11Beta-hydroxysteroid-dehydrogenase isoforms: tissue distribution and implications for clinical medicine

Normal and Premature Adrenarche

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.

Cortisol Dose-Dependently Impairs Migration and Tube-like Formation in a Trophoblast Cell Line and Modulates Inflammatory and Angiogenic Genes

Several stimuli can change maternal hormone levels during pregnancy. These changes may affect trophoblastic cells and modulate the development of the embryo and the placental tissue itself. Changes in cortisol levels are associated with impaired trophoblast implantation and function, in addition to other pregnancy complications. This study aims to analyze the effects of low and high doses of cortisol on an extravillous trophoblast cell line, and the effects of various exposures to this hormone. SGHPL-4 cells were treated with cortisol at five doses (0-1000 nM) and two exposures (continuous: 24 h/day; and intermittent: 2 h/day). In intermittent treatment, cortisol acted mainly as an anti-inflammatory hormone, repressing gene expression of kinin B1 receptors, interleukin-6, and interleukin-1β. Continuous treatment modulated inflammatory and angiogenic pathways, significantly repressing angiogenic factors and their receptors. Cortisol affected cell migration and tube-like structures formation. In conclusion, both continuous and intermittent exposure to cortisol repressed the expression of inflammatory genes, while only continuous exposure repressed the expression of angiogenic genes, suggesting that a sustained increase in the levels of this hormone is more harmful than a high short-term increase. Cortisol also impaired tube-like structures formation, and kinin receptors may be involved in this response.

A Lower Maternal Cortisol-to-Cortisone Ratio Precedes Clinical Diagnosis of Preterm and Term Preeclampsia by Many Weeks

CONTEXT

Previous studies have shown reduced placental levels of 11-β-hydroxysteroid dehydrogenase type 2 (11βHSD2) in preeclampsia (PE). However, it is unknown if the maternal cortisol-to-cortisone ratio is predictive of placental complications of pregnancy.

OBJECTIVE

To determine the relationship between the maternal serum cortisol-to-cortisone ratio at different stages of pregnancy and the risk of PE or fetal growth restriction (FGR).

DESIGN

Women from the Pregnancy Outcome Prediction Study experiencing PE (n = 194) or FGR (n = 185), plus a random sample of healthy controls (n = 279), were studied. Steroids were measured at ∼12, ∼20, ∼28, and ∼36 weeks of gestational age (wkGA). Separate analyses were performed for outcomes with term or preterm delivery. Associations were modeled using logistic regression.

RESULTS

At 28 wkGA, the cortisol-to-cortisone ratio was negatively associated (OR per 1 SD increase, 95% CI)] with preterm PE (OR 0.33, 95% CI 0.19 to 0.57), term PE (OR 0.61, 95% CI 0.49 to 0.76), and preterm FGR (OR 0.50, 95% CI 0.29 to 0.85). At 36 wkGA, the cortisol-to-cortisone ratio was negatively associated with term PE (OR 0.42, 95% CI 0.32 to 0.55) but not term FGR (OR 1.07, 95% CI 0.87 to 1.31). Associations were not materially affected by adjustment for maternal characteristics.

CONCLUSIONS

A lower maternal serum cortisol-to-cortisone ratio precedes clinical manifestation of PE and preterm FGR by many weeks, despite previous reports of reduced levels of placental 11βHSD2 in these conditions. Our observations implicate enhanced maternal 11βHSD2 activity or reduced 11βHSD type 1 activity in the pathophysiology of PE.

Gut microbiota, hypertension and chronic kidney disease: Recent advances

A large number of different microbial species populates intestine. Extensive research has studied the entire microbial population and their genes (microbiome) by using metagenomics, metatranscriptomics and metabolomic analysis. Studies suggest that the imbalances of the microbial community causes alterations in the intestinal homeostasis, leading to repercussions on other systems: metabolic, nervous, cardiovascular, immune. These studies have also shown that alterations in the structure and function of the gut microbiota play a key role in the pathogenesis and complications of Hypertension (HTN) and Chronic Kidney Disease (CKD). Increased blood pressure (BP) and CKD are two leading risk factors for cardiovascular disease and their treatment represents a challenge for the clinicians. In this Review, we discuss mechanisms whereby gut microbiota (GM) and its metabolites act on downstream cellular targets to contribute to the pathogenesis of HTN and CKD, and potential therapeutic implications.

Phytosteroids beyond estrogens: Regulators of reproductive and endocrine function in natural products

Foods and botanical supplements can interfere with the endocrine system through the presence of phytosteroids - chemicals that interact with steroids receptors. Phytoestrogens are well studied, but compounds such as kaempferol, apigenin, genistein, ginsenoside Rf, and glycyrrhetinic acid have been shown to interact with non-estrogen nuclear receptors. These compounds can have agonist, antagonist, or mixed agonist/antagonist activity depending on compound, receptor, cell line or tissue, and concentration. Some phytosteroids have also been shown to inhibit steroid metabolizing enzymes, resulting in biological effects through altered endogenous steroid concentrations. An interesting example, compound A (4-[1-chloro-2-(methylamino)ethyl]phenyl acetate hydrochloride (1:1)) is a promising selective glucocorticoid receptor modulator (SGRM) based on a phytosteroid isolated from Salsola tuberculatiformis Botschantzev. Given that $6.9 billion of herbal supplements are sold each year, is clear that further identification and characterization of phytosteroids is needed to ensure the safe and effective use of botanical supplements.

Management of endocrine disease: Secondary osteoporosis: pathophysiology and management

Osteoporosis is a skeletal disorder characterized by decreased mass and compromised bone strength predisposing to an increased risk of fractures. Although idiopathic osteoporosis is the most common form of osteoporosis, secondary factors may contribute to the bone loss and increased fracture risk in patients presenting with fragility fractures or osteoporosis. Several medical conditions and medications significantly increase the risk for bone loss and skeletal fragility. This review focuses on some of the common causes of osteoporosis, addressing the underlying mechanisms, diagnostic approach and treatment of low bone mass in the presence of these conditions.

Modulation of the pancreatic islet-stress axis as a novel potential therapeutic target in diabetes mellitus

Loss of pancreatic islet function and insulin-producing beta cell mass is a central hallmark in the pathogenesis of both type 1 and type 2 diabetes. While in type 1 diabetes this phenomenon is due to an extensive destruction of beta cells caused by an autoimmune process, the mechanisms resulting in beta cell failure in type 2 diabetes are different and less clear. Also, beta cell destruction in type 1 diabetes occurs early and is the initial step in the pathogenetic process, while beta cell loss in type 2 diabetes after an initial phase of hyperinsulinemia due to the underlying insulin resistance occurs relatively late and it is less pronounced. Since diabetes mellitus is the most frequent endocrine disease, with an increasing high prevalence worldwide, huge efforts have been made over the past many decades to identify predisposing genetic, environmental, and nutritional factors in order to develop effective strategies to prevent the disease. In parallel, extensive studies in different cell systems and animal models have helped to elucidate our understanding of the physiologic function of islets and to gain insight into the immunological and non-immunological mechanisms of beta cell destruction and failure. Furthermore, currently emerging concepts of beta cell regeneration (e.g., the restoration of the beta cell pool by regenerative, proliferative and antiapoptotic processes, and recovery of physiologic islet function) apparently is yielding the first promising results. Recent insights into the complex endocrine and paracrine mechanisms regulating the physiologic function of pancreatic islets, as well as beta cell life and death, constitute an essential part of this new and exciting area of diabetology. For example, understanding of the physiological role of glucagon-like peptide 1 has resulted in the successful clinical implementation of incretin-based therapies over the last years. Further, recent data suggesting paracrine effects of growth hormone-releasing hormone and corticotropin-releasing hormone on the regulation of pancreatic islet function, survival, and proliferation as well as on local glucocorticoid metabolism provide evidence for a potential role of the pancreatic islet-stress axis in the pathophysiology of diabetes mellitus. In this chapter, we provide a comprehensive overview of current preventive and regenerative concepts as a basis for the development of novel therapeutic approaches to the treatment of diabetes mellitus. A particular focus is given on the potential of the pancreatic islet-stress axis in the development of novel regenerative strategies.

Local blockade of glucocorticoid activation reverses stress- and glucocorticoid-induced delays in cutaneous wound healing

Stress slows cutaneous wound healing (WH) in an endogenous glucocorticoid (GC)-dependent fashion. We investigated whether stress/GC-induced delays in WH require further intracutaneous activation of endogenous GC; and whether blockade or down-regulation of peripheral activation normalizes WH in the face of stress. Delayed WH in our motion-restricted murine model of stress could be attributed to elevated systemic GC, because blockade of GC production (using corticotropin-releasing factor inhibitor, antalarmin), or of peripheral binding to the GC receptor [GCr], with an antagonist, Ru-486, normalized WH. We next investigated whether local blockade or down-regulation of the peripheral GC-activating enzyme, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), accelerates cutaneous WH. Topical applications of nonspecific (carbenoxolone) as well as an isoform-specific 11β-HSD1 inhibitor overcame stress and exogenous GC-induced delays in WH. Moreover, two liver X receptor ligands, TO901317 and GW3695, down-regulated expression of 11β-HSD1, attenuating stress-induced delays in WH. Combined inhibitor and liver X receptor ligand applications accelerated WH in the face of stress/systemic GC. Thus: (1) intracutaneous conversion of inactive-to-active GC accounts for stress (GC)-induced delays in WH; and (2) blockade or down-regulation of 11β-HSD1 and/or GCr normalize cutaneous WH in the face of stress/GC. Local blockade or down-regulation of cutaneous GC activation could help enhance WH in various clinical settings.

Corticosteroid-induced osteoporosis: an update for dermatologists

Long-term corticosteroid treatment is the most common secondary cause of bone loss. Patients treated with long-term corticosteroid therapy may develop osteopenia or osteoporosis, and many have fractures. It is difficult to predict which corticosteroid-treated patients will develop significant skeletal complications because of variability in the underlying diseases treated with corticosteroids, and because of variation in corticosteroid dose over time. Corticosteroid therapy causes an alteration in the ratio between osteoprotegerin (OPG) and receptor activator of nuclear factor κ B (RANK) ligand (RANKL), which leads to early increased bone resorption for the first 3-6 months, with long-term treatment leading primarily to suppression of bone formation. Recently published recommendations advise the use of bisphosphonates or teriparatide in high-risk patients, depending on fracture risk assessed by bone mineral density testing. This article gives an update of current knowledge regarding the pathophysiology, clinical presentation and evaluation, and prevention and treatment of patients with corticosteroid-induced osteoporosis.

Grapefruit juice and licorice increase cortisol availability in patients with Addison's disease

OBJECTIVE

Failure to mirror the diurnal cortisol profile could contribute to the impaired subjective health status in Addison's disease (AD). Some patients report benefit from the use of various nutritional compounds. The objective of this study was to investigate the impact of licorice and grapefruit juice (GFJ) on the absorption and metabolism of cortisone acetate (CA).

DESIGN

Patients (n=17) with AD on stable CA replacement therapy were recruited from the outpatient clinic at Haukeland University Hospital, Norway. They were assessed on their ordinary CA medication and following two 3-day periods of co-administration of licorice or GFJ.

METHODS

Time series of glucocorticoids (GCs) in serum and saliva were obtained, and GCs in 24 h urine samples were determined. The main outcome measure was the area under the curve (AUC) for serum cortisol in the first 2.6 h after orally administered CA.

RESULTS

Compared with the ordinary treatment, the median AUC for serum cortisol increased with licorice (53 783 vs 50 882, P<0.05) and GFJ (60 661 vs 50 882, P<0.05). Median cortisol levels in serum were also elevated 2.6 h after tablet ingestion (licorice 223 vs 186 nmol/l, P<0.05; GFJ 337 vs 186 nmol/l, P<0.01). Licorice increased the median urinary cortisol/cortisone ratio (0.43 vs 0.21, P<0.00001), whereas GFJ increased the (allo-tetrahydrocortisol+tetrahydrocortisol)/tetrahydrocortisone ratio (0.55 vs 0.43, P<0.05).

CONCLUSION

Licorice and in particular GFJ increased cortisol available to tissues in the hours following oral CA administration. Both patients and physicians should be aware of these interactions.

Therapies for adrenal insufficiency

Adrenal insufficiency is a life-threatening disorder. In the treatment of adrenal insufficiency, it is essential to administer the optimal medication at the optimal dose. Glucocorticoids are the main therapeutic approach in all forms of adrenal insufficiency. The recommended protocol for maintenance therapy is 15-25 mg of hydrocortisone, divided into two or three separate doses. Patients with primary adrenal insufficiency generally receive mineralocorticoid replacement comprised of fludrocortisone 0.05-0.2 mg/day. Recently, dehydroepiandrosterone has been proposed as a new therapeutic approach, despite the lack of strong evidence for beneficial effects. Additional glucocorticoid supplementation should be administered in stressful states. During critical illness, inadequate or no temporary increase in the dose of the replacement glucocorticoid can lead to acute adrenal failure. When acute adrenal failure occurs, it becomes necessary to administer intravenous hydrocortisone.

Mechanisms of glucocorticoid-induced osteoporosis

Glucocorticoids modify osteoblastic cell differentiation, number, and function. Glucocorticoids stimulate osteoclastogenesis and increase the expression of receptor activator of Nuclear factor-kappaB ligand and colony-stimulating factor-1, and decrease the expression of osteoprotegerin. However, the most significant effect of glucocorticoids in bone is an inhibition of bone formation. This inhibition is caused by a decrease in the number of osteoblasts secondary to a shift in the differentiation of mesenchymal cells away from the osteoblastic lineage, and an increase in the death of mature osteoblasts. Glucocorticoids decrease the function of the remaining osteoblasts directly and indirectly through the inhibition of insulin-like growth factor I expression. The stimulation of bone resorption is likely responsible for the initial bone loss after glucocorticoid exposure. Eventually, the inhibition of bone formation will cause a decrease in bone remodeling and a continued increased risk of fractures.

Impact of the GH-cortisol ratio on the age-dependent changes in body composition

Aging is associated with a decrease in GH levels and this is paralleled by changes in body composition, i.e., increased visceral fat, and decreased lean body mass and bone mineral density. Similar changes in body composition are seen in the state of hypercortisolism. Increasing age has been shown to be associated with elevated evening cortisol levels in men. An increased exposure of several tissues to glucocorticoids with aging, i.e., visceral fat cells, in combination with the reduction of the lipolytic effects of declining GH levels, may contribute to the age-dependent increase of visceral fat accumulation. We hypothesize that the age-dependent changes in body fat are the result of an age-dependent decrease of the GH/cortisol ratio at the level of the adipocyte. This is caused by the decline in GH concentrations and the increase in cortisol levels and/or metabolism at the adipocyte.