Longitudinal Increases in Adiposity Contribute to Worsening Adipokine Profile over Time in Mexican Americans

The Association of Resistin with Metabolic Health and Obesity in a Mexican-American Population

Research on the relationship between resistin levels, metabolic health, and obesity has produced inconsistent findings across different ethnic groups, making it unclear whether lower resistin levels are associated with these conditions in Mexican-Americans. This cross-sectional study investigated the relationship between resistin, metabolic health, and obesity in an adult Mexican-American cohort (n = 1511) using multivariable linear regression analysis. Related adipokines (leptin and adiponectin) were measured simultaneously. Participants were categorized into four groups by metabolic health (healthy/unhealthy) and obesity (obese/non-obese) status. "Metabolically unhealthy" was defined as ≥2 cardiometabolic abnormalities. Obesity was defined as a BMI ≥ 30 kg/m2. We also investigated the associations of related proinflammatory cytokines, demographic/anthropometric variables, and medications with each outcome variable of interest. The results showed no statistically significant differences in resistin levels between the groups. Leptin was higher and adiponectin was lower in groups with obesity and/or metabolically unhealthy status. The resistin findings contrast studies in other populations, while other leptin and adiponectin findings confirm those seen in many ethnic groups. Thiazolidinedione use was associated with lower resistin, confirming earlier research. These findings suggest that resistin's role in metabolic health may be different in Mexican-Americans compared to other populations.

Increases in BMI contribute to worsening inflammatory biomarkers related to breast cancer risk in women: a longitudinal study

BACKGROUND

Inflammatory adipokines and cytokines play a pivotal role in linking obesity and breast cancer (BC) risk in women. We investigated the longitudinal associations between BMI change and trajectories of inflammatory biomarkers related to BC risk.

METHODS

A longitudinal study was conducted among 442 Chinese women with 3-year repeated measures from 2019 to 2021. Plasma circulating inflammatory biomarkers related to BC risk, including adiponectin (ADP), resistin (RETN), soluble leptin receptor (sOB-R), insulin-like growth factor-binding protein-3 (IGFBP-3), and C-reactive protein (CRP), were examined annually. Linear mixed-effect models (LMM) were applied to investigate associations of time-varying BMI with trajectories of biomarkers. We additionally examined the modification effect of baseline BMI groups, menopausal status, and metabolic syndrome.

RESULTS

BMI was associated with increased levels of RETN, CRP, sOB-R, and decreased levels of ADP at baseline. An increasing BMI rate was significantly associated with an average 3-year increase in RETN (β = 0.019, 95% CI 0.004 to 0.034) and sOB-R (β = 0.022, 95% CI 0.009 to 0.035), as well as a decrease in ADP (β =  - 0.006, 95% CI  - 0.012 to 0.001). These associations persisted across different baseline BMI groups. An increasing BMI rate was significantly associated with an average 3-year increase in CRP levels among normal weight (β = 0.045, 95% CI 0.001 to 0.088) and overweight (β = 0.060, 95% CI 0.014 to 0.107) women. As BMI increased over time, a more remarkable decrease in ADP was observed among women with metabolic syndrome (β =  - 0.016, 95% CI - 0.029 to - 0.004) than those without metabolic syndrome at baseline.

CONCLUSIONS

A higher increase rate of BMI was associated with poorer trajectories of inflammatory biomarkers related to BC risk. Recommendations for BMI reduction may benefit BC prevention in women, particularly for those with metabolic syndrome.

Serum Levels of IL-1 RA Increase with Obesity and Type 2 Diabetes in Relation to Adipose Tissue Dysfunction and are Reduced After Bariatric Surgery in Parallel to Adiposity

Background

Excess adiposity leads to a dysfunctional adipose tissue that contributes to the development of obesity-associated comorbidities such as type 2 diabetes (T2D). Interleukin-1 receptor antagonist (IL-1RA) is a naturally occurring antagonist of the IL-1 receptor with anti-inflammatory properties. The aim of the present study was to compare the circulating concentrations of IL-1RA and its mRNA expression in visceral adipose tissue (VAT) in subjects with normal weight (NW), obesity with normoglycemia (OB-NG), or obesity with impaired glucose tolerance or T2D (OB-IGT&T2D) and to analyze the effect of changes in body fat percentage (BF%) on IL-1RA levels.

Methods

Serum concentrations of IL-1RA were measured in 156 volunteers. Expression of IL1RN mRNA in VAT obtained from 36 individuals was determined. In addition, the concentrations of IL-1RA were measured before and after weight gain as well as weight loss following a dietetic program or Roux-en-Y gastric bypass (RYGB).

Results

Serum levels of IL-1RA were significantly increased in individuals with obesity, being further increased in the OB-IGT&T2D group (NW 440 ± 316, OB-NG 899 ± 562, OB-IGT&T2D 1265 ± 739 pg/mL; P<0.001) and associated with markers of inflammation and fatty liver. IL1RN mRNA expression in VAT was significantly increased in the OB-IGT&T2D group and correlated in the global cohort with the mRNA expression of SPP1, CCL2, CD68, and MMP9. Levels of IL-1RA were not modified after modest changes in BF%, but RYGB-induced weight loss significantly decreased IL-1RA concentrations from 1233 ± 1009 to 660 ± 538 pg/mL (P<0.001).

Conclusion

Serum IL-1RA concentrations are increased in patients with obesity being further elevated in obesity-associated IGT and T2D in association with markers of adipose tissue dysfunction. The mRNA expression of IL1RN is markedly increased in VAT of subjects with obesity and T2D in relation with genes involved in macrophage recruitment, inflammation and matrix remodeling. Serum IL-1RA concentrations are reduced when a notable amount of BF% is loss. Measurement of IL-1RA is an excellent biomarker of adipose tissue dysfunction in obesity-associated metabolic alterations.

Resistin levels decrease as insulin resistance increases in a Mexican-American cohort

AIMS

Links between resistin, insulin resistance (IR), and resistin-stimulated cytokine signaling remain unknown in Mexican-Americans. A Mexican-American cohort was examined to determine (1) relationships between circulating resistin and IR, (2) resistin's associations with cytokines and demographic and anthropometric variables, and (3) similar measurements with other adipokines.

METHODS

For cross sectional analyses, 953 adults (367 males and 586 females) in the Cameron County Hispanic Cohort (CCHC) were stratified into three groups: normal glucose tolerance, prediabetes, and diabetes mellitus. Differences in resistin and other adipokine levels were examined using linear regression via unadjusted model (Model 1), model adjusted for cytokines (Model 2), and model further adjusted for demographic and anthropometric variables (Model 3).

RESULTS

HOMA-IR increased with worsening glucose tolerance (p < 0.0001). In all models, resistin significantly decreased as glucose tolerance deteriorated. Model 3 resistin was positively associated with IL-1β (p = 0.0252) and IL-8 (p < 0.0001), inversely associated with TNF-α (p = 0.0352), but nonsignificantly associated with IL-6 (p = 0.8671). Model 3 leptin was significantly lower in diabetes mellitus compared to other groups (p < 0.005) and positively associated with female sex (p < 0.0001), age (p = 0.024), and BMI (p < 0.0001), without significant cytokine associations. Adiponectin displayed no significant associations with glucose tolerance, but was significantly associated with sex, BMI, and lipids (Model 3).

CONCLUSIONS

Resistin unexpectedly decreased as IR increased while supporting evidence of a resistin-stimulated cytokine pathway in this Mexican-American cohort. Leptin fell with elevated IR after adjusting for cytokines, demographic and anthropometric variables. Adiponectin nonsignificantly decreased as IR increased while showing significant associations with sex, BMI, and lipids.

The Emerging Role of Sfrp5 and Wnt5a in the Pathogenesis of Obesity: Implications for a Healthy Diet and Lifestyle

In recent decades, the prevalence of obesity has risen dramatically worldwide among all age groups. Obesity is characterized by excess fat accumulation and chronic low-grade inflammation. The adipose tissue functions as a metabolically active endocrine organ secreting adipokines. A novel duo of adipokines, the anti-inflammatory secreted frizzled-related protein 5 (Sfrp5) and the proinflammatory wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (Wnt5a), signal via the non-canonical Wnt pathway. Recent evidence suggests that Sfpr5 and Wnt5a play a key role in the pathogenesis of obesity and its metabolic complications. This review summarizes the current knowledge on the novel regulatory system of anti-inflammatory Sfrp5 and pro-inflammatory Wnt5a, and their relation to obesity and obesity-related complications. Future studies are required to investigate the potential role of Sfrp5 and Wnt5a as biomarkers for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors. These adipokines may also serve as novel therapeutic targets for obesity-related disorders.

Prospective Study of Long-Term Interrelationships Among Adiposity-Associated Biomarkers in Women

OBJECTIVE

This study aimed to investigate the prospective interrelationships among biomarkers that may provide mechanistic insights into obesity-related diseases.

METHODS

A total of 850 women in the Nurses' Health Study II with two fasting blood measurements (1996-1999 and 2010-2011) of adiponectin, leptin, soluble leptin receptor, insulin, retinol-binding protein 4, high-sensitivity C-reactive protein (hsCRP), and interleukin-6 were included. Biomarker interrelationships were examined in the following three ways: (1) cross-sectional associations at baseline and follow-up, (2) longitudinal associations of concurrent biomarker changes, and (3) prospective associations of each baseline biomarker with other biomarker changes.

RESULTS

In cross-sectional analyses, most biomarkers were correlated after multivariable adjustment including BMI, with the strongest correlations observed between leptin and insulin and between hsCRP and interleukin-6. In longitudinal analyses, similar results were observed after multivariable adjustment including weight change. However, in prospective analyses, only three associations observed in cross-sectional and longitudinal analyses were consistently significant (P < 0.05). Every doubling in baseline adiponectin was associated with -9.0% insulin change. The corresponding estimate was 9.3% for baseline leptin and hsCRP change and 3.1% for baseline hsCRP and leptin change.

CONCLUSIONS

Baseline adiponectin concentrations were inversely associated with subsequent insulin change, whereas baseline leptin concentrations were positively associated with hsCRP change and vice versa.

A diet high in sugar-sweetened beverage and low in fruits and vegetables is associated with adiposity and a pro-inflammatory adipokine profile

Diet, obesity and adipokines play important roles in diabetes and CVD; yet, limited studies have assessed the relationship between diet and multiple adipokines. This cross-sectional study assessed associations between diet, adiposity and adipokines in Mexican Americans. The cohort included 1128 participants (age 34·7±8·2 years, BMI 29·5±5·9 kg/m2, 73·2 % female). Dietary intake was assessed by 12-month food frequency questionnaire. Adiposity was measured by BMI, total percentage body fat and percentage trunk fat using dual-energy X-ray absorptiometry. Adiponectin, apelin, C-reactive protein (CRP), dipeptidyl peptidase-4 (DPP-IV), IL-1β, IL-1ra, IL-6, IL-18, leptin, lipocalin, monocyte chemo-attractant protein-1 (MCP-1), resistin, secreted frizzled protein 4 (SFRP-4), SFRP-5, TNF-α and visfatin were assayed with multiplex kits or ELISA. Joint multivariate associations between diet, adiposity and adipokines were analysed using canonical correlations adjusted for age, sex, energy intake and kinship. The median (interquartile range) energy intake was 9514 (7314, 11912) kJ/d. Overall, 55 % of total intake was accounted for by carbohydrates (24 % from sugar). A total of 66 % of the shared variation between diet and adiposity, and 34 % of diet and adipokines were explained by the top canonical correlation. The diet component was most represented by sugar-sweetened beverages (SSB), fruit and vegetables. Participants consuming a diet high in SSB and low in fruits and vegetables had higher adiposity, CRP, leptin, and MCP-1, but lower SFRP-5 than participants with high fruit and vegetable and low SSB intake. In Mexican Americans, diets high in SSB but low in fruits and vegetables contribute to adiposity and a pro-inflammatory adipokine profile.

Association of weight gain and fifteen adipokines with declining beta-cell function in Mexican Americans

Obesity and adipokines are associated with development of type 2 diabetes. However, limited longitudinal studies have examined their roles on declining β-cell function over time. This report assessed three adiposity measures (BMI, percent body fat, trunk fat), insulin resistance, and fifteen adipokines in relationship to longitudinal change in β-cell function measured by disposition index (DI) from frequently-sampled-intravenous-glucose-tolerance testing. The results showed that three factors were significantly and independently associated with rate of change in DI over time: rate of change in BMI (negative), rate of change in IL-6 (negative), and baseline adiponectin (positive). The association was the strongest for changing BMI and was largely explained by changing insulin resistance; the association with changing IL-6 was also largely explained by changing insulin resistance. Baseline adiponectin remained positively associated after adjustment for changing insulin resistance, suggesting an independent effect of adiponectin to preserve or improve β-cell function. These findings provide evidence and potential mechanisms for the role of obesity in promoting β-cell dysfunction, highlighting the potential importance of mitigating obesity and its metabolic effects in preventing and treating type 2 diabetes.

Telmisartan prevents diet-induced obesity and preserves leptin transport across the blood-brain barrier in high-fat diet-fed mice

Obesity is a global health problem and treatment options are still insufficient. When chronically treated with the angiotensin II receptor blocker telmisartan (TEL), rodents do not develop diet-induced obesity (DIO). However, the underlying mechanism for this is still unclear. Here we investigated whether TEL prevents leptin resistance by enhancing leptin uptake across the blood-brain barrier (BBB). To address this question, we fed C57BL/6 mice a high-fat diet (HFD) and treated them daily with TEL by oral gavage. In addition to broadly characterizing the metabolism of leptin, we determined leptin uptake into the brain by measuring BBB transport of radioactively labeled leptin after long-term and short-term TEL treatment. Additionally, we assessed BBB integrity in response to angiotensin II in vitro and in vivo. We found that HFD markedly increased body weight, energy intake, and leptin concentration but that this effect was abolished under TEL treatment. Furthermore, glucose control and, most importantly, leptin uptake across the BBB were impaired in mice on HFD, but, again, both were preserved under TEL treatment. BBB integrity was not impaired due to angiotensin II or blocking of angiotensin II receptors. However, TEL did not exhibit an acute effect on leptin uptake across the BBB. Our results confirm that TEL prevents DIO and show that TEL preserves leptin transport and thereby prevents leptin resistance. We conclude that the preservation of leptin sensitivity is, however, more a consequence than the cause of TEL preventing body weight gain.