Abdominal fat radiodensity, quantity and cardiometabolic risk: The Multi-Ethnic Study of Atherosclerosis

AI-based abdominal CT measurements of orthotopic and ectopic fat predict mortality and cardiometabolic disease risk in adults

OBJECTIVES

To evaluate the utility of CT-based abdominal fat measures for predicting the risk of death and cardiometabolic disease in an asymptomatic adult screening population.

METHODS

Fully automated AI tools quantifying abdominal adipose tissue (L3 level visceral [VAT] and subcutaneous [SAT] fat area, visceral-to-subcutaneous fat ratio [VSR], VAT attenuation), muscle attenuation (L3 level), and liver attenuation were applied to non-contrast CT scans in asymptomatic adults undergoing CT colonography (CTC). Longitudinal follow-up documented subsequent deaths, cardiovascular events, and diabetes. ROC and time-to-event analyses were performed to generate AUCs and hazard ratios (HR) binned by octile.

RESULTS

A total of 9223 adults (mean age, 57 years; 4071:5152 M:F) underwent screening CTC from April 2004 to December 2016. 549 patients died on follow-up (median, nine years). Fat measures outperformed BMI for predicting mortality risk-5-year AUCs for muscle attenuation, VSR, and BMI were 0.721, 0.661, and 0.499, respectively. Higher visceral, muscle, and liver fat were associated with increased mortality risk-VSR > 1.53, HR = 3.1; muscle attenuation < 15 HU, HR = 5.4; liver attenuation < 45 HU, HR = 2.3. Higher VAT area and VSR were associated with increased cardiovascular event and diabetes risk-VSR > 1.59, HR = 2.6 for cardiovascular event; VAT area > 291 cm2, HR = 6.3 for diabetes (p < 0.001). A U-shaped association was observed for SAT with a higher risk of death for very low and very high SAT.

CONCLUSION

Fully automated CT-based measures of abdominal fat are predictive of mortality and cardiometabolic disease risk in asymptomatic adults and uncover trends that are not reflected in anthropomorphic measures.

CLINICAL RELEVANCE STATEMENT

Fully automated CT-based measures of abdominal fat soundly outperform anthropometric measures for mortality and cardiometabolic risk prediction in asymptomatic patients.

KEY POINTS

Abdominal fat depots associated with metabolic dysregulation and cardiovascular disease can be derived from abdominal CT. Fully automated AI body composition tools can measure factors associated with increased mortality and cardiometabolic risk. CT-based abdominal fat measures uncover trends in mortality and cardiometabolic risk not captured by BMI in asymptomatic outpatients.

A novel body composition risk score (B-Score) and overall survival among patients with nonmetastatic breast cancer

BACKGROUND & AIMS

Measurements (amount, distribution, and radiodensity) of muscle and adipose tissue were reported to be individually associated with overall survival in patients with breast cancer. However, they were not typically combined to develop an overall risk score, which can identify patients at high risk of death and prioritize patients in need of dietary and lifestyle interventions. Thus, we aimed to develop a novel composite body composition risk score (B-Score).

METHODS

We included 3105 patients with stage II or III breast cancer at Kaiser Permanente Northern California and Dana Farber Cancer Institute. From CT scans at diagnosis, we assessed areas and radiodensity of muscle and adipose tissue at the third lumber vertebrae. We considered skeletal muscle index (SMI), subcutaneous adipose tissue index (SATI) and SAT radiodensity as they were independent prognostic factors for overall survival. Each measurement was dichotomized using optimal stratification, with low SMI (<40.1 cm2/m2), high SATI (≥75.7 cm2/m2), and high SAT radiodensity (≥-97.2HU) considered risk factors. We calculated B-Score as the sum of these factors and estimated its association with overall survival using Cox proportional hazards regression with adjustment for clinicopathologic factors.

RESULTS

Mean (standard deviation) age was 53.9 (11.8) years, 70.3% were Non-Hispanic White, and 60.5% were stage II. Most patients (60.6%) had only one body composition risk factor (B-Score = 1). Compared to those with no risk factors (B-Score = 0), the risk of death increased with more body composition risk factors: the adjusted hazard ratios were 1.10 (95% CI: 0.85, 1.42), 1.47 (95% CI: 1.12, 1.92), and 2.11 (95% CI: 1.26, 3.53) for B-Scores of 1, 2, and 3, respectively (Ptrend < 0.001).

CONCLUSIONS

More unfavorable body composition characteristics were associated with increased risks of overall mortality in a dose-response manner. Considering body composition measurements together as a composite score (B-Score) may improve risk stratification and inform dietary and lifestyle interventions following breast cancer diagnosis.

Pre-operative visceral adipose tissue radiodensity is a potentially novel prognostic biomarker for early endoscopic post-operative recurrence in Crohn's disease

BACKGROUND

Evidence suggests inflammatory mesenteric fat is involved in post-operative recurrence (POR) of Crohn's disease (CD). However, its prognostic value is uncertain, in part, due to difficulties studying it non-invasively.

AIM

To evaluate the prognostic value of pre-operative radiographic mesenteric parameters for early endoscopic POR (ePOR).

METHODS

We conducted a retrospective cohort study of CD subjects ≥ 12 years who underwent ileocecal or small bowel resection between 1/1/2007 to 12/31/2021 with computerized tomography abdomen/pelvis ≤ 6 months pre-operatively and underwent ileocolonoscopy ≤ 15 months post-operatively. Visceral adipose tissue (VAT) volume (cm3), ratio of VAT:subcutaneous adipose tissue (SAT) volume, VAT radiodensity, and ratio of VAT:SAT radiodensity were generated semiautomatically. Mesenteric lymphadenopathy (LAD, largest lymph node > 10 mm) and severe vasa recta (VR) engorgement (diameter of the VR supplying diseased bowel ≥ 2 × VR supplying healthy bowel) were derived manually. The primary outcome was early ePOR (Rutgeert's score ≥ i2 on first endoscopy ≤ 15 months post-operatively) and the secondary outcome was ePOR severity (Rutgeert's score i0-4). Regression analyses were performed adjusting for demographic and disease-related characteristics to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI).

RESULTS

Of the 139 subjects included, 45% of subjects developed early ePOR (n = 63). VAT radiodensity (aOR 0.59, 95%CI: 0.38-0.90) and VAT:SAT radiodensity (aOR 8.54, 95%CI: 1.48-49.28) were associated with early ePOR, whereas, VAT volume (aOR 1.23, 95%CI: 0.78-1.95), VAT:SAT volume (aOR 0.80, 95%CI: 0.53-1.20), severe VR engorgement (aOR 1.53, 95%CI: 0.64-3.66), and mesenteric LAD (aOR 1.59, 95%CI: 0.67-3.79) were not. Similar results were observed for severity of ePOR.

CONCLUSION

VAT radiodensity is potentially a novel non-invasive prognostic imaging marker to help risk stratify CD patients for POR.

Adipose tissue composition determines its computed tomography radiodensity

OBJECTIVES

Adipose tissue radiodensity in computed tomography (CT) performed before surgeries can predict surgical difficulty. Despite its clinical importance, little is known about what influences radiodensity. This study combines desorption electrospray ionization mass spectrometry imaging (DESI-MSI) and electrospray ionization (ESI) with machine learning to unveil how chemical composition of adipose tissue determines its radiodensity.

METHODS

Patients in the study underwent abdominal surgeries. Before surgery, CT radiodensity of fat near operated sites was measured. Fifty-three fat samples were collected and analyzed by DESI-MSI, ESI, and histology, and then sorted by radiodensity, demographic parameters, and adipocyte size. A non-negative matrix factorization (NMF) algorithm was developed to differentiate between high and low radiodensities.

RESULTS

No associations between radiodensity and patient age, gender, weight, height, or fat origin were found. Body mass index showed negative correlation with radiodensity. A substantial difference in chemical composition between adipose tissues of high and low radiodensities was observed. More radiodense tissues exhibited greater abundance of high molecular weight species, such as phospholipids of various types, ceramides, cholesterol esters and diglycerides, and about 70% smaller adipocyte size. Less radiodense tissue showed high abundance of short acyl-tail fatty acids.

CONCLUSIONS

This study unveils the connection between abdominal adipose tissue radiodensity and its chemical composition. Because the radiodensity of the fat around the surgical site is associated with surgical difficulty, it is important to understand how adipose tissue composition affects this parameter. We conclude that fat tissue with a higher content of various phospholipids and waxy lipids is more CT radiodense.

CLINICAL RELEVANCE STATEMENT

This study establishes the connection between the CT radiodensity of adipose tissue and its chemical composition. Clinicians may use this information for preoperative planning of surgical procedures, potentially modifying their surgical approach (for example, performing partial nephrectomy openly rather than laparoscopically).

KEY POINTS

• Adipose tissue radiodensity values in computed tomography images taken prior to the surgery can potentially predict surgery difficulty. • Fifty-three human specimens were analyzed by advanced mass spectrometry, molecular imaging, and machine learning to establish the key features that determine Hounsfield units' values of adipose tissue. • The findings of this research will enable clinicians to better prepare for surgical procedures and select operative strategies.

Association between increased Subcutaneous Adipose Tissue Radiodensity and cancer mortality: Automated computation, comparison of cancer types, gender, and scanner bias

PURPOSE

Body composition analysis using computed tomography (CT) is proposed as a predictor of cancer mortality. An association between subcutaneous adipose tissue radiodensity (SATr) and cancer-specific mortality was established, while gender effects and equipment bias were estimated.

METHODS

7,475 CT studies were selected from 17 cohorts containing CT images of untreated cancer patients who underwent follow-up for a period of 2.1-118.8 months. SATr measures were collected from published data (n = 6,718) or calculated according to CT images using a deep-learning network (n = 757). The association between SATr and mortality was ascertained for each cohort and gender using the p-value from either logistic regression or ROC analysis. The Kruskal-Wallis test was used to analyze differences between gender distributions, and automatic segmentation was evaluated using the Dice score and five-point Likert quality scale. Gender effect, scanner bias and changes in the Hounsfield unit (HU) to detect hazards were also estimated.

RESULTS

Higher SATr was associated with mortality in eight cancer types (p < 0.05). Automatic segmentation produced a score of 0.949 while the quality scale measurement was good to excellent. The extent of gender effect was 5.2 HU while the scanner bias was 10.3 HU. The minimum proposed HU change to detect a patient at risk of death was between 5.6 and 8.3 HU.

CONCLUSIONS

CT imaging provides valuable assessments of body composition as part of the staging process for several cancer types, saving both time and cost. Gender specific scales and scanner bias adjustments should be carried out to successfully implement SATr measures in clinical practice.

Greater aortic perivascular adipose tissue density is associated with aging, aortic stiffness, and central blood pressure in humans

Aging results in aortic perivascular adipose tissue (aPVAT)-mediated aortic stiffening in preclinical animal models to promote cardiovascular dysfunction. We hypothesized that greater human aPVAT density will be associated with aging, higher aortic stiffness, and blood pressure (BP). Fourteen apparently healthy adults (6 M/8 F, age range 20-79 yr) were recruited for this study. Aortic stiffness, assessed by carotid-femoral pulse wave velocity (cfPWV), resting aortic BP via pulse wave analysis, and aPVAT and abdominal visceral adipose tissue (VAT) density by computed tomography attenuation were acquired. aPVAT and epididymal (visceral) fat from young (4-6 mo) and old (27-29 mo) mice were used for ex vivo-conditioned media intrinsic mechanical stiffness experiments. Compared with younger adults, older adults had higher cfPWV (8.6 ± 0.4 vs. 6.2 ± 0.6 m/s, P < 0.05) and greater aPVAT attenuation (-80.2 ± 2.0 vs. -95.9 ± 1.5 HU, P < 0.05), but not VAT attenuation (P > 0.05). aPVAT-conditioned media from old mice compared with young mice increased intrinsic mechanical stiffness of the aorta (4,519 ± 510 vs. 2,325 ± 563 kPa, P < 0.05), which was not observed with epididymal fat-conditioned media from old mice (P > 0.05). aPVAT, but not VAT density, was positively associated with age (r = 0.89), cfPWV (r = 0.56), resting augmentation index normalized to heart rate 75 (AIxHR75; r = 0.67), aortic systolic BP (r = 0.58), and aortic pulse pressure (PP; r = 0.59; P < 0.05, all) and were independent of VAT density (P < 0.05, all). These data herein provide evidence for aPVAT as a novel fat depot and therapeutic target to lower aortic stiffness and future cardiovascular disease risk with aging in humans.NEW & NOTEWORTHY Aortic perivascular adipose tissue (aPVAT) promotes age-related aortic stiffening in preclinical animal models, but the relation between aPVAT density and cardiovascular function in adults is unknown. We demonstrate that aPVAT, but not abdominal visceral adipose tissue density, is positively associated with aging, aortic stiffness, and higher resting aortic blood pressure in apparently healthy adults. These findings provide novel evidence for aPVAT as a viable therapeutic target for improving cardiovascular function in humans.

Association Between Perivascular Adipose Tissue Density and Atherosclerosis in the Descending Thoracic Aorta

Radiodensity measured by computed tomography (CT) in Hounsfield Units (HU) is emerging as a clinical tool for detecting perivascular adipose tissue (PVAT) inflammation. In the present study, we hypothesized that PVAT radiodensity might predict the risk of descending thoracic aorta atherosclerosis. A total of 73 subjects who underwent CT angiography to investigate aortic disease were retrospectively analyzed. PVAT radiodensity, aortic complex plaque (ACP), mean plaque-burden score (MPBS), and plaque density were measured, and the association between them was analyzed. Perivascular adipose tissue radiodensity (HU) in patients with different aortic plaques grades (grade 1, 2, 3, and 4) were -93.71 ± 2.50, -93.63 ± 3.93, -90.24 ± 4.49, and -89.90 ± 5.18, respectively, and the difference was significant (P = .010). In the regression analysis, PVAT radiodensity was an independent predictor of ACP, with an OR of 1.263. In the linear analysis, PVAT radiodensity was an independent predictor of MPBS, with a β-coefficient of .073. In the univariate analysis, only the PVAT radiodensity was significantly associated with plaque density, with a β-coefficient of -1.666. In conclusion, PVAT density was independently related to descending thoracic aorta atherosclerosis.

Abdominal Fat Characteristics and Mortality in Rectal Cancer: A Retrospective Study

The aim of this study was to evaluate the association of adipose tissue characteristics with survival in rectal cancer patients. All consecutive patients, diagnosed with stage II-IV rectal cancer between 2010-2016 using baseline unenhanced Computed Tomography (CT), were included. Baseline total, subcutaneous and visceral adipose tissue areas (TAT, SAT, VAT) and densities (TATd, SATd, VATd) at third lumbar vertebra (L3) were retrospectively measured. The association of these tissues with cancer-specific and progression-free survival (CCS, PFS) was assessed by using competitive risk models adjusted by age, sex and stage. Among the 274 included patients (median age 70 years, 41.2% females), the protective effect of increasing adipose tissue area on survival could be due to random fluctuations (e.g., sub-distribution hazard ratio-SHR for one cm² increase in SAT = 0.997; 95%confidence interval-CI = 0.994-1.000; p = 0.057, for CSS), while increasing density was associated with poorer survival (e.g., SHR for one Hounsfield Unit-HU increase in SATd = 1.03, 95% CI = 1.01-1.05, p = 0.002, for CSS). In models considering each adipose tissue area and respective density, the association with CSS tended to disappear for areas, while it did not change for TATd and SATd. No association was found with PFS. In conclusion, adipose tissue density influenced survival in rectal cancer patients, raising awareness on a routinely measurable variable that requires more research efforts.

Adipose tissue radiodensity and mortality among patients with nonmetastatic breast cancer

BACKGROUND & AIMS

Computed tomography (CT) scans can measure quantity and distribution of adipose tissue, which are associated with breast cancer prognosis. As a novel prognostic marker, radiodensity of adipose tissue has been examined in multiple cancer types, but never in breast cancer. Lower density indicates larger adipocytes with greater lipid content, whereas higher density can reflect inflammation, fibrosis, vascularity, or even metabolic changes; and both may impact breast cancer prognosis.

METHODS

We included 2868 nonmetastatic patients with breast cancer diagnosed between January 2005 and December 2013 at Kaiser Permanente Northern California, an integrated healthcare system. From CT scans at diagnosis, we assessed the radiodensity of subcutaneous (SAT) and visceral adipose tissue (VAT) at the third lumbar vertebra and categorized their radiodensity into three levels: low (<1 standard deviation [SD] below the mean), middle (mean ± 1 SD), and high (>1 SD above the mean). Using multivariable Cox proportional hazards regression with adjustment for clinicopathological characteristics including body mass index, we calculated hazard ratios (HRs [95% confidence intervals]) for the associations of adipose tissue radiodensity with overall mortality and breast-cancer-specific mortality.

RESULTS

Median age at diagnosis of breast cancer was 56.0 years, most (63.3%) were non-Hispanic White and nearly half (45.6%) were stage II. Compared to middle SAT radiodensity, high SAT radiodensity was significantly associated with increased risk of overall mortality (HR: 1.45 [1.15-1.81]), non-significantly with breast-cancer-specific mortality (HR: 1.32 [0.95-1.84]). Neither low SAT radiodensity nor high or low VAT radiodensity was significantly associated with overall or breast-cancer-specific mortality.

CONCLUSIONS

High radiodensity of SAT at diagnosis of nonmetastatic breast cancer was associated with increased risk of overall mortality, independent of adiposity and other prognostic factors. Considering both radiodensity and quantity of adipose tissue at different locations could deepen understanding of the role of adiposity in breast cancer survival.

Inflammaging: The ground for sarcopenia?

Sarcopenia is a progressive skeletal muscle disease that occurs most commonly in the elderly population, contributing to increased costs and hospitalization. Exercise and nutritional therapy have been proven to be effective for sarcopenia, and some drugs can also alleviate declines in muscle mass and function due to sarcopenia. However, there is no specific pharmacological treatment for sarcopenia at present. This review will mainly discuss the relationship between inflammaging and sarcopenia. The increased secretion of proinflammatory cytokines with aging may be because of cellular senescence, immunosenescence, alterations in adipose tissue, damage-associated molecular patterns (DAMPs), and gut microbes due to aging. These sources of inflammaging can impact the sarcopenia process through direct or indirect pathways. Conversely, sarcopenia can also aggravate the process of inflammaging, creating a vicious cycle. Targeting sources of inflammaging can influence muscle function, which could be considered a therapeutic target for sarcopenia. Moreover, not only proinflammatory cytokines but also anti-inflammatory cytokines can influence muscle and inflammation and participate in the progression of sarcopenia. This review focuses on the effects of TNF-α, IL-6, and IL-10, which can be detected in plasma. Therefore, clearing chronic inflammation by targeting proinflammatory cytokines (TNF-α, IL-1, IL-6) and the inflammatory pathway (JAK/STAT, autophagy, NF-κB) may be effective in treating sarcopenia.

Value-added Opportunistic CT Screening: State of the Art

Opportunistic CT screening leverages robust imaging data embedded within abdominal and thoracic scans that are generally unrelated to the specific clinical indication and have heretofore gone largely unused. This incidental imaging information may prove beneficial to patients in terms of wellness, prevention, risk profiling, and presymptomatic detection of relevant disease. The growing interest in CT-based opportunistic screening relates to a confluence of factors: the objective and generalizable nature of CT-based body composition measures, the emergence of fully automated explainable AI solutions, the sheer volume of body CT scans performed, and the increasing emphasis on precision medicine and value-added initiatives. With a systematic approach to body composition and other useful CT markers, initial evidence suggests that their ability to help radiologists assess biologic age and predict future adverse cardiometabolic events rivals even the best available clinical reference standards. Emerging data suggest that standalone "intended" CT screening over an unorganized opportunistic approach may be justified, especially when combined with established cancer screening. This review will discuss the current status of opportunistic CT screening, including specific body composition markers and the various disease processes that may be impacted. The remaining hurdles to widespread clinical adoption include generalization to more diverse patient populations, disparate technical settings, and reimbursement.

Chronic Stress Burden, Visceral Adipose Tissue, and Adiposity-Related Inflammation: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

We investigated the role of chronic stress burden on adiposity and adiposity-related inflammation with two hypotheses: a) greater chronic stress is associated with higher central adiposity and selective accumulation of visceral adipose tissue (VAT) compared with subcutaneous adipose tissue (SAT), and b) associations between VAT and inflammatory biomarkers are exacerbated when chronic stress is high.

METHODS

Data come from 1809 participants included in a Multi-Ethnic Study of Atherosclerosis ancillary study of body composition and adiposity-related inflammation. Chronic psychosocial stress was measured with a five-item version of the Chronic Stress Burden Scale. First, we tested associations between chronic stress (three-level categorical variable) and VAT, SAT, and VAT/SAT ratio. Second, we tested whether associations between VAT and inflammatory biomarkers varied by level of chronic stress.

RESULTS

Participants were approximately 65 years, 50% female, and 40.5% White, 25.6% Hispanic, 21.2% African American, and 12.8% Chinese American. About half of the sample reported little to no stress, and a quarter and a fifth of the sample reported medium and high levels of stress. Higher levels of chronic stress were associated with greater VAT and SAT, but not VAT/SAT ratio. Greater levels of VAT were associated with increased levels of adiposity-related inflammation in a graded pattern. These associations did not vary by stress level.

CONCLUSIONS

Greater chronic stress burden is associated with both central and subcutaneous adiposity. We found no evidence that the associations between VAT and inflammatory biomarkers are exacerbated by chronic stress. Findings contribute to ongoing literature untangling pathways in which psychosocial stress contributes to adiposity-related inflammation.

Abdominal adipose tissue radiodensity is associated with survival after colorectal cancer

BACKGROUND

Adipose tissue radiodensity may have prognostic importance for colorectal cancer (CRC) survival. Lower radiodensity is indicative of larger adipocytes, while higher radiodensity may represent adipocyte atrophy, inflammation, or edema.

OBJECTIVES

We investigated associations of adipose tissue radiodensity and longitudinal changes in adipose tissue radiodensity with mortality among patients with nonmetastatic CRC.

METHODS

In 3023 patients with stage I-III CRC, radiodensities of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were quantified from diagnostic computed tomography (CT) images. There were 1775 patients with follow-up images available. Cox proportional hazards models and restricted cubic splines were used to examine associations of at-diagnosis values and of longitudinal changes in VAT and SAT radiodensities with risks of death after adjusting for potential confounders, including body size and comorbidities.

RESULTS

VAT and SAT radiodensities were linearly associated with all-cause mortality: the HRs for death per SD increase were 1.21 (95% CI, 1.11-1.32) for VAT radiodensity and 1.18 (95% CI, 1.11-1.26) for SAT radiodensity. Changes in adipose tissue radiodensity had curvilinear associations with risks of death. The HR for an increase in VAT radiodensity of at least 1 SD was 1.53 (95% CI, 1.23-1.90), while the HR for a decrease of at least 1 SD was nonsignificant at 1.11 (95% CI, 0.84-1.47) compared with maintaining radiodensity within 1 SD of baseline. Similarly, increases (HR, 1.88; 95% CI, 1.48-2.40) but not decreases (HR, 1.20; 95% CI, 0.94-1.54) in SAT radiodensity significantly increased the risk of death compared with no change in radiodensity.

CONCLUSIONS

In patients with nonmetastatic CRC, adipose tissue radiodensity is a novel risk factor for total mortality that is independent of BMI and changes in body weight.

Association of Visceral Adipose Tissue and Insulin Resistance with Incident Metabolic Syndrome Independent of Obesity Status: The IRAS Family Study

OBJECTIVE

Although increasing evidence suggests that visceral adipose tissue (VAT) is a major underlying cause of metabolic syndrome (MetS), few studies have measured VAT at multiple time points in diverse populations. VAT and insulin resistance were hypothesized to differ by MetS status within BMI category in the Insulin Resistance Atherosclerosis Study (IRAS) Family Study and, further, that baseline VAT and insulin resistance and increases over time are associated with incident MetS.

METHODS

Generalized estimating equations were used for differences in body fat distribution and insulin resistance by MetS status. Mixed effects logistic regression was used for the association of baseline and change in adiposity and insulin resistance with incident MetS across 5 years, adjusted for age, sex, race/ethnicity, and family correlation.

RESULTS

VAT and insulin sensitivity differed significantly by MetS status and BMI category at baseline. VAT and homeostatic model assessment of insulin resistance (HOMA-IR) at baseline (VAT odds ratio [OR] = 1.16 [95% CI: 1.12-2.31]; HOMA-IR OR = 1.85 [95% CI: 1.32-2.58]) and increases over time (VAT OR = 1.55 [95% CI: 1.22-1.98]; HOMA-IR OR = 3.23 [95% CI: 2.20-4.73]) were associated with incident MetS independent of BMI category.

CONCLUSIONS

Differing levels of VAT may be driving metabolic heterogeneity within BMI categories. Both overall and abdominal obesity (VAT) may play a role in the development of MetS. Increased VAT over time contributed additional risk.

Abdominal periaortic and renal sinus fat attenuation indices measured on computed tomography are associated with metabolic syndrome

OBJECTIVES

To investigate the association between abdominal periaortic (APA) and renal sinus (RS) fat attenuation index (FAI) measured on MDCT and metabolic syndrome in non-obese and obese individuals.

METHODS

Visceral, subcutaneous, RS, and APA adipose tissue were measured in preoperative abdominal CT scans of individuals who underwent donor nephrectomy (n = 84) or bariatric surgery (n = 155). FAI was defined as the mean attenuation of measured fat volume. Participants were categorized into four groups: non-obese without metabolic syndrome (n = 64), non-obese with metabolic syndrome (n = 25), obese without metabolic syndrome (n = 21), and obese with metabolic syndrome (n = 129). The volume and FAI of each fat segment were compared among the groups. Receiver operator characteristics curve analysis was used to assess the association between the FAIs and metabolic syndrome.

RESULTS

FAIs of all abdominal fat segments were significantly lower in the obese group than in the non-obese group (p < 0.001). RS, APA, and the visceral adipose tissue FAIs were significantly lower in participants with metabolic syndrome than in those without metabolic syndrome in the non-obese group (p < 0.001, p = 0.006, and p < 0.001, respectively). The area under the curve for predicting metabolic syndrome was significantly higher for APA FAI (0.790) than subcutaneous, visceral, and RS FAI in all groups (0.649, 0.647, and 0.655, respectively).

CONCLUSION

Both metabolic syndrome and obesity were associated with lower RS and APA adipose tissue FAI, and APA FAI performed best for predicting metabolic syndrome.

KEY POINTS

• The volume and FAI of RS, APA, and visceral adipose tissue showed opposite trends with regard to metabolic syndrome or obesity. • Both metabolic syndrome and obesity were associated with lower RS FAI and APA FAI. • APA FAI performed best for predicting metabolic syndrome among FAIs of abdominal fat segments.

Opportunistic Screening at Abdominal CT: Use of Automated Body Composition Biomarkers for Added Cardiometabolic Value

Abdominal CT is a frequently performed imaging examination for a wide variety of clinical indications. In addition to the immediate reason for scanning, each CT examination contains robust additional data on body composition that generally go unused in routine clinical practice. There is now growing interest in harnessing this additional information. Prime examples of cardiometabolic information include measurement of bone mineral density for osteoporosis screening, quantification of aortic calcium for assessment of cardiovascular risk, quantification of visceral fat for evaluation of metabolic syndrome, assessment of muscle bulk and density for diagnosis of sarcopenia, and quantification of liver fat for assessment of hepatic steatosis. All of these relevant biometric measures can now be fully automated through the use of artificial intelligence algorithms, which provide rapid and objective assessment and allow large-scale population-based screening. Initial investigations into these measures of body composition have demonstrated promising performance for prediction of future adverse events that matches or exceeds the best available clinical prediction models, particularly when these CT-based measures are used in combination. In this review, the concept of CT-based opportunistic screening is discussed, and an overview of the various automated biomarkers that can be derived from essentially all abdominal CT examinations is provided, drawing heavily on the authors' experience. As radiology transitions from a volume-based to a value-based practice, opportunistic screening represents a promising example of adding value to services that are already provided. If the potentially high added value of these objective CT-based automated measures is ultimately confirmed in subsequent investigations, this opportunistic screening approach could be considered for intentional CT-based screening. ^©RSNA, 2021.

Change in abdominal, but not femoral subcutaneous fat CT-radiodensity is associated with improved metabolic profile after bariatric surgery

BACKGROUND AND AIMS

Computed tomography (CT)-derived adipose tissue radiodensity represents a potential noninvasive surrogate marker for lipid deposition and obesity-related metabolic disease risk. We studied the effects of bariatric surgery on CT-derived adipose radiodensities in abdominal and femoral areas and their relationships to circulating metabolites in morbidly obese patients.

METHODS AND RESULTS

We examined 23 morbidly obese women who underwent CT imaging before and 6 months after bariatric surgery. Fifteen healthy non-obese women served as controls. Radiodensities of the abdominal subcutaneous (SAT) and visceral adipose tissue (VAT), and the femoral SAT, adipose tissue masses were measured in all participants. Circulating metabolites were measured by NMR. At baseline, radiodensities of abdominal fat depots were lower in the obese patients as compared to the controls. Surprisingly, radiodensity of femoral SAT was higher in the obese as compared to the controls. In the abdominal SAT depot, radiodensity strongly correlated with SAT mass (r = -0.72, p < 0.001). After surgery, the radiodensities of abdominal fat increased significantly (both p < 0.01), while femoral SAT radiodensity remained unchanged. Circulating ApoB/ApoA-I, leucine, valine, and GlycA decreased, while glycine levels significantly increased as compared to pre-surgical values (all p < 0.05). The increase in abdominal fat radiodensity correlated negatively with the decreased levels of ApoB/ApoA-I ratio, leucine and GlycA (all p < 0.05). The increase in abdominal SAT density was significantly correlated with the decrease in the fat depot mass (r = -0.66, p = 0.002).

CONCLUSION

Higher lipid content in abdominal fat depots, and lower content in femoral subcutaneous fat, constitute prominent pathophysiological features in morbid obesity. Further studies are needed to clarify the role of non-abdominal subcutaneous fat in the pathogenesis of obesity.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01373892.

Utilizing Fully Automated Abdominal CT-Based Biomarkers for Opportunistic Screening for Metabolic Syndrome in Adults Without Symptoms

OBJECTIVE

Metabolic syndrome describes a constellation of reversible cardiometabolic abnormalities associated with cardiovascular risk and diabetes. The present study investigates the use of fully automated abdominal CT-based biometric measures for opportunistic identification of metabolic syndrome in adults without symptoms.

MATERIALS AND METHODS

International Diabetes Federation criteria were applied to a cohort of 9223 adults without symptoms who underwent unenhanced abdominal CT. After patients with insufficient clinical data for diagnosis were excluded, the final cohort consisted of 7785 adults (mean age, 57.0 years; 4361 women and 3424 men). Previously validated and fully automated CT-based algorithms for quantifying muscle, visceral and subcutaneous fat, liver fat, and abdominal aortic calcification were applied to this final cohort.

RESULTS

A total of 738 subjects (9.5% of all subjects; mean age, 56.7 years; 372 women and 366 men) met the clinical criteria for metabolic syndrome. Subsequent major cardiovascular events occurred more frequently in the cohort with metabolic syndrome (p < 0.001). Significant differences were observed between the two groups for all CT-based biomarkers (p < 0.001). Univariate L1-level total abdominal fat (area under the ROC curve [AUROC] = 0.909; odds ratio [OR] = 27.2), L3-level skeletal muscle index (AUROC = 0.776; OR = 5.8), and volumetric liver attenuation (AUROC = 0.738; OR = 5.1) performed well when compared with abdominal aortic calcification scoring (AUROC = 0.578; OR = 1.6). An L1-level total abdominal fat threshold of 460.6 cm² was 80.1% sensitive and 85.4% specific for metabolic syndrome. For women, the AUROC was 0.930 when fat and muscle measures were combined.

CONCLUSION

Fully automated quantitative tissue measures of fat, muscle, and liver derived from abdominal CT scans can help identify individuals who are at risk for metabolic syndrome. These visceral measures can be opportunistically applied to CT scans obtained for other clinical indications, and they may ultimately provide a more direct and useful definition of metabolic syndrome.

Review article: prognostic significance of body composition abnormalities in patients with cirrhosis

BACKGROUND

Recent advances in evaluation of body composition show body mass index to be inadequate in differentiating between body compartments in cirrhosis. Given the limitations of body mass index, body composition evaluation using computed tomography has been increasingly used as a non-invasive clinical tool with prognostic value. Another factor influencing prognosis includes sex-specific differences in body composition that are seen in cirrhosis.

AIM

To review current knowledge regarding the frequency and clinical implications of abnormal body composition features in cirrhosis.

METHODS

We searched PubMed database and limited the literature search to full-text papers published in English. Studies using inappropriate landmarks or demarcation of body composition components on computed tomography images were eliminated.

RESULTS

Sarcopenia is a well established factor affecting morbidity and mortality in cirrhosis. Other important body composition components that have been overlooked thus far include subcutaneous adipose tissue and visceral adipose tissue. Female patients with cirrhosis and low subcutaneous adiposity have a higher risk of mortality, whereas male patients with high visceral adiposity have a higher risk of hepatocellular carcinoma and recurrence following liver transplantation. Increased adipose tissue radiodensity has been associated with risk of decompensation and mortality.

CONCLUSIONS

Further evaluation of body composition abnormalities may help with development of targeted therapeutic strategies and improve outcome in patients with cirrhosis. Moreover, recognition of these abnormalities could improve prioritisation for liver transplantation as our current method based solely on liver function might lead to risk misclassification.

Adipose Tissue Composition in Obesity and After Bariatric Surgery

The adipose tissue is a complex organ that regulates food intake and energy expenditure as well as induces low-grade inflammation. This review deals with changes in the composition and activity of the adipose organ after bariatric surgery, focusing on epicardial and ectopic fat and on relationships between white and brown adipose tissues. Postoperative improvements of ectopic fat and epicardial fat size and composition account for the metabolic recovery and the decreased cardiovascular risk. Following Roux-en-Y gastric bypass or biliopancreatic diversion, a proportional increase in the size and activity of the metabolically active brown adipose tissue was observed, most likely related to the postoperative rearrangement of the entero-hormonal pattern with an increase of GLP-1 production: this aspect would promote the postoperative weight loss and maintenance of post-surgery benefits.

Associations of Thigh and Abdominal Adipose Tissue Radiodensity with Glucose and Insulin in Nondiabetic African-Ancestry Men

OBJECTIVE

Decreased radiodensity of adipose tissue (AT) located in the visceral AT (VAT), subcutaneous AT (SAT), and intermuscular AT (IMAT) abdominal depots is associated with hyperglycemia, hyperinsulinemia, and insulin resistance independent of AT volumes. These associations were sought in African-ancestry men, who have higher risk for type 2 diabetes and have been underrepresented in previous studies.

METHODS

This cross-sectional analysis included 505 nondiabetic men of African-Caribbean ancestry (median age: 61 years; median BMI: 26.8 kg/m² ) from the Tobago Health Study. AT volumes and radiodensities were assessed using computed tomography, including abdominal (VAT and SAT) and thigh (IMAT) depots. Associations between AT radiodensities were assessed with fasting serum glucose and insulin and with insulin resistance (updated homeostatic model assessment of insulin resistance, HOMA2-IR).

RESULTS

Higher radiodensity in any AT depot was associated with lower log-insulin and log-HOMA2-IR (β range: -0.16 to -0.18 for each; all P < 0.0001). No AT radiodensity was associated with glucose. Thigh IMAT radiodensity associations were independent of, and similar in magnitude to, VAT radiodensities. Model fit statistics suggested that AT radiodensities were a better predictor for insulin and insulin resistance compared with AT volumes in individuals with overweight and obesity.

CONCLUSIONS

AT radiodensities at multiple depots are significantly associated with insulin and insulin resistance in African-ancestry men.

Quantitative bias analysis of the association of type 2 diabetes mellitus with 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153)

An association between serum concentrations of persistent organic pollutants (POPs), such as 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153), and risk of type 2 diabetes mellitus (T2DM) has been reported. Conditional on body mass index (BMI) and waist circumference (WC), a higher serum PCB-153 concentration may be a marker of T2DM risk because it reflects other aspects of obesity that are related to T2DM risk and to PCB-153 clearance. To estimate the amount of residual confounding by other aspects of obesity, we performed a quantitative bias analysis on the results of a specific study. A physiologically-based pharmacokinetic (PBPK) model was developed to predict serum levels of PCB-153 for a simulated population. T2DM status was assigned to simulated subjects based on age, sex, BMI, WC, and visceral adipose tissue mass. The distributions of age, BMI, WC, and T2DM prevalence of the simulated population were tailored to closely match the target population. Analysis of the simulated data showed that a small part of the observed association appeared to be due to residual confounding. For example, the predicted odds ratio of T2DM that would have been obtained had the results been adjusted for visceral adipose tissue mass, for the ≥90th percentile of PCB-153 serum concentration, was 6.60 (95% CI 2.46-17.74), compared with an observed odds ratio of 7.13 (95% CI 2.65-19.13). Our results predict that the association between PCB-153 and risk of type 2 diabetes mellitus would not be substantially changed by additional adjustment for visceral adipose tissue mass in epidemiologic analyses. Confirmation of these predictions with longitudinal data would be reassuring.

CoreSlicer: a web toolkit for analytic morphomics

BACKGROUND

Analytic morphomics, or more simply, "morphomics," refers to the measurement of specific biomarkers of body composition from medical imaging, most commonly computed tomography (CT) images. An emerging body of literature supports the use of morphomic markers measured on single-slice CT images for risk prediction in a range of clinical populations. However, uptake by healthcare providers been limited due to the lack of clinician-friendly software to facilitate measurements. The objectives of this study were to describe the interface and functionality of CoreSlicer- a free and open-source web-based interface aiming to facilitate measurement of analytic morphomics by clinicians - and to validate muscle and fat measurements performed in CoreSlicer against reference software.

RESULTS

Measurements of muscle and fat obtained in CoreSlicer show high agreement with established reference software. CoreSlicer features a full set of DICOM viewing tools and extensible plugin interface to facilitate rapid prototyping and validation of new morphomic markers by researchers. We present published studies illustrating the use of CoreSlicer by clinicians with no prior knowledge of medical image segmentation techniques and no formal training in radiology, where CoreSlicer was successfully used to predict operative risk in three distinct populations of cardiovascular patients.

CONCLUSIONS

CoreSlicer enables extraction of morphomic markers from CT images by non-technically skilled clinicians. Measurements were reproducible and accurate in relation to reference software.

Associations of abdominal intermuscular adipose tissue and inflammation: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

This study examined the associations between abdominal IMAT area and density with inflammatory markers associated with cardiometabolic disease.

METHODS

1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis underwent computed tomography to quantify body composition and measurements of adiponectin, leptin, interleukin-6 (IL-6), C-reactive protein (CRP), and resistin.

RESULTS

The mean age and body mass index of participants was 65years and 28kg/m2, respectively, and 50% were female. After adjustment for age, sex, and race/ethnicity, as IMAT area increased and density decreased from the first to fourth quartile, markers of inflammation increased linearly (p<0.01). Using linear regression, and with adjustment for demographics, cardiovascular disease risk factors, and abdominal muscle area and density, a 1-standard deviation (SD) increase in total abdominal IMAT area was associated with a 21%, 36% and 20% higher IL-6, leptin, and CRP, respectively, and 19% lower adiponectin (p<0.001). With similar adjustment, a 1-SD decrease in total abdominal IMAT density was associated with a 14%, 32%, and 15% higher IL-6, leptin, and CRP, respectively, and 22% lower adiponectin (p<0.001). These associations were attenuated with the addition of visceral fat (p>0.05).

CONCLUSIONS

Abdominal IMAT area and density are associated with inflammatory markers, with these associations attenuated by central adiposity.

A comparison of perinephric fat surface area and Mayo Adhesive Probability score in predicting malignancy in T1 renal masses

INTRODUCTION

Recent studies have proposed that nearby fat deposits may have metabolic influence on kidney cancer pathobiology. Both fat quantity and quality may play unique roles in this complex relationship. As such, we investigated whether perinephric fat surface area (PFA), a quantitative measure of fat, or Mayo Adhesive Probability (MAP) score, a qualitative measure, were predictive of malignant pathology or Fuhrman grade in small renal masses.

METHODS

A total of 317 patients undergoing minimally invasive partial nephrectomy between 2010 and 2016 for renal masses were retrospectively reviewed. Preoperative abdominal CT and MRI scans were measured for PFA and MAP scores. Multiple binary logistic regression models were created to identify predictive factors of malignant disease and Fuhrman grade.

RESULTS

A total of 253 patients had malignant masses, while 64 had benign masses. A total of 189 of the malignant masses were T1a, while 64 were designated T1b. A total of 221 patients with malignant masses had reported Fuhrman grades. Of these 211 patients, 143 (64.7%) had low-grade and 78 (35.3%) had high-grade disease. Mean PFA was 18.0 ± 13.3 cm², while mean MAP score was 2.6 ± 1.2. Binary logistic regression analysis yielded three variables in the best-fit model for predictors of malignant pathology: MAP score (OR = 1.374, 95% CI: 1.007-1.873, P = 0.045), male sex (OR = 2.058, 95% CI: 1.004-4.218, P = 0.049), and BMI (OR = 1.064, 95% CI: 0.998-1.135, P = 0.059). Neither MAP nor PFA was predictive of Fuhrman grade.

CONCLUSIONS

MAP score, a measure of perinephric fat quality, but not PFA, a qualitative measure of fat quantity, was predictive of malignant pathology, raising the question whether fat quality rather than quantity may be involved in the pathophysiology of RCC in a large and diverse patient population. Understanding the increasing burden of obesity, further studies are needed to elaborate on these findings and to discern the exact relationship between perinephric fat deposits and renal tumorigenesis.

Ultrasound-assessed visceral fat and associations with glucose homeostasis and cardiovascular risk in clinical practice

BACKGROUND AND AIMS

Despite the lack of evidence that assessing the global cardiovascular risk leads to a decreased incidence of cardiovascular events, accurate patient profiling is paramount in preventive medicine. An excess of visceral fat (VF) is associated with an enhanced cardiovascular risk; importantly, VF is quantifiable rapidly, cheaply and safely by ultrasound, which makes it suitable for use in clinical practice. In the present study, we aimed to evaluate if US-measured VF (USVF) could be a better predictor of glucose homeostasis and cardiovascular risk than simple anthropometric measures.

METHODS AND RESULTS

One-hundred sixty-two patients attending a Metabolic Disorders Clinic underwent a cross-sectional study for which USVF, anthropometric measures, a standard oral glucose tolerance test (OGTT), and calculation of cardiovascular Framingham score and vascular age were obtained. USVF was directly correlated with fasting and 2-h plasma glucose (respectively: r = 0.26, p < 0.001; r = 0.28, p < 0.0001), fasting and 2-h plasma insulin (for both: r = 0.41, p < 0.0001), homeostatic model assessment of insulin resistance (HOMA-IR; r = 0.42, p < 0.0001), cardiovascular Framingham score (r = 0.44 p < 0.0001) and vascular age (r = 0.30 p < 0.001). In receiver operator characteristic curves USVF had good diagnostic abilities for type 2 diabetes mellitus, fatty liver and metabolic syndrome, in both genders. At multivariate analysis, body mass index (BMI) outperformed USVF in the prediction of HOMA-IR; neverthless, USVF, not BMI, was an independent predictor of cardiovascular risk. Finally, models including USVF were the most parssimonious to predict Framingham score, vascular age and HOMA-IR.

CONCLUSION

In overweight and obese subjects, USVF could usefully complement other parameters for cardiovascular risk stratification.

Brown adipose tissue lipid metabolism in morbid obesity: Effect of bariatric surgery-induced weight loss

OBJECTIVE

We aimed to investigate the effect of bariatric surgery on lipid metabolism in supraclavicular brown adipose tissue in morbidly obese women. We hypothesized that lipid metabolism improves after surgery-induced weight loss.

MATERIALS AND METHODS

A total of 23 morbidly obese women (BMI, 42.1 ± 4.2 kg/m² ; age, 43.8 ± 9.8 years) were assessed before and 6 months after bariatric surgery and 15 age- and sex-matched controls (22.6 ± 2.8 kg/m² ) were assessed once. In the supraclavicular fat depot, fractional (FUR) and NEFA uptake rates were measured with ¹⁸ F-FTHA-PET. We assessed tissue morphology (triglyceride content) using computed tomography (CT)-radiodensity (in Hounsfield Units[HU]) and the proportion of fat with high density (sBAT [%]) in the entire supraclavicular fat depot.

RESULTS

The supraclavicular fractional uptake rate was lower in obese women compared to controls (0.0055 ± 0.0035 vs 0.0161 ± 0.0177 1/min, P = .001). Both FUR (to 0.0074 ± 0.0035 1/min, P = .01) and NEFA uptake rates (to 0.50 ± 0.50 μmol/100 g/min, P = .001) increased after surgery. Compared to controls, obese women had lower CT-radiodensity (-101.2 ± 10.1 vs -82.5 ± 5.8 HU, P < .001) and sBAT (43.4 ± 8.4% vs 64.5 ± 12.4%, P < .001). After surgery, CT-radiodensity increased (to -82.5 ± 9.6 HU, P < .001), signifying decreased triglyceride content and sBAT improved (to 58.0 ± 10.7%, P < .001), indicating an increased proportion of brown fat. The change in tissue morphology, reflected as increase in CT-radiodensity and sBAT (%), was associated with a decrease in adiposity indices and an increase in whole-body insulin sensitivity.

CONCLUSIONS

A decrease in triglyceride content, coupled with the increased proportion of brown adipose tissue in the supraclavicular fat depot, may play a role in the improvement of whole-body insulin sensitivity observed in morbidly obese women after surgery-induced weight loss.

Computed tomography-based fat and muscle characteristics are associated with mortality after transcatheter aortic valve replacement

BACKGROUND

Computed tomography (CT)-based fat and muscle measures are associated with outcome in large populations. We tested if muscle and fat characteristics are associated with long-term outcomes after TAVR.

METHODS

We included 403 clinical CTs performed prior to TAVR at our center between 2008 and 2016, measuring area (cm2) and density (Hounsfield units, HU) of both psoas muscles (PM), subcutaneous adipose (SAT), and visceral adipose tissue (VAT). Area measures were indexed to height, log-transformed and both area and density were standardized for analysis. We assessed the association of each measure with all-cause mortality (adjusted for age, sex, body mass index (BMI), and the Society of Thoracic Surgeons (STS) risk score.

RESULTS

Of the 403 individuals (83 ± 8 years; 52% female), 167 (41.4%) died during a median follow-up of 458 days (interquartile range IQR 297-840). Fat measures were feasible and rapid. Fat area was available in 242 (60%) patients with an adequate field of view. Individuals with the lowest PM area, SAT area or VAT area exhibited the highest hazard of mortality. In addition, greater SAT density was associated with a higher mortality hazard (adjusted HR per standard deviation increase in density = 1.35, 95%CI 1.10-1.67, P = 0.005).

CONCLUSION

Rapid CT-based tissue characterization is feasible in patients referred for TAVR. Decreased PM area and increased SAT density are associated with long-term mortality after TAVR, even after accounting for age, sex, BMI, and STS score. Further studies are necessary to interrogate sex-specific relationships between CT tissue metrics and mortality and whether CT measures are incremental to well-established frailty metrics.

Effect of Pericardial Fat Volume and Density on Markers of Insulin Resistance and Inflammation in Patients With Human Immunodeficiency Virus Infection

Treated human immunodeficiency virus (HIV) infection is characterized by ectopic fat deposition, a persistent inflammatory state, and increased cardiometabolic risk. In this secondary analysis of a placebo controlled trial of rosuvastatin among 147 HIV+ subjects (median age 46; 78% men) on stable antiretroviral therapy, we aimed to evaluate longitudinal associations between computed tomography (CT) measures of pericardial fat (PCF) volume and density, insulin resistance, and inflammation. We measured PCF volume and density (mean attenuation in Hounsfield units) by noncontrast gated CT at baseline and week 96. Homeostatic model of insulin resistance was calculated from fasting insulin and glucose at entry, 24, 48, and 96 weeks. At baseline, insulin resistance correlated positively with PCF volume and negatively with density. Similarly divergent correlations of volume and density were observed with waist:hip ratio, nadir CD4+ count, and duration of antiretroviral therapy. In a linear mixed model, PCF density was associated with insulin resistance independent of PCF volume, body mass index, metabolic syndrome, and biomarkers of immune activation and systemic inflammation; however, baseline PCF measures were not associated with longitudinal changes in insulin resistance. Soluble CD163, a marker of monocyte activation, positively correlated with PCF volume and was associated with insulin resistance in linear models. Statin treatment assignment did not affect PCF volume or density change (both p > 0.8). In conclusion, the quantity and quality (i.e., radiodensity) of PCF are differentially related to insulin resistance and inflammation in patients with treated HIV infection.

WISP1 Is a Marker of Systemic and Adipose Tissue Inflammation in Dysmetabolic Subjects With or Without Type 2 Diabetes

Context:

Wnt1-inducible signaling pathway protein 1 (WISP1) is a novel adipokine participating in adipose tissue (AT) dysfunction; so far, no data on WISP1 in diabetes are available.

Objectives:

To evaluate plasma WISP1 in subjects with type 2 diabetes (T2D) and its correlates linked to AT inflammation.

Design and Participants:

For this cross-sectional study, 97 consecutive dysmetabolic patients were recruited at the diabetes outpatient clinics of Sapienza University in Rome; 71 of them had T2D, with (n = 35) or without (n = 36) obesity, and 26 were obese patients without diabetes. Twenty-one normal-weight nondiabetic individuals were enrolled as a control group. Study participants underwent clinical workup and blood sampling for metabolic/inflammatory characterization; magnetic resonance imaging (MRI) data on subcutaneous AT and visceral AT (VAT) area, hepatic fat content, and VAT homogeneity were available for most diabetic patients.

Results:

Plasma WISP1 significantly increased throughout classes of obesity and correlated with greater VAT area, interleukin-8 (IL-8), and lower adiponectin levels, without differing between diabetic and nondiabetic participants. Higher IL-8 was the main determinant of increased WISP1. MRI-assessed VAT inhomogeneity was associated with higher WISP1, IL-8 and C-reactive protein levels, independent of obesity; high WISP1 strongly predicted VAT inhomogeneity (P < 0.001).

Conclusions:

WISP1 levels are increased in obese persons and are directly related to adiposity, independent of glycemic status or insulin resistance; moreover, they are strongly associated with increased plasma IL-8 and signal abnormalities of VAT. The overall data add insights to the mechanisms underlying metabolic alterations and may open a scenario for innovative therapeutic approaches for diabetes prevention and care.