Skin Manifestations of Insulin Resistance: From a Biochemical Stance to a Clinical Diagnosis and Management

Spaceflight induces changes in gene expression profiles linked to insulin and estrogen

Organismal adaptations to spaceflight have been characterized at the molecular level in model organisms, including Drosophila and C. elegans. Here, we extend molecular work to energy metabolism and sex hormone signaling in mice and humans. We found spaceflight induced changes in insulin and estrogen signaling in rodents and humans. Murine changes were most prominent in the liver, where we observed inhibition of insulin and estrogen receptor signaling with concomitant hepatic insulin resistance and steatosis. Based on the metabolic demand, metabolic pathways mediated by insulin and estrogen vary among muscles, specifically between the soleus and extensor digitorum longus. In humans, spaceflight induced changes in insulin and estrogen related genes and pathways. Pathway analysis demonstrated spaceflight induced changes in insulin resistance, estrogen signaling, stress response, and viral infection. These data strongly suggest the need for further research on the metabolic and reproductive endocrinologic effects of space travel, if we are to become a successful interplanetary species.

Acanthosis nigricans independently predicts hepatic fibrosis in people with type 2 diabetes in North India

BACKGROUND

Acanthosis nigricans (AN) is a skin condition characterized by hyperpigmentation and thickening, often found in individuals with insulin resistance. Despite this well-established association, the potential link between AN and hepatic fibrosis in people with type 2 diabetes (T2D) has yet to be thoroughly explored.

METHODOLOGY

We recruited a total of 300 people with T2D, half of whom had AN (n, 150), and the other half without AN (n, 150). We evaluated body composition, biochemistry, and hepatic fat analysis (using the controlled attenuation parameter, CAP), as well as assessments of hepatic stiffness (using the kilopascal, kPa) using Fibroscan. We used multivariable regression analysis to find independent predictors of AN and their relationship to hepatic fibrosis. Furthermore, we developed a prediction equation and AUC for hepatic fibrosis.

RESULTS

Upon comparison between AN vs. NAN group, following were significatly higher; weight, BMI, hepatic transaminases, liver span, CAP, and kPa. After adjusting for age, weight, body mass index, diabetes duration, and specific anti-hyperglycaemic drugs (gliclazide, DPP-4 inhibitors, pioglitazone, and Glucagon-like peptide-1 receptor agonists), adjusted OR for AN were, liver span, 1.78 (95% CI: 0.91-3.49, p = 0.09), CAP, 7.55 (95% CI: 0.93-61.1, p = 0.05), and kPa, 2.47 (95% CI: 1.50-4.06, p = 0.001). A ROC analysis of predictive score for hepatic fibrosis showed optimal sensitivity and specificity at a score cut-off of 25.2 (sensitivity 62%, specificity 63%), with an AUC of 0.6452 (95% CI: 0.61235-0.76420).

CONCLUSION

Acanthosis nigricans has the potential to be used as an easy-to-identify clinical marker for risk of hepatic fat and fibrosis in Asian Indians with T2D, allowing for early detection and management strategies.

In Vitro and In Vivo Evaluation of Chitosan/HPMC/Insulin Hydrogel for Wound Healing Applications

Treatment of chronic wounds is challenging, and the development of different formulations based on insulin has shown efficacy due to their ability to regulate oxidative stress and inflammatory reactions. The formulation of insulin with polysaccharides in biohybrid hydrogel systems has the advantage of synergistically combining the bioactivity of the protein with the biocompatibility and hydrogel properties of polysaccharides. In this study, a hydrogel formulation containing insulin, chitosan, and hydroxypropyl methyl cellulose (Chi/HPMC/Ins) was prepared and characterized by FTIR, thermogravimetric, and gel point analyses. The in vitro cell viability and cell migration potential of the Chi/HPMC/Ins hydrogel were evaluated in human keratinocyte cells (HaCat) by MTT and wound scratch assay. The hydrogel was applied to excisional full-thickness wounds in diabetic mice for twenty days for in vivo studies. Cell viability studies indicated no cytotoxicity of the Chi/HPMC/Ins hydrogel. Moreover, the Chi/HPMC/Ins hydrogel promoted faster gap closure in the scratch assay. In vivo, the wounds treated with the Chi/HPMC/Ins hydrogel resulted in faster wound closure, formation of a more organized granulation tissue, and hair follicle regeneration. These results suggest that Chi/HPMC/Ins hydrogels might promote wound healing in vitro and in vivo and could be a new potential dressing for wound healing.

Influence of Sociodemographic Variables and Healthy Habits on the Values of Insulin Resistance Indicators in 386,924 Spanish Workers

BACKGROUND

Insulin resistance (IR) is an alteration of the action of insulin in cells, which do not respond adequately to this action, leading to an increase in blood glucose levels. IR produces a very diverse clinical picture and increases the cardiometabolic risk of the population that suffers from it. Among the factors that influence IR are genetics, unhealthy lifestyle habits, overweight, and obesity. The objective of this work was to determine how different sociodemographic variables and healthy habits influence the values of different scales that assess the risk of presenting IR in a group of Spanish workers.

METHODS

An observational, cross-sectional, descriptive study was carried out in 386,924 workers from different Spanish regions. Different sociodemographic variables and lifestyle habits were studied (age, social class, educational level, smoking, Mediterranean diet, physical exercise) along with their association with four scales to evaluate the risk of insulin resistance (TyG index, TyG-BMI, METS-IR, TG/HDL-c). To analyse the quantitative variables, Student's t test was used, while the Chi-squared test was used for the qualitative variables. A multinomial logistic regression analysis was performed, calculating the odds ratio with its 95% confidence intervals. The accepted level of statistical significance was set at p < 0.05.

RESULTS

In the multivariate analysis, all variables, except educational level, increased the risk of presenting high values on the IR risk scales, especially a sedentary lifestyle and low adherence to the Mediterranean diet.

CONCLUSIONS

Our results demonstrate an association between the practice of regular physical exercise and a reduction in the risk of IR; a strong role of the Mediterranean diet as a protective factor for IR; an association between aging and increased IR, which has also been suggested in other studies; and, finally, a relationship between a low socioeconomic level and an increase in IR.

Skin manifestations and biophysical changes following weight reduction induced by bariatric surgery: A 2-year prospective study

Skin manifestations and biophysical changes are observed in patients with morbid obesity. However, reports of changes after significant weight loss, particularly through post-bariatric surgery (BaS), are limited. The aim of this 2-year prospective study was to evaluate the prevalence of skin signs and their changes in patients with morbid obesity who underwent BaS. Thirty-one patients were recruited for the study, with a mean age of 38.35 (SD 10.61) years and a male preponderance (male = 19 [61.29%], female = 12 [38.71%]). Patients were scheduled for multiple visits at months 0, 3, 6, 12, 18, and 24 post-BaS. Each subject had a thorough skin examination, biophysical measurements, and laboratory tests at each visit. Striae, acanthosis nigricans (AN), and plantar hyperkeratosis were the most common skin findings (n = 30 [96.77%], 29 [93.55%], 29 [93.55%], respectively). BaS provided improvements in many skin manifestations, namely striae, AN, acrochordons, plantar hyperkeratosis, hirsutism, lymphedema, pruritus, acne, finger pebbles, and chronic venous insufficiency with varied cumulative rates of improvements. However, acute telogen effluvium was observed in 17 (54.84%) patients. Regarding skin biophysical properties, transepidermal water loss, skin hydration, and pH did not change, while sebum production on the face significantly decreased at months 3 and 6, and elasticity decreased at months 6 and 24. In conclusion, weight reduction by BaS provided improvements in various skin signs, although telogen effluvium was a common sequelae.

Untargeted metabolomics analysis of plasma metabolic characteristics in patients with acne and insulin resistance

Acne vulgaris is a chronic inflammatory disease with high incidence, diverse clinical manifestations, poor clinical efficacy, and easy recurrence. Recent studies have found that the occurrence of acne is related to metabolic factors such as insulin resistance; however, the specific mechanism of action remains unclear. This study aimed to identify significantly different metabolites and related metabolic pathways in the serum of acne vulgaris patients with or without insulin resistance. LC-MS/MS was used to analyze serum samples from patients about acne with insulin resistance (n = 51) and acne without insulin resistance (n = 69) to identify significant metabolites and metabolic pathways. In this study, 18 significant differential metabolites were screened for the first time. In the positive-ion mode, the upregulated substances were creatine, sarcosine, D-proline, uracil, Phe-Phe, L-pipecolic acid, and DL-phenylalanine; the downregulated substances were tridecanoic acid (tridecylic acid), L-lysine, cyclohexylamine, sphingomyelin (d18:1/18:0), gamma-L-Glu-epsilon-L-Lys, and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine. In the negative-ion mode, the upregulated substance was cholesterol sulfate, and the downregulated substances were D(-)-beta-hydroxybutyric acid, myristic acid, D-galacturonic acid, and dihydrothymine. Cholesterol sulfate showed the most significant expression among all differential metabolites (VIP = 7.3411). Based on the KEGG database, necroptosis and ABC transporters were the most significantly enriched metabolic pathways in this experiment. The differential metabolites and pathways identified in this study may provide new possibilities for the clinical diagnosis and development of targeted drugs for acne patients with insulin resistance.

Vitiligo and insulin resistance as a component of metabolic syndrome: an analysis

There have been many studies on the association between vitiligo and metabolic syndrome, while only few scientific papers on vitiligo and insulin resistance. In recent years, there have been significant developments in research to trace and understand the aetiology of both conditions. In this article we have analysed pathophysiological mechanisms and the association of insulin resistance (as a component of metabolic syndrome) and vitiligo.

Acanthosis nigricans in a patient with metastatic insulinoma post peptide receptor radionuclide therapy

Summary

Acanthosis nigricans (AN) is a common dermatosis associated with hyperinsulinemia and insulin resistance. However, AN has been rarely reported in patients with insulinoma, a state of persistent hyperinsulinemia. We present a case of metastatic insulinoma, in whom AN manifested after the first cycle of peptide receptor radionuclide therapy (PRRT). A 40-year-old man was diagnosed with metastatic insulinoma after 5 months of symptomatic hypoglycemia. Within 1 month post PRRT, the patient became euglycemic but developed a pigmented, pruritic rash which was confirmed on biopsy as AN. We discuss the rare manifestation of AN in subjects with insulinoma, the role of insulin in the pathogenesis of AN, malignant AN in non-insulin-secreting malignancies and association with other insulin-resistant endocrinopathies such as acromegaly.

Learning points

Acanthosis nigricans (AN) is a common dermatosis which is typically asymptomatic and associated with the hyperinsulinemic state. Malignant AN can rapidly spread, cause pruritus and affect mucosa and the oral cavity. AN is extremely rare in patients with insulinoma despite marked hyperinsulinemia. Peptide receptor radionuclide therapy might have triggered TGF-α secretion in this subject which led to malignant AN. Rapid spread or unusual distribution of pruritic AN warrants further investigation to exclude underlying malignancy.

Insulin Resistance in Gestational Diabetes Mellitus and Its Association With Anthropometric Fetal Indices

Background:

In pregnant women with gestational diabetes mellitus (GDM), insulin resistance (IR) increases the risk of developing manifest type 2 diabetes mellitus and is associated with complications in both mother and fetus.

Objectives:

This research aimed to evaluate the associations between IR evaluated by 3 indices (namely updated homeostasis model assessment model (HOMA2), QUICKI, and McAuley’s index) and the diabetes risk factors and the fetal growth indices in Vietnamese women with GDM.

Methods:

A cross-sectional descriptive study was conducted on 370 women with GDM and 40 healthy pregnant women from January 2015 to May 2019. IR was calculated by HOMA2 (HOMA2-IR), QUICKI, and McAuley’s index. Fetal anthropometric measurements were assessed via ultrasound which was performed and interpreted by ultrasound experts.

Results:

In the simple regression analysis, McAuley’s index illustrated had statistically significant correlations to the highest number of risk factors of diabetes mellitus compared with HOMA2-IR and QUICKI indices. Moreover, McAuley’s index correlated statistically significantly to the highest number of fetal ultrasound measurements factors such as including biparietal diameter (BPD) (r = −0.271, P < .001), head circumference (HC) (r = −0.225, P < .001), abdominal circumference (AC) (r = −0.214, P < .001), femur length (FL) (r = −0.231, P < .001), estimated fetal weight (EFW) (r = −0.239, P < .001) and fetal estimated age (r = −0.299, P < .001). In the multivariable analysis, the McAuley’s index contributed the greatest to AC (Standardized B of −0.656, P < .001).

Conclusion:

The McAuley’s index was significantly associated with a higher number of more risk factors for diabetes mellitus as well as fetal ultrasound sonography findings measurements than compared with HOMA2-IR and QUICKI indices.

Metabolic Syndrome and Its Components are Linked with Increased Risk of Non-Melanoma Skin Cancers in Iranian Subjects: A Case-Control Study

The associations between components of metabolic syndrome (MetS), insulin resistance (IR), and several malignancies have been reported. However, the possible link between IR and dermal malignancies, including non-melanoma skin cancers (NMSCs), has not been investigated to date. In this study, we aimed to examine the possible association between components of MetS, IR, adhesion molecules, and NMSC for the first time. This was a case-control study comprising 73 confirmed cases of NMSC and 72 unrelated healthy controls. Anthropometric and biochemical assessments including fasting blood lipid profile, glucose and insulin assays were performed. To evaluate IR, HOMA-IR formula was used. Though fasting serum glucose showed no significant between-group difference, serum concentrations of insulin (p = 0.048) as well as HOMA-IR (p = 0.037) were both significantly higher in NMSC group than in controls. Logistic regression analysis revealed significant associations between waist circumference (OR: 1.04, 95% CI: 1.007-1.080, p = 0.018), percent of visceral fat (OR: 1.10, 95% CI: 1.024-1.190, p = 0.01), HOMA-IR (OR: 1.169, 95% CI: 1.004-1.360, p = 0.044), circulating VCAM-1 concentrations (OR: 1.005, 95% CI: 1.003-1.007, p < 0.001) and NMSC risk. Interestingly, the occurrence of MetS was significantly higher in subjects with NMSC than in healthy controls (p = 0.038). MetS and its components were associated with increased NMSC risk.

Severe respiratory failure in a patient with COVID-19 and acromegaly: rapid improvement after adding octreotide

Acromegaly is a rare disorder of unregulated hypersecretion of growth hormone that causes cardiovascular, metabolic and respiratory complications. Herein, we describe the case of a middle-aged man admitted to the hospital with severe COVID-19 found to have clinical and biochemical evidence of acromegaly. His respiratory status declined despite initiation of standard treatments, prompting initiation of subcutaneous octreotide. Following initiation of this therapy, he rapidly improved and was discharged from the hospital 2 days later. Subsequent workup revealed a pituitary macroadenoma that was surgically removed, with improvement in his acromegaly symptoms. COVID-19 disease severity is increased by pre-existing diabetes, lung disease and immunosuppression. Although this patient had obstructive sleep apnoea and pre-diabetes, we hypothesise that our patient's acromegaly contributed to his severe course, as reflected by his rapid improvement after starting treatment with subcutaneous octreotide. Acromegaly may predispose to more severe outcomes in patients with COVID-19.

Assessment of Patients with Periorbital Melanosis for Hyperinsulinemia and Insulin Resistance

Background:

Periorbital melanosis (PM) is one of the most common dermatological condition seen in routine practice. Several cutaneous markers such as acanthosis nigricans have been associated with insulin resistance (IR). However, the association of PM with IR needs to be substantiated.

Objective:

The objective of the study is to evaluate the association of circulating adipokines and IR with PM.

Materials and Methods:

In this cross-sectional study, we recruited 100 patients with PM and 100 age- and gender-matched healthy controls. The serum levels of leptin, adiponectin, fasting glucose, fasting insulin, insulin-like growth factor-1 (IGF-1), homeostatic model assessment of insulin resistance (HOMA-IR), and leptin: adiponectin ratio (L/A ratio) were assayed.

Results:

The serum levels of leptin, fasting glucose, fasting insulin, HOMA-IR, L/A ratio were significantly higher in patients with PM as compared to controls. The serum levels of adiponectin were significantly lower in cases as compared to controls. On multivariate regression analysis, leptin, adiponectin, and HOMA-IR were found to be significant, even after adjusting for BMI, blood pressure and LDL and HDL cholesterol.

Conclusion:

Our findings suggest that patients with PM have hyperinsulinemia, IR, and elevated L/A ratio. PM as a marker of IR in adults may help in identifying patients early and thus aid in the early prevention and management of the disease.

Evaluation of Insulin Resistance Induced Brain Tissue Dysfunction in Obese Dams and their Neonates: Role of Ipriflavone Amelioration

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is associated with activation of liver fibrogenesis and predisposes to cirrhosis and associated morbi-mortality. A high fat high cholesterol diet (HFD) was provided to female albino rats to establish a NASH model. It is well known that the offspring of obese mothers have an increased risk of obesity and diabetes. The present study aimed at evaluating the ameliorative effects of ipriflavone (IP) as a natural food supplement on lipid metabolism, improving insulin sensitivity, reducing oxidative stress and inflammation, modifying metabolic risk factors and/or reduce brain damage, in both neonates and their dams.

MATERIALS AND METHODS

The present aim was achieved by evaluating the oxidative stress and antioxidant defense system biomarkers, as thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) activities. In addition, the neurotransmitter acetylcholine (Ach) and acetylcholine esterase (AchE) activities, as well as levels of the apolipoprotein E4 (APOE4); β-secretase, hyper phosphor-tau and β-amyloid 42; 3-hydroxy- 3-methyl glutaryl coenzyme A reductase (HMG CoA R)" and COX-II by immunoblotting assays in the brain tissue of neonates and their dams in all the studied groups.

RESULTS

A very significant amelioration in acetylcholine and acetylcholine esterase neurotransmitters, Alzheimer's makers (β-amyloid), antioxidants (reduced glutathione (GSH) contents, catalase (CAT) and superoxide dismutase (SOD); and inflammatory cytokines in NASH model is observed upon administrating ipriflavone (IP) as a natural food supplement. The multifunctional activities of ipriflavone as an antioxidant, anti-inflammatory and anti-insulin resistance drug were discussed and correlated with other investigations.

CONCLUSION

Regarding steatohepatitis, the present study confirmed the anti-inflammatory effects of the ipriflavone (IP). Therefore, future studies should focus on hepatic fatty acid uptake, hepatic lipogenesis, and fatty acid oxidation and the role of IP in regulating hepatic fat metabolism. In addition, natural products like IP could be combined with the highly used pharmaceutical drugs to reduce the side effects of nonalcoholic steatohepatitis, and minimize progression of dementia. Moreover, the present study supports further attempts to heal the neural dysfunction via antioxidant and anti-inflammatory cascade activities using ipriflavone (IP).

Clinical Implications of Polycystic Ovary Syndrome in Adolescents

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy, affecting as many as 5% to 20% of women of reproductive age, depending on the diagnostic criteria applied. Features of PCOS include physiologic anovulation, hyperandrogenism, elevated luteinizing hormone, and increased gonadotropin-releasing hormone pulse frequency, which often manifest physically as acne and hirsutism. The clinical presentation of PCOS often mimics normal pubertal physiologic development, which may delay diagnosis and treatment of the condition in adolescent girls. A diagnosis of PCOS has life-long implications and is associated with increased risk for infertility, obesity, Type 2 diabetes, endometrial hyperplasia, uterine carcinoma, metabolic disorder, and cardiovascular disease. In this article, we provide an overview of clinical presentation, diagnostic criteria, health consequences, and current evidence-based clinical guidelines for the appropriate diagnosis and management of PCOS in adolescents.

Cross-sectional study of the association between skin tags and vascular risk factors in a bariatric clinic-based cohort of Irish adults with morbid obesity

OBJECTIVE

Skin tags are associated with an insulin resistant phenotype but studies in White Europeans with morbid obesity are lacking. We sought to determine whether the presence of cervical or axillary skin tags was associated with increased cardiovascular risk in Irish adults with morbid obesity. We conducted a cross-sectional study of patients attending our Irish regional bariatric centre with a BMI ≥ 40 kg m^-2 (or ≥ 35 kg m^-2 with co-morbidities). We compared anthropometric and metabolic characteristics in those with versus without skin tags.

RESULTS

Of 164 patients, 100 (31 male, 37 with type 2 diabetes, 36 on lipid lowering therapy, 41 on antihypertensive therapy) participated. Mean age was 53.7 ± 11.3 (range 31.1-80) years. Cervical or axillary tags were present in 85 patients. Those with tags had higher systolic blood pressure 138.0 ± 16.0 versus 125.1 ± 8.3 mmHg, p = 0.003) and HbA1c (46.5 ± 13.2 versus 36.8 ± 3.5 mmol/mol, p = 0.017). Tags were present in 94.6% of patients with diabetes, compared to 79.4% of those without diabetes (p = 0.039). Antihypertensive therapy was used by 45.8% of patients with skin tags compared to 13.3% without tags (p = 0.018). In bariatric clinic attenders skin tags were associated with higher SBP and HbA1c and a higher prevalence of diabetes and hypertension, consistent with increased vascular risk, but lipid profiles were similar.

Ghrelin, resistin and insulin in obese diabetic women in Wad-Madani, Sudan

BACKGROUND

Obesity in the Sudan is increasing at alarming rate with the tendency of reaching an epidemic proportion in women. It is commonly associated with type 2 diabetes (T2D). Some adipokine hormones such as resistin are associated with obesity.

OBJECTIVES

To study how the levels of resistin, ghrelin and insulin are associated with obesity,fat distribution and (T2D) and to ascertain any interrelationships between them.

SUBJECTS AND METHODS

150 women, age ≥18 years old, resident in Wad-Madani town, Sudan were participated in the study. They were divided into 3 groups according to body mass index (BMI) value: I (normal weight), II (overweight) and III (obese diabetic). Fasting serum resistin and ghrelin concentrations were measured using ELISA method. Insulin levels were determined by radioimmunoassay(RIA).

RESULTS

The mean±SD levels of resistin 5.80±4.91ng/mL,Ghrelin107.60±26.67pg/M and Insulin 11.92±8.54mLU/ml in obese diabetic were found to be greater than in normal or overweight women. In normal weight values were 3.07±2.15 ng/mL 83.30±13.38pg/mL, and 6.62±6.77mLU/ml for resistini, ghrelin and Insulin, respectively. Values for overweight women 3.64±2.63 pg/mL 90±17.35 pg/mL and 8.13±7.54 mLU/ml for resistin, ghrelin and insulin respectively.

CONCLUSIONS AND RECOMMENDATIONS

Increased BMI, waist circumference (WC) and hormones (ghrelin and resistin) were associated with insulin resistance. Further studies are needed to accept or refute these findings.

Acanthosis Nigricans in the Knuckles of Infants: A Novel Clinical Marker of High Metabolic Risk

INTRODUCTION

Acanthosis nigricans (AN) is an early clinical sign of insulin resistance (IR) primarily in adults. The prevalence and association of AN and IR in infants, however, remains uncertain. We aimed to describe the prevalence of AN and its association with IR in a group of Latin-American infants.

METHODS

We studied a random sample of 227 healthy infants between 9 and 24 months of age. After a complete clinical history was obtained and a physical examination was performed, fasting plasma glucose and serum insulin were measured. Three blinded evaluators assessed AN in each patient. Infants with AN were categorized as cases. The HOMA-IR index cutoffs of ≥ 90th and ≥ 95th percentiles were considered IR.

RESULTS

There were 49 infants with AN (21.6%) (cases) and 178 without AN (78.4%) (controls). Cases had a significantly higher mean serum insulin, fasting plasma glucose, and HOMA-IR levels of 3.67 ± 2.56 µU/ml vs. 2.42 ± 1.45 µU/ml, P = 0.005; 84.2 ± 12.6 mg/dL vs. 77 ± SD 9.9 mg/dL, P ≤ 0.001; HOMA-IR 0.77 ± 0.54 vs. 0.46 ± 0.28, P ≤ 0.001, respectively. More cases than controls presented HOMA-IR levels ≥ 95th percentile (cases 18.4%; controls 0.5%, P ≤ 0.001) and ≥ 90th percentile (cases 32.7%; controls 1.6%, P ≤ 0.001). AN in the knuckles had a high sensitivity and a negative predictive value (NPV) for detecting patients with HOMA-IR levels above the 95th percentile (sensitivity 90%; NPV 99.4%) and above the 90th percentile (sensitivity 84.2%; NPV 98.3%).

CONCLUSION

AN in the knuckles is a prevalent, non-invasive, costless, and reliable screening clinical tool that can be used for early detection of infants with IR and a high metabolic risk.

Acanthosis nigricans as a clinical marker of insulin resistance among overweight adolescents

PURPOSE

Acanthosis nigricans (AN) is a hyperpigmented dermatosis associated with obesity and insulin resistance (IR). There is no consensus whether AN extension scoring offers added value to the clinical estimation of IR. In this study we aimed to assess and score AN using both a short and an extended version of the scale proposed by Burke et al. and analyze the relationships of both versions with hyperinsulinemia and IR.

METHODS

We analyzed data from 139 overweight adolescents (body mass index ≥85th percentile) aged 12-18 with (n=67) or without (n=72) AN who were followed at a pediatric obesity clinic.

RESULTS

Adolescents with AN had higher levels of insulin (d=0.56, P=0.003) and HOMA-IR (d=0.55, P=0.003) compared to those without. Neither the short nor the extended versions of AN scores explained either hyperinsulinemia (β=1.10, P=0.316; β=1.15, P=0.251) or IR (β=1.07, P=0.422; β=1.10, P=0.374). The presence of AN alone predicted hyperinsulinemia and the presence of IR in 7.3% (β=2.68, P=0.008) and 7.1% (β=2.59, P=0.009) of adolescents, respectively.

CONCLUSION

Screening for AN at the neck and axilla is a noninvasive and cost-effective way to identify asymptomatic overweight adolescents with or at risk of developing IR.

Acanthosis nigricans: To be or not to be afraid

Acanthosis nigricans (AN), a skin disorder with high prevalence, represents a dermatological condition with esthetic implications, but otherwise mild symptoms. For any clinician, it is in fact the tip of the iceberg, leading him/her to investigate what lies beneath the surface, since AN points to a systemic problem or disease: metabolic disorder (most frequently), endocrine syndrome, medication side effects, malignancy, and genetic factors. Sometimes, it is the first observed sign of a malignancy or of diabetes mellitus, especially in patients with chronic metabolic disorder; therefore, it is not to be taken lightly. The present review summarizes the information in literature regarding the etiopathogenesis of AN. We propose a new classification that aims to better organize the different types of AN, with implications on the extent and urgency of the investigation plan, as well as various therapeutic algorithms. Therapy options are also presented, both systemic treatments that target the underlying disease, and local ones for esthetic reasons.

Insulin receptor plays a central role in skin carcinogenesis by regulating cytoskeleton assembly

Diabetes mellitus prevalence is increasing rapidly and is a major cause of mortality and morbidity worldwide. In addition to the known severe complications associated with the disease, in recent years diabetes has been recognized as a major risk factor for cancer. Patients with diabetes experience significantly higher incidence of and higher mortality rates from many types of cancer. However, to date there are no conclusive data on the pathophysiology underlying the association between these two diseases. We previously reported that insulin regulates skin proliferation and differentiation, while IGF1 had different sometimes contrasting effects to those of insulin, suggesting direct involvement of insulin in transformation. To this end, we developed an epidermal skin-specific insulin receptor knockout (SIRKO) mouse, in which the insulin receptor (IR) is inactivated only in skin, with no other metabolic consequences. We found that IR inactivation by itself resulted in a marked decrease in skin tumorigenesis. In the control group 100% of the mice developed tumors, but in the SIRKO group tumor incidence was over 60% lower, and 25% of the SIRKO mice did not develop tumors at all, and the tumors that did develop were smaller and benign in their appearance. Furthermore, IR inactivation in vitro not only prevented cell transformation but also reversed the keratinocyte-transformed phenotype. We found that IR inactivation led to a striking abnormality in the major keratin cytoskeleton filaments structure in both in vivo and in vitro, a change that we were able to link to the decreased transformation potential in IR-null cells. In summary, we identified a unique pathway in which IR regulates cytoskeletal assembly, thus affecting skin transformation, opening a new potential target for cancer treatment and prevention.-Weingarten, G., Ben Yaakov, A., Dror, E., Russ, J., Magin, T. M., Kahn, C. R., Wertheimer, E. Insulin receptor plays a central role in skin carcinogenesis by regulating cytoskeleton assembly.