Effects of abdominal visceral fat compared with those of subcutaneous fat on the association between PM10 and hypertension in Korean men: A cross-sectional study

Parameters of body composition do not predict survival in patients with multiple myeloma undergoing autologous stem cell transplantation

Studies regarding the influence of body composition parameters as predictors on overall survival (OS) in patients with multiple myeloma (MM) are scarce. OS and progression-free survival (PFS) were retrospectively assessed in 129 patients with MM undergoing autologous stem cell transplantation (ASCT) after a follow-up of 2 years. A computed tomography (CT) based semi-automated assessment of body composition was performed. No statistically significant differences were noted in 2-year OS, PFS, or post-transplant adverse events in the body composition groups of subcutaneous adipose tissue (SAT) (low vs. high-SAT), visceral adipose tissue (VAT) (low vs. high-VAT), visceral-to-subcutaneous fat ratio (VSR) (low vs. high VSR), and sarcopenia in terms of skeletal muscle index (SMI) (non-sarcopenic vs. sarcopenic). In conclusion, adipose and muscle tissue do not limit OS or affect the PFS in patients with MM undergoing ASCT.

Effects of the abdominal fat distribution on the relationship between exposure to air pollutants and thyroid hormones among Korean adult males

BACKGROUND

Several significant associations between air pollution and thyroid function have been reported, but few studies have identified whether these associations differ by obesity, particularly its regional distribution. We assessed the relationship between ambient air pollution and thyroid hormone, and whether this relationship is modified by abdominal adiposity, as indicated by the waist circumference, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and visceral-to-subcutaneous fat ratio (VSR) in Korean men.

METHODS

We included 2440 male adults in the final analysis and used each person's annual average exposure to four air pollutants: particulate matter with an aerodynamic diameter ≤ 10 μm (PM10), nitrogen dioxide, sulfur dioxide (SO2), and carbon monoxide (CO). Abdominal fat deposition was quantified by computed tomography. Serum thyrotropin (TSH) and free thyroxine (FT4) concentrations were measured for thyroid hormone. To evaluate the relationship between air pollution and thyroid hormone according to adiposity, we performed multiple linear regression analysis on the two subgroups stratified by abdominal fat level.

RESULTS

Abdominal adiposity was significantly related to FT4 concentration. The exposures to air pollutants were associated with increased TSH and decreased FT4 concentrations. In stratified analysis using abdominal fat traits, ambient air pollution except for SO2 was significantly related to increased TSH and decreased FT4 concentrations in the high adiposity group (all p < 0.05), but not in the normal adiposity group. Among the air pollutants, PM10 showed an association with an increase of TSH concentration in all group with high adiposity, including high VAT, high SAT, and high VSR groups (all p < 0.05). In case of FT4, CO showed a similar pattern. Among the abdominal fat-related traits, the VSR in the high adiposity group had the largest effect on the relationship between exposure to air pollutants and thyroid hormone.

CONCLUSIONS

This study suggests the first clue that the relationship between air pollution exposure and thyroid hormone differs according to abdominal fat distribution among Korean adult males.

A genome-wide by PM10 exposure interaction study for blood pressure in Korean adults

Blood pressure (BP) is a typical complex trait, and the genetic susceptibility of individuals to changes in BP induced by air pollution exposure is different. Although interactions of exposure to air pollutants with several candidate genes have been identified, genome-wide interaction studies (GWISs) are needed to understand the association between them with BP. Therefore, we aimed to discover the unique genetic loci for BP that interact with exposure to air pollutants in Korean adults. We ultimately included 1868 participants in the discovery step and classified them into groups of those with low-to-moderate exposure and high exposure to average annual concentration of particulate matter with an aerodynamic diameter ≤ 10 μm (PM10). Because none of the single nucleotide polymorphisms (SNPs) achieved a genome-wide level of significance of pint < 5 × 10-8 for either systolic BP (SBP) or diastolic BP (DBP), we considered the top 10 ranking SNPs for each BP trait. To validate these suggestive SNPs, we finally selected six genetic variants for SBP and five variants for DBP, respectively. In a replication result for SBP, only one SNP (rs12914147) located in an intergenic region of the NR2F2 showed a significant interaction. We also identified several genetic susceptibility loci (e.g., CHST11, TEK, and ITGA1) implicated in candidate mechanisms such as inflammation and oxidative stress in the discovery step, although their interaction effects were not replicated. Our study reports the first GWIS finding to our knowledge, and the association between exposure to PM10 and BP levels may be determined in part by several newly discovered genetic suggestive loci, including NR2F2.

Obesity-related hypertension and chronic kidney disease: from evaluation to management

With the recent obesity pandemic, obesity-related hypertension and its complications (e.g., heart failure, coronary disease, and chronic kidney disease [CKD]) are gaining attention in clinical and research fields. Obesity-related hypertension frequently precedes the onset of CKD and aggravates its progression. In this review, we discuss the role of visceral fat in the pathophysiology of obesity-related hypertension and the potential therapeutic strategies for its prevention and management. Various factors, including the sympathetic nervous system, renin-angiotensin-aldosterone system, and inflammatory pathways, are intricately involved in the pathogenesis of obesity-related hypertension. These factors individually and jointly contribute to the development of hypertension (usually sodium-sensitive or resistant hypertension) and, ultimately, to the progression of CKD. From a clinical standpoint, a decline in renal function in advanced CKD further makes blood pressure control challenging since only a few options are available for blood pressure-lowering medications. Proactive lifestyle modification, pharmacological treatment for obesity, and bariatric surgery can be considered for obesity control and management. Furthermore, intensive blood pressure control is required to prevent and halt the development and progression of CKD.

Association Between Abdominal Adipose Tissue Distribution and Risk of Endometrial Cancer: A Case-Control Study

Background:

Obesity contributes to endometrial cancer (EC). However, it is not clear whether the distribution of adipose tissue affects the occurrence of endometrial carcinoma. This study aimed to evaluate the relationship between abdominal adipose tissue distribution and EC.

Methods:

We designed a case-control study with 115 women with EC and a control group. The total abdominal adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue were measured by single slice computerized tomography at the level of umbilicus. Univariate and multivariate logistic regression models were used to calculate odds ratios (ORs) for the risk of EC associated with adipose tissue distribution. Furthermore, we analyzed the correlation between adipose tissue distribution and clinicopathologic features of endometrial carcinoma.

Results:

Multivariate analysis showed that a larger visceral adipose tissue ratio was associated with an increased risk of EC after adjusting for body mass index (BMI) and diabetes (OR = 1.046, 95% confidence interval = [1.008-1.079]). The ratio of International Federation of Obstetrics and Gynecology (FIGO) stage I and type I EC was higher in EC patients with larger visceral adipose tissue (84.5% vs 63.2%, P = .009; 91.4% vs 75.4%, P = .021). There was a higher positive ratio of progesterone receptor in EC patients with a larger subcutaneous adipose tissue area (91.2% vs 77.6%; P = .044).

Conclusions:

Higher visceral adipose tissue ratio, independent of BMI, was associated with an increased risk of EC. Therefore, this study demonstrated that women with normal BMI, but abnormal abdominal adipose tissue distribution, have an increased risk for EC.

A Genome-Wide Association Study on Abdominal Adiposity-Related Traits in Adult Korean Men

INTRODUCTION

Although previous genome-wide association studies (GWASs) have identified genetic susceptibility loci for abdominal adiposity, GWASs on Asian samples remain scarce. Therefore, we performed a GWAS for abdominal adipose tissue depots in a Korean population.

METHODS

A total of 1,937 Korean men were included in the study. Areas of abdominal fat were quantified by computed tomography. We performed a GWAS analysis under an additive model, and a replication study was conducted on 480 additional Korean adult men.

RESULTS

In the discovery step, we identified a total of 10 single-nucleotide polymorphisms (SNPs) associated with adiposity indicators (p < 1 × 10-5). The top SNP, rs1028014, for visceral adipose tissue (VAT) was located in the ZMAT4 gene and remained significant after adjustment for body mass index (BMI). Three additional SNPs were also associated with VAT-adj-BMI and located within the SLC26A10, FAM155A, and COL4A1-COL4A2 genes, respectively. In addition, we identified a SNP (rs4668224) of the MYO3B gene for visceral-to-subcutaneous fat ratio. For subcutaneous adipose tissue and total adipose tissue, two (rs6585735 and rs363527) and three SNPs (rs1487892, rs9357565, and rs1985358) were found, respectively. Overall, eight SNPs were used in the replication study; however, none of the SNPs reached our level of significance for replication (p < 0.0063). Nevertheless, rs4773144 of COL4A1-COL4A2 for VAT-adj-BMI was the most interesting SNP identified in previous GWASs for coronary artery disease (based on the same risk allele "G"), along with functional effects.

CONCLUSION

This study suggests for the first time that an SNP (rs4773144) of COL4A1-COL4A2 may contribute to the increase in VAT level, especially in adult Korean men.

Long Non-Coding RNAs in Brown Adipose Tissue

Obesity has become a widespread disease that is harmful to human health. Fat homeostasis is essentially maintained by fat accumulation and energy expenditure. Studies on brown adipose tissue (BAT) represent a promising opportunity to identify a pharmaceutical intervention against obesity through increased energy expenditure. Long non-coding RNAs (lncRNAs) were thought to be critical regulators in a variety of biological processes. Recent studies have revealed that lncRNAs, including ones that are BAT-specific, conserved, and located at key protein-coding genes, function in brown adipogenesis, white adipose browning (ie, beige adipogenesis), and brown thermogenesis. In this review, we describe lncRNA properties and highlight functional lncRNAs in these biological processes, with the goal of establishing links between lncRNAs and BAT. Based on the advances of lncRNAs in the regulation of BAT, we discussed the advantages of potential lncRNA-based obesity drugs. Further BAT lncRNA-based drug development may provide new exciting approaches to defend obesity by regulation of fat homeostasis.

Hepatoprotective Effects of Streptococcus thermophilus LM1012 in Mice Exposed to Air Pollutants

In this study, we explored whether the use of Streptococcus thermophilus LM1012 (TL-LM1012) as a safe probiotic exerts hepatoprotective effects by suppressing oxidative stress and inflammation in vitro and alleviating aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) production in vivo. In a series of safety tests, TL-LM1012 was found to have a negative response to hemolysis and biogenic amines, as well as susceptibility to antibiotics. TL-LM1012 protected cell viability and suppressed cytotoxicity by inhibiting oxidative stress and induced heme oxygenase-1 and superoxide dismutase activity in a dose-dependent manner in diesel exhaust particulate matter (DEPM)-treated HepG2 cells. Moreover, proinflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6, and IL-1β, were suppressed in DEPM-treated splenocytes. In DEPM-treated mice, oral administration of TL-LM1012 regulated AST, ALT, and LDH production in the serum after 14 days of treatment. These findings indicate that TL-LM1012, a safe probiotic, provides a potent preventive or therapeutic effect against liver disease caused by air pollution.

Genome-wide identification and characterization of long non-coding RNAs during differentiation of visceral preadipocytes in rabbit

Emerging evidence suggests that long non-coding RNAs (lncRNAs) are critical regulators of diverse biological processes, including adipogenesis. Despite being considered an ideal animal model for studying adipogenesis, little is known about the roles of lncRNAs in the regulation of rabbit preadipocyte differentiation. In the present study, visceral preadipocytes isolated from newborn rabbits were cultured in vitro and induced for differentiation, and global lncRNA expression profiles of adipocytes collected at days 0, 3, and 9 of differentiation were analyzed by RNA-seq. A total of 2066 lncRNAs were identified from nine RNA-seq libraries. Compared to protein-coding transcripts, lncRNA transcripts exhibited characteristics of a longer length and lower expression level. Furthermore, 486 and 357 differentially expressed (DE) lncRNAs were identified when comparing day 3 vs. day 0 and day 9 vs. day 3, respectively. Target genes of DE lncRNAs were predicted by the cis-regulating approach. Prediction of functions revealed that DE lncRNAs when comparing day 3 vs. day 0 were involved in gene ontology (GO) terms of developmental growth, growth, developmental cell growth, and stem cell proliferation, and involved in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of PI3K-Akt signaling pathway, fatty acid biosynthesis, and the insulin signaling pathway. The DE lncRNAs when comparing day 9 vs. day 3 were involved in GO terms that associated with epigenetic modification and were involved in the KEGG pathway of cAMP signaling pathway. This study provides further insight into the regulatory function of lncRNAs in rabbit visceral adipose and facilitates a better understanding of different stages of preadipocyte differentiation.