Inhibition of 11β-HSD1 Expression by Insulin in Skin: Impact for Diabetic Wound Healing

Role of corticosteroids in skin physiology and therapeutic potential of an 11β-HSD1 inhibitor: A review

Skin is a major site of cortisol bioconversion by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzymes which catalyze intracellular inactive cortisone into physiologically active cortisol. 11β-HSD1 is highly expressed in skin, especially in dermal fibroblasts, epidermal keratinocytes, melanocytes, and hair follicles, and plays important roles in regulating keratinocytes, fibroblast proliferation, and has roles in skin aging. Inhibition of 11β-HSD1 may reverse decreased collagen levels observed in extrinsically and intrinsically aged skin. Inhibitors of 11β-HSD1 may also have the potential to reverse decreased collagen observed in skin atrophy induced by glucocorticoid treatment. This systematic review aimed to summarize the current knowledge of roles for 11β-HSD1 inhibitor in skin physiology and potential for future use in medications. Studies have demonstrated that immediately following experimental insult in an animal model, there is increased expression of 11β-HSD1, and that topical application of an 11β-HSD1 inhibitor increases the rate of healing, increases skin collagen content, increases dermal fibroblasts, and increases dermal thickness. Furthermore, in patients with type 2 diabetes mellitus, 11β-HSD1 inhibitors reduce wound diameter after injury. Further development of 11β-HSD1 inhibitors appears to be a promising area for treating aging skin, aiding wound healing, and mitigating effects of systemic glucocorticoid use. Both topically and orally administered 11β-HSD1 inhibitors appear to be viable avenues for future research.

Hypoglycemic Effects and Quality Marker Screening of Dendrobium nobile Lindl. at Different Growth Years

(1) Background: The effect of Dendrobium nobile Lindl. (D. nobile) on hyperglycemic syndrome has only been recently known for several years. Materials of D. nobile were always collected from the plants cultivated in various growth ages. However, regarding the efficacy of D. nobile on hyperglycemic syndrome, it was still unknown as to which cultivation age would be selected. On the other hand, with the lack of quality markers, it is difficult to control the quality of D. nobile to treat hyperglycemic syndrome. (2) Methods: The effects of D. nobile cultivated at year 1 and year 3 were checked on alloxan-induced diabetic mice while their body weight, diet, water intake, and urinary output were monitored. Moreover, levels of glycosylated serum protein and insulin were measured using Elisa kits. The constituents of D. nobile were identified and analyzed by using UPLC-Q/trap. Quality markers were screened out by integrating the data from UPLC-Q/trap into a network pharmacology model. (3) Results: The D. nobile cultivated at both year 1 and year 3 showed a significant effect on hyperglycemic syndrome at the high dosage level; however, regarding the significant level, D. nobile from year 1 showed the better effect. In D. nobile, most of the metabolites were identified as alkaloids and sesquiterpene glycosides. Alkaloids, represented by dendrobine, were enriched in D. nobile from year 1, while sesquiterpene glycosides were enriched in D. nobile from year 3. Twenty one metabolites were differentially expressed between D. nobile from year 1 and year 3. The aforementioned 21 metabolites were enriched to 34 therapeutic targets directly related to diabetes. (4) Conclusions: Regarding the therapy for hyperglycemic syndrome, D. nobile cultivated at year 1 was more recommended than that at year 3. Alkaloids were recommended to be used as markers to control the quality of D. nobile for hyperglycemic syndrome treatment.

Advances in Zebrafish for Diabetes Mellitus with Wound Model

Diabetic foot ulcers cause great suffering and are costly for the healthcare system. Normal wound healing involves hemostasis, inflammation, proliferation, and remodeling. However, the negative factors associated with diabetes, such as bacterial biofilms, persistent inflammation, impaired angiogenesis, inhibited cell proliferation, and pathological scarring, greatly interfere with the smooth progress of the entire healing process. It is this impaired wound healing that leads to diabetic foot ulcers and even amputations. Therefore, drug screening is challenging due to the complexity of damaged healing mechanisms. The establishment of a scientific and reasonable animal experimental model contributes significantly to the in-depth research of diabetic wound pathology, prevention, diagnosis, and treatment. In addition to the low cost and transparency of the embryo (for imaging transgene applications), zebrafish have a discrete wound healing process for the separate study of each stage, resulting in their potential as the ideal model animal for diabetic wound healing in the future. In this review, we examine the reasons behind the delayed healing of diabetic wounds, systematically review various studies using zebrafish as a diabetic wound model by different induction methods, as well as summarize the challenges and improvement strategies which provide references for establishing a more reasonable diabetic wound zebrafish model.

Skin 11β-hydroxysteroid dehydrogenase type 1 enzyme expression regulates burn wound healing and can be targeted to modify scar characteristics

BACKGROUND

Excessive scarring and fibrosis are the most severe and common complications of burn injury. Prolonged exposure to high levels of glucocorticoids detrimentally impacts on skin, leading to skin thinning and impaired wound healing. Skin can generate active glucocorticoids locally through expression and activity of the 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). We hypothesised that burn injury would induce 11β-HSD1 expression and local glucocorticoid metabolism, which would have important impacts on wound healing, fibrosis and scarring. We additionally proposed that pharmacological manipulation of this system could improve aspects of post-burn scarring.

METHODS

Skin 11β-HSD1 expression in burns patients and mice was examined. The impacts of 11β-HSD1 mediating glucocorticoid metabolism on burn wound healing, scar formation and scar elasticity and quality were additionally examined using a murine 11β-HSD1 genetic knockout model. Slow-release scaffolds containing therapeutic agents, including active and inactive glucocorticoids, were developed and pre-clinically tested in mice with burn injury.

RESULTS

We demonstrate that 11β-HSD1 expression levels increased substantially in both human and mouse skin after burn injury. 11β-HSD1 knockout mice experienced faster wound healing than wild type mice but the healed wounds manifested significantly more collagen deposition, tensile strength and stiffness, features characteristic of excessive scarring. Application of slow-release prednisone, an inactive glucocorticoid, slowed the initial rate of wound closure but significantly reduced post-burn scarring via reductions in inflammation, myofibroblast generation, collagen production and scar stiffness.

CONCLUSIONS

Skin 11β-HSD1 expression is a key regulator of wound healing and scarring after burn injury. Application of an inactive glucocorticoid capable of activation by local 11β-HSD1 in skin slows the initial rate of wound closure but significantlyimproves scar characteristics post burn injury.

Wound Healing Impairment in Type 2 Diabetes Model of Leptin-Deficient Mice—A Mechanistic Systematic Review

Type II diabetes mellitus (T2DM) is one of the most prevalent diseases in the world, associated with diabetic foot ulcers and impaired wound healing. There is an ongoing need for interventions effective in treating these two problems. Pre-clinical studies in this field rely on adequate animal models. However, producing such a model is near-impossible given the complex and multifactorial pathogenesis of T2DM. A leptin-deficient murine model was developed in 1959 and relies on either dysfunctional leptin (ob/ob) or a leptin receptor (db/db). Though monogenic, this model has been used in hundreds of studies, including diabetic wound healing research. In this study, we systematically summarize data from over one hundred studies, which described the mechanisms underlying wound healing impairment in this model. We briefly review the wound healing dynamics, growth factors’ dysregulation, angiogenesis, inflammation, the function of leptin and insulin, the role of advanced glycation end-products, extracellular matrix abnormalities, stem cells’ dysregulation, and the role of non-coding RNAs. Some studies investigated novel chronic diabetes wound models, based on a leptin-deficient murine model, which was also described. We also discussed the interventions studied in vivo, which passed into human clinical trials. It is our hope that this review will help plan future research.

Regulation of 11β-HSD1 by GH/IGF-1 in key metabolic tissues may contribute to metabolic disease in GH deficient patients

Patients with growth hormone deficiency (GHD) have many clinical features in common with Cushing's syndrome (glucocorticoid excess) - notably visceral obesity, insulin resistance, muscle myopathy and increased vascular mortality. Within key metabolic tissues, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts cortisone to the active glucocorticoid, cortisol (11-dehydrocorticosterone and corticosterone in rodents respectively), and thus amplifies local glucocorticoid action. We hypothesize that 11β-HSD1 expression is negatively regulated by growth hormone (GH), and that GHD patients have elevated 11β-HSD1 within key metabolic tissues (leading to increased intracellular cortisol generation) which contributes to the clinical features of this disease. To identify the impact of GH excess/resistance on 11β-HSD1 in vivo, we measured mRNA expression in key metabolic tissues of giant mice expressing the bovine GH (bGH) gene, dwarf mice with a disrupted GH receptor (GHRKO) gene and mice expressing a gene encoding a GH receptor antagonist (GHA). Additionally, we assessed urine steroid markers of 11β-HSD1 activity in both GHRKO and bGH animals. 11β-HSD1 expression was decreased in gastrocnemius muscle (0.43-fold, p < 0.05), subcutaneous adipose (0.53-fold, p < 0.05) and epididymal adipose tissue (0.40-fold, p < 0.05), but not liver, in bGH mice compared to WT controls. This was paralleled by an increased percentage of 11-DHC (inactive glucocorticoid) present in the urine of bGH mice compared to WT controls (2.5-fold, p < 0.01) - consistent with decreased systemic 11β-HSD1 activity. By contrast, expression of 11β-HSD1 was increased in the liver of GHRKO (2.7-fold, p < 0.05) and GHA mice (2.0-fold, p < 0.05) compared to WT controls, but not gastrocnemius muscle, subcutaneous adipose tissue or epididymal adipose tissue. In summary, we have demonstrated a negative relationship between GH action and 11β-HSD1 expression which appears to be tissue specific. These data provide evidence that increased intracellular cortisol production within key tissues may contribute to metabolic disease in GHD patients.

A randomised controlled pilot trial of oral 11β-HSD1 inhibitor AZD4017 for wound healing in adults with type 2 diabetes mellitus.. [DOI: 10.1101/2021.03.23.21254200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Chronic wounds (e.g. diabetic foot ulcers) have a major impact on quality of life, yet treatments remain limited. Glucocorticoids impair wound healing; preclinical research suggests that blocking glucocorticoid activation by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves wound repair. This investigator-initiated double-blind, randomised, placebo-controlled parallel-group phase 2b pilot trial investigated efficacy, safety and feasibility of 11β-HSD1 inhibition for 35 days by oral AZD4017 (AZD) treatment in adults with type 2 diabetes (n=14) compared to placebo (PCB, n=14) in a single-centre secondary care setting. Computer-generated 1:1 randomisation was pharmacy-administered. From 300 screening invitations, 36 attended, 28 were randomised. There was no proof-of-concept that AZD inhibited 24 hour skin 11β-HSD1 activity at day 28 (primary outcome: adjusted difference AZD-PCB 90% CI (diffCI)=-3.4,5.5) but systemic 11β-HSD1 activity (median urinary [THF+alloTHF]/THE ratio) was 87% lower with AZD at day 35 (PCB 1.00, AZD 0.13, diffCI=-1.04,-0.69). Mean wound gap diameter (mm) following baseline 2mm punch biopsy was 34% smaller at day 2 (PCB 1.51, AZD 0.98, diffCI=-0.95,-0.10) and 48% smaller after repeat wounding at day 30 (PCB 1.35, AZD 0.70, diffCI=-1.15,-0.16); results also suggested greater epidermal integrity but modestly impaired barrier function with AZD. AZD was well-tolerated with minimal side effects and comparable adverse events between treatments. Staff availability restricted recruitment (2.9/month); retention (27/28) and data completeness (95.3%) were excellent. These preliminary findings suggest that AZD may improve wound healing in patients with type 2 diabetes and warrant a fully-powered trial in patients with active ulcers. [Trial Registry: www.isrctn.com/ISRCTN74621291.

Funding

MRC Confidence in Concept and NIHR Senior Investigator Award.]

Single Sentence Summary

AZD4017 was safe; data suggested improved skin healing / integrity, and modestly reduced epidermal barrier function in patients with type 2 diabetes.

Disclosure Summary

I certify that neither I nor my co-authors have a conflict of interest as described above that is relevant to the subject matter or materials included in this Work.