Visceral Adipose Tissue Density Research Articles

Lower estimates of myocardial perfusion are associated with greater aortic perivascular adipose tissue density in humans independent of aortic stiffness.

Aortic perivascular adipose tissue (aPVAT) density is associated with age-related aortic stiffness in humans and therefore, may contribute to cardiovascular dysfunction. A lower subendocardial viability ratio (SEVR), an estimate of myocardial perfusion, indicates greater cardiovascular disease (CVD) risk and is associated with aortic stiffness in clinical populations. However, the influence of aortic stiffness on the relation between aPVAT density and SEVR/cardiovascular (CV) hemodynamics in apparently healthy adults is unknown. We hypothesize that greater aPVAT density will be associated with lower SEVR and higher CV hemodynamics independent of aortic stiffness. Fourteen (6 males/8 females; mean age, 55.4 ± 5.6 yr; body mass index, 25.5 ± 0.6 kg/m2) adults completed resting measures of myocardial perfusion (SEVR), CV hemodynamics (pulse wave analysis), aortic stiffness [carotid-femoral pulse wave velocity (cfPWV)], and a computed tomography scan to acquire aPVAT and visceral adipose tissue (VAT) density. Greater aPVAT density (i.e., higher density) was associated with lower SEVR (r = -0.78, P < 0.001) and a higher systolic pressure time integral (r = 0.49, P = 0.03), forward pulse height (r = 0.49, P = 0.03), reflected pulse height (r = 0.55, P = 0.02), ejection duration (r = 0.56, P = 0.02), and augmentation pressure (r = 0.69, P = 0.003), but not with the diastolic pressure time integral (r = -0.22, P = 0.22). VAT density was not associated with SEVR or any CV hemodynamic endpoints (all, P > 0.05). Furthermore, the relation between aPVAT density and SEVR remained after adjusting for aortic stiffness (r = -0.66, P = 0.01) but not age (r = -0.24, P > 0.05). These data provide initial evidence for aPVAT as a novel yet understudied local fat depot contributing to lower myocardial perfusion in apparently healthy adults with aging.NEW & NOTEWORTHY Aortic perivascular adipose tissue (aPVAT) density is associated with aging and aortic stiffness in humans and, therefore, may contribute to lower myocardial perfusion. We demonstrate that greater aPVAT, but not visceral adipose tissue density is associated with lower myocardial perfusion and augmentation pressure independent of aortic stiffness, but not independent of age. These data provide novel evidence for aPVAT as a potential therapeutic target to improve myocardial perfusion and cardiovascular function in humans with aging.

Computed tomography-based body composition parameters can predict short-term prognosis in ulcerative colitis patients.

Emerging evidence suggests a potential relationship between body composition and short-term prognosis of ulcerative colitis (UC). Early and accurate assessment of rapid remission based on conventional therapy via abdominal computed tomography (CT) images has rarely been investigated. This study aimed to build a prediction model using CT-based body composition parameters for UC risk stratification. In total, 138 patients with abdominal CT images were enrolled. Eleven quantitative parameters related to body composition involving skeletal muscle mass, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were measured and calculated using a semi-automated segmentation method. A prediction model was established with significant parameters using a multivariable logistic regression. The receiver operating characteristic (ROC) curve was plotted to evaluate prediction performance. Subgroup analyses were implemented to evaluate the diagnostic efficiency of the prediction model between different disease locations, centers, and CT scanners. The Delong test was used for statistical comparison of ROC curves. VAT density, SAT density, gender, and visceral obesity were significantly statistically different between remission and invalidation groups (all p < 0.05). The accuracy, sensitivity, specificity, and area under the ROC curve (AUC) of the prediction model were 82.61%, 95.45%, 69.89%, and 0.855 (0.792-0.917), respectively. The positive predictive value and negative predictive value were 70.79% and 93.88%, respectively. No significant differences in the AUC of the prediction model were found in different subgroups (all p > 0.05). The predicting model constructed with CT-based body composition parameters is a potential non-invasive approach for short-term prognosis identification and risk stratification. Additionally, VAT density was an independent predictor for escalating therapeutic regimens in UC cohorts. The CT images were used for evaluating body composition and risk stratification of ulcerative colitis patients, and a potential non-invasive prediction model was constructed to identify non-responders with conventional therapy for making therapeutic regimens timely and accurately. • CT-based prediction models help divide patients into invalidation and remission groups in UC. • Results of the subgroup analysis confirmed the stability of the prediction model with a high AUC (all > 0.820). • The visceral adipose tissue density was an independent predictor of bad short-term prognosis in UC.

The association of body composition and outcomes following autologous hematopoietic stem cell transplantation in patients with non-Hodgkin lymphoma.

Recently there has been a growing interest in evaluating body composition as a marker for prognosis in cancer patients. The association of body composition parameters and outcomes has not been deeply investigated in patients with autologous hematopoietic stem cell transplantation (HSCT) recipients with non-Hodgkin lymphoma (NHL). We conducted a retrospective cohort study of 264 NHL patients who received autologous HSCT. PreHSCT abdominal CT scans at the levels of L3 were assessed for body composition measures. We evaluated sarcopenia, myosteatosis, high visceral adipose tissue (VAT) and high visceral adipose tissue density (VATD). Using multivariable Cox proportional regression, we analyzed the association of clinical and transplant-related characteristics with overall survival (OS), relapse-free survival (RFS), and non-relapse mortality (NRM). In a multivariate regression model, patients with higher VATD had worse OS (HR 1.78; 95% confidence intervals CI 1.08-2.95, p = 0.02) and worse NRM (HR 2.31 95% CI 1.08-4.95, p = 0.02) than with lower VATD. Patients with lower levels of VAT also had worse RFS (HR 1.49 95% CI 1.03-2.15, p = 0.03). Sarcopenia and myosteatosis were not associated with outcomes. High pre-transplant VATD was associated with lower OS and higher NRM, and low pre-transplant VAT was associated with worse RFS in patients with NHL undergoing autologous HSCT.

Aerobic Exercise Modulates Visceral Adipose Tissue of Estrogen Deprived Rats in an Experimental Model of Dyslipidemia

Abstract Introduction Menopausal women have an increase deposition of body fat and changes in the lipid profile, being especially susceptible to cardiovascular diseases, and type 2 diabetes. However, physical activity can mitigate this situation. Thus, the aim of the present study is to evaluate the effects of moderate aerobic exercise on visceral adipose tissue (VAT) of female LDL-receptor knockout ovariectomized mice. Methods We used 48 animals, divided into six groups (n = 8/per group): sedentary control (SC), sedentary ovariectomized control (SCO), trained ovariectomized control (TCO), sedentary non-ovariectomized LDL-receptor knockout (KS), sedentary ovariectomized LDL-receptor knockout (KOS), and trained LDL-receptor knockout ovariectomized (KOT). We analyzed the VAT through morphometric and stereological parameters in hematoxylin and eosin stained sections. Additionally, we evaluated biochemical parameters as glucose, triglycerides, and total cholesterol. Finally, immunohistochemical techniques for matrix remodeling, inflammation, apoptosis, and oxidative stress were evaluated. Results We observed that menopause is related to increased visceral adiposity, inflammation, oxidative stress, macrophages activity, serum levels of glucose, triglycerides, and total cholesterol. However, exercise was effective in reducing these parameters, as well as being associated with increased vascularization of VAT and interstitial volume density. Conclusions Moderate exercise is a key factor in mitigating the effects of dyslipidemia in estrogen deprivation. However, further studies are needed to corroborate with our findings.

Discovering the Physio-Pathological Mechanisms of Interaction between Bone Mineral Density, Muscle Mass, and Visceral Adipose Tissue in Female Older Adults through Structural Equation Modeling

This study aims to examine the relation between visceral adipose tissue (VAT), as a proxy for metabolically unhealthy obesity, muscle, as a proxy for muscle quality and sarcopenia, and bone, as a proxy for bone mineral density and osteoporosis. Other variables, such metabolic syndrome, nutritional status, number of diseases, kidney and liver function and inflammation were assessed as direct or indirect effects. This study used structural equation modeling (SEM) in a sample of 713 older women (mean age 82.1 ± 6.3). The results indicate a positive statistically significant association between bone and muscle mass (β = 0.195, <0.001) and nutritional status and muscle mass (β = 0.139, p < 0.001), but negative association between age with muscle mass (β = -0.509, p < 0.001) and nutritional status (estimates: -2.264, p < 0.001). A negative association between VAT and muscle mass was also reported (β = -1.88, p < 0.001). A negative statistically significant association was reported between bone mineral density and functional status (β = -1.081, p < 0.001), and a positive association between functional status and muscle mass (β = 9.000, p < 0.001). In addition, functional status was positively statistically associated with cognitive performance (β = 0.032, p < 0.001). The SEM method demonstrates that the VAT, muscle mass and bone mineral density are associated, but the form of the relation is different in relation to different factors, such as nutritional status, mental and functional status, age, and number of pathologies, having different impacts on metabolic outcomes. SEM is a feasible technique for understanding the complex mechanisms of frailty in the elderly.

Abstract P674: Associations Between Visceral Adipose Tissue Area and Density With Renal Artery Calcification

Introduction: Visceral adipose tissue (VAT) has been associated with higher levels of atherosclerosis. Renal artery calcification (RAC) secondary to atherosclerosis has been found to be associated with hypertension and an increase in all-cause mortality. Hypothesis: There are significant associations between VAT area and density with the presence and extent of renal artery calcification. Methods: Within the Multi-Ethnic Study of Atherosclerosis (MESA) abdominal aortic calcification ancillary study, 1,978 participants from five of the six field centers around the US underwent abdominal CT imaging to measure VAT and RAC. Standardized questionnaires were used to obtain demographic and health history data. Blood samples were assayed for lipid, glucose, creatinine, and adipokine levels. Rate ratio regression was used to estimate prevalence ratios (PRs) for the presence of RAC, while linear regression was used to estimate linear coefficients for the severity of RAC among participants with RAC &gt; 0. Results: Of the 1,978 participants, 1,196 participants had complete visceral adiposity and renal artery measurements. After controlling for sociodemographic variables, CVD risk factors, adipokine levels, and VAT density, VAT area was not associated with RAC presence (PR 1.02, 95% CI 0.89, 1.16, p = 0.80), while greater VAT density was borderline protective for RAC presence (PR 0.89, 95% CI 0.78, 1.02, p = 0.10) when controlling for the same factors and VAT area. 354 participants had RAC &gt; 0 and were included in linear regression analyses assessing RAC severity. After controlling for sociodemographic variables, CVD risk factors, adipokine levels, and VAT density, VAT area was significantly associated with RAC severity (slope 63.32, 95% CI 11.84, 114.81, p = 0.02), while VAT density was not associated with RAC severity (slope 9.78, 95% CI -40.87, 60.44, p = 0.71). Conclusions: In this relatively large, multi-ethnic cohort of adults from five communities in the US, we have demonstrated that higher density VAT may be protective for RAC presence, while greater VAT area is significantly associated with RAC severity. While this is the first study examining the relationship between VAT and RAC, our results are consistent with previous studies describing associations between increased VAT area and decreased VAT density with outcomes including hypertension, hypercholesterolemia, and metabolic syndrome. Category: Subclinical Cardiovascular Disease

Accumulation in Visceral Adipose Tissue Over 6 Years Is Associated With Lower Paraspinal Muscle Density.

Visceral adipose tissue (VAT) has been recognized to be a metabolically active fat depot that may have paracrine effects on surrounding tissues, including muscle. Since many adults accumulate VAT as they age, the effect of changes in VAT on muscle is of interest. We determined the association between 6-year changes in VAT and paraspinal muscle density, an indicator of fatty infiltration. This study included 1145 participants from the Framingham Study third-generation cohort who had both quantitative computed tomography scans of the spine at baseline and 6-year's follow-up, on whom muscle density was measured along with VAT. We implemented multiple regression to determine the association of muscle density at follow-up as primary outcome measure with changes in VAT (follow-up minus baseline divided by 100), adjusting for VAT at baseline, age, sex, height, menopausal status, presence of diabetes, and physical activity. Analyses were performed in men and women separately. After adjustment for covariates, individuals with the greatest accumulation of VAT over 6 years had significantly lower paraspinal density at the follow-up with an estimated 0.302 (95% CI, -0.380 to -0.224) and 0.476 (95% CI: -0.598 to -0.354) lower muscle density (HU) per 100-cm3 increase in VAT (both P values < .001) in men and women, respectively. These results highlight that age-related accumulation of VAT in men and women is associated with lower muscle density. VAT may represent a modifiable risk factor for poor musculoskeletal outcomes with aging.

The relationship between perianal fistula activity and abdominal adipose tissue in Crohn’s disease: an observational study

ObjectiveThe aim of this study was to analyze the relationship between abdominal adipose tissue and perianal fistula activity in patients with Crohn's disease (CD) using cross-sectional imaging.MethodsPatients with perianal fistulizing CD who underwent pelvic magnetic resonance imaging (MRI) and abdominal computed tomography (CT) were retrospectively enrolled. We scored the fistulas in each patient's MRI images based on Van Assche's classification. The area and density of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) (at the third, fourth, and fifth lumbar (L3, L4, and L5) levels were measured by averaging five slices of measurements at each vertebral level in CT images, and areas were further standardized by the lumbar height2 (heightL1-5). The VAT/SAT ratio (VSR) and VAT/Total adipose tissue (VA/TA) index were calculated. Based on MRI scores, patients were divided into two groups with low and high activity, and their clinical, MRI features, and CT parameters were compared. We evaluated patients with follow-up MRI and compared the differences in clinical and radiological indicators among patients with different outcomes.ResultsOverall, 136 patients were included, 77 in the low-activity group and 59 in the high-activity group. Patients in the high activity group had lower subcutaneous adipose index (all levels, p < 0.05) and visceral adipose index (L3 level, p < 0.01), but higher SAT and VAT density (all levels, p < 0.01), VSR (L5 level, p = 0.07) and VA/TA index (L5 level, p < 0.05).ConclusionThere were differences in adipose tissue composition among CD patients with different active perianal fistulas.

Associations of radiological features of adipose tissues with postoperative complications and overall survival of gastric cancer patients.

To evaluate the associations of the radiological features of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) with the postoperative complications and overall survival (OS) of patients undergoing laparoscopic radical gastrectomy for gastric cancer. One hundred forty-two patients underwent laparoscopic radical gastrectomy for gastric cancer from February 2013 to May 2016. The radiological features of SAT and VAT were studied by preoperative computed tomography, and the relationships between the parameters of adipose tissues and the intraoperative and postoperative conditions and OS rate of patients were evaluated. A positive linear correlation was found between VAT area and operation duration, and a negative linear correlation was found between VAT density and intraoperative blood loss (p < 0.05 in both). VAT area was an independent risk factor for postoperative complications. VAT area and VAT density were independent risk factors for OS in gastric cancer. A high VAT area was an independent risk factor for postoperative complications of gastric cancer, whereas a low VAT area and high VAT density were independent risk factors for poor prognosis in terms of OS in gastric cancer. • A large visceral adipose tissue (VAT) area is an unfavourable factor affecting the outcomes of radical gastrectomy for gastric cancer. • Low VAT density may be more likely to cause intraoperative bleeding. • VAT area and VAT density were independent risk factors for the OS of patients with gastric cancer.

Visceral adipose tissue quality was associated with nonalcoholic fatty liver disease, independent of its quantity

Background and aimsNonalcoholic fatty liver disease (NAFLD) is a serious liver disease. Recent studies have shown that both visceral adipose tissue (VAT) quantity and density (as an indirect measure of quality) are associated with metabolic profiles. Therefore, we investigated the association between VAT quantity and quality, and the prevalence and incidence of NAFLD. Methods and resultsIn this cross-sectional, retrospective cohort study, the prevalence and incidence of NAFLD were analyzed in 627 and 360 middle-aged subjects, respectively. VAT was evaluated using an unenhanced computed tomography scan, while NAFLD was evaluated using ultrasonography. The VAT area was normalized to the square value of the subjects’ height in meters, the visceral fat area (VFA) index. The VAT density was described as the visceral fat density (VFD). The VFA index and VFD had an interaction effect on the prevalence of NAFLD (P = 0.0059). The VFA index (adjusted odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01–1.07; P = 0.0145, per 1.0 cm2/m2) and the VFD (OR, 0.90; 95% CI, 0.84–0.96; P = 0.0026, per 1.0 Hounsfield unit [HU]) were independently associated with the prevalence of NAFLD. In our cohort, 36 subjects developed NAFLD. The VFD (adjusted hazards ratio [HR], 0.84; 95% CI, 0.77–0.91; P < 0.0001, per 1.0 HU) was independently associated with the incidence of NAFLD, whereas the VFA index was not. ConclusionBoth the VFA index and VFD were independently associated with NAFLD prevalence. The VFD might be more related to the incidence of NAFLD than the VFA index.

Potential role of epicardial adipose tissue as a biomarker of anthracycline cardiotoxicity

BackgroundWe investigated the radiodensity of epicardial (EAT), subcutaneous (SAT), and visceral adipose tissue (VAT) before and after treatment with anthracyclines in a population of breast cancer (BC) patients, and in controls not treated with anthracyclines, to detect a potential role of EAT density as a biomarker of changes related to chemotherapy cardiotoxicity.MethodsWe reviewed BC patients treated with anthracyclines who underwent CT before (CT-t0) and after (CT-t1) chemotherapy, and age- and sex-matched controls who underwent two CT examinations at comparable intervals. On non-contrast scans, EAT was segmented contouring the pericardium and thresholding between -190 and -30 Hounsfield units (HU), and SAT and VAT were segmented with two 15-mm diameter regions of interest thresholded between -195 and -45 HU.ResultsThirty-two female patients and 32 controls were included. There were no differences in age (p = 0.439) and follow-up duration (p = 0.162) between patients and controls. Between CT-t0 and CT-t1, EAT density decreased in BC patients (-66 HU, interquartile range [IQR] -71 to -63 HU, to -71 HU, IQR -75 to -66 HU, p = 0.003), while it did not vary in controls (p = 0.955). SAT density increased from CT-t0 to CT-t1 in BC patients (-107 HU, IQR -111 to -105 HU, to -105 HU, IQR -110 to -100 HU, p = 0.014), whereas it did not change in controls (p = 0.477). VAT density did not vary in either BC patients (p = 0.911) or controls (p = 0.627).ConclusionsEAT density appears to be influenced by anthracycline treatment for BC, well known for its cardiotoxicity, shifting towards lower values indicative of a less active metabolism.

Associations of Visceral Adipose Tissue and Skeletal Muscle Density With Incident Stroke, Myocardial Infarction, and All‐Cause Mortality in Community‐Dwelling 70‐Year‐Old Individuals: A Prospective Cohort Study

BackgroundAging leads to increased visceral adipose tissue (VAT) and reduced skeletal muscle density. To which extent these are associated with the risk of stroke, myocardial infarction (MI), and all‐cause mortality in older adults is unknown.Methods and ResultsA total of 3294 70‐year‐old individuals (49.6% women) underwent a health examination in Umeå, Sweden, during 2012 to 2018. VAT and muscle density were measured using dual‐energy x‐ray absorptiometry and peripheral quantitative computed tomography. Cases of stroke, MI, and all‐cause mortality were collected through national registers. Cox regressions were used to calculate hazard ratios (HRs) and 95% CIs per SD greater VAT and per SD lower muscle density. During a mean follow‐up of 3.6 years, there were 108 cases of stroke or MI, and 97 deaths. Greater VAT (adjusted HR [aHR], 1.56; 95% CI, 1.09–2.22), but not lower muscle density (aHR, 1.14; 95% CI, 0.97–1.34), was associated with increased risk of stroke or MI. Neither VAT (aHR, 0.95; 95% CI, 0.65–1.41) nor muscle density (aHR, 1.11; 95% CI, 0.92–1.34) was associated with all‐cause mortality. The association of VAT with stroke or MI was only significant in men (aHR, 1.86; 95% CI, 1.19–2.91) but not women (aHR, 0.60; 95% CI, 0.25–1.42) (P interaction=0.038).ConclusionsWith the limitation of being an observational study, these findings suggest that VAT is an important obesity‐related predictor of cardiovascular risk in 70‐year‐old men, and by implication, that decreasing VAT may potentially reduce their risk of cardiovascular disease.

Clinical Outcomes of Subcutaneous and Visceral Adipose Tissue Characteristics Assessed in Patients Underwent Transcatheter Aortic Valve Replacement

BackgroundAdipose tissue (AT) characteristics are considered to be a marker for predicting clinical outcomes. This study aimed to investigate the prognostic value of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) computed tomography (CT) assessment in patients who underwent transcatheter aortic valve replacement (TAVR). MethodsWe used the Japanese multicentre registry data of 1372 patients (age: 84.5 ± 5.0 years, women: 70.6%) who underwent TAVR. The SAT and VAT were assessed according to the preprocedural CT area and density. Baseline characteristics and clinical outcomes were compared based on the differences in AT characteristics. The independent associations with all-cause mortality after TAVR were evaluated according to the CT area and density of AT. ResultsLow-volume area of SAT and VAT was associated with worse clinical outcomes compared with high-volume area of SAT and VAT in patients who underwent TAVR (log-rank test P = 0.016 and P = 0.014). High CT density of SAT and VAT was associated with increasing mortality in comparison with low CT density of SAT and VAT (log-rank test P < 0.001 and P = 0.007). The Cox regression multivariate analysis demonstrated the independent association of increased all-cause mortality in the high SAT and VAT density (hazard ratio [HR]: 1.41, 95% confidence interval [CI]: 1.06-1.88, P = 0.019, and HR: 1.34, 95% CI: 1.03-1.76, P = 0.031, respectively), but not in the low SAT and VAT area (HR: 0.85, 95% CI: 0.74-1.29, P = 0.85, and HR: 0.78, 95% CI: 0.60-1.03, P = 0.085, respectively). ConclusionsCT-derived AT characteristics, particularly the qualitative assessments, were useful for predicting the prognosis in patients after TAVR.

Prognostic significance of adipose tissue distribution and metabolic activity in PET-CT images of patients with metastatic colorectal cancer.

e16038 Background: The metabolic activity in visceral and subcutaneous adipose tissue have different metabolic risk profiles for colorectal cancer. The aim of this study was to investigate the prognostic significance of adipose tıssue distribution and metabolic activity in PET-CT and predict the overall survival in patients with metastatic colorectal cancer (mCRC). Methods: A total of 83 patients diagnosed with mCRC between 2010-2018 were evaluated retrospectively. Pretreatment PET-CT images were reevaluated to determine adipose tissue distribution and metabolic activity. Volume and metabolic activity of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) on FDG PET-CT images were measured. SAT volume, SAT density (HU), SAT ratio (SAT volume/ SAT density) were calculated. The maximum standardized uptake (SUV) of tumor tissue was measured. The relationship between adipose tissue and overall survival was examined. Results: 53 patients died during follow-up and the median overall survival was 33.76 months (95% CI: 28.185-39.349). According to univariate analysis results, tumor location (HR:2.5; 95% CI 1.27-4.98, p = 0.008) and SAT ratio (HR:0.5; 95% CI 0.34-1.00, p = 0.053) were the significant parameters for the OAS. VAT volume (p = 0.774), VAT density (p = 0.899), VAT suv mean (p = 0.831) and SAT volume (p = 0.423), SAT density (p = 0.353), SAT suv mean (p = 0.575), tumor suv max (p = 0.589) values were not correlated with OAS. In the multivariate analysis, SAT ratio (p = 0.011) and tumor location (p = 0.001) were correlated significantly with OAS. The median OAS for the patients with SAT ratio value &lt; -1.1 and -1.1 were 38.5 (95% CI 31.54-45.58) and 24.5 (95% CI 14.13-34.93) months, respectively (p = 0.05). Conclusions: This study showed that SAT ratio was an independent prognostic factor for OAS in patients with mCRC. We need prospective studies for to observe the relationship between adipose tissue distribution and response to treatment in mCRC.

Associations between subcutaneous fat density and systemic inflammation differ by HIV serostatus and are independent of fat quantity.

Adipose tissue (AT) density measurement may provide information about AT quality among people living with HIV. We assessed AT density and evaluated relationships between AT density and immunometabolic biomarker concentrations in men with HIV. Cross-sectional analysis of men enrolled in the Multicenter AIDS Cohort Study. Abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density (Hounsfield units, HU; less negative = more dense) were quantified from computed tomography (CT) scans. Multivariate linear regression models described relationships between abdominal AT density and circulating biomarker concentrations. HIV+ men had denser SAT (-95 vs -98 HU HIV-, P < 0.001), whereas VAT density was equivalent by HIV serostatus men (382 HIV-, 462 HIV+). Historical thymidine analog nucleoside reverse transcriptase inhibitor (tNRTI) use was associated with denser SAT but not VAT. In adjusted models, a 1 s.d. greater SAT or VAT density was associated with higher levels of adiponectin, leptin, HOMA-IR and triglyceride:HDL cholesterol ratio and lower hs-CRP concentrations in HIV- men. Conversely, in HIV+ men, each s.d. greater SAT density was not associated with metabolic parameter improvements and was significantly (P < 0.05) associated with higher systemic inflammation. Trends toward higher inflammatory biomarker concentrations per 1 s.d. greater VAT density were also observed among HIV+ men. Among men living with HIV, greater SAT density was associated with greater systemic inflammation independent of SAT area. AT density measurement provides additional insight into AT density beyond measurement of AT quantity alone, and may have implications for metabolic disease risk.

Prognostic value of adipose tissue and muscle mass in advanced colorectal cancer: a post hoc analysis of two non-randomized phase II trials

BackgroundThe prognostic value of body composition in cancer patients has been widely studied during the last decade. The main finding of these studies is that sarcopenia, or skeletal muscle depletion, assessed by CT imaging correlates with a reduced overall survival (OS). By contrast, the prognostic value of fat mass remains ill-defined. This study aims to analyze the influence of body composition including both muscle mass and adipose tissue on OS in a homogeneous population of advanced colorectal cancer (CRC) patients.MethodsAmong 235 patients with chemorefractory advanced CRC included in the SoMore and RegARd-C trials, body composition was assessed in 217 patients on baseline CT images. The relationship between body composition (sarcopenia, muscle density, subcutaneous and visceral fat index and density), body mass index (BMI) and OS were evaluated.ResultsPatients with a higher BMI had a better OS (≥30 versus < 30, HR: 0.50; 0.33–0.76). Those with low muscle index and muscle density had an increased mortality (HR: 2.06; 1.45–2.93 and HR: 1.54; 1.09–2.18, respectively). Likewise, low subcutaneous and visceral fat index were associated with an increased risk of dying (HR: 1.63; 1.23–2.17 and 1.48; 1.09–2.02 respectively), as were a high subcutaneous and visceral adipose tissue density (HR: 1.93; 1.44–2.57 and 2.40; 1.79–3.20 respectively). In multivariate analysis, a high visceral fat density was the main predictor of poor survival.ConclusionsOur results confirm the protective role of obesity in CRC patients at an advanced stage, as well as the negative prognostic impact of muscle depletion on survival. More importantly, our data show for the first time that visceral adipose tissue density is an important prognostic factor in metastatic CRC.Trial registrationNCT01290926, 07/02/2011 and NCT01929616, 28/08/2013.

Micro Computed Tomography Detects Changes in Liver Density in Control and in Prediabetes Rats

Fatty liver disease is an early event in the development of insulin resistance that predicts the presence and progression of the metabolic syndrome. In humans, fatty liver diagnosis is usually performed by imaging techniques based on ultrasound, computed tomography and magnetic resonance. Rodent models are often used in metabolic research allowing access to tissue biopsies however, studies describing ex vivo computed tomography of biological samples are scarce. X-ray Micro Computed Tomography (Micro-CT) is an imaging technique that reveals the internal structure of materials in great detail, also allowing a quantitative analysis of properties such as density measured as arbitrary Hounsfield Units (HU). Herein, we tested the hypothesis that Micro-CT detects changes in liver tomographic density induced by metabolic diseases and its reversal upon therapeutic surgical intervention. Two groups of male Wistar rats were used: a group submitted to a hypercaloric diet for 14 weeks to induce prediabetes and the control group submitted to a standard diet). The animals were randomly submitted to a surgical treatment and maintained on their respective diets after the procedure for 11 more weeks. Liver and adipose tissues samples were excised and samples were scanned using a compact X-ray micro-CT scanner. The projection images obtained were analyzed and reconstructed and values of HU density were calculated after calibration for all samples. Results showed that liver density was lower in prediabetes rats (74.8±5.87 HU) than in control animals (97.2±6.3 HU), p<0.05. Liver density was not affected by surgical treatment in control animals however, in prediabetes animals, the surgical therapy restored liver density to control values. Visceral fat density was significantly lower than hepatic density, as expected and was affected, neither by the disease condition nor by the surgical treatment. We concluded that micro-CT detects metabolic disease-induced changes in liver density, but not in visceral adipose tissue density in biopsy samples ex vivo. Changes in hepatic density, assessed by micro-CT, correlate with disease state and with therapeutic interventions.

Impact of visceral fat volume and fat density on biochemical outcome after radical prostatectomy and postoperative radiotherapy.

To assess the predictive value of visceral adipose tissue (VAT) and adipose tissue density after both radical prostatectomy (RP) and adjuvant or salvage external beam radiotherapy (EBRT). We randomly selected 201 patients treated with RP and EBRT between 2005 and 2015. Visceral adipose tissue and subcutaneous adipose tissue volumes were manually contoured and corresponding tissue densities in Hounsfield units (HU) calculated. Time to biochemical recurrence (BCR) was calculated using the Kaplan-Meier method and comparisons were made using the log-rank test. Cox regression analysis was done for multivariate analysis. Median time to BCR or last follow-up was 32 months. In univariate analysis for BCR, VAT volume and fat density were both associated with a better outcome (p=0.025 and p=0.024, respectively) as well as seminal vesicle involvement (p=0.024). Body mass index (BMI) was not predictive of BCR (p=0.32). In a multivariate model including seminal vesicle involvement, both a VAT volume above the median (HR2.5, 95%CI 1.1-5.7, p=0.03) and a VAT density (HR 2.4, 95%CI 1.1-5.1, p=0.028) above the median remained predictive for a better biochemical outcome. Adjusting for BMI did not significantly change the model. In both univariate and multivariate analysis, patients with both a larger VAT volume and density had a better biochemical outcome. The interaction between prostate cancer aggressiveness and visceral fat volume and density needs to be further evaluated to provide a better understanding of this disease.

Associations of BMI and adipose tissue area and density with incident mobility limitation and poor performance in older adults

Obesity is a risk factor for disability, but risk of specific adipose depots is not completely understood. We investigated associations between mobility limitation, performance, and the following adipose measures: body mass index (BMI) and areas and densities of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) in older adults. This was a prospective population-based study of men (n = 1459) and women (n = 1552) initially aged 70-79 y and free from mobility limitation. BMI was determined from measured height and weight. Adipose tissue area and density in Hounsfield units were measured in the thigh and abdomen by using computed tomography. Mobility limitation was defined as 2 consecutive reports of difficulty walking one-quarter mile or climbing 10 steps during semiannual assessments over 13 y. Poor performance was defined as a gait speed <1 m/s after 9 y of follow-up (n = 1542). In models adjusted for disability risk factors, BMI, and areas of VAT, abdominal SAT, and IMAT were positively associated with mobility limitation in men and women. In women, thigh SAT area was positively associated with mobility limitation risk, whereas VAT density was inversely associated. Associations were similar for poor performance. BMI and thigh IMAT area (independent of BMI) were particularly strong indicators of incident mobility limitation and poor performance. For example, in women, the HR (95% CI) and OR (95% CI) associated with an SD increment in BMI for mobility limitation and poor performance were 1.31 (1.21, 1.42) and 1.41 (1.13, 1.76), respectively. In men, the HR (95% CI) and OR (95% CI) associated with an SD increment in thigh IMAT for mobility limitation and poor performance were 1.37 (1.27, 1.47) and 1.54 (1.18, 2.02), respectively. Even into old age, higher BMI is associated with mobility limitation and poor performance. The amount of adipose tissue in abdominal and thigh depots may also convey risk beyond BMI.

Adipose Tissue Density, a Novel Biomarker Predicting Mortality Risk in Older Adults

Knowledge of adipose composition in relation to mortality may help delineate inconsistent relationships between obesity and mortality in old age. We evaluated relationships between abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density, mortality, biomarkers, and characteristics. VAT and SAT density were determined from computed tomography scans in persons aged 65 and older, Health ABC (n = 2,735) and AGES-Reykjavik (n = 5,131), and 24 nonhuman primates (NHPs). Associations between adipose density and mortality (4-13 years follow-up) were assessed with Cox proportional hazards models. In NHPs, adipose density was related to serum markers and tissue characteristics. Higher density adipose tissue was associated with mortality in both studies with adjustment for risk factors including adipose area, total fat, and body mass index. In women, hazard ratio and 95% CI for the densest quintile (Q5) versus least dense (Q1) for VAT density were 1.95 (1.36-2.80; Health ABC) and 1.88 (1.31-2.69; AGES-Reykjavik) and for SAT density, 1.76 (1.35-2.28; Health ABC) and 1.56 (1.15-2.11; AGES-Reykjavik). In men, VAT density was associated with mortality in Health ABC, 1.52 (1.12-2.08), whereas SAT density was associated with mortality in both Health ABC, 1.58 (1.21-2.07), and AGES-Reykjavik, 1.43 (1.07-1.91). Higher density adipose tissue was associated with smaller adipocytes in NHPs. There were no consistent associations with inflammation in any group. Higher density adipose tissue was associated with lower serum leptin in Health ABC and NHPs, lower leptin mRNA expression in NHPs, and higher serum adiponectin in Health ABC and NHPs. VAT and SAT density provide a unique marker of mortality risk that does not appear to be inflammation related.