Transcriptional Features of Cattle Visceral and Subcutaneous Adipose Tissues: A Study of RNA-seq

Visceral and subcutaneous are the two major types of bovine adipose tissues, and they show metabolic and functional differences according to their distribution, exploring the transcriptional features of visceral and subcutaneous adipose tissues is necessary. In the present study, we conducted RNA-seq analysis to compare the transcriptome between visceral (great omental) and subcutaneous (backfat) adipose tissues from Chinese Simmental cattle and validate them by qRT-PCR. We found that 5864 genes were differentially expressed between two tissues, including 2979 up-regulated and 2885 down-regulated in visceral adipose tissue. Functional analysis revealed a variety of differentially expressed genes (DEGs) involved in lipid metabolism and immune response processes. This may provide valuable information to further our understanding of the complexity of gene regulation governing the physiology of different fat depots. This work highlighted potential genes regulating lipid metabolism and immune responses;it may contribute to a better understanding of the metabolic and functional differences between visceral and subcutaneous adipose tissues.

Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders.These people store fat in subcutaneous adipose tissue(SAT)rather than in visceral adipose tissue(VAT).However,the molecules participating in this specific scenario remain elusive.Rab18,a lipid droplet(LD)-associated protein,mediates the contact between the endoplasmic reticulum(ER)and LDs to facilitate LD growth and maturation.In the present study,we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice.Rab18 adipocyte-specific knockout(Rab18 AKO)mice had a decreased volume ratio of SAT to VAT compared with wildtype mice.When subjected to high-fat diet(HFD),Rab18 AKO mice had increased ER stress and inflammation,reduced adiponectin,and decreased triacylglycerol(TAG)accumulation in SAT.In contrast,TAG accumulation in VAT,brown adipose tissue(BAT)or liver of Rab18AKO mice had a moderate increase without ER stress stimulation.Rab18 AKO mice developed insulin resistance and systematic inflammation.Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT,similar to the counterpart mice.Furthermore,Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress,indicating the involvement of Rab18 in alleviating lipid toxicity.Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT.In conclusion,our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

Prepartum dietary energy intake alters adipose tissue transcriptome profiles during the periparturient period in Holstein dairy cows

Background:The aim of the study was to investigate the effect of energy overfeeding during the dry period on adipose tissue transcriptome profiles during the periparturient period in dairy cows.Methods:Fourteen primiparous Holstein cows from a larger cohort receiving a higher-energy diet(1.62 Mcal of net energy for lactation/kg of dry matter;15%crude protein)for ad libitum intake to supply 150%(OVR)or 100%(CTR)of energy requirements from dry off until parturition were used.After calving,all cows received the same lactation diet.Subcutaneous adipose tissue(SAT)biopsies were collected at−14,1,and 14d fromparturition(d)and used for transcriptome profiling using a bovine oligonucleotide microarray.Data mining of differentially expressed genes(DEG)between treatments and due to sampling time was performed using the Dynamic Impact Approach(DIA)and Ingenuity Pathway Analysis(IPA).Results:There was a strong effect of over-feeding energy on DEG with 2434(False discovery rate-corrected P<0.05)between OVR and CTR at−14 d,and only 340 and 538 at 1 and 14 d.The most-impacted and activated pathways in the Kyoto Encyclopedia of Genes and Genomes(KEGG)database that were highlighted by DIA analysis at−14 d in OVR vs.CTR included 9 associated with carbohydrate metabolism,with‘Pyruvate metabolism’,‘Glycolysis/gluconeogenesis’,and‘Pentose phosphate pathway’among the most-activated.Not surprisingly,OVR led to marked activation of lipid metabolism(e.g.‘Fatty acid biosynthesis’and‘Glycerolipid metabolism’).Unexpected metabolic pathways that were activated at−14 d in OVR included several related to metabolism of amino acids(e.g.branched chain)and of cofactors and vitamins(thiamin).Among endocrine and immune system pathways,at−14 d OVR led to marked activation of‘PPAR signalling’and‘Antigen processing and presentation’.Among key pathways affected over time in OVR,a number were related to translation(e.g.mTOR signaling),endocrine/immune signaling(CXCR4 and IGF1),and lipid metabolism(oxidative phosphorylation)with greater activation in OVR vs.CTR specifically at−14 d.Although statistical differences for several pathways in OVR vs.CTR nearly disappeared at 1 and 14 vs.−14 d,despite the well-known catabolic state of adipose depots after calving,the bioinformatics analyses suggested important roles for a number of signaling mechanisms at−14 vs.14 than 1 vs.-14 d.This was particularly evident in cows fed to meet predicted energy requirements during the dry period(CTR).Conclusions:Data underscored a strong activation by overfeeding energy of anabolic processes in the SAT exclusively prepartum.The study confirmed that higher-energy diets prepartum drive a transcriptional cascade of events orchestrated in part by the activation of PPARγthat regulate preadipocyte differentiation and lipid storage in SAT.Novel aspects of SAT biology to energy overfeeding or change in physiologic state also were uncovered,including the role of amino acid metabolism,mTOR signaling,and the immune system.

Characteristics and mechanisms of subcutaneous and visceral adipose tissue aging

Aging is one of the most significant health challenges worldwide and is a primary cause of chronic diseases and physiological decline.Among the myriad changes that occur with aging,alterations in adipose tissue distribution and function have gained considerable attention because of their profound impact on metabolic health and overall well-being.Subcutaneous adipose tissue(SAT)and visceral adipose tissue(VAT)are the two major depots of white adipose tissue,each with distinct roles in metabolism and health.Understanding the characteristics and underlying mechanisms of SAT and VAT is crucial for elucidating the aging process and developing strategies to promote healthy aging.This review focuses on delineating and analyzing the characteristics and intrinsic mechanisms underlying the aging of subcutaneous and visceral adipose tissue during the aging process,which can contribute to a better understanding of the aging process and enhance healthy aging.

Adipose stromal/stem cells in regenerative medicine:Potentials and limitations

This article presents the stem and progenitor cells from subcutaneous adipose tissue,briefly comparing them with their bone marrow counterparts,and discussing their potential for use in regenerative medicine.Subcutaneous adipose tissue differs from other mesenchymal stromal/stem cells(MSCs)sources in that it contains a pre-adipocyte population that dwells in the adventitia of robust blood vessels.Pre-adipocytes are present both in the stromal-vascular fraction(SVF;freshly isolated cells)and in the adherent fraction of adipose stromal/stem cells(ASCs;in vitro expanded cells),and have an active role on the chronic inflammation environment established in obesity,likely due their monocyticmacrophage lineage identity.The SVF and ASCs have been explored in cell therapy protocols with relative success,given their paracrine and immunomodulatory effects.Importantly,the widely explored multipotentiality of ASCs has direct application in bone,cartilage and adipose tissue engineering.The aim of this editorial is to reinforce the peculiarities of the stem and progenitor cells from subcutaneous adipose tissue,revealing the spheroids as a recently described biotechnological tool for cell therapy and tissue engineering.Innovative cell culture techniques,in particular 3D scaffold-free cultures such as spheroids,are now available to increase the potential for regeneration and differentiation of mesenchymal lineages.Spheroids are being explored not only as a model for cell differentiation,but also as powerful 3D cell culture tools to maintain the stemness and expand the regenerative and differentiation capacities of mesenchymal cell lineages.

Determinants of Regional Obesity (Visceral and Subcutaneous Obesity) within Cardiovascular Risk Factors in the Cardiology Department of the University Clinics of Kinshasa

Objective: This study aimed to determine searching for the determinants of regional obesity (visceral and subcutaneous obesity) within the cardiovascular risk factors (CVRF) in patients followed in cardiology at the University Clinics of Kinshasa (UCK) in the Democratic Republic of Congo (DRC). Material and Methods: Cross-sectional and analytical study had sought the determinants of regional obesity (visceral and subcutaneous obesity) by bio-impedance inside the CVRF during the period from July 1 to September 31, 2014. The multivariate analysis (logistic regression) has established the levels of association between regional obesity and CVRF. The statistical significance threshold was set at p Results: A total of 642 patients participated in the present study. The frequencies of visceral and subcutaneous obesity were respectively 45.5% (without significant distinction between the two sexes: Men 48% n = 92/188 vs. Women 44.1 n = 200/454;p = 0.148) and 60.7% with a predominance in women (36.2 n = 68/188 vs. 70.9% n = 322/454;p that alongside regional obesity was: advanced age, tobacco use, alcohol use, physical inactivity, high blood pressure (HBP), diabetes mellitus (DM) and Chronic renal failure (CRF) in the respective proportions of 50.8%, 13.4%, 44.2%, 86.3%, 10.7%, 13.4% and 0.3%. The determinants of regional obesity were advanced age, smoking and obesity on body mass index (BMI) for visceral obesity;advanced age, female gender, alcohol intake and obesity on BMI and waist circumference (WC) as well as hypertriglyceridemia for subcutaneous obesity. Conclusion: This study showed a significant frequency of regional obesity with the following determinants: advanced age, female gender, smoking, alcohol, BMI/WC obesity and hypertriglyceridemia.

Dissecting the Contributing Role of Divergent Adipose Tissue to Multidimensional Frailty in Cirrhosis

Background and Aims:Emerging evidence has demonstrated that abnormal body composition may potentiate the development of frailty,whereas little work focuses on the role of divergent adipose tissue.Therefore,we aimed to determine the potential contribution of adipose tissue distribution to multidimensional frailty in decompensated cirrhosis.Methods:We conducted a retrospective cohort study.Divergent adipose tissues were assessed by computed tomography-derived subcutaneous adipose tissue index(SATI),visceral adipose tissue index(VATI)and total adipose tissue index(TATI),respectively.Frailty was identified by our validated self-reported Frailty Index.Multiple binary logistic models incorporating different covariates were established to assess the relationship between adipose tissue distribution and frailty.Results:The study cohort comprised 245 cirrhotic patients with 45.3%being male.The median Frailty Index,body mass index(BMI)and model for end-stage liver disease(MELD)score were 0.11,24.3 kg/m2 and 8.9 points,respectively.In both men and women,patients who were frail exhibited lower levels of SATI in comparison with nonfrail patients.SATI inversely correlated with Frailty Index in the entire cohort(rs=−0.1361,p=0.0332).Furthermore,SATI or TATI was independently associated with frail phenotype in several multiple logistic regression models adjusting for age,BMI,presence of ascites,sodium,Child-Pugh class or MELD score in isolation.Conclusions:In the context of decompensated cirrhosis,low SATI and concomitant TATI were associated with higher risk of being frail.These findings highlight the importance to further apply tissue-specific tools of body composition in place of crude metric like BMI.

Preoperative Assessment of Abdominal Adipose Tissue to Predict Microvascular Invasion in Small Hepatocellular Carcinoma

Background and Aims:Microvascular invasion(MVI)affects recurrence after treatment of small hepatocellular carcinoma(sHCC)of≤3 cm in size.The present study aimed to investigate whether abdominal subcutaneous adipose tissue(SAT),visceral adipose tissue(VAT),and intermuscular adipose tissue(IMAT)are associated with MVI in patients with sHCC.Methods:A total of 124 patients with pathologicallyconfirmed sHCC diagnosed on surgical resection at the First Hospital Affiliated to Army Military University were recruited and divided into two groups according to MVI classification criteria(i.e.,MVI-positive or MVI-negative).The SAT,VAT,and IMAT areas at the lumbar 3 vertebral level were imaged with abdominal computed tomography and measured using ImageJ software.Their association with MVI in sHCC was analyzed.Results:Of the 124 patients with sHCC,67 were MVIpositive and 57 were MVInegative.Univariate analysis revealed a significant difference in the abdominal VAT and SAT between the MVI-positive and MVI-negative groups(p<0.05),with an area under the receiver operating characteristic curve of 0.76 and 0.65,respectively.Conclusions:The results of this study suggest that the areas of abdominal SAT and VAT are of significant clinical value because they can effectively predict the MVI status in patients with sHCC.

Semi-automated segmentation of magnetic resonance images for thigh skeletal muscle and fat using threshold technique after spinal cord injury

Magnetic resonance imaging is considered the ＂gold standard＂ technique for quantifying thigh muscle and fat cross-sectional area. We have developed a semi-automated technique to segment seven thigh compartments in persons with spinal cord injury. Thigh magnetic resonance images from 18 men（18–50 years old） with traumatic motor-complete spinal cord injury were analyzed in a blinded fashion using the threshold technique. The cross-sectional area values acquired by thresholding were compared to the manual tracing technique. The percentage errors for thigh circumference were（threshold： 170.71 ± 38.67; manual： 169.45 ± 38.27 cm2） 0.74%, subcutaneous adipose tissue（threshold： 65.99±30.79; manual： 62.68 ± 30.22） 5.2%, whole muscle（threshold： 98.18 ± 20.19; manual： 98.20 ± 20.08 cm2） 0.13%, femoral bone（threshold： 6.53 ± 1.09; manual： 6.53 ± 1.09 cm2） 0.64%, bone marrow fat（threshold： 3.12 ± 1.12; manual： 3.1 ± 1.11 cm2） 0.36%, knee extensor（threshold： 43.98 ± 7.66; manual： 44.61 ± 7.81 cm2） 1.78% and % intramuscular fat（threshold： 10.45 ± 4.29; manual： 10.92 ± 8.35%） 0.47%. Collectively, these results suggest that the threshold technique provided a robust accuracy in measuring the seven main thigh compartments, while greatly reducing the analysis time.

A comparative study on the tolerance of tilapia(Oreochromis niloticus)to high carbohydrate and high lipid diets

A 12-wk trial was conducted to compare the tolerance of tilapia to high carbohydrate and high lipid diets.Three isonitrogenous and isoenergetic diets,whose carbohydrate and lipid levels were the following:35.0%and 8%(control),44.2%and 4%(D1,high carbohydrate),and 25.8%and 12%(D2,high lipid),respectively.Three hundred tilapias(27±0.11 g)were fed the diets for 10 wk(4 replicates per group);72 fish from the D1 group were continually fed the D1(D1D1)and 72 fish from the D2 were continually fed the D2(D2D2)diet for 2 wk(3 replicates each group)to evaluate the tilapia's capacity to tolerate high carbohydrate and high lipid diets,respectively.Another 36 fish from D1 group were continually fed D2(D1D2)for comparison with D1D1 and D2D2 groups.In phase 1,hepatosomatic index,liver triglycerides(TG),glucose tolerance(GT)and crude protein in the whole body in D1 group were higher than those in D2 group(P<0.05).During phase 2,D1D1 group had lower feed intake and weight gain,as well as lower serum total protein and albumin than that of D2D2 group(P<0.05),while its liver glycogen was significantly higher than that in D1D2 and D2D2 groups(P<0.05).Moreover,serum glucose and GT were higher in D1D1 and D1D2 groups than those in D2D2 group(P<0.05).By contrast,D2D2 group had significantly higher intraperitoneal fat,subcutaneous adipose tissue(SCAT)and liver TG than those in D1D1 group(P<0.05).The mRNA expression of brain npy,hepatic nrf2,gst1 and hepatic transcriptomic data showed that immune-related genes(gama,mrc2,mhc2 and cd163),were downregulated in D1D1 group compared to D2D2 and D1D2 groups.Taken together:1)tilapia have higher tolerance to a high lipid diet than high carbohydrate diet;2)despite retention of glucose tolerance,the continuous feeding of D1 diet impaired tilapia's appetite,weight gain rate and host immune response;3)specific distri-bution of fat in intraperitoneal regions,SCAT and liver may be a risk-avoidance strategy in tilapia in response to a continuous D2 diet.

Sex-and age-specific associations between abdominal fat and non-alcoholic fatty liver disease:a prospective cohort study

Obesity is closely related to non-alcoholic fatty liver disease(NAFLD).Although sex differences in body fat distribution have been well demonstrated,little is known about the sex-specific associations between adipose tissue and the development of NAFLD.Using community-based cohort data,we evaluated the associations between magnetic resonance imaging quantified areas of abdominal adipose tissue,including visceral adipose tissue(VAT)and subcutaneous adipose tissue(SAT),and incident NAFLD in 2830 participants(1205 males and 1625 females)aged 55–70 years.During a 4.6-year median follow-up,the cumulative incidence rates of NAFLD increased with areas of VAT and SAT both in males and in females.Further analyses showed that the abovementioned positive associations were stronger in males than in females,especially in participants under 60 years old.In contrast,these sex differences disappeared in those over 60 years old.Furthermore,the risk of developing NAFLD increased non-linearly with increasing fat area in a sex-specific pattern.Additionally,sex-specific potential mediators,such as insulin resistance,lipid metabolism,inflammation,and adipokines,may exist in the associations between adipose tissue and NAFLD.This study showed that the associations between abdominal fat and the risk of NAFLD were stratified by sex and age,highlighting the potential need for sex-and age-specific management of NAFLD.