Short-term isotretinoin treatment decreases insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels: does isotretinoin affect growth hormone physiology?

Acne Transcriptomics: Fundamentals of Acne Pathogenesis and Isotretinoin Treatment

This review on acne transcriptomics allows for deeper insights into the pathogenesis of acne and isotretinoin's mode of action. Puberty-induced insulin-like growth factor 1 (IGF-1), insulin and androgen signaling activate the kinase AKT and mechanistic target of rapamycin complex 1 (mTORC1). A Western diet (hyperglycemic carbohydrates and milk/dairy products) also co-stimulates AKT/mTORC1 signaling. The AKT-mediated phosphorylation of nuclear FoxO1 and FoxO3 results in their extrusion into the cytoplasm, a critical switch which enhances the transactivation of lipogenic and proinflammatory transcription factors, including androgen receptor (AR), sterol regulatory element-binding transcription factor 1 (SREBF1), peroxisome proliferator-activated receptor γ (PPARγ) and signal transducer and activator of transcription 3 (STAT3), but reduces the FoxO1-dependent expression of GATA binding protein 6 (GATA6), the key transcription factor for infundibular keratinocyte homeostasis. The AKT-mediated phosphorylation of the p53-binding protein MDM2 promotes the degradation of p53. In contrast, isotretinoin enhances the expression of p53, FoxO1 and FoxO3 in the sebaceous glands of acne patients. The overexpression of these proapoptotic transcription factors explains isotretinoin's desirable sebum-suppressive effect via the induction of sebocyte apoptosis and the depletion of BLIMP1(+) sebocyte progenitor cells; it also explains its adverse effects, including teratogenicity (neural crest cell apoptosis), a reduced ovarian reserve (granulosa cell apoptosis), the risk of depression (the apoptosis of hypothalamic neurons), VLDL hyperlipidemia, intracranial hypertension and dry skin.

Effects of high-dose all-trans retinoic acid on longitudinal bone growth of young rats

OBJECTIVE

The signaling axis consisting of GH-IGF1-IGFBP3 is the primary signal taht acts prepubertally to influence height development. Growth plate thinning and even premature closure have been reported in children with tumors treated with retinoid chemotherapy, resulting in long bone dysplasia. Growth failure may occur despite received GH treatment, but the reason is unknown. This study investigate the effect of high-dose all-trans retinoic acid (ATRA) on the development of long bones in growing SD rats.

METHODS

A total of 20 three-week-old male SD rats were randomly divided into a control group and an experimental group (n = 10). Rats were treated by gavage with or without high-dose ATRA for 10 days. The body weights of the rats were recorded daily. At the end of the experiment, we measured the length of nose-tail and tibia, stained the tibia and liver for pathological tissue and RT-PCR reaction, and measured the levels of serum GH, IGF1 and IGFBP3, and so on.

RESULTS

Compared with controls, experimental rats exhibited reduced body weight and shortened nasal-tail and radial tibial length. Cyp26b1 enzyme activity in the liver was elevated, and histopathological staining revealed that the cartilaginous epiphyseal plate was narrowed, the medullary cavity of trabecular bone was sparse, the number of trabecular bones was decreased, trabecular separation was increased, bone marrow mineralization was enhanced, osteoclastic activity was increased, and circulating GH-IGF1-IGFBP3 levels were decreased. However, RT-PCR reaction results of localized proximal tibiae showed upregulation of IGF1 and downregulation of IGFBP3.

CONCLUSIONS

High-dose ATRA intake over a short period of time can reduce GH-IGF1-IGFBP3 levels, affect cartilage and bone homeostasis, and inhibit bone growth in developing animals.

Isotretinoin Induced Hyperlipidemia and Impact of Leptin Gene rs 7799039 Polymorphism in Safety of Acne Patients

Background

Acne vulgaris (AV) is a chronic inflammatory disease that affects the pilosebaceous unit. Leptin (LEP) gene polymorphisms is associated with higher risk of multiple disorders. Insulin-like growth factor-1 (IGF-1) exerts comedogenic effect by stimulating the sebaceous glands. Isotretinoin is an effective oral therapy for AV with many side effects including hyperlipidemia and increased serum levels of liver enzymes.

Purpose

To evaluate the impact of LEP gene rs7799039 polymorphism in acne patients' clinical response lipid profile and liver enzymes following 6 months oral isotretinoin therapy in Egyptian AV patients.

Methods

One hundred eligible AV patients received 0.5 mg/kg oral isotretinoin for 6 months. Patients' demographics and clinical data were obtained. Body mass index (BMI), lipid profile, liver enzymes and IGF-1 were measured at baseline and after 6 months of therapy. Genotyping was done for LEP gene rs 7799039.

Results

Six month administration of oral isotretinoin in Egyptian AV patients is associated with significantly elevated aspartate transaminase (AST) in CC and AC genotypes (P<0.001). Significant alanine aminotransferase (ALT) elevation was observed in CC, AC and AA genotypes (P <0.001, 0.004, 0.002, respectively). Total cholesterol (TC), triglycerides (TG) and low density lipoprotein (LDL) were elevated significantly P<0.001) in the three genotypes. IGF-1 was decreased significantly in CC and AC genotypes (P<0.001). CC genotype is associated with highest response (P<0.001).

Conclusion

LEP rs7799039 gene had an impact on the clinical response, lipid profile and liver enzymes in AV patients treated with oral isotretinoin. LEP rs7799039 CC genotype is predicted to be the treatment candidate for 6 month oral isotretinoin.

Predictors of quality of life in adults and adolescents with acne: A cross-sectional study

Background:

Acne is becoming more prevalent in adults, particularly women across the globe. Although previous studies have compared clinical and epidemiologic characteristics of adolescent and adult acne, an adequate understanding of the quality of life (QoL) of adult acne patients and associated comorbidities are still lacking.

Objectives:

We sought to compare the differences between adolescent and adult patient groups, regarding gender, socio-clinico-demographic factors, and comorbid associations, as well as their relatedness with life quality.

Methods:

This is a cross-sectional study with 1013 acne patients. Data on the severity, onset and location of acne, sex, family history of acne, smoking and alcohol habits, medication history, presence of seborrhea, and other comorbidities were collected. We employed the classification used by the American Academy of Dermatology for assessing acne severity. To assess the QoL in the patients, the Dermatology Life Quality Index (DLQI) score was used.

Results:

Of the 1013 patients included in this study; 380 (female: 333, male: 47) were adult, and 633 (female: 535 and male: 98) were adolescent cases. The median total DLQI scores of adult and adolescent groups were not significantly different. Our results showed that factors such as age, gender, duration, body mass index, family history, and psychiatric disorders exhibited no impact on QoL in both adolescents and adults. Age of onset was correlated with DLQI scores in the adult group. The main influencers of DLQI in the adult group were allergic disorders, hormonal imbalances, and previous treatment history. Besides, major influencers in adolescent patients were acne severity, acne location, hirsutism, hyperseborrhea, premenstrual exacerbation, menstrual irregularities, previous treatment history, and smoking.

Conclusions:

The findings of our current study have shown that DLQI has been influenced by different factors in adolescents and adults that should be kept in mind.

Do acne treatments affect insulin-like growth factor-1 serum levels? A clinical and laboratory study on patients with acne vulgaris

Acne is a chronic inflammatory disease affecting sebaceous gland follicles. Lately, acne has considered an insulin-like growth factor-1 (IGF-1) mediated disease. Recent research demonstrated that IGF-1 levels decrease after 3 months of isotretinoin. The purpose of our study is evaluating the influence of acne treatments on IGF-1 serum levels. Forty-six subjects with acne vulgaris aged 14 to 30 years were subdivided into three groups according to their severity of acne and treated following the European Dermatology Forum guidelines. IGF-1 was measured in patients before and after the treatment and then compared to the IGF-1 of a healthy population of the same age. IGF-1 resulted higher in patients than in controls but there was not a statistically significant variation after treatment. To the best of our knowledge, this is the first study evaluating the influence of topical and systemic acne treatment on IGF-1 serum levels. In contrast with the literature, our results suggest that common therapies for acne are not able to significantly modify IGF-1 serum levels.

Effects of isotretinoin on body mass index, serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients

Introduction

Isotretinoin has been successfully used for the treatment of acne vulgaris.

Aim

To investigate the effects of isotretinoin on body mass index (BMI), to determine whether isotretinoin causes any changes in serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients, and to correlate variables.

Material and methods

Thirty-two patients were included in this study. Oral isotretinoin was begun at a dose of 0.5–0.6 mg/kg and raised to 0.6–0.75 mg/kg. Pretreatment and posttreatment third-month BMI and adiponectin, leptin, and ghrelin serum levels were measured.

Results

The pre- and posttreatment BMI values were not significantly different. In addition, serum adiponectin and leptin levels were significantly increased following isotretinoin therapy while serum ghrelin levels were not different.

Conclusions

Isotretinoin may exert its anti-inflammatory activity by increasing leptin and adiponectin levels.

Linking diet to acne metabolomics, inflammation, and comedogenesis: an update

Acne vulgaris, an epidemic inflammatory skin disease of adolescence, is closely related to Western diet. Three major food classes that promote acne are: 1) hyperglycemic carbohydrates, 2) milk and dairy products, 3) saturated fats including trans-fats and deficient ω-3 polyunsaturated fatty acids (PUFAs). Diet-induced insulin/insulin-like growth factor (IGF-1)-signaling is superimposed on elevated IGF-1 levels during puberty, thereby unmasking the impact of aberrant nutrigenomics on sebaceous gland homeostasis. Western diet provides abundant branched-chain amino acids (BCAAs), glutamine, and palmitic acid. Insulin and IGF-1 suppress the activity of the metabolic transcription factor forkhead box O1 (FoxO1). Insulin, IGF-1, BCAAs, glutamine, and palmitate activate the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the key regulator of anabolism and lipogenesis. FoxO1 is a negative coregulator of androgen receptor, peroxisome proliferator-activated receptor-γ (PPARγ), liver X receptor-α, and sterol response element binding protein-1c (SREBP-1c), crucial transcription factors of sebaceous lipogenesis. mTORC1 stimulates the expression of PPARγ and SREBP-1c, promoting sebum production. SREBP-1c upregulates stearoyl-CoA- and Δ6-desaturase, enhancing the proportion of monounsaturated fatty acids in sebum triglycerides. Diet-mediated aberrations in sebum quantity (hyperseborrhea) and composition (dysseborrhea) promote Propionibacterium acnes overgrowth and biofilm formation with overexpression of the virulence factor triglyceride lipase increasing follicular levels of free palmitate and oleate. Free palmitate functions as a "danger signal," stimulating toll-like receptor-2-mediated inflammasome activation with interleukin-1β release, Th17 differentiation, and interleukin-17-mediated keratinocyte proliferation. Oleate stimulates P. acnes adhesion, keratinocyte proliferation, and comedogenesis via interleukin-1α release. Thus, diet-induced metabolomic alterations promote the visible sebofollicular inflammasomopathy acne vulgaris. Nutrition therapy of acne has to increase FoxO1 and to attenuate mTORC1/SREBP-1c signaling. Patients should balance total calorie uptake and restrict refined carbohydrates, milk, dairy protein supplements, saturated fats, and trans-fats. A paleolithic-like diet enriched in vegetables and fish is recommended. Plant-derived mTORC1 inhibitors and ω-3-PUFAs are promising dietary supplements supporting nutrition therapy of acne vulgaris.

Oral toxicity of isotretinoin, misoprostol, methotrexate, mifepristone and levonorgestrel as pregnancy category X medications in female mice

An oral toxicity study of several pregnancy category X drugs was performed in female ICR mice. The drugs were administered orally once daily for 3 days at doses of 1, 10 and 100 μg/kg for isotretinoin; 6.7, 67 and 670 μg/kg for misoprostol; 83, 830 and 8,300 μg/kg for methotrexate; 3.3, 33 and 330 μg/kg for mifepristone; and 25, 250 and 2,500 μg/kg for levonorgestrel. During the test period, clinical signs, mortality, body weight, hematology, serum biochemistry and necropsy findings were examined. Following administration of methotrexate at 8,300 μg/kg, a number of animals exhibited decreased spontaneous activity, and one animal died. In the hematological analysis, compared with those treated with the control, the animals treated with the drugs exhibited similar significant decreases in the number of granulocytes and granulocyte differentiation, and increases in lymphocyte differentiation. In the serum biochemical analysis, animals receiving high doses of the five drugs demonstrated significant changes in uric acid, glucose, alkaline phosphatase, total bilirubin, lipase, total cholesterol and calcium. At necropsy, intestinal redness was frequently observed in animals that received the high dose of methotrexate. Uterus enlargement and ovary dropsy were also detected in the groups receiving mifepristone and levonorgestrel. Despite the short-term exposure, these drugs exhibited significant side effects, including white blood cell toxicity, in the mouse model. Category X drugs can be traded illegally via the internet for the purpose of early pregnancy termination. Thus, illegal abuse of the drugs should be further discouraged to protect mothers.

Insulin-like growth factor-I gene polymorphism in acne vulgaris

BACKGROUND

Acne vulgaris is a multifactorial disease of the skin. Several studies have shown that elevated levels of serum insulin-like growth factor-I (IGF-I) correlate with overproduction of sebum and acne. Recently functional relationship between IGF-I (CA) polymorphism and circulating IGF-I levels in adults has been reported.

AIMS

The aim of our study was to investigate for the first time whether IGF-I (CA) polymorphism might be involved in the pathogenesis of acne or not.

METHODS

We included 115 acne patients and 117 healthy subjects to the study. The clinical grade of acne was assessed based on the Global Acne Grading System. Participants were questioned about diabetes mellitus, PCOS and other systemic disease. We searched for the IGF-I (CA) 19 polymorphism in this study. The IGF-I (CA) 19 polymorphism was performed by polymerase chain reaction.

RESULTS

We categorized the IGF-I (CA) 19 polymorphism area into three groups as lower than 192 bp, 192–194 bp and higher than 194 bp. We found that the frequency of genotype IGF-1 (CA) 19 gene was significantly different between control and acne patients (P = 0.0002). A significant association between IGF-I (CA) genotypes and severity of acne was found (P = 0.015). No significant difference was found between male and female patients (P > 0.05).

CONCLUSIONS

Our results suggest that IGF-I (CA) 19 polymorphism may contribute to a predisposition to acne in Turkish patients.

Potential role of FoxO1 and mTORC1 in the pathogenesis of Western diet-induced acne

Acne in adolescents of developed countries is an epidemic skin disease and has currently been linked to the Western diet (WD). It is the intention of this viewpoint to discuss the possible impact of WD-mediated nutrient signalling in the pathogenesis of acne. High glycaemic load and dairy protein consumption both increase insulin/insulin-like growth factor-1 (IGF-1) signalling (IIS) that is superimposed on elevated IGF-1 signalling of puberty. The cell's nutritional status is primarily sensed by the forkhead box transcription factor O1 (FoxO1) and the serine/threonine kinase mammalian target of rapamycin complex 1 (mTORC1). Increased IIS extrudes FoxO1 into the cytoplasm, whereas nuclear FoxO1 suppresses hepatic IGF-1 synthesis and thus impairs somatic growth. FoxO1 attenuates androgen signalling, interacts with regulatory proteins important for sebaceous lipogenesis, regulates the activity of innate and adaptive immunity, antagonizes oxidative stress and most importantly functions as a rheostat of mTORC1, the master regulator of cell growth, proliferation and metabolic homoeostasis. Thus, FoxO1 links nutrient availability to mTORC1-driven processes: increased protein and lipid synthesis, cell proliferation, cell differentiation including hyperproliferation of acroinfundibular keratinocytes, sebaceous gland hyperplasia, increased sebaceous lipogenesis, insulin resistance and increased body mass index. Enhanced androgen, TNF-α and IGF-1 signalling due to genetic polymorphisms promoting the risk of acne all converge in mTORC1 activation, which is further enhanced by nutrient signalling of WD. Deeper insights into the molecular interplay of FoxO1/mTORC1-mediated nutrient signalling are thus of critical importance to understand the impact of WD on the promotion of epidemic acne and more serious mTORC1-driven diseases of civilization.

Dietary intervention in acne: Attenuation of increased mTORC1 signaling promoted by Western diet

The purpose of this paper is to highlight the endocrine signaling of Western diet, a fundamental environmental factor involved in the pathogenesis of epidemic acne. Western nutrition is characterized by high calorie uptake, high glycemic load, high fat and meat intake, as well as increased consumption of insulin- and IGF-1-level elevating dairy proteins. Metabolic signals of Western diet are sensed by the nutrient-sensitive kinase, mammalian target of rapamycin complex 1 (mTORC1), which integrates signals of cellular energy, growth factors (insulin, IGF-1) and protein-derived signals, predominantly leucine, provided in high amounts by milk proteins and meat. mTORC1 activates SREBP, the master transcription factor of lipogenesis. Leucine stimulates mTORC1-SREBP signaling and leucine is directly converted by sebocytes into fatty acids and sterols for sebaceous lipid synthesis. Over-activated mTORC1 increases androgen hormone secretion and most likely amplifies androgen-driven mTORC1 signaling of sebaceous follicles. Testosterone directly activates mTORC1. Future research should investigate the effects of isotretinoin on sebocyte mTORC1 activity. It is conceivable that isotretinoin may downregulate mTORC1 in sebocytes by upregulation of nuclear levels of FoxO1. The role of Western diet in acne can only be fully appreciated when all stimulatory inputs for maximal mTORC1 activation, i.e., glucose, insulin, IGF-1 and leucine, are adequately considered. Epidemic acne has to be recognized as an mTORC1-driven disease of civilization like obesity, type 2 diabetes, cancer and neurodegenerative diseases. These new insights into Western diet-mediated mTORC1-hyperactivity provide a rational basis for dietary intervention in acne by attenuating mTORC1 signaling by reducing (1) total energy intake, (2) hyperglycemic carbohydrates, (3) insulinotropic dairy proteins and (4) leucine-rich meat and dairy proteins. The necessary dietary changes are opposed to the evolution of industrialized food and fast food distribution of Westernized countries. An attenuation of mTORC1 signaling is only possible by increasing the consumption of vegetables and fruit, the major components of vegan or Paleolithic diets. The dermatologist bears a tremendous responsibility for his young acne patients who should be advised to modify their dietary habits in order to reduce activating stimuli of mTORC1, not only to improve acne but to prevent the harmful and expensive march to other mTORC1-related chronic diseases later in life.

The effects of retinoids on secondary wound healing: biometrical and histopathological study in rats

OBJECTIVE

A wound healing is a complex process, and the role of retinoids in this process is debated and controversial. In this study, the effect of topical tretinoin and oral acitretin on wound healing process was investigated in full-thickness skin lesions on rat model.

METHOD

A circular full-thickness wound was created by 6 mm punch biopsy on the back side of 32 male rats. The rats were seperated into four equal. The first group was assigned as a control group and was observed with no treatment. The second group was administered dexpanthenol once a day over wound area. In the third group, 0.1% tretinoin cream was applied daily. In the fourth group, 2.5 mg/kg/day acitretin was given daily. Additionally, the biopsies were taken from wounds for the histopathologic examination.

RESULTS

The complete recovery time was remarkably longer in the tretionin group than the control group and the dexpantenol group (p < 0.05). The average complete recovery time was significantly longer in the acitretin group than the control and dexpanthenol groups whereas it was statistically shorter in the acitrein group than the tretionin group (p < 0.05).

CONCLUSION

Based on our findings, topical tretinoin and oral acitretin can delay secondary wound healing, epithelization and angiogenesis.

Isotretinoin and FoxO1: A scientific hypothesis

Oral isotretinoin (13-cis retinoic acid) is the most effective drug in the treatment of acne and restores all major pathogenetic factors of acne vulgaris. isotretinoin is regarded as a prodrug which after isomerizisation to all-trans-retinoic acid (ATRA) induces apoptosis in cells cultured from human sebaceous glands, meibomian glands, neuroblastoma cells, hypothalamic cells, hippocampus cells, Dalton's lymphoma ascites cells, B16F-10 melanoma cells, and neuronal crest cells and others. By means of translational research this paper provides substantial indirect evidence for isotretinoin's mode of action by upregulation of forkhead box class O (FoxO) transcription factors. FoxOs play a pivotal role in the regulation of androgen receptor transactivation, insulin/insulin like growth factor-1 (IGF-1)-signaling, peroxisome proliferator-activated receptor-γ (PPArγ)- and liver X receptor-α (LXrα)-mediated lipogenesis, β-catenin signaling, cell proliferation, apoptosis, reactive oxygene homeostasis, innate and acquired immunity, stem cell homeostasis, as well as anti-cancer effects. An accumulating body of evidence suggests that the therapeutic, adverse, teratogenic and chemopreventive effecs of isotretinoin are all mediated by upregulation of FoxO-mediated gene transcription. These FoxO-driven transcriptional changes of the second response of retinoic acid receptor (RAR)-mediated signaling counterbalance gene expression of acne due to increased growth factor signaling with downregulated nuclear FoxO proteins. The proposed isotretinoin→ATRA→RAR→FoxO interaction offers intriguing new insights into the mode of isotretinoin action and explains most therapeutic, adverse and teratogenic effects of isotretinoin in the treatment of acne by a common mode of FoxO-mediated transcriptional regulation.

Propionibacterium acnes activates the IGF-1/IGF-1R system in the epidermis and induces keratinocyte proliferation

Propionibacterium acnes has a major role in the development of acne lesions. IGF-1 stimulates the proliferation of keratinocytes via an activation of the IGF-1 receptor (IGF-1R). Zinc has been proven to work efficiently against inflammatory acne and to modulate the IGF-1 system. Our objectives were to study the modulation of IGF-1 and IGF-1R expression by P. acnes extracts and to determine their modulation by zinc gluconate. In vivo, we analyzed biopsies of acne lesions and healthy skin, and in vitro we used skin explants incubated with two P. acnes extracts--membrane fraction (MF) and cytosolic proteins--with or without zinc. IGF-1 and IGF-1R expression was evaluated using immunohistochemistry, and the IGF-1 production in supernatants was measured by ELISA. Then, IGF-1 and IGF-1R mRNA levels were analyzed using quantitative PCR on normal human epidermal keratinocytes (NHEKs). IGF-1 and IGF-1R were overexpressed in acne lesions. MF increased IGF-1 and IGF-1R expression in the epidermis of explants and was associated with an overexpression of both Ki-67 and filaggrin. Zinc had the effect of downregulating IGF-1 and IGF-1R levels. These observations were confirmed at the mRNA level for IGF-1R in NHEKs. These results demonstrate that P. acnes can induce the formation of comedones by stimulating the IGF/IGF-1R system. Moreover, zinc downregulates this pathway.

Does inflammatory acne result from imbalance in the keratinocyte innate immune response?

Acne is a multifactorial chronic disease affecting around 80% of teenage population. The pathogenesis of acne involves inflammatory reactions and colonization by the Propionibacterium acnes (P. acnes) strain. P. acnes stimulates the keratinocytes involved in the innate immune response, the intensity of which could be influenced either by bacterial intrinsic factors or by endogenous factors of the host.