MRI-measured pelvic bone marrow adipose tissue is inversely related to DXA-measured bone mineral in younger and older adults.

BACKGROUND/OBJECTIVES: Recent research has shown an inverse relationship between bone marrow adipose tissue (BMAT) and bone mineral density (BMD). There is a lack of evidence at the macro-imaging level to establish whether increased BMAT is a cause or effect of bone loss. This cross-sectional study compared the BMAT and BMD relationship between a younger adult group at or approaching peak bone mass (PBM; age 18.0-39.9 years) and an older group with potential bone loss (PoBL; age 40.0-88.0 years). SUBJECTS/METHODS: Pelvic BMAT was evaluated in 560 healthy men and women with T1-weighted whole-body magnetic resonance imaging. BMD was measured using whole-body dual-energy X-ray absorptiometry. RESULTS: An inverse correlation was observed between pelvic BMAT and pelvic, total and spine BMD in the younger PBM group (r=-0.419 to -0.461, P<0.001) and in the older PoBL group (r=-0.405 to -0.500, P<0.001). After adjusting for age, sex, ethnicity, menopausal status, total body fat, skeletal muscle, subcutaneous and visceral adipose tissue, neither subject group (younger PBM vs older PoBL) nor its interaction with pelvic BMAT significantly contributed to the regression models with BMD as dependent variable and pelvic BMAT as independent variable (P=0.434-0.928). CONCLUSIONS: Our findings indicate that an inverse relationship between pelvic BMAT and BMD is present both in younger subjects who have not yet experienced bone loss and also in older subjects. These results provide support at the macro-imaging level for the hypothesis that low BMD may be a result of preferential differentiation of mesenchymal stem cells from osteoblasts to adipocytes.

Ethnic and sex differences in bone marrow adipose tissue and bone mineral density relationship.

UNLABELLED: The relationship between bone marrow adipose tissue and bone mineral density is different between African Americans and Caucasians as well as between men and women. This suggests that the mechanisms that regulate the differentiation and proliferation of bone marrow stromal cells may differ in these populations. INTRODUCTION: It has long been established that there are ethnic and sex differences in bone mineral density (BMD) and fracture risk. Recent studies suggest that bone marrow adipose tissue (BMAT) may play a role in the pathogenesis of osteoporosis. It is unknown whether ethnic and sex differences exist in the relationship between BMAT and BMD. METHODS: Pelvic BMAT was evaluated in 455 healthy African American and Caucasian men and women (age 18-88 years) using whole-body T1-weighted magnetic resonance imaging. BMD was measured using whole-body dual-energy X-ray absorptiometry. RESULTS: A negative correlation was observed between pelvic BMAT and total body BMD or pelvic BMD (r = -0.533, -0.576, respectively; P < 0.001). In multiple regression analyses with BMD as the dependent variable, ethnicity significantly entered the regression models as either an individual term or an interaction with BMAT. Menopausal status significantly entered the regression model with total body BMD as the dependent variable. African Americans had higher total body BMD than Caucasians for the same amount of BMAT, and the ethnic difference for pelvic BMD was greater in those participants with a higher BMAT. Men and premenopausal women had higher total body BMD levels than postmenopausal women for the same amount of BMAT. CONCLUSIONS: An inverse relationship exists between BMAT and BMD in African American and Caucasian men and women. The observed ethnic and sex differences between BMAT and BMD in the present study suggest the possibility that the mechanisms regulating the differentiation and proliferation of bone marrow stromal cells may differ in these populations.

Intermuscular and subcutaneous adipose tissue distributions differ in HIV+ versus HIV-men and women.

BACKGROUND: Loss of subcutaneous (SAT) with sparing of visceral (VAT) adipose tissue (AT) has been documented in HIV + men and women. Intermuscular AT (IMAT) rivals VAT in independent associations with cardiovascular risk. OBJECTIVE: To determine whether the size and distribution of IMAT differs in HIV+ vs. HIV- men and/or women. DESIGN: We used whole-body MRI to measure VAT, IMAT and four SAT compartments and compared them by HIV status using whole-body skeletal muscle (SM) or total AT (TAT) as co-variates in multi-ethnic groups of healthy HIV- (n=86) and stable HIV+ (n=76) men and women. RESULTS: The sizes of AT depots (adjusting for SM) did not differ by HIV status, except for smaller gluteal SAT (lower trunk, between L(4)-L(5) to greater trochanter) in both sexes (P<0.05). The AT distribution (adjusting for TAT) was significantly different, with larger VAT (P<0.05) and smaller gluteal and limb SAT (P<0.05) in both HIV+ sexes; IMAT increased more with TAT in HIV+ vs. HIV- men (P<0.05 for slope interaction) but there were no significant differences in women. There were significant race by HIV interactions in AT distribution with more pronounced VAT differences in non-Hispanic white men and larger trunk SAT in African Americans HIV+ vs. HIV-. CONCLUSION: The AT distribution differed markedly in HIV+ vs. HIV- with limb and lower body SAT representing a smaller proportion of TAT in HIV+ in both sexes and IMAT representing a larger proportion of TAT in HIV+ vs. HIV- men.

A female perspective on living with HIV disease.

The study discussed in this article explored women's views of the positive and negative aspects of life with HIV. Even in the face of a stigmatizing physical illness and with elevated levels of depression and anxiety, the 55 women interviewed for the study were able to identify a large number of positive events; for many, HIV served as a motivating force for positive change. Common negative experiences included physical symptoms, a limited life span, alienation, and stigma. Results suggest that whereas women demonstrate a remarkable capacity to adapt, there are a number of specific areas where social services and community interventions can be targeted.

Interactions among sex, HIV infection, and fat redistribution.

The interactions among sex, HIV infection, and body fat redistribution are uncertain. We retrospectively compared total, subcutaneous, and visceral adipose tissue (TAT, SAT, VAT) contents, as determined by whole body MRI, in 85 HIV-infected persons, including 48 HIV-positive persons with self-reported changes in body shape, and matched healthy controls. The effect of sex on regional fat contents differed among HIV-infected persons with and without self-reported changes in body shape. Women without changes had significantly less SAT and TAT than did controls, while men with changes had significantly less SAT and TAT than did controls. Higher contents of VAT were found in both men and women with self-reported changes in body shape.

Fat distribution in HIV-infected patients reporting truncal enlargement quantified by whole-body magnetic resonance imaging.

BACKGROUND: Antiretroviral therapy has improved the prospects for people infected with HIV, but some develop a syndrome of profound body habitus and metabolic alterations that include truncal enlargement. OBJECTIVE: The purpose of this study was to define the body-composition changes associated with this syndrome by using techniques with the power to estimate regional body composition. DESIGN: We compared whole-body and regional skeletal muscle and adipose tissue contents measured by magnetic resonance imaging and dual-energy X-ray absorptiometry (DXA) in 26 HIV-infected patients and 26 matched control subjects. Twelve of the HIV-infected patients had evidence of truncal enlargement. RESULTS: HIV-infected men and women who noted truncal enlargement had similar amounts of skeletal muscle and subcutaneous adipose tissue but greater visceral adipose tissue than HIV-infected patients without truncal enlargement; these values were larger in men (P < 0.001) than in women (P = 0.08). The ratio of visceral to subcutaneous adipose tissue was greater in both men (P < 0.02) and women (P = 0.05) with truncal enlargement. Two subjects with MRI-confirmed visceral adiposity syndrome (VAS) were not taking protease inhibitors. CD4+ lymphocyte counts were higher (P < 0.001) and plasma viral burdens tended to be lower (P = 0.08) in HIV-infected patients with VAS. CONCLUSIONS: There was significantly more visceral adipose tissue in the subgroup of HIV-infected patients with truncal enlargement than in those without this sign. VAS occurs in both men and women, is associated with higher CD4+ lymphocyte counts and lower plasma HIV viral burdens, and is not limited to those receiving protease inhibitor therapy.

Effects of megestrol acetate and testosterone on body composition in castrated male Sprague-Dawley rats.

The interrelationships among sex hormones, caloric intake, and intermediary metabolism in health and disease are uncertain. Studies in malnourished patients with AIDS and cancer show that megestrol acetate (MA) therapy increases appetite, body weight, and body fat, while it decreases serum testosterone (T) concentration. In this study, the separate and combined effects of MA and T were investigated in 65 young adult, male, castrated, Sprague-Dawley rats who received subcutaneous implants containing placebo, MA, T, or both MA and T for 11 wk. By hierarchical multiple regression analysis, MA therapy decreased weight gain and food intake (P < 0.01), increased body fat (P = 0.024), decreased body protein (P < 0.001), and decreased the portion of calories accrued as protein rather than fat (P ratio, P < 0.03). T alone decreased fat (P < 0.03), but had no significant effect on food intake, the relative number of consumed calories utilized for growth (food efficiency), body weight, or protein. The interaction of MA and T did not affect food intake or food efficiency, but increased body weight (P < 0.02), protein (P < 0.05) and the P ratio (P < 0.02). The portion of weight gain as fat was reduced from 47.3% with MA alone to 27.4% when MA and T were combined. Thus, megestrol acetate has significant antianabolic effects that are independent of its effects upon food intake. The addition of testosterone to megestrol acetate partially antagonized MA's inhibition of lean mass accretion in these rats.

Relative influences of sex, race, environment, and HIV infection on body composition in adults.

BACKGROUND: The factors that control body composition in disease are uncertain. OBJECTIVE: We planned to compare the relative influences of HIV infection, sex, race, and environment on body composition. METHODS: We analyzed results of body composition studies performed by bioelectrical impedance analysis in 1415 adults from 2 cohorts: white and African American men and women from the United States, and African men and women (279 HIV-infected and 1136 control). The effects of sex and HIV infection on weight, body cell mass, and fat-free mass were analyzed by using both unadjusted and age-, weight-, and height-adjusted data. RESULTS: Control men weighed more and had more body cell mass and fat-free mass than did control women, although control women had more fat. The strongest correlates with body composition were height and weight, followed by sex. HIV infection, age, environment, and race. Control men and women weighed more and had more body cell mass, fat-free mass, and fat than did HIV-infected men. However, differences in body composition between HIV-infected and control groups were strongly influenced by sex. Of the differences in weight between HIV-infected and uninfected subjects, fat-free mass accounted for 51% in men but only 18% in women, in whom the remainder was fat. Sex effects were similar in African and American groups. CONCLUSIONS: Sex has a marked effect on the changes in body composition during HIV infection, with women losing disproportionately more fat than men. Sex-related differences in body composition were narrower in the HIV-infected groups. Race and environment had smaller effects than sex and HIV infection.

The relationship of mood, endocrine, and sexual disorders in human immunodeficiency virus positive (HIV+) women: an exploratory study.

OBJECTIVE: This exploratory study assessed the prevalence of mood disorders, sexual disorders, and endocrine abnormalities, and explored the relationship between these parameters in a sample of HIV+ women. METHOD: Fifty-four HIV+ women were evaluated with the Structured Clinical Interview for DSM-III-R (SCID) and measures of psychiatric symptom severity, psychological well-being, and sexual problems. Women also provided blood to establish CD4 cell count, serum total testosterone, and dehydroepiandrosterone sulfate (DHEAS) levels. RESULTS: Although overall levels of current Axis I diagnosis were low, Hypoactive Sexual Desire Disorder (HSDD) was diagnosed in 39% of the women. Forty-eight percent of the sample had deficient testosterone levels (below 20.0 ng/dl) and 27% had deficient DHEAS levels (below 35.0 microg/dl). We found no significant relationship between diminished sexual desire and deficient levels of testosterone, DHEAS, or mood disorder diagnoses. However, HSDD was significantly related to more depressive symptoms and lower life satisfaction. Women whose perceived risk factor for HIV infection included sexual contact were more than five times more likely to be diagnosed with a new onset HSDD than women who reported intravenous drug use (IVDU) as their only risk factor (47% vs. 9%, respectively). CONCLUSIONS: We observed what seems to be high rates of HSDD and endocrine abnormalities with very low rates of mood disorders. Interestingly, endocrine abnormalities were not associated with low sexual desire. Our findings suggest that there is a significant unmet need for treatment of Hypoactive Sexual Desire Disorder among urban HIV+ women.

Transpancreatic catheterization of the right hepatic artery for chemoembolization using a new infusion system.

The right hepatic artery was catheterized for chemoembolization in a patient with liver-dominant metastatic breast carcinoma and occlusion of the celiac artery by tumor compression. This was accomplished by use of a new coaxial infusion catheter-steerable guidewire system passed through the superior mesenteric artery and posterior pancreatic arcade.

The microvasculature in skeletal muscle. II. Arteriolar network anatomy in normotensive and spontaneously hypertensive rats.

A quantitative comparison of the anatomical arrangement of arterioles in the skeletal muscle of mature (16 to 20-week-old) Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) is provided. In both species several feeding arterioles supply blood to a network of arterioles covering the entire muscle, designated as arcade arterioles. The connections from the arcade arterioles to the capillary network are provided by the transverse arterioles. Comparison of the spinotrapezius muscle of the WKY and the SHR shows several types of rearrangement of the network. In both species there is a wide distribution of vessel size in the arcade and transverse arterioles. The length of the arcade arterioles per unit muscle volume is higher in the SHR, forming a denser network. There are almost twice as many transverse arteriolar trees per unit tissue volume in hypertensive animals although on the average each transverse tree has shorter branches. No evidence for significant anatomical rarefaction was found among arcade and transverse arterioles. Arcade arterioles following maximal dilation were found to be 25% narrower in the SHR, whereas for transverse arterioles no differences in diameter could be detected under these vasodilated conditions.

The microvasculature in skeletal muscle. I. Arteriolar network in rat spinotrapezius muscle.

A quantitative analysis of blood flow dynamics in skeletal muscle requires a detailed picture of the microvascular network. This report presents an analysis of the arteriolar network structure in the spinotrapezius muscle of the rat. The microvasculature is visualized by injection of a carbon suspension and recorded in the form of photomicrographs with a complete reconstruction of the microvasculature on transparent overlays. The spinotrapezius muscle has several major feeding arterioles which supply blood into an extensive meshwork of interconnecting or arcading arterioles spanning the entire muscle. The connections from the arcade arterioles to the capillaries are provided by transverse arterioles, which branch from the arcades at regular intervals. Each transverse arteriole forms a single asymmetric dichotomous tree and within each muscle there is a wide range in the size of transverse arterioles. A new branching schema is proposed to describe the arteriolar network. A set of network parameters is derived and typical values of these parameters in the spinotrapezius muscle of the rat are provided.

The microvasculature in skeletal muscle. III. Venous network anatomy in normotensive and spontaneously hypertensive rats.

A quantitative description of the anatomical arrangement of venules in the spinotrapezius muscle of mature (12-15 week old) Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) is provided. In both strains, asymmetric, dichotomous collecting venule trees route blood from the capillaries to a network of interconnected or arcade venules which spans the entire muscle. The arcade network is drained of blood through several draining venules which exit the muscle. A new branching scheme is proposed for the venular microvascular network. Comparison of WKY and SHR values shows that the arcade venules in the WKY are, on the average, narrower. Conversely, SHR postcapillary vessels are narrower than those in the WKY. Aside from these differences, however, the venular microvasculature and network pattern in the two strains is similar.