However, patients closed during full thigh abduction had significantly lower deformity severity scores for the hip/thigh complex when compared with patients treated without full thigh abduction (p < 0.05). Complications in these 19 patients consisted of one 6-cm superficial skin layer dehiscence due to a broken polyester suture that healed spontaneously. There were three seromas that responded to a short series of aspirations or catheter drainage. There were no infections. Distal abdominal flap tip skin necrosis in four patients responded to outpatient débridement and healed secondarily. A new grading system for body contour deformities was successfully utilized to judge differences in the quality of trunk and thigh deformity and outcome in 19 patients with adequate photographic records. Tight suture closure in full thigh abduction in the prone position results in improved treatment of significant saddlebag deformity and midthigh skin laxity in the massive weight loss patient. The essential principles are meticulous planning, careful isolation, tight closure of the lateral trunk and thigh subcutaneous fascial system, and artistic contouring of remaining tissues. Dehiscence, undesirable scarring, and seromas were minor issues in the entire group of 43 patients.     

Responses of adipose tissue lipoprotein lipase to weight loss affect lipid levels and weight regain in women

This study determines whether changes in abdominal (ABD) and gluteal (GLT) adipose tissue lipoprotein lipase (LPL) activity in response to a 6-mo weight loss intervention, comprised of a hypocaloric diet and low-intensity walking, affect changes in body composition, fat distribution, lipid metabolism, and the magnitude of weight regain in 36 obese postmenopausal women. Average adipose tissue LPL activity did not change with an average 5.6-kg weight loss, but changes in LPL activity were inversely related to baseline LPL activity (ABD: r = -0.60, GLT: r = -0.48; P < 0.01). The loss of abdominal body fat and decreases in total and low-density lipoprotein cholesterol were greater in women whose adipose tissue LPL activity decreased with weight loss despite a similar loss of total body weight and fat mass. Moreover, weight regain after a 6-mo follow-up was less in women whose adipose tissue LPL activity decreased than in women whose LPL increased (ABD: 0.9 +/- 0.5 vs. 2.8 +/- 0.6 kg, P < 0.05; GLT: 0.2 +/- 0.5 vs. 2.8 +/- 0.5 kg, P < 0.01). These results suggest that a reduction in adipose tissue LPL activity with weight loss is associated with improvements in lipid metabolic risk factors with weight loss and with diminished weight regain in postmenopausal women.     

Changes in the biochemical composition of fat body stores during adult development of female crickets, Gryllus bimaculatus

Age-dependent changes in the fat body composition and aspects of lipogenesis in the free abdominal fat body of female crickets, Gryllus bimaculatus, were studied. Lipid, protein, glycogen, and free carbohydrate content of the fat body, and fat body wet weight increased simultaneously and sharply from day 0 onwards and were doubled/almost doubled by day 2 after adult emergence. Lipogenic activity of the fat body, fat body weight, and the energy stores in the fat body peaked on day 2, except for free carbohydrate, which peaked on day 3. On day 2, the fat body was mainly comprised of lipid (53.8%) and protein (6.6%), while glycogen and free carbohydrate together contributed less than 1% of the fat body wet weight. After peaking, both lipogenesis and energy stores decreased in a synchronous manner. The depletion of the fat body energy stores and the consequent decrease in the fat body weight were concomitant with a fast and massive gain in ovary weight (day 2: 19.5 +/- 1.5 mg; day 4: 332.8 +/- 31.5 mg) due to the vitellogenic oocyte growth that started on day 2. Our data clearly underline the importance of the free abdominal fat body as a source of energy for reproduction in the cricket. Fat body fatty acid synthase activity coincided with lipogenic activity. Adipokinetic hormone inhibits lipid synthesis in the fat body, but treatment of the fat body with adipokinetic hormone in vitro showed no consistent effect on fatty acid synthase activity.     

Abdominal wall partitioning (the accordion effect) for reconstruction of major defects: a retrospective review of 10 patients

Ten patients underwent abdominal wall reconstruction using the technique of abdominal wall partitioning. All defects were closed in the midline by approximating fascia to fascia with the assistance of a general surgeon. One patient had skin grafted small bowel. Five patients had chronically infected mesh and previous failed attempts at repair. Four patients had large ventral hernias following gastric reduction operations and massive weight loss. No defect in any dimension was less than 20 cm. All patients had secure abdominal wall repair by reconstruction of a midline anchor for the abdominal wall musculature. One patient was lost to follow-up after 3 weeks. The average follow-up time for the remaining nine patients was 18.6 months (range, 6 months to 4.7 years). One patient required readmission to the hospital for management of a limited area of skin necrosis. Two patients had minor wound infections, and three patients had subcutaneous seromas, all of which were managed on an outpatient basis. One patient developed a 2 x 2-cm subxiphoid hernia recurrence. Technical details include subcutaneous undermining of the abdominal skin to the anterior axillary lines bilaterally, mobilization of the viscera to expose the white lines of Toldt bilaterally, and parallel, parasagittal, staggered releases of the transversalis fascia, transversalis muscle, external oblique fascia, external oblique muscle, and rectus fascia. These multiple releases allow expansion and translation of the abdominal wall by an accordion-like effect. This accordion-like effect allows closure of abdominal wall defects that are substantially larger than what can be closed with current techniques.     

BMI and Metabolic Profile in Patients With Prolactinoma Before and After Treatment With Dopamine Agonists

Hyperprolactinemia might be related to weight gain, metabolic syndrome (MS), and insulin resistance (IR). Treatment with dopamine agonist (DA) has been shown to reduce body weight and improve metabolic parameters. The objectives of this study were to determine the prevalence of obesity, overweight, MS, and IR in patients with prolactinoma before and after therapy with DA and to evaluate the relation between prolactin (PRL), body weight, fat distribution, leptin levels, IR, and lipid profile before treatment. In addition, we investigated the correlation of the reduction in PRL levels with weight loss and metabolic profile improvement. Twenty‐two patients with prolactinoma completed 6 months of treatment with DA. These patients were submitted to clinical (BMI, waist circumference, blood pressure (BP)), laboratory evaluation (leptin, glucose, low‐density lipoprotein (LDL)‐cholesterol, and triglyceride (TG) levels) and abdominal computed tomography (CT) before and after treatment. The statistical analyses were done by nonparametric tests. At the beginning of the study, the prevalence of obesity, overweight, MS, and IR was 45, 27, 27, and 18%, respectively. After 6 months of treatment with DA, PRL levels normalized, but no significant difference in BMI was observed. However, there was a significant decrease on homeostasis model assessment of insulin resistance (HOMA_IR) index, glucose, LDL‐cholesterol, and TG levels. This study suggests a possible involvement of prolactinoma on the prevalence of obesity. We should consider that DA may be effective on improving metabolic parameters, and we speculate that a period longer than 6 months of treatment is necessary to conclude whether this drug can interfere in the body weight of patients with prolactinoma.     

Weight-Loss Induced Changes in Physical Activity and Activity Energy Expenditure in Overweight and Obese Subjects before and after Energy Restriction

Activity energy expenditure (AEE) is the component of daily energy expenditure that is mainly influenced by the amount of physical activity (PA) and by the weight of the body displaced. This study aimed at analyzing the effect of weight loss on PA and AEE. The body weight and PA of 66 overweight and obese subjects were measured at baseline and after 12 weeks of 67% energy restriction. PA was measured using a tri-axial accelerometer for movement registration (Tracmor) and quantified in activity counts. Tracmor recordings were also processed using a classification algorithm to recognize 6 common activity types engaged in during the day. A doubly-labeled water validated equation based on Tracmor output was used to estimate AEE. After weight loss, body weight decreased by 13±4%, daily activity counts augmented by 9% (95% CI: +2%, +15%), and this increase was weakly associated with the decrease in body weight (R² = 7%; P<0.05). After weight loss subjects were significantly (P<0.05) less sedentary (–26 min/d), and increased the time spent walking (+11 min/d) and bicycling (+4 min/d). However, AEE decreased by 0.6±0.4 MJ/d after weight loss. On average, a 2-hour/day reduction of sedentary time by increasing ambulatory and generic activities was required to restore baseline levels of AEE. In conclusion, after weight loss PA increased but the related metabolic demand did not offset the reduction in AEE due to the lower body weight. Promoting physical activity according to the extent of weight loss might increase successfulness of weight maintenance.     

A technique of brachioplasty

Various techniques for the management of upper extremity contour deformities have been suggested since aesthetic brachioplasty was first described. Such deformities are commonplace with aging, after normal weight loss, and especially after massive weight loss such as is seen following bariatric surgery. Despite the multiplicity of procedures described for the correction of these deformities, there are still problems associated with current brachioplasty techniques, including incorrectly placed incisions, widened hypertrophic scars, and postoperative contour deformities. In addition, postoperative skin laxity and ptosis in the axillary region are frequently encountered in the more extreme deformities. The authors present their technique for upper extremity brachioplasty. This technique is suitable for patients with severe brachial ptosis and skin laxity, with relatively little lipomatous tissue, which may extend from the olecranon to the chest wall. The described surgical approach provides excellent overall extremity contour with favorable scars while simultaneously addressing axillary contour deformities.     

Long-term beneficial effect of a 16-week very low calorie diet on pericardial fat in obese type 2 diabetes mellitus patients

Pericardial fat accumulation has been associated with an increased cardiovascular risk. A very low calorie diet (VLCD) improves the cardiovascular risk profile in patients with type 2 diabetes mellitus (T2DM), by improving the metabolic profile, heart function, and triglyceride (TG) stores in (non)adipose tissues. However, long-term effects of a VLCD on pericardial fat volume and tissue-specific TG accumulation have not been documented. The aim of this study was therefore to assess the effects of a 16-week VLCD and of subsequent 14 months follow-up on a regular diet on pericardial fat in relation to other TG stores in obese T2DM patients. We included 14 obese patients with insulin-treated T2DM (mean ± s.e.m.: age 53 ± 2 years; BMI 35 ± 1 kg/m(2)). Pericardial fat and other (non)adipose TG stores were measured using magnetic resonance (MR) imaging and proton spectroscopy before and after a 16-week VLCD and after a 14-month follow-up without dietary interventions. A 16-week VLCD reduced body weight, pericardial fat, hepatic TG content, visceral and subcutaneous abdominal fat volumes to 78, 83, 16, 40, and 53% of baseline values respectively, (all P < 0.05). After an additional 14 months of follow-up on a regular diet, the reduction in pericardial fat volume sustained, despite a substantial regain in body weight, visceral abdominal fat, and hepatic TG content (respectively 90, 83 and 73% of baseline values). In conclusion, VLCD-induced weight loss in obese T2DM patients is accompanied by a substantial decrease in pericardial fat volume, which is sustained even after subsequent weight regain.     

France Verus Wales

Assessment of roentgenographic measurements of cortical bone of the radius in 196 elderly females, including 63 diabetics, revealed that: (1) in the non-diabetic group there was a significant loss of cortical bone relative to the number of years after the menopause and to body weight; (2) although there was a significant loss of cortical bone relative to years postmenopausal in a group of diabetic patients the cortex in the diabetic group was better preserved than in those non-diabetic controls in whom no vertebral compressions were diagnosed in the roentgenograms; no correlation between bone loss and body weight was found among the diabetics; (3) the thinnest cortical bone and the lowest average body weight was found in the 34 non-diabetics with vertebral compression deformities. It thus appears that involutional osteoporosis will be less prevalent among old women suffering from diabetes mellitus than in comparable non-diabetic subjects, and more prevalent among non-diabetics of low body weight than in old women who are obese or of normal weight.     

Diet versus exercise in “the biggest loser” weight loss competition

Background:

Obesity experts have criticized The Biggest Loser television show for its portrayal of an unrealistic intervention that raises false expectations for weight loss. However, the magnitude of the diet and exercise intervention has not been previously quantified.

Design and Methods:

Using a validated computational model of metabolism, I quantified the diet and exercise intervention by integrating data on energy expenditure, body weight and fat mass collected during The Biggest Loser competition.

Results:

Participant body mass index, weight, and percent body fat at baseline were 48.7 ± 10.1 kg/m², 144.9 ± 39.4 kg, and 49 ± 6% (mean ± SD), respectively. During the first phase of the competition when the contestants were isolated in a boot camp environment, the average rate of weight loss was 0.4 ± 0.1 kg/d and decreased to 0.19 ± 0.1 kg/d after returning home. Total weight loss was 58.2 ± 26 kg with 81.6 ± 8.4% coming from body fat. The computer simulations closely matched these data and calculated that average energy intake decreased by 65% during the first phase to 1300 kcal/d while participating in 3.1 h/d of vigorous exercise. After returning home, energy intake increased to 1900 kcal/d and vigorous exercise decreased to 1.1 h/d. Simulation of diet alone resulted in 34 kg of weight loss with 65% coming from body fat, whereas exercise alone resulted in a loss of 27 kg with 102% from fat.

Conclusion:

The intense diet and exercise intervention during The Biggest Loser competition were not sustainable. However, a relatively modest permanent lifestyle intervention of 20% caloric restriction and 20 min/d of vigorous exercise could maintain the massive weight loss.     

Massive trichuriasis in an adult diagnosed by colonoscopy

A case of massive trichuriasis in a 37-year-old female from a rural locality of the Metropolitan Region of Chile, with antecedents of alcoholism, chronic hepatic damage and portal cavernomatosis, is presented. Since 12 year ago she has had geophagia. In the last six months she has frequently presented liquid diarrhea, colic abdominal pains, tenesmus and sensation of abdominal distention. Clinical and laboratory tests confirmed her hepatic affection associated with a celiac disease with anemia and hypereosinophilia. Within a week diarrhea became worse and dysentery appeared. A colonoscopy revealed an impressive and massive trichuriasis. The patient was successfully treated with two cures of 200 mg tablets of mebendazole twice daily for three days with a week interval. After the first cure she evacuated a big amount of Tricuris trichiura, fecal evacuations became normal, geophagia disappeared and recovered 4 kg of body weight.     

Role of adipokines in the obesity-inflammation relationship: the effect of fat removal

During the past 10 years, there has been a dramatic increase in the prevalence of obesity in the United States and other developed nations. Recent studies indicate that adipose tissue is an endocrine organ producing numerous proteins, collectively referred to as adipokines, with broad biological activity, that play an important autocrine role in obesity-associated complications. Adipose tissue in general and visceral fat in particular are thought to be key regulators of inflammation. Inflammation is heavily involved in the onset and development of atherothrombotic disease. Moreover, chronic inflammation may also represent a triggering factor in the origin of the metabolic syndrome and type 2 diabetes mellitus. According to a hypothesis, stimuli such as overnutrition, physical inactivity, and aging would result in cytokine hypersecretion and eventually lead to insulin resistance and diabetes in genetically or metabolically predisposed individuals. This article discusses the current understanding of important adipokines thought to be involved in the metabolic and cardiovascular risk associated with obesity. Available evidence linking fat removal by liposuction to modification of cardiovascular risk and vascular inflammatory markers in the obese patient is also presented. Most studies have shown that liposuction produces beneficial effects on insulin resistance and vascular inflammation in the obese patient, reducing its cardiovascular risk. Besides having a significant role in body contouring of the obese patient at the end of the lengthy process of bariatric surgery and massive weight loss, plastic surgery should be incorporated into a multifaceted program of lifestyle changes that allows the obese patient to obtain weight loss and, more importantly, to maintain the reduced weight in the long term.     

Body Fat Loss Automatically Reduces Lean Mass by Changing the Fat‐Free Component of Adipose Tissue

Fat‐free mass or lean tissue mass includes nonskeletal muscle components such as the fat‐free component of adipose tissue fat cells. This fat‐free component of adipose tissue may need to be taken into consideration when large changes in body fat occur following a weight loss intervention. It is not uncommon to see a loss of lean mass with interventions designed to promote the loss of large amounts of fat mass. However, after eliminating the influence of the fat‐free component of adipose tissue on dual‐energy x‐ray absorptiometry (DXA)‐derived lean mass, the original loss of lean mass is no longer observed or is markedly reduced. This suggests that the majority of the lean mass lost with dieting may be the fat‐free component of adipose tissue. To accurately estimate the change in lean tissue, eliminating the fat‐free adipose tissue from DXA‐derived lean mass is needed when large changes in body fat occur following an intervention.     

Overweight,Obesity, and Blood Pressure: The Effects of Modest Weight Reduction

Several large epidemiological studies have shown an association between body mass index and blood pressure in normal weight and overweight patients. Weight gain in adult life especially seems to be an important risk factor for the development of hypertension. Weight loss has been recommended for the obese hypertensive patient and has been shown to be the most effective nonpharmacological treatment approach. However, long‐term results of weight loss programs are disappointing with people often regaining most of the weight initially lost. In recent years, a modest weight loss, defined as a weight loss of 5% to 10% of baseline weight, has received increasing attention as a new treatment strategy for overweight and obese patients. A more gradual and moderate weight loss is more likely to be maintained over a longer period of time. Several studies have confirmed the blood pressure‐lowering effect of a modest weight loss in both hypertensive and nonhypertensive patients. A modest weight loss can normalize blood pressure levels even without reaching ideal weight. In patients taking antihypertensive medication, a modest weight loss has been shown to lower or even discontinue the need for antihypertensive medication. In patients with high normal blood pressure, a modest weight loss can prevent the onset of frank hypertension. The blood pressure‐lowering effect of weight loss is most likely a result of an improvement in insulin sensitivity and a decrease in sympathetic nervous system activity and occurs independent of salt restriction. In conclusion, a modest weight loss that can be maintained over a longer period of time is a valuable treatment goal in hypertensive patients.     

Effect of weight loss on the rate of muscle protein synthesis during fasted and fed conditions in obese older adults

Although weight loss ameliorates many of the metabolic abnormalities associated with obesity, there has been reluctance to prescribe weight loss in obese, older individuals because of the fear that it will cause debilitating loss of muscle mass and impair physical function. To gain insight into the mechanisms responsible for the weight loss-induced changes in muscle mass, we measured the rate of muscle protein synthesis (by using stable isotope labeled tracer methodology) during basal, postabsorptive conditions and during mixed meal ingestion in eight obese, older adults: (i) before weight loss therapy, (ii) ~3 months after starting the weight loss intervention (i.e., during the active weight loss phase), when subjects had lost ~7% of their initial body weight, and (iii) after they had lost ~10% of their body weight and maintained this new body weight for ~6 months (~12 months after starting the weight loss intervention). The basal muscle protein fractional synthesis rate (FSR) was not affected by weight loss. Mixed meal ingestion stimulated the rate of muscle protein synthesis, and the anabolic response (i.e., increase in the protein synthesis rate above basal values) was greater (P < 0.05) during negative energy balance and active weight loss at 3 months (0.033 ± 0.012%·per hour, mean ± s.e.m.) than during weight maintenance before and at 12 months of weight loss therapy (0.003 ± 0.003 and 0.008 ± 0.012%·per hour, respectively). We conclude that during dietary calorie restriction and weight loss in older adults, the rate of muscle protein synthesis is not impaired. Thus, the loss of muscle mass must be mediated predominately by adverse effects of dietary calorie restriction on muscle proteolysis.     

Intra-abdominal fat burden discriminated in vivo using proton magnetic resonance spectroscopy

Objective: To assess proton magnetic resonance spectroscopy (¹H‐MRS) as a means to distinguish among mice with disparate intra‐abdominal body fat compositions, and to measure changes in intra‐abdominal fat burden during weight loss and regain. Research Methods and Procedures: Intra‐abdominal fat burden was analyzed as a ratio of integrated areas under the curves of fat to water ¹H‐MRS signals collected from a region of interest standardized across B6.V‐Lep^ob, C57BL/6, and A‐ZIP/F mice that exhibited various genotypically related body fat compositions, ranging from obese (B6.V‐Lep^ob) to minimal body fat (A‐ZIP/F). ¹H‐MRS analysis of fat burden was compared with intra‐abdominal fat volume and with a single cross‐sectional intra‐abdominal fat area calculated from segmented magnetic resonance images. Similar measurements were made from obese B6.V‐Lep^ob mice before, during, and after they were induced to lose weight by leptin administration. Results: Relative amounts of intra‐abdominal fat analyzed by ¹H‐MRS differed significantly according to body composition and genotype of the three strains of mice (p < 0.05). Intra‐abdominal fat assessed by ¹H‐MRS correlated with both intra‐abdominal fat volume (r = 0.88, p < 0.001) and body weight (r = 0.82, p < 0.001) among, but not within, all three genotypes. During weight loss and regain, there was a significant overall pattern of changes in intra‐abdominal fat quantity that occurred, which was reflected by ¹H‐MRS (p = 0.006). Discussion: Results support the use of localized ¹H‐MRS for assessing differences in intra‐abdominal fat. Refinements in ¹H‐MRS voxel region of interest size and location as well as instrument precision may result in improved correlations within certain body compositions.     

Weight loss increases cardiovagal baroreflex function in obese young and older men

We tested the hypothesis that reductions in total body and abdominal visceral fat with energy restriction would be associated with increases in cardiovagal baroreflex sensitivity (BRS) in overweight/obese older men. To address this, overweight/obese (25 < or = body mass index < or = 35 kg/m(2)) young (OB-Y, n = 10, age = 32.9 +/- 2.3 yr) and older (OB-O, n = 6, age = 60 +/- 2.7 yr) men underwent 3 mo of energy restriction at a level designed to reduce body weight by 5-10%. Cardiovagal BRS (modified Oxford technique), body composition (dual-energy X-ray absorptiometry), and abdominal fat distribution (computed tomography) were measured in the overweight/obese men before weight loss and after 4 wk of weight stability at their reduced weight and compared with a group of nonobese young men (NO-Y, n = 13, age = 21.1 +/- 1.0 yr). Before weight loss, cardiovagal BRS was approximately 35% and approximately 60% lower (P < 0.05) in the OB-Y and OB-O compared with NO-Y. Body weight (-7.8 +/- 1.1 vs. -7.3 +/- 0.7 kg), total fat mass (-4.1 +/- 1.0 vs. -4.4 +/- 0.8 kg), and abdominal visceral fat (-27.6 +/- 6.9 vs. -43.5 +/- 10.1 cm(2)) were reduced (all P < 0.05) after weight loss, but the magnitude of reduction did not differ (all P > 0.05) between OB-Y and OB-O, respectively. Cardiovagal BRS increased (11.5 +/- 1.9 vs. 18.5 +/- 2.6 ms/mmHg and 6.7 +/- 1.2 vs. 12.8 +/- 4.2 ms/mmHg) after weight loss (both P < 0.05) in OB-Y and OB-O, respectively. After weight loss, cardiovagal BRS in the obese/overweight young and older men was approximately 105% and approximately 73% (P > 0.05) of NO-Y (17.5 +/- 2.2 ms/mmHg). Therefore, the results of this study indicate that weight loss increases the sensitivity of the cardiovagal baroreflex in overweight/obese young and older men.