Association of retinol binding protein4 (RBP4) and ghrelin plasma levels with insulin resistance and disease severity in non‐diabetic patients with hidradenitis suppurativa

[Hidradenitis suppurativa]

Hidradenitis suppurativa (HS) is a chronic and debilitating inflammatory disease derived from the pilosebaceous unit, that affects approximately 1% of the general population. Clinically, it is characterized by inflammatory nodules, abscesses, and tunnels in the intertriginous areas of the body, especially in the axillary, inguinal, and anogenital regions. The etiopathogenesis of HS is not completely understood, although it is considered to be multifactorial, and the result of a complex interaction between genetic, hormonal, environmental, and immunological factors. In this sense, several proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-L-1β, and IL-17, among others, appear to play a crucial role in the pathogenesis of the disease. Currently, HS is recognized as a systemic disease associated with numerous comorbidities, including cardiovascular, immune-mediated, and endocrine-metabolic diseases. The treatment of HS must be carried out with an individualized and patient-oriented approach, considering medical and surgical treatment modalities.

Angiopoietin-like 2 Protein and Hidradenitis Suppurativa: A New Biomarker for Disease Severity

Hidradenitis suppurativa (HS) is a chronic inflammatory disease whose pathogenesis is not fully understood at present. The role of proinflammatory cytokines, several adipokines, retinol-binding protein 4, angiopoietin-2 and other molecules has been previously reported. Angiopoietin-like 2 protein (ANGPTL2) is a glycoprotein belonging to the angiopoietin-like family that may play a pivotal role in the pathogenesis of several chronic inflammatory diseases. To our knowledge, the role of serum ANGPTL2 levels in HS has not been assessed to date. In the current case-control study, we aimed to investigate serum ANGPTL2 levels in HS patients and controls and to assess whether ANGPTL2 levels could be associated with the severity of HS. Ninety-four patients with HS and sixty controls of similar age and sex were included in the study. Demographic, anthropometric, and clinical data, as well as routine laboratory parameters and serum concentrations of ANGPTL2, were assessed in all participants. HS patients had significantly higher serum ANGPTL2 levels than controls after adjusting for confounders. Moreover, ANGPTL2 concentrations positively correlated with disease duration and severity. Our results indicate for the first time that serum ANGPTL2 concentrations are elevated in HS patients compared to controls and correlate with the duration of the disease. Besides, ANGPTL2 might serve as a biomarker of HS severity.

Adipokines as an important link between hidradenitis suppurativa and obesity: a narrative review

Hidradenitis suppurativa (HS) is a chronic, recurrent, debilitating disorder of the pilosebaceous unit. Although its pathophysiology is not fully explained, inflammation seems to play an essential role in the development of HS. A link between obesity - often considered a state of chronic inflammation - and a higher prevalence of HS has been described. Nevertheless, the exact association is not well understood. Adipose tissue is a highly active endocrine organ that produces and secretes a variety of metabolically and immunologically active molecules called adipokines. The imbalances in concentrations of several adipokines in patients with HS have already been described. A shift towards the overproduction of proinflammatory adipokines (including leptin, resistin and visfatin) with the suppression of anti-inflammatory ones (adiponectin) has been noted. We conducted a review of the available data on adipokines in HS, concentrating on the described imbalances in adipokine concentrations, as well as possible implications in HS pathogenesis. Moreover, new, unstudied adipokines with possible implications in the development of HS are proposed.

The Role of Hormones in Hidradenitis Suppurativa: A Systematic Review

Hidradenitis suppurativa (HS) is a chronic inflammatory disease manifesting in inverse body regions. In a systematic review, the role of hormones in HS will be presented to better understand the pathomechanisms of HS. The review is based on the PRISMA criteria. Systematic research was carried out using keywords. Subsequently, the data were analyzed based on the clinical response and other relevant information. The main focus of our systematic review was on HS manifestation, exacerbation, sex hormones, antiandrogen therapy, thyroid function, polycystic ovary syndrome, insulin resistance, and adipokines. In HS, there appears to be a dysregulated adipokine release that is shifted towards pro-inflammatory adipokines. Insulin resistance is significantly more common in HS than in healthy patients regardless of BMI, age, and gender. Insulin resistance in HS patients leads to further cardiovascular disease. The mechanism of insulin resistance and role of adipokines should be investigated in future studies to better provide the pathomechanisms of HS. The role of androgens seems to be important in a certain subgroup of female patients. Anti-androgenic therapy can be useful and helpful in some patients. However, further studies are needed to better understand the hormonal relationship in HS.

Serum levels of ghrelin and LEAP2 in patients with type 2 diabetes mellitus: correlation with circulating glucose and lipids

Objective

Ghrelin regulates body weight, food intake, and blood glucose. It also regulates insulin secretion from pancreatic islet cells. LEAP2 is a newly discovered endogenous ligand of the growth hormone secretagogue's receptor (GHSR). It not only antagonizes the stimulation of GHSR by ghrelin but also inhibits the constitutive activation of GHSR as an inverse agonist. Type 2 diabetes (T2D) patients have endocrine disorders with metabolic imbalance. Plasma levels of ghrelin and LEAP2 may be changed in obese and T2D patients. However, there is no report yet on circulating LEAP2 levels or ghrelin/LEAP2 ratio in T2D patients. In this study, fasting serum ghrelin and LEAP2 levels in healthy adults and T2D patients were assessed to clarify the association of two hormones with different clinical anthropometric and metabolic parameters.

Design

A total of 16 females and 40 males, ages 23-68 years old normal (n = 27), and T2D patients (n = 29) were enrolled as a cross-sectional cohort.

Results

Serum levels of ghrelin were lower but serum levels of LEAP2 were higher in T2D patients. Ghrelin levels were positively correlated with fasting serum insulin levels and HOMA-IR in healthy adults. LEAP2 levels were positively correlated with age and hemoglobin A1c (HbA1c) in all tested samples. Ghrelin/LEAP2 ratio was negatively correlated with age, fasting blood glucose, and HbA1c.

Conclusions

This study demonstrated a decrease in serum ghrelin levels and an increase in serum LEAP2 levels in T2D patients. LEAP2 levels were positively correlated with HbA1c, suggesting that LEAP2 was associated with T2D development. The ghrelin/LEAP2 ratio was closely associated with glycemic control in T2D patients showing a negative correlation with glucose and HbA1c.

The Effects of RBP4 and Vitamin D on the Proliferation and Migration of Vascular Smooth Muscle Cells via the JAK2/STAT3 Signaling Pathway

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are one of the main causes of the development of diabetic atherosclerotic process. The aim of our study was to assess the role of RBP4 in the proliferation and migration of VSMCs and the inhibitory effect of vitamin D on the mechanisms. In an in vivo experiment, rats were randomly classified into 6 groups: the control group, diabetic rats, diabetic atherosclerotic rats (diabetic rats intraperitoneally injected with RBP4), diabetic atherosclerotic rats treated with 0.075 μg kg⁻¹ d⁻¹ vitamin D, 0.15 μg kg⁻¹ d⁻¹ vitamin D and 0.3 μg kg⁻¹ d⁻¹ vitamin D. We found that the levels of JAK2, STAT3, cylinD1, and Bcl-2 were increased in diabetic atherosclerotic rats, and these increases were improved after vitamin D supplementation. Furthermore, to investigate the underlying molecular mechanisms, cells were cultured with glucose in the presence of RBP4 and the absence of RBP4, respectively, and vitamin D of different concentrations and different intervention times was simultaneously adopted. The proliferation and migration of VSMCs was enhanced and the levels of JAK2, STAT3, cyclinD1, and Bcl-2 were increased in the cells transfected with RBP4 overexpression plasmid. Moreover, vitamin D supplementation was detected to lower the expressions of JAK2, STAT3, cyclinD1, and Bcl-2 and inhibit the abnormal proliferation of VSMCs caused by the RBP4/JAK2/STAT3 signaling pathway. RBP4 can promote the proliferation and migration of VSMCs and contributes to the development of diabetic macroangiopathy via regulating the JAK2/STAT3 signaling pathway. This mechanism of RBP4 can be inhibited by vitamin D supplementation.