FGF21 Is Associated with Acanthosis Nigricans in Obese Patients

A comparison of brown fat tissue related hormone levels in metabolically healthy and unhealthy individuals with obesity

PURPOSE

One of the key functions of brown adipose tissue is its positive impact on metabolism. This study aimed to examine the potential involvement of brown fat-related hormones in the development of metabolically healthy obesity. Specifically, we sought to compare the levels of NRG4, FGF21, and irisin between metabolically healthy and unhealthy individuals with obesity.

METHODS

Patients with BMI ≥ 30 kg/m2 and aged between 20 and 50 years were included in the study. Among these patients, those who did not have any metabolic syndrome criteria except for increased waist circumference were defined as metabolically healthy obese. Age, gender, BMI, body fat, and muscle mass, matched metabolically healthy and unhealthy obese groups were compared in terms of FGF21, irisin, and NRG4 levels.

RESULTS

Metabolically healthy and unhealthy obese groups were similar in terms of age and gender. There was no difference between the two groups in terms of BMI, weight, total body fat, muscle, fat-free mass, distribution of body fat and muscle mass. No statistically significant difference was found between irisin, NRG4, and FGF21 levels between metabolically healthy and unhealthy individuals with obesity. It was found that irisin had a significant inverse correlation with BMI and body fat percentage.

CONCLUSION

The present study showed no difference between metabolically healthy and unhealthy obese individuals in terms of irisin, FGF21, and NRG4 levels. The weak association between irisin and BMI and body fat percentage may suggest a potential link between irisin with metabolic health.

Acanthosis nigricans in the pediatric population: a narrative review of the current approach to management in primary care

Objective

This narrative review aims to provide readers with a comprehensive overview of the current literature of acanthosis nigricans (AN) in the pediatric and adolescent population, including best practices for identifying the condition, with a focus on the recommended management in the primary care setting to enable early and enhanced intervention.

Background

AN is frequently seen in obese and overweight children and adolescents. Current research suggests an association with insulin resistance, type 2 diabetes mellitus, and obesity, and often primary care physicians are the first point of contact for individuals with this dermatologic condition. However, identifying the condition at an early stage may be difficult.

Methods

We identified case and cross-sectional studies, clinical trials, and literature reviews of pediatric AN for ages 0 to 18 years in the United States and internationally. We considered publications for background from before the year 2000 and publications for approach to management from after the year 2000.

Conclusions

AN in the pediatric population can be a harbinger for underlying metabolic syndrome and insulin resistance. A thorough investigation and appropriate screening of children at risk, with a focus on early identification of the dermatologic condition and its associated comorbidities in the primary care setting, and early treatment is recommended to prevent long term consequences and decrease the risk of cardiovascular complications.

Acanthosis Nigricans: An Updated Review

BACKGROUND

Early recognition of acanthosis nigricans is important because acanthosis nigricans can be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy.

OBJECTIVE

The purpose of this article is to familiarize pediatricians with the clinical manifestations, evaluation, diagnosis, and management of acanthosis nigricans.

METHODS

A search was conducted in November 2021in PubMed Clinical Queries using the key term "acanthosis nigricans". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Acanthosis nigricans is characterized by symmetric, hyperpigmented, and velvety plaques with ill-defined borders, typically involving intertriginous areas. Obesity is the most common cause of acanthosis nigricans which is increasingly observed in obese children and adolescents and can serve as a cutaneous marker of insulin resistance. Early recognition of acanthosis nigricans is important because acanthosis nigricans can also be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy. This may consist of weight reduction, discontinuation of causative drugs, treatment of underlying endocrinopathy, or treatment of an underlying malignancy. For patients with isolated acanthosis nigricans and for those whose underlying cause is not amenable to treatment, treatment of the lesion may be considered for cosmetic reasons. Topical retinoids, vitamin D analogs, chemical peels, and other keratolytics are often used for the treatment of localized lesions. Seldom, systemic therapy such as oral retinoids may be considered for extensive or generalized acanthosis nigricans and acanthosis nigricans unresponsive to topical therapy. Other uncommon treatment modalities include dermabrasion, laser therapy, and surgical removal.

CONCLUSION

Although acanthosis nigricans is treatable, a complete cure is difficult to achieve. The underlying cause should be treated, if possible, to resolve and prevent the recurrence of acanthosis nigricans. The diagnosis is mainly clinical, based on the characteristic appearance (symmetrically distributed, hyperpigmented, velvety, papillomatous, hyperkeratotic plaques with ill-defined borders) and the typical sites (intertriginous areas, flexural area, and skin folds) of the lesions. The diagnosis might be difficult for lesions that have atypical morphology or are in an unusual location. Clinicians should be familiar with the clinical signs, evaluation, diagnosis, and therapy of acanthosis nigricans because of the link between it and underlying diseases.

FGF21 serum levels are related to insulin resistance, metabolic changes and obesity in Mexican people living with HIV (PLWH)

Background

Antiretroviral therapy has significantly improved prognosis in treatment against HIV infection, however, prolonged exposure is associated to cardiovascular diseases, lipodystrophy, type 2 diabetes, insulin resistance, metabolic alteration, as obesity which includes the accumulation of oxidative stress in adipose tissue. FGF21 is a peptide hormone that is known to regulate glucose and lipid metabolism. FGF21 is expressed and secreted primarily in the liver and adipose tissue, promoting oxidation of glucose/fatty acids and insulin sensitivity. Alterations in FGF21 may be associated with the development of insulin resistance, metabolic syndrome and cardiovascular disease. We hypothesized that FGF21 protein levels are associated with metabolic abnormalities, placing special attention to the alterations in relation to the concurrence of overweight/obesity in people living with HIV (PLWH).

Design

Serum FGF21 was analyzed in 241 subjects, 160 PLWH and 81 unrelated HIV-uninfected subjects as a control group. Clinical records were consulted to obtain CD4+ cell counting and number of viral RNA copies. Serum FGF21 levels were tested for correlation with anthropometric and metabolic parameters; glucose, cholesterol, HDL, LDL, VLDL, triglycerides, insulin and indexes of atherogenesis and insulin resistance (HOMA).

Results

The participants were classified into four groups: (i) PLWH with normal weight, (ii) PLWH with overweight/obesity, (iii) HIV-uninfected with normal weight, and (iv) HIV-uninfected with overweight/obesity.

Insulin levels were higher in normal-weight PLWH than in the HIV-uninfected group but not statistically significant, however, for the overweight/obesity PLWH group, insulin levels were significantly higher in comparison with the other three groups (p<0.0001). For FGF21, serum levels were slightly higher in the overweight/obesity groups in both patients and controls.

In HIV-infected subjects, FGF21 levels showed a strong positive correlation with triglycerides, insulin levels and insulin resistance with a p-value <0.0001. In the seronegative group, FGF21 was only correlated with weight and waist circumference, showing an important association of FGF21 levels with the degree of obesity of the individuals.

Conclusion

Insulin resistance and FGF21 elevations were observed in overweight-obese PLWH. FGF21 elevation could be viewed as a compensation mechanism as, in the control group, FGF21 correlations appeared to be confined to weight and waist circumference. This can be explained based on the action of FGF21 promoting the uptake of glucose in adipose tissue. In PLWH, FGF21 was low, possibly as a result of a change in adiposity leading to a metabolic disruption.

The Associations of Serum Uric Acid with Obesity-Related Acanthosis nigricans and Related Metabolic Indices

Objective. Recent studies have shown that hyperuricemia (HUA) is associated with hypertension, dyslipidemia, insulin resistance, and metabolic syndrome (MetS). We aimed to examine the relationship of serum UA with Acanthosis nigricans (AN) and related metabolic indices in obese patients. Methods. A cross-sectional study with 411 obese patients recruited from our department was analyzed in this study. Weight, body mass index (BMI), UA, lipid profile, liver function, and renal function were measured in all participants. Oral glucose tolerance tests were performed, and serum glucose, insulin, and C peptide were measured at 0, 30, 60, 120, and 180 min. Results. AN group had higher serum UA levels than OB group. Circulating UA levels were associated with BMI, dyslipidemia, hypertension, IR, and AN. In logistic regression analyses (multivariable-adjusted), a high serum UA level was associated with high odds ratios (ORs) (95% confidence interval [CI]) for AN in females (ORs = 3.00 and 95% CI [1.02-8.84]) and males (ORs = 6.07 and 95% CI [2.16-17.06]) in the highest quartile (Q4) of serum UA. Conclusions. Serum UA levels were positively associated with multiple metabolic abnormalities including obesity, hypertension, hyperglycemia, hyperlipidemia, and AN and may be an important risk factor in the development of AN; further evidences in vitro and in vivo are needed to investigate the direct or indirect relationship.