Prognostic Significance of Adipose Tissue Distribution and Metabolic Activity in PET / CT in Patients with Metastatic Colorectal Cancer

Purpose: In this study, we aimed to evaluate prognostic significance of adipose tissue distribution and metabolic activity in PET/CT to predict survival in patients with metastatic colorectal cancer (mCRC).Methods: The volume, density (HU) and FDG uptake (standardized uptake value-[SUV]) of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and maximum FDG uptake of the tumor tissue were measured. Subcutaneous adipose tissue of volume-to-density ratio (SAT ratio) was calculated.Results: The median OS for the patients with SAT ratio value <-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). During follow up, 69 patients experienced disease progression. The median progression-free survival (PFS) was 11.03 months (95% CI: 9.11-12.95). Median PFS for patients with tumor SUV max value <11.5 and ≥11.5 were 9.2 (95% CI 7.25-11.27) and 12.6 (95% CI 10.02-15.27) months, respectively (p=0.14). 48 patients received bevacizumab therapy. VAT SUV mean (HR: 0.09; 95% CI 0.01-0.52, p=0.008) was significantly associated with PFS in patients receiving bevacizumab. SAT ratio was the significant parameter for the OS (HR: 0.58; 95% CI 0.33-1.01, p=0.05) and PFS (HR: 1.99; 95% CI 1.02-3.91, p=0.043).Conclusions: SAT ratio was an independent prognostic factor for survival in patients with mCRC. Higher SAT volume is correlated with longer survival in mCRC patients

Adipocyte heterogeneity underlying adipose tissue functions

Adipose tissue distribution in the human body is highly heterogeneous, and the relative mass of different depots is differentially associated with metabolic disease risk. Distinct functions of adipose depots are mediated by their content of specialized adipocyte subtypes, best exemplified by thermogenic adipocytes found in specific depots. Single-cell transcriptome profiling has been used to define the cellular composition of many tissues and organs, but the large size, buoyancy and fragility of adipocytes have rendered it challenging to apply these techniques to understand the full complexity of adipocyte subtypes in different depots. Discussed here are strategies that have been recently developed for investigating adipocyte heterogeneity, including single-cell RNASeq profiling of the stromal vascular fraction to identify diverse adipocyte progenitors, and single-nuclei profiling to characterize mature adipocytes. These efforts are yielding a more complete characterization of adipocyte subtypes in different depots, insights into the mechanisms of their development, and perturbations associated with different physiological states such as obesity. A better understanding of the adipocyte subtypes that compose different depots will help explain metabolic disease phenotypes associated with adipose tissue distribution and suggest new strategies for improving metabolic health.

Prognostic Value of Pretreatment Overweight/Obesity and Adipose Tissue Distribution in Resectable Gastric Cancer: A Retrospective Cohort Study

BackgroundThis is a study aimed at exploring the relationship between pretreatment overweight/obesity, adipose tissue distribution, and long-term prognosis of gastric cancer.MethodsA total of 607 gastric cancer patients were involved in the retrospective cohort study. Overweight/obese patients were defined as body mass index (BMI) greater than 25 kg/m2, and adipose tissue distribution parameters, including visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and VAT/SAT ratio were measured at the level of the third lumbar vertebra using computerized tomography images within 15 days before the surgery. Multiple Cox regression models were applied to evaluate the association between overweight/obesity and disease-specific survival (DSS) of gastric cancer, and covariates including age, gender, T stage, N stage, and chemotherapy were adjusted. Furthermore, multiple Cox regression models were performed to evaluate the association between adipose tissue distribution parameters and DSS of gastric cancer; except for covariates mentioned above, overweight/obesity was adjusted additionally.ResultsOverweight/obesity was a predictive factor (HR = 0.61, 95% CI: 0.37–0.99) for the prognosis of gastric cancer. After additionally adjusting for overweight/obesity, high SAT percentage was an independent protective factor (HR = 0.59, 95% CI: 0.36–0.96), while high VAT percentage (HR = 1.68, 95% CI: 1.06–2.68) and high VAT/SAT ratio (HR = 1.99, 95% CI: 1.19–3.34) were independent risk factors for DSS of gastric cancer. Compared with other patients (overweight/obesity with low VAT/SAT ratio group, non-overweight/obesity or high VAT/SAT ratio group), patients in the non-overweight/obesity with high VAT/SAT ratio group had a worse prognosis (HR = 1.89, 95% CI: 1.28–2.77).ConclusionThese results suggest that overweight/obesity is a predictive factor for the prognosis of gastric cancer. The VAT/SAT ratio could be used as a promising prognostic factor for gastric cancer. Therefore, in preoperative evaluation of gastric cancer patients, attention should be paid not only to BMI but also to adipose tissue distribution.

Prognostic Value of Pretreatment Overweight/obesity and Adipose Tissue Distribution in Resectable Gastric Cancer: A Retrospective Cohort Study

Background: This is a study aimed at exploring the relationship between pretreatment overweight/obesity, adipose tissue distribution, and long-term prognosis of gastric cancer.Methods: A total of 607 gastric cancer patients were involved in the retrospective cohort study. Overweight/obese patients was defined as body mass index (BMI) greater than 25 kg/m2 and adipose tissue distribution parameters, including visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and VAT/SAT ratio were measured at the level of the third lumbar vertebra using computerized tomography images within 15 days before the surgery. Multiple Cox regression models were applied to evaluate the association between overweight/obesity and disease-specific survival (DSS) of gastric cancer and covariates including age, gender, T stage, N stage, and chemotherapy were adjusted. Furthermore, multiple Cox regression models were performed to evaluate the association between adipose tissue distribution parameters and DSS of gastric cancer, expect for covariates mentioned above, overweight/obesity was adjusted additionally.Results: Overweight/obesity was a protective factor (HR = 0.61, 95% CI: 0.37-0.99) for the prognosis of gastric cancer. While high SAT percentage was independently related to a good prognosis, high VAT percentage and high VAT/SAT ratio were independently related to poor prognosis of resectable gastric cancer.Conclusion: These results suggest that overweight/obesity is a protective factor for the prognosis of gastric cancer. The VAT/SAT ratio could be used as a promising prognostic factor for gastric cancer. Therefore, in preoperative evaluation of gastric cancer patients, attention should be paid not only to BMI but also to adipose tissue distribution.

CT-based determination of excessive visceral adipose tissue is associated with an impaired survival in critically ill patients

Objective Obesity is a negative prognostic factor for various clinical conditions. In this observational cohort study, we evaluated a CT-based assessment of the adipose tissue distribution as a potential non-invasive prognostic parameter in critical illness. Methods Routine CT-scans upon admission to the intensive care unit (ICU) were used to analyze the visceral and subcutaneous adipose tissue areas at the 3rd lumbar vertebra in 155 patients. Results were correlated with various prognostic markers and both short-term- and overall survival. Multiple statistical tools were used for data analysis. Results We observed a significantly larger visceral adipose tissue area in septic patients compared to non-sepsis patients. Interestingly, patients requiring mechanical ventilation had a significantly higher amount of visceral adipose tissue correlating with the duration of mechanical ventilation. Moreover, both visceral and subcutaneous adipose tissue area significantly correlated with several laboratory markers. While neither the visceral nor the subcutaneous adipose tissue area was predictive for short-term ICU survival, patients with a visceral adipose tissue area above the optimal cut-off (241.4 cm2) had a significantly impaired overall survival compared to patients with a lower visceral adipose tissue area. Conclusions Our study supports a prognostic role of the individual adipose tissue distribution in critically ill patients. However, additional investigations need to confirm our suggestion that routine CT-based assessment of adipose tissue distribution can be used to yield further information on the patients’ clinical course. Moreover, future studies should address functional and metabolic analysis of different adipose tissue compartments in critical illness.

Adipose tissue distribution from body MRI is associated with cross-sectional and longitudinal brain age in adults

There is an intimate body-brain connection in ageing, and obesity is a key risk factor for poor cardiometabolic health and neurodegenerative conditions. Although research has demonstrated deleterious effects of obesity on brain structure and function, the majority of studies have used conventional measures such as waist-to-hip ratio, waist circumference, and body mass index. While sensitive to gross features of body composition, such global anthropomorphic features fail to describe regional differences in body fat distribution and composition, and to determine visceral adiposity, which is related to a range of metabolic conditions. In this mixed cross-sectional and longitudinal design (interval mean and standard deviation = 19.7 ± 0.5 months), including 790 healthy individuals (mean (range) age = 46.7 (18-94) years, 53% women), we investigated cross-sectional body magnetic resonance imaging (MRI, n = 286) measures of adipose tissue distribution in relation to longitudinal brain structure using MRI-based morphometry and diffusion tensor imaging (DTI). We estimated tissue-specific brain age at two time points and performed Bayesian multilevel modelling to investigate the associations between adipose measures at follow-up and brain age gap (BAG) at baseline and follow-up. We also tested for interactions between BAG and both time and age on each adipose measure. The results showed credible associations between T1-based BAG and liver fat, muscle fat infiltration (MFI), and weight-to-muscle ratio (WMR), indicating older-appearing brains in people with higher measures of adipose tissue. Longitudinal evidence supported interaction effects between time and MFI and WMR on T1-based BAG, indicating accelerated ageing over the course of the study period in people with higher measures of adipose tissue. The results show that specific measures of fat distribution are associated with brain ageing and that different compartments of adipose tissue may be differentially linked with increased brain ageing, with potential to identify key processes involved in age-related transdiagnostic disease processes.

Subcutaneous adipose tissue distribution and serum lipid/lipoprotein in unmedicated postmenopausal women: A B-mode ultrasound study

Background:It has been observed that gluteal-femoral adipose tissue has a protective effect against risk factors for cardiovascular disease but has not yet been concluded how different evaluation methods of fat distribution affect the results.Methods:To test the hypothesis that B-mode ultrasound-measured subcutaneous adipose tissue distribution is associated with cardiovascular risk factors, 326 Japanese unmedicated postmenopausal women aged 50-70 years were analyzed. Subcutaneous adipose tissue thickness at 6 sites (anterior and posterior aspects of trunk, upper-arm, and thigh) and serum total (TC) and high-density lipoprotein cholesterol (HDLC) was measured, and a ratio of HDLC to TC (HDLC/TC) was calculated. We used Bayesian linear regression with 4 separate models with each model predicting HDLC/TC.Results:Our first model provided evidence for an inverse correlation (r = –0.23) between ultrasound measured body fat (6 site measurement) and HDLC/TC. The second model noted evidence for an inverse correlation between trunk fat and HDLC/TC and found evidence for the null with respect to the correlation between thigh fat and HDLC/TC. Therefore, we added thigh fat to the null model to produce Distribution Model 2. Within this model, we noted an inverse correlation (r = –0.353) between trunk fat and HDLC/TC. Our last model determined that within the trunk fatness, the abdominal area (anterior trunk) was a larger predictor than the subscapular site (posterior trunk).Conclusion:These results support the evidence that ultrasound-measured abdominal subcutaneous adipose tissue thickness is a non-invasive predictor for monitoring the risk for dyslipidemia in postmenopausal women.