Resistin gene polymorphisms are associated with acne and serum lipid levels, providing a potential nexus between lipid metabolism and inflammation

Genetic Variants Associated with Acne Vulgaris

Acne vulgaris (AV) ranks among the common chronic inflammatory disorders that impact the sebaceous components of hair follicles. Acne vulgaris is characterised by cardinal manifestations such as the presence of pimples, nodules, pustules, and cysts, which have the potential to lead to the development of acne scarring and pigmentation. The phenomenon is influenced by polygenic inheritance or can be ascribed to the interplay between multiple genes and environmental factors. In recent years, some researchers have found that some genes (such as IL, TNF, RETN, CYP family, MMPs and TIMPs genes et al) are associated with acne vulgaris and may affect the progression and prognosis of the disease. The number of reviews addressing acne-associated genetic variants, however, is limited. In that case, we have compiled a list of prevalent genes associated with acne in recent times. This helps us understand acne's genetic basis and lets us step in early for people prone to severe acne, lowering the chance of acne scars.

Serum resistin levels and resistin gene polymorphism in patients with acne vulgaris: does it correlate with disease severity?

BACKGROUND

Acne vulgaris is a disease that inflames the sebaceous gland with multiple etiologies. Many proinflammatory adipokines contribute to this pathogenesis. Resistin is a proinflammatory mediator that activates kappa B, a nuclear factor, and c-Jun N-terminal kinases pathways inducing toll-like receptor-2, interleukin-1, 6, and tumor necrosis factor alpha. Resistin gene affects the promoter and intron regions' polymorphisms' expression levels. We aimed to study the association of resistin gene polymorphisms (RETN -420 C/G) and the development of acne vulgaris and whether it is associated with serum resistin levels and disease severity.

SUBJECTS AND METHODS

Resistin (RETN) gene (rs1862513) genotypes were identified using restriction fragment length polymorphism (RFLP), and serum resistin presence was assessed by enzyme-linked immunosorbent assay in 40 patients with acne vulgaris and 40 age- and sex-matched healthy controls as a cross-reference. Patients were divided into mild, moderate, and severe groups. Global Acne Grading System (GAGS) was used to assess the severity of acne vulgaris.

RESULTS

CG and GG genotypes were present in cases (P = 0.006) odds ratio (OR)₁  = 4.43; 95% confidence interval (CI) (1.53, 12.7) and OR₂  = 5.47; 95% CI (0.99, 30.1); G-allele statistically dominated in the patient group where P = 0.001 and OR = 3.57; 95% CI (1.63, 7.80). A positive significant relationship between RETN genotypes and serum resistin levels and GAGS score was present.

CONCLUSION

RETN genes rs1862513 GG and G allele are correlated to acne vulgaris development and severity in a sample of the Egyptian population. This study comprised a small sample size. The cases may not accurately represent the general population; only one clinic was enrolled in the study.

Association between resistin gene (-420 C > G) polymorphism and acne vulgaris

BACKGROUND

Acne vulgaris (AV) is the most prevalent inflammatory skin disease and develops on the face and upper trunk. Resistin, a member of the cysteine-rich secretory proteins family, is an adipokine expressed primarily in macrophages and monocytes; it has a role to play in the inflammatory period.

AIMS

This study's purpose was to detect whether known resistin gene (-420 C > G) polymorphism plays a role in the pathogenesis of AV.

METHODS

Patients with AV (n = 94) and healthy controls (n = 94) were enrolled in this investigation. Resistin gene (-420 C > G) polymorphism was decided by PCR-RFLP procedure.

RESULTS

The distribution of genotype frequencies of resistin gene (-420 C > G) polymorphism was significantly different between the AV and healthy controls (p = 0.002). We found that the resistin gene (-420 C > G) CG genotype exhibited a significant association with decreased acne vulgaris risk.

CONCLUSIONS

Our study is the first report investigating the relationship between the risk of AV and resistin gene (-420 C > G) polymorphism in the Turkish population. Resistin gene (-420 C > G) polymorphism is related to AV pathogenesis. CG genotype has a protective role and may be linked to a reduced risk of AV development. Furthermore, studies are needed to verify these findings in other populations.

Gene variants associated with acne vulgaris presentation and severity: a systematic review and meta-analysis

BACKGROUND

Multiple factors have been attributed to acne vulgaris predisposition and individual variations in the severity of skin symptoms, and genetics stood out as one of the major factors.

METHODS

We performed a systematic review on the genes and their variants that have been investigated for association with acne presentation and severity. A random-effect meta-analysis using the allele model (minor allele vs. major allele) was also conducted to provide an overall estimation of risk effects of frequently reported gene variants. This included a subset data of 982 acne cases and 846 controls extracted from our existing GWAS database on various allergic and skin diseases among Singapore Chinese.

RESULTS

Systematic review of 51 articles covering Asians and Caucasians found 60 genes/loci and their 100 variants implicated in acne; majority of them were in the intron, coding region/missense, and promoter regions. The commonly studied candidate genes/gene families include tumor necrosis factor (TNF), and the interleukin (IL) and cytochrome P450 (CYP) gene families. Our meta-analysis showed that most of the analyzed gene variants exhibited insignificant pooled odds ratio (pOR) and significant heterogeneity between studies. Nevertheless, we found that TNF rs1800629 A allele carriers and CYP17A1 rs743572 T allele carriers had significantly reduced mild acne risk [pOR: 0.60; 95% Confidence Interval (CI): 0.33-0.86] and severe acne risk (pOR: 0.59; 95% CI: 0.40-0.79), respectively, across populations. Overall, FST (follistatin) rs629725 A allele poses a significantly modest increased risk for acne presentation (pOR: 1.19, 95% CI: 1.14, 1.23), but neither TIMP2 (TIMP metallopeptidase inhibitor 2) rs8179090 nor CYP1A1 rs4646903 (pOR: 0.96, 95% CI: 0.80-1.12; pOR: 0.95, 95% CI: 0.83, 1.08), respectively. We discovered 15 novel SNPs in the 3' UTR region of the Toll-like Receptor 4 gene (TLR4) associated with acne presentation.

CONCLUSIONS

This systematic review and meta-analysis suggest that genes influencing inflammatory responses, specifically TNF, and genes influencing the function and activity of sebaceous glands, specifically CYP17A1 and FST, have potential risk variants for acne presentation and severity across populations. Understanding the genetic susceptibility factors and biological pathways involved in the pathogenesis of acne will help us to gain insights into developing effective acne treatments.

Adipokines in the Skin and in Dermatological Diseases

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.

Variants in RETN gene are associated with steroid-induced osteonecrosis of the femoral head risk among Han Chinese people

Background

Gene polymorphism has an important influence on RETN gene expression level, and the increased level of resistin encoded in RETN will lead to metabolic disorder, especially lipid metabolism. Moreover, steroid-induced osteonecrosis of the femoral head (steroid-induced ONFH) is closely related to lipid metabolism level, so this study is intended to explore the relationship of RETN polymorphisms with susceptibility to steroid-induced ONFH in the Chinese Han population.

Methods

In this case-control study, eight single-nucleotide polymorphisms (SNPs) of RETN were genotyped by the Agena MassARRAY system in 199 steroid-induced ONFH patients and 200 healthy controls. The relationship between RETN polymorphisms and steroid-induced ONFH risk was assessed using genetic models and haplotype analyses. Odds ratio (OR) and 95% confidence intervals (CIs) were obtained by logistic regression adjusted for age.

Results

We found significant differences in the distribution of HDL-C, TG/HDL-C, and LDL-C/HDL-C between the patients and the control group (p < 0.05). In allele model and genotype model analysis, rs34861192, rs3219175, rs3745368, and rs1477341 could reduce the risk of steroid-induced ONFH. Further stratified analysis showed that rs3745367 was related to the clinical stage of patients, and rs1477341 was significantly correlated with an increased TG level and a decreased TC/HDL-C level. The linkage analysis showed that two SNPs (rs34861192 and rs3219175) in RETN even significant linkage disequilibrium.

Conclusions

Our results provide the firstly evidence that RETN gene polymorphisms were associated with a reduced risk of steroid-induced ONFH in Chinese Han population.

Resistin adipokin in atopic dermatitis patients: A clinical, biochemical, and genetic study

BACKGROUND/OBJECTIVES

Atopic dermatitis (AD) is an inflammatory chronic skin disorder. The etiology of AD is not fully understood. Therefore, we aimed by this study to shed light on the potential role of resistin in an etiopathogenesis of AD through investigation of resistin rs3745367 single nucleotide polymorphism (SNP) and resistin serum levels, and their relation to leukocytic count in a sample of Egyptian patients having atopic dermatitis.

METHODS

This case-control study included 45 patients having AD and 40 controls. SCORAD index was assessed to evaluate the severity of AD. CBC, ELISA, and PCR-RFLP were performed to detect leukocytic count, resistin serum level, and resistin rs3745367 SNP, respectively.

RESULTS

Atopic dermatitis patients had significant low serum resistin concentrations (P = .036) and a significantly high frequency of leukocytosis (P = .003). Low resistin serum levels were significantly related to AD disease severity (P < .001) and the presence of leukocytosis (P < .001). Resistin rs3745367 GG genotype (P = .030), as well as its G allele (P = .019), was expressively associated with AD development, and both increased the risk of AD by 3- and 2-fold, respectively. Resistin rs3745367 GG genotype was significantly linked to low resistin serum levels (P < .001), AD-positive family history (P = .015), and the presence of leukocytosis (P < .001).

CONCLUSIONS

Resistin rs3745367 gene polymorphism may contribute to the development of AD. Resistin may have an immune-modulating active character in the AD etiopathogenesis that could be mediated through its anti-inflammatory effect. From this piece of work, we may suggest resistin as a new therapy to mitigate the pro-inflammatory environment found in AD.

Vitamin D, Adiponectin, Oxidative Stress, Lipid Profile, and Nutrient Intakes in the Females with Acne Vulgaris: A Case-Control Study

Background

Acne vulgaris is a dermatological disorder that is related to inflammation and oxidative stress. Recent studies have also suggested diet as a potential reason for acne. Considering the inconsistency of the few previous reports, the present study aimed to determine the levels of vitamin D, adiponectin, oxidative stress, lipid profile and nutrient intakes in females with acne.

Materials and Methods

Forty females with acne vulgaris and 40 age-matched healthy females were included in this study in Shiraz, Iran. Data on their sociodemographic status, acne history, and anthropometric indices were collected. Blood samples were taken to determine the levels of 25-hydroxyvitamin D, adiponectin, malondialdehyde, total antioxidant capacity, and lipid profile. Three 24-hour dietary recalls were also obtained from each of the individuals to evaluate nutrient intakes. Data were analyzed using the Chi-square test, Independent-samples t-test or Mann-Whitney U-test, and Logistic Regression.

Results

Patients with acne had a significantly higher family history of acne compared to controls (P=0.006). Serum level of malondialdehyde was significantly higher in cases (P=0.01), while high-density lipoprotein cholesterol was significantly lower (P=0.02). Moreover, significantly lower fiber intake was observed in cases compared with controls (P=0.007). In the multivariate analysis, a family history of acne and increased malondialdehyde levels were risk factors for acne, whereas a higher fiber intake was protective.

Conclusion

Family history of acne, oxidative stress, dyslipidemia, and lower dietary fiber intakes may play a role in acne pathogenesis. An early assessment of these parameters may be useful for planning treatment procedures.

Resistin-like Molecule α Provides Vitamin-A-Dependent Antimicrobial Protection in the Skin

Vitamin A deficiency increases susceptibility to skin infection. However, the mechanisms by which vitamin A regulates skin immunity remain unclear. Here, we show that resistin-like molecule α (RELMα), a small secreted cysteine-rich protein, is expressed by epidermal keratinocytes and sebocytes and serves as an antimicrobial protein that is required for vitamin-A-dependent resistance to skin infection. RELMα was induced by microbiota colonization of the murine skin, was bactericidal in vitro, and was protected against bacterial infection of the skin in vivo. RELMα expression required dietary vitamin A and was induced by the therapeutic vitamin A analog isotretinoin, which protected against skin infection in a RELMα-dependent manner. The RELM family member Resistin was expressed in human skin, was induced by vitamin A analogs, and killed skin bacteria, indicating a conserved function for RELM proteins in skin innate immunity. Our findings provide insight into how vitamin A promotes resistance to skin infection.

Resistin up-regulates LPL expression through the PPARγ-dependent PI3K/AKT signaling pathway impacting lipid accumulation in RAW264.7 macrophages

Resistin is a cysteine-rich cytokine, which has been indicated as a mediator of insulin resistance and inflammation. Previous studies demonstrated that lipoprotein lipase (LPL) was an important enzyme that could mediate lipid accumulation in macrophages. Additionally, the intracellular molecules phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT)/peroxisome proliferator-activated receptor (PPARγ) were supposed to be involved in the lipid accumulation process in cells. However, it remains unclear whether resistin was correlated with the dysregulation of lipid metabolism in macrophages. The present study investigated that resistin could up-regulate the expression of LPL and increase the contents of intracellular triglyceride (TG) and total cholesterol (TC) in RAW264.7 macrophages. In addition, intracellular molecules PI3K, AKT and PPARγ were significantly up-regulated and activated in resitin-stimulated RAW264.7 macrophages (P < 0.05). In contrast, the effects of resistin on RAW264.7 macrophages could be abrogated by specific inhibitors for LPL (LPL-siRNA) and PI3K/AKT signaling pathway (LY294002). All together, this study demonstrated that resistin could up-regulate the expression of LPL and induce lipid accumulation in RAW264.7 macrophages. More importantly, the PPARγ-dependent PI3K/AKT signaling pathway was relevant to the lipid accumulation process in resistin-stimulated macrophages.

Expression of Three Adipokines (Adiponectin, Leptin and Resistin) in Normal Canine Skin: a Pilot Study

Adipokines are biologically active cytokines that are mainly produced in adipose tissue. There is evidence, in man and mice, that some adipokines may be secreted in other tissues including the vascular endothelium, epithelia and sebaceous glands. Moreover, modified serum levels of adipokines have been detected in people with acne vulgaris or psoriasis; it is suspected that adipokines could contribute to local and systemic inflammatory conditions. We aimed to evaluate the expression of three adipokines (i.e. leptin, adiponectin and resistin) in normal canine skin. Formalin-fixed, paraffin wax-embedded punch biopsy samples were obtained from the sparsely-haired skin of the caudal ventral abdomen of a single clinically healthy dog with no history of skin disease. Immunohistochemistry was applied, using rabbit polyclonal primary antibodies specific for leptin, adiponectin and resistin. Adipokines were not expressed in normal canine dermis or hypodermis. In contrast, they were detected in the keratinocytes of all epidermal layers and hair follicle segments, sebocytes, apocrine gland cells and in the vascular endothelium. This is the first report on the expression of adipokines in normal canine skin, a first step in studying their role in the skin physiology and inflammatory skin diseases of dogs.

Association between Resistin Gene Polymorphisms and Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory skin disorder. It is characterized by an inappropriate skin barrier function, allergen sensitization, and recurrent skin infections. Resistin is an adipokine expressed mainly in macrophages and monocytes; it has a role in the inflammatory process and is associated with multiple inflammatory human diseases; however, only few studies linked resistin to atopic dermatitis. This study tested the association between G>A (rs3745367) and C>T (rs3219177) single nucleotide polymorphisms (SNPs) of the RETN gene with atopic dermatitis. In addition, it explored the relationship between serum resistin protein and atopic dermatitis. To achieve objectives of this study, 162 atopic dermatitis patients and 161 healthy participants were recruited in the study. A significant association was detected between rs3745367 and atopic dermatitis with age and gender specificity (p < 0.05), while no significant association between rs3219177 and atopic dermatitis was found (p > 0.05). For the serum resistin levels, a significant decrease was indicated in atopic dermatitis patients compared to healthy subjects (p < 0.05). In conclusion, rs3745367 may play a gender and age-specific role in atopic dermatitis. In addition, the significant decrease in the resistin protein level confirmed this association.

Emu Oil Reduces LPS-Induced Production of Nitric Oxide and TNF-α but not Phagocytosis in RAW 264 Macrophages

Emu is the second-largest extant bird native to Australia. Emu oil, obtained from the emu's fat deposits, is used as an ingredient in cosmetic skincare products. Emu oil has been reported to improve several inflammatory symptoms; however, the mechanisms of these anti-inflammatory effects are largely unknown. This study investigated the effects of emu oil on the inflammatory macrophage response in vitro. A murine macrophage cell line, RAW 264, was incubated in culture media supplemented with or without emu oil and stimulated with lipopolysaccharide (LPS). We determined phagocytic activity by measuring the number of fluorescent microspheres taken up by the cells. The phagocytic activity of RAW 264 cells in the presence of LPS was unaffected by emu oil. We also determined production of nitric oxide (NO) and tumor necrosis factor (TNF)-α in the culture medium using the Griess reaction and an enzyme-linked immunosorbent assay, respectively, and the protein expression of inducible NO synthase (iNOS) using western blotting. The results indicated that emu oil reduced the LPS-induced production of NO, TNF-α, and iNOS expression in a dose-dependent manner. The results suggested that emu oil does not reduce the phagocytic clearance rate of inflammatory matter; however, it does reduce the production of NO and TNF-α in macrophages. These latter products enhance the inflammatory response and emu oil thereby demonstrated anti-inflammatory properties.