Imaging spectrum of abnormal subcutaneous and visceral fat distribution

Lumbar localized fat distribution parameters are independent predictors of osteoporotic vertebral compression re-fractures (OVCRFs) following Percutaneous Kyphoplasty (PKP): a retrospective matched case-control study

OBJECTIVE

To investigate potential risk factors for osteoporotic vertebral compression re-fractures (OVCRFs) following percutaneous kyphoplasty (PKP).

MATERIALS AND METHODS

Patients who underwent PKP from January 2012 to January 2020 were included in this study within the same institution. Cases were defined as patients who experienced OVCRFs, while controls were matched based on corresponding clinical characteristics from those patients without OVCRFs. The lumbar localized fat distribution parameters, including the fat infiltration ratio (FIR) in muscles [multifidus (MF), erector spinae (ES), paravertebral muscles (PVM), and psoas major (PS)] and subcutaneous fat thickness (SFT), were compared between the two groups through radiological data. And other clinical data that may be relevant were also compared. Independent risk factors for OVCRFs after PKP were identified through a binary logistic regression analysis.

RESULT

A total of 1391 patients who underwent PKP were included in this study. 51 patients were categorized into the re-fracture group, and 102 patients were selected as matched controls from the remaining cohort. There were statistically significant differences between the two groups in metrics including MF-FIR, ES-FIR, PVM-FIR, PS-FIR, bone mineral density (BMD), body-mass index (BMI), SFT, hemoglobin (Hb), albumin (ALB), alkaline phosphatase (ALP), and triglycerides (TG) (P < 0.05). Binary logistic regression analysis demonstrated that PVM-FIR (P = 0.003), SFT (P < 0.001), BMD (P = 0.011), and ALP (P = 0.005) were independent predictors for the occurrence of OVCRFs.

CONCLUSION

This study discovered that lumbar localized fat distribution parameters including PVM-FIR and SFT are independent predictors of OVCRFs. Additionally, BMD and ALP were found to be independent predictors of OVCRFs.

Differential chromatin accessibility and Gene Expression Associated with Backfat Deposition in pigs

BACKGROUND

Backfat serves as a vital fat reservoir in pigs, and its excessive accumulation will adversely impact pig growth performance, farming efficiency, and pork quality. The aim of this research is to integrate assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) to explore the molecular mechanisms underlying porcine backfat deposition.

RESULTS

ATAC-seq analysis identified 568 genes originating from 698 regions exhibiting differential accessibility, which were significantly enriched in pathways pertinent to adipocyte differentiation and lipid metabolism. Besides, a total of 283 transcription factors (TFs) were identified by motif analysis. RNA-seq analysis revealed 978 differentially expressed genes (DEGs), which were enriched in pathways related to energy metabolism, cell cycle and signal transduction. The integration of ATAC-seq and RNA-seq data indicates that DEG expression levels are associated with chromatin accessibility. This comprehensive study highlights the involvement of critical pathways, including the Wnt signaling pathway, Jak-STAT signaling pathway, and fatty acid degradation, in the regulation of backfat deposition. Through rigorous analysis, we identified several candidate genes (LEP, CTBP2, EHHADH, OSMR, TCF7L2, BCL2, FGF1, UCP2, CCND1, TIMP1, and VDR) as potentially significant contributors to backfat deposition. Additionally, we constructed TF-TF and TF-target gene regulatory networks and identified a series of potential TFs related to backfat deposition (FOS, STAT3, SMAD3, and ESR1).

CONCLUSIONS

This study represents the first application of ATAC-seq and RNA-seq, affording a novel perspective into the mechanisms underlying backfat deposition and providing invaluable resources for the enhancement of pig breeding programs.

Convolutional Neural Network-Based Automated Segmentation of Skeletal Muscle and Subcutaneous Adipose Tissue on Thigh MRI in Muscular Dystrophy Patients

We aim to develop a deep learning-based algorithm for automated segmentation of thigh muscles and subcutaneous adipose tissue (SAT) from T1-weighted muscle MRIs from patients affected by muscular dystrophies (MDs). From March 2019 to February 2022, adult and pediatric patients affected by MDs were enrolled from Azienda Ospedaliera Universitaria Pisana, Pisa, Italy (Institution 1) and the IRCCS Stella Maris Foundation, Calambrone-Pisa, Italy (Institution 2), respectively. All patients underwent a bilateral thighs MRI including an axial T1 weighted in- and out-of-phase (dual-echo). Both muscles and SAT were manually and separately segmented on out-of-phase image sets by a radiologist with 6 years of experience in musculoskeletal imaging. A U-Net1 and U-Net3 were built to automatically segment the SAT, all the thigh muscles together and the three muscular compartments separately. The dataset was randomly split into the on train, validation, and test set. The segmentation performance was assessed through the Dice similarity coefficient (DSC). The final cohort included 23 patients. The estimated DSC for U-Net1 was 96.8%, 95.3%, and 95.6% on train, validation, and test set, respectively, while the estimated accuracy for U-Net3 was 94.1%, 92.9%, and 93.9%. Both of the U-Nets achieved a median DSC of 0.95 for SAT segmentation. The U-Net1 and the U-Net3 achieved an optimal agreement with manual segmentation for the automatic segmentation. The so-developed neural networks have the potential to automatically segment thigh muscles and SAT in patients affected by MDs.

Body Composition in Advanced Non-Small Cell Lung Cancer Treated With Immunotherapy

Importance

The association between body composition (BC) and cancer outcomes is complex and incompletely understood. Previous research in non-small-cell lung cancer (NSCLC) has been limited to small, single-institution studies and yielded promising, albeit heterogeneous, results.

Objectives

To evaluate the association of BC with oncologic outcomes in patients receiving immunotherapy for advanced or metastatic NSCLC.

Design, Setting, and Participants

This comprehensive multicohort analysis included clinical data from cohorts receiving treatment at the Dana-Farber Brigham Cancer Center (DFBCC) who received immunotherapy given alone or in combination with chemotherapy and prospectively collected data from the phase 1/2 Study 1108 and the chemotherapy arm of the phase 3 MYSTIC trial. Baseline and follow-up computed tomography (CT) scans were collected and analyzed using deep neural networks for automatic L3 slice selection and body compartment segmentation (skeletal muscle [SM], subcutaneous adipose tissue [SAT], and visceral adipose tissue). Outcomes were compared based on baseline BC measures or their change at the first follow-up scan. The data were analyzed between July 2022 and April 2023.

Main Outcomes and Measures

Hazard ratios (HRs) for the association of BC measurements with overall survival (OS) and progression-free survival (PFS).

Results

A total of 1791 patients (878 women [49%]) with NSCLC were analyzed, of whom 487 (27.2%) received chemoimmunotherapy at DFBCC (DFBCC-CIO), 825 (46.1%) received ICI monotherapy at DFBCC (DFBCC-IO), 222 (12.4%) were treated with durvalumab monotherapy on Study 1108, and 257 (14.3%) were treated with chemotherapy on MYSTIC; median (IQR) ages were 65 (58-74), 66 (57-71), 65 (26-87), and 63 (30-84) years, respectively. A loss in SM mass, as indicated by a change in the L3 SM area, was associated with worse oncologic outcome across patient groups (HR, 0.59 [95% CI, 0.43-0.81] and 0.61 [95% CI, 0.47-0.79] for OS and PFS, respectively, in DFBCC-CIO; HR, 0.74 [95% CI, 0.60-0.91] for OS in DFBCC-IO; HR, 0.46 [95% CI, 0.33-0.64] and 0.47 [95% CI, 0.34-0.64] for OS and PFS, respectively, in Study 1108; HR, 0.76 [95% CI, 0.61-0.96] for PFS in the MYSTIC trial). This association was most prominent among male patients, with a nonsignificant association among female patients in the MYSTIC trial and DFBCC-CIO cohorts on Kaplan-Meier analysis. An increase of more than 5% in SAT density, as quantified by the average CT attenuation in Hounsfield units of the SAT compartment, was associated with poorer OS in 3 patient cohorts (HR, 0.61 [95% CI, 0.43-0.86] for DFBCC-CIO; HR, 0.62 [95% CI, 0.49-0.79] for DFBCC-IO; and HR, 0.56 [95% CI, 0.40-0.77] for Study 1108). The change in SAT density was also associated with PFS for DFBCC-CIO (HR, 0.73; 95% CI, 0.54-0.97). This was primarily observed in female patients on Kaplan-Meier analysis.

Conclusions and Relevance

The results of this multicohort study suggest that loss in SM mass during systemic therapy for NSCLC is a marker of poor outcomes, especially in male patients. SAT density changes are also associated with prognosis, particularly in female patients. Automated CT-derived BC measurements should be considered in determining NSCLC prognosis.

Exploring the Interplay between Vitamin D, Insulin Resistance, Obesity and Skeletal Health

Vitamin D (ViD), plays an important role in calcium absorption and bone mineralization, is associated with bone mineral density. Severe deficiency in ViD has long been linked to conditions such as rickets in children and osteomalacia in adults, revealing its substantial role in skeletal health. Additionally, investigations show an existing interconnection between ViD and insulin resistance (Ins-R), especially in patients with type 2 diabetes mellitus (T2DM). Obesity, in conjunction with Ins-R, may augment the risk of osteoporosis and deterioration of skeletal health. This review aims to examine recent studies on the interplay between ViD, Ins-R, obesity, and their impact on skeletal health, to offer insights into potential therapeutic strategies. Cochrane Library, Google Scholar, and Pubmed were searched to investigate relevant studies until December 2023. Current research demonstrates ViD's impact on pancreatic β-cell function, systemic inflammation, and insulin action regulation. Our findings highlight an intricate association between ViD, Ins-R, obesity, and skeletal health, providing a perspective for the prevention and/or treatment of skeletal disorders in patients with obesity, Ins-R, and T2DM.

Lenvatinib or Sorafenib Treatment Causing a Decrease in Skeletal Muscle Mass, an Independent Prognostic Factor in Hepatocellular Carcinoma: A Survival Analysis Using Time-Varying Covariates

This study aimed to assess the effects of lenvatinib (LEN) or sorafenib (SOR) treatment for hepatocellular carcinoma (HCC) on body composition and changes in body composition on survival. This study enrolled 77 HCC patients. Skeletal muscle index (SMI), subcutaneous and visceral adipose tissue indices (SATI and VATI), AFP, PIVKA-II, and ALBI scores were analyzed at the time of LEN/SOR introduction, three months after the introduction, at treatment discontinuation, and the last observational time. The differences between chronological changes in these values were analyzed using a paired t-test. The Cox proportional hazards model was used to analyze prognostic factors using time-varying covariates. The chronological changes in each factor were 45.5-43.6-40.6-39.8 (cm2/m2) for SMI, 41.7-41.6-36.3-33.7 (cm2/m2) for SATI, 41.9-41.1-37.1-34.8 (cm2/m2) for VATI, 2.379-26.42-33.61-36.32 (×103 ng/mL) for AFP, 9.404-13.39-61.34-25.70 (×103 mAU/mL) for PIVKA-II, and -2.56--2.38--1.99--1.90 for the ALBI score. The presence of pre-treatment (p = 0.042), AFP (p = 0.002), PIVKA-II (p < 0.001), ALBI score (p < 0.001), and SMI (p = 0.001) were independent prognostic factors. Skeletal muscle mass decreases significantly during LEN/SOR treatment and is an independent prognostic factor for HCC.

Preoperative prediction of early recurrence of HBV-related hepatocellular carcinoma (≤5 cm) by visceral adipose tissue index

Background

This study aimed to investigate whether visceral adipose tissue index (VATI) is a significant risk factor for the early recurrence (ER) of HBV-related hepatocellular carcinoma (HCC) (≤5 cm) after hepatectomy.

Methods

The recruited cohort patients who were positive for hepatitis B virus, presented with surgically confirmed HCC (≤5 cm) from Army Medical University (internal training cohort: n = 192) and Chongqing Medical University (external validation group: n = 46). We measured VATI, subcutaneous adipose tissue index (SATI) via computed tomography (CT). ER was defined as recurrence within 2 years after hepatectomy. The impact of parameters on outcome after hepatectomy for HCC was analyzed.

Results

Univariate analysis showed that alpha-fetoprotein levels (p = 0.044), body mass index (BMI) (p < 0.001), SATI (p < 0.001), and VATI (p < 0.001) were significantly different between ER and non-ER groups in internal training cohort. Multivariate analysis identified VATI as an independent risk factor for ER (odds ratio = 1.07, 95% confidence interval: 1.047-1.094, p < 0.001), with a AUC of 0.802, based on the cut-off value of VATI, which was divided into high risk (≥37.45 cm²/m²) and low risk (<37.45 cm²/m²) groups. The prognosis of low risk group was significantly higher than that of high risk group (p < 0.001). The AUC value of VATI in external validation group was 0.854.

Conclusion

VATI was an independent risk factor for the ER, and higher VATI was closely related to poor outcomes after hepatectomy for HBV-related HCC (≤5 cm).

Is Fat Deposition of Renal Sinus a Concomitant Finding to Fatty Liver Disease? The First Study Regarding the Relationship Between Kidney and Liver Fat Content with Non-Contrast Computed Tomography

INTRODUCTION

It has been established that abnormal fat deposits are associated with fat deposition in other abdominal regions and linked to obesity, diabetes mellitus, hypertension, vascular and metabolic diseases. This study aimed to determine whether there was a relationship between fat deposition of the renal (i.e., kidney) sinus (FRS) and fatty liver disease (FLD) in a sample of adults. The authors hypothesized that FRS could be a diagnostic finding associated with Hepatosteatosis (HS) in a sample of younger patients. This study was the first apparent investigation of this possible phenomenon.

METHODS

A convenience sample of 92 adult patients of which 19 (20.7%) were females and 73 (79.3%) were males, and with a mean age of 30.19 (SD = 6.00) were included. The authors calculated Hounsfield Units (HU) (i.e., relative quantitative measurement of radio density) of patients' livers and spleens on non-contrast computed tomography (CT). Liver and spleen differences < 10 HU were considered steatosis (FLD). The authors stratified sample patients into two analytic subgroups according to the presence of FLD or not and compared them based on their FRS widths.

RESULTS

In the FLD subgroup (N = 48), the difference of HU values between liver and spleen was -5.19 (SD = 11.32), with a range of -38 - 8 HU, while, in the non-steatosis subgroup (N = 44), the mean difference was 16.36 (SD = 3.90), range of 11 - 26 HU. The average diameter of FRS width was 12.5 mm in those patients with steatosis (FLD subgroup) although 9.3 mm in non-FLD patients. (p = 0.02).

CONCLUSIONS

Based on these results, FRS may be able to be used by radiologists as an ancillary method in the detection of hepatic steatosis in younger adults. The effectiveness of premedical processes (e.g., exercise and diet modification) can also be increased by non-radiologists after detection of lower-grade HS.

Effects of Obesity on Infections with Emphasis on Skin Infections and Wound Healing

Obesity represents a serious health problem as it is rapidly increasing worldwide. Obesity is associated with reduced health span and life span, decreased responses to infections and vaccination and increased frequency of inflammatory conditions. In this review, we summarize published data showing that obesity increases the risk of different types of infections, with a special focus on skin infections. Obesity also induces skin changes and conditions (inflammation-based and hypertrophic) which are often associated with fungi or bacteria overgrowth. The association of obesity with the skin microbiome has been established in both mice and humans. Balance of commensal microbes controls skin homeostasis and the host immune response, while changes in normal physiologic skin microbiome composition and pathologic bacteria contribute to skin diseases. We also summarize the major steps in wound healing and how obesity affects each of them. The role that immune cells have in this process is also described. Although the studies summarized in this review clearly demonstrate the deleterious effects of obesity on wound healing, additional studies are needed to better characterize the cellular and molecular mechanisms involved and identify specific targets of intervention.

Multiple symmetric and multiple familial lipomatosis

Lipomas are the most common soft tissue tumors and are malignant in only 1% of cases. Lipomatosis is defined as the presence of multiple benign lipomas on the body, without lipoatrophy. Their impact on quality of life is significant. Different entities have been described such as symmetrical multiple lipomatosis (MSL), also called Madelung's disease and familial multiple lipomatosis (FML). MSL occurs preferentially in men (but also women) who are alcohol abuser. There are different subtypes of the disease, the most classic of which affects the upper body and the nuchal region with a buffalo hump appearance. A metabolic component with obesity is frequent. In contrast to Dercum's disease, there is no pain. SAOS, complications of the metabolic syndrome and of alcohol abuse including cancers, may be associated and should be screened. FML has been little described in the literature since Brodie's first report in 1846. FML occurs preferentially in the third decade but equally in women and men. Its autosomal dominant component is classically accepted with variable penetrance within the same family. Association with naevi, angiomas, polyneuropathies and with gastrointestinal comorbidities has been reported. Interestingly, and in contrast with most lipodystrophy disorders, the patients show an insulin sensitivity profile. A better understanding of the underlying pathophysiological mechanisms would open up avenues on therapeutic research, since treatments are only symptomatic to date.

Mass-Like Fat at the Medial Midfoot: A Common Pseudolesion

Background Fatty masses are common and may be encountered in the foot and ankle. In some cases, normal subcutaneous fat may be mistaken for a discrete mass.

Aims The aim of this study was to evaluate the common finding of prominent subcutaneous fat at the medial midfoot resembling a lipoma and to determine the prevalence of this pseudolesion by applying a series of potential size cutoff criteria.

Materials and Methods Three musculoskeletal radiologists retrospectively evaluated 91 sequentially performed magnetic resonance imaging examinations of the ankle to measure fat resembling a discrete lipoma at the medial midfoot. Each blinded reader measured the largest area of continuous subcutaneous fat in orthogonal axial, coronal craniocaudal, and coronal transverse dimensions. Patient age, sex, and study indications were also recorded. Statistical analysis was performed with R and SAS 9.4 software

Results A discrete fatty pseudolesion as defined by measuring at least 1 cm in all planes by measurements of at least two of three readers was present in 87% of cases (79 of 91). When a size criterion of 1.5 cm was used, a pseudolesion was documented in 14% of cases (13 of 91). There was a significant correlation between larger pseudolesion size and female sex in the axial plane; however, there was no correlation in the coronal craniocaudal and coronal transverse dimensions.

Conclusions Subcutaneous fat at the medial midfoot often has a mass-like appearance that could be mistaken for a lipoma. It is important to recognize this pseudolesion variant and not to confuse the imaging appearance for a discrete mass.

Rapid Depletion of Subcutaneous Adipose Tissue during Sorafenib Treatment Predicts Poor Survival in Patients with Hepatocellular Carcinoma

The aim of this study was to assess the annualized changes in body composition, including skeletal muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) before, during, and after sorafenib treatment in patients with hepatocellular carcinoma (HCC). This retrospective study evaluated 61 HCC patients treated with sorafenib. Annualized changes (Δ; cm2/m2/year) in skeletal muscle index (SMI), SAT index (SATI), and VAT index (VATI), which were defined as the cross-sectional areas (cm2) of those areas on computed tomography normalized by the square of one's height (m2), before (pre), during (during), and after (post) sorafenib treatment, were calculated. Patients within the 20th percentile cutoffs for these indices were classified into the rapid depletion group and the effects of these values on survival were analyzed using the Kaplan-Meier analysis and Cox proportional-hazards model. Annualized depletion rates of SMI (ΔSMIpre: -3.5, ΔSMIduring: -3.5, ΔSMIpost: -8.0) and VATI (ΔVATIpre: -3.2, ΔVATIduring: -2.8, ΔVATIpost: -15.1) accelerated after the cancellation of sorafenib, whereas that of SATI (ΔSATIpre: -4.8, ΔSATIduring; -7.6, ΔSATIpost; -8.0) had already accelerated during sorafenib treatment. Patients with rapid depletion of ΔSATIduring experienced significantly worse survival rates (p < 0.001), and it was an independent predictor of survival (p = 0.009), together with therapeutic effect (p < 0.001). Rapid depletion of SAT during sorafenib treatment can be used to predict survival in patients with HCC.