Search Results
You are looking at 1 - 10 of 29 items for
- Author: Wiebke Arlt x
- All content x
Wiebke Arlt
Androgens in women either derive from direct ovarian production or from peripheral conversion of the adrenal sex steroid precursor, dehydroepiandrosterone, towards active androgens. Therefore, loss of adrenal or ovarian function, caused by Addison’s disease or consequent to bilateral oophorectomy, results in severe androgen deficiency, clinically often associated with a loss of libido and energy. Importantly, physiological menopause does not necessarily lead to androgen deficiency, as androgen synthesis in the ovaries may persist despite the decline in estrogen production. However, the definition of female androgen deficiency, as recently provided by the Princeton consensus statement, is not precise enough and may lead to over-diagnosis due to the high prevalence of its diagnostic criteria: androgen levels below or within the lower quartile of the normal range and concurrent sexual dysfunction. Importantly, physiological menopause is not necessarily associated with androgen deficiency and therefore does not routinely require androgen therapy. Current replacement options include transdermal testosterone administration or dehydroepiandrosterone treatment, both of which have been shown to result in significant improvements, in particular in libido and mood, while effects on body composition and muscular function are not well documented. It is important to keep in mind that the number of randomized controlled trials is still limited and that currently none of the available preparations is officially approved for use in women. Currently, androgen replacement should be reserved for women with severe androgen deficiency due to an established cause and matching clinical signs and symptoms.
Katherine White and Wiebke Arlt
Context
Adrenal crisis is a life-threatening event that occurs regularly in Addison's patients receiving standard replacement therapy. Patient reports suggest that it is an underestimated and under-managed event.
Objective
To assess the frequency of adrenal crisis in diagnosed patients and to understand the factors contributing to the risks of adrenal crisis.
Design
We conducted a postal survey of Addison's patients in four countries, UK (n=485), Canada (n=148), Australia (n=123) and New Zealand (n=85) in 2003, asking about patients' experiences of adrenal crisis and their demographic characteristics. In 2006, a shorter follow-up survey was conducted in the UK (n=261).
Method
The frequency and causes of adrenal crisis were compared across both surveys. Demographic data from the 2003 survey were analysed to establish the main variables associated with an elevated risk of crisis.
Results
Around 8% of diagnosed cases can be expected to need hospital treatment for adrenal crisis annually. Exposure to gastric infection is the single most important factor predicting the likelihood of adrenal crisis. Concomitant diabetes and/or asthma increase the frequency of adrenal crises reported by patients.
Conclusion
The endocrinologist has a responsibility to ensure that Addison's patients have adequate access to life-saving emergency injection materials and repeated, practical training sessions in how to use them, while the general practitioner plays a vital role as in arranging prompt emergency admissions.
Lina Schiffer, Punith Kempegowda, Wiebke Arlt, and Michael W O’Reilly
Female androgen excess and male androgen deficiency manifest with an overlapping adverse metabolic phenotype, including abdominal obesity, insulin resistance, type 2 diabetes mellitus, non-alcoholic fatty liver disease and an increased risk of cardiovascular disease. Here, we review the impact of androgens on metabolic target tissues in an attempt to unravel the complex mechanistic links with metabolic dysfunction; we also evaluate clinical studies examining the associations between metabolic disease and disorders of androgen metabolism in men and women. We conceptualise that an equilibrium between androgen effects on adipose tissue and skeletal muscle underpins the metabolic phenotype observed in female androgen excess and male androgen deficiency. Androgens induce adipose tissue dysfunction, with effects on lipid metabolism, insulin resistance and fat mass expansion, while anabolic effects on skeletal muscle may confer metabolic benefits. We hypothesise that serum androgen concentrations observed in female androgen excess and male hypogonadism are metabolically disadvantageous, promoting adipose and liver lipid accumulation, central fat mass expansion and insulin resistance.
Anna C Phillips, Douglas Carroll, Catharine R Gale, Janet M Lord, Wiebke Arlt, and G David Batty
Objectives
The aim of these analyses was to examine the association of cortisol, DHEAS and the cortisol:DHEAS ratio with the metabolic syndrome (MetS) and its components.
Design
The analyses were cross-sectional.
Methods
Participants were 4255 Vietnam era US army veterans. From military service files, telephone interviews and a medical examination, occupational, socio-demographic and health data were collected. MetS was ascertained from data on body mass index; fasting blood glucose or a diagnosis of diabetes; blood pressure or a diagnosis of hypertension; high-density lipoprotein cholesterol; and triglyceride levels. Contemporary morning fasted cortisol and DHEAS concentrations were determined. The outcomes were MetS and its components. Analysis was by logistic regression, first adjusting for age and then additionally for an array of candidate confounders.
Results
Cortisol, although not in the fully adjusted analysis, and DHEAS were both related to MetS. Whereas high cortisol concentrations were associated with an increased risk of MetS, high DHEAS concentrations appeared protective. By far, the strongest associations with MetS were observed for the cortisol:DHEAS ratio; the higher the ratio, the greater the risk of having MetS. The ratio was also significantly related to four of the five MetS components.
Conclusions
The cortisol:DHEAS ratio is positively associated with MetS. Prospective analyses are needed to help untangle direction of causality, but this study suggests that the cortisol:DHEAS ratio is worthy of further study in this and other health contexts.
Wiebke Arlt, Olaf M Dekkers, Juliane Léger, and Robert K Semple
Irina Bancos, Jon Hazeldine, Vasileios Chortis, Peter Hampson, Angela E Taylor, Janet M Lord, and Wiebke Arlt
Anna C Phillips, Douglas Carroll, Catharine R Gale, Janet M Lord, Wiebke Arlt, and G David Batty
Objectives
The aim of the present analyses was to examine the association between cortisol, DHEA sulphate (DHEAS) and the cortisol:DHEAS ratio and mortality.
Design
This was a prospective cohort analysis.
Methods
Participants were 4255 Vietnam-era US army veterans. From military service files, telephone interviews and a medical examination, occupational, socio-demographic and health data were collected. Contemporary morning fasted cortisol and DHEAS concentrations were determined. Mortality was tracked over the subsequent 15 years. The outcomes were all-cause, cardiovascular disease, cancer, other medical mortality and external causes of death. Cox proportional hazard models were tested, initially with adjustment for age, and then with adjustment for a range of candidate confounders.
Results
In general, cortisol concentrations did not show an association with all-cause or cause-specific mortality. However, in age-adjusted and fully adjusted analyses, DHEAS was negatively related to all-cause, all cancers and other medical mortality; high DHEAS concentrations were protective. The cortisol:DHEAS ratio was also associated with these outcomes in both age-adjusted and fully adjusted models; the higher the ratio, the greater the risk of death.
Conclusions
DHEAS was negatively associated, and the ratio of cortisol to DHEAS was positively associated with all-cause, cancer and other medical cause mortality. Further experimental study is needed to elucidate the mechanisms involved in these relationships.
Dorota Tomalik-Scharte, Dominique Maiter, Julia Kirchheiner, Hannah E Ivison, Uwe Fuhr, and Wiebke Arlt
Objective
Patients with congenital adrenal hyperplasia due to P450 oxidoreductase (POR) deficiency (ORD) present with disordered sex development and glucocorticoid deficiency. This is due to disruption of electron transfer from mutant POR to microsomal cytochrome P450 (CYP) enzymes that play a key role in glucocorticoid and sex steroid synthesis. POR also transfers electrons to all major drug-metabolizing CYP enzymes, including CYP3A4 that inactivates glucocorticoid and oestrogens. However, whether ORD results in impairment of in vivo drug metabolism has never been studied.
Design
We studied an adult patient with ORD due to homozygous POR A287P, the most frequent POR mutation in Caucasians, and her clinically unaffected, heterozygous mother. The patient had received standard dose oestrogen replacement from 17 until 37 years of age when it was stopped after she developed breast cancer.
Methods
Both subjects underwent in vivo cocktail phenotyping comprising the oral administration of caffeine, tolbutamide, omeprazole, dextromethorphan hydrobromide and midazolam to assess the five major drug-metabolizing CYP enzymes. We also performed genotyping for variant CYP alleles known to affect drug metabolism.
Results
Though CYP enzyme genotyping predicted normal or high enzymatic activities in both subjects, in vivo assessment showed subnormal activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in the patient and of CYP1A2 and CYP2C9 in her mother.
Conclusions
Our results provide in vivo evidence for an important role of POR in regulating drug metabolism and detoxification. In patients with ORD, in vivo assessment of drug-metabolizing activities with subsequent tailoring of drug therapy and steroid replacement should be considered.
Irina Bancos, Jon Hazeldine, Vasileios Chortis, Peter Hampson, Angela E Taylor, Janet M Lord, and Wiebke Arlt
Objective
Mortality in patients with primary adrenal insufficiency (PAI) is significantly increased, with respiratory infections as a major cause of death. Moreover, patients with PAI report an increased rate of non-fatal infections. Neutrophils and natural killer (NK) cells are innate immune cells that provide frontline protection against invading pathogens. Thus, we compared the function and phenotype of NK cells and neutrophils isolated from PAI patients and healthy controls to ascertain whether altered innate immune responses could be a contributory factor for the increased susceptibility of PAI patients to infection.
Design and methods
We undertook a cross-sectional study of 42 patients with PAI due to autoimmune adrenalitis (n = 37) or bilateral adrenalectomy (n = 5) and 58 sex- and age-matched controls. A comprehensive screen of innate immune function, consisting of measurements of neutrophil phagocytosis, reactive oxygen species production, NK cell cytotoxicity (NKCC) and NK cell surface receptor expression, was performed on all subjects.
Results
Neutrophil function did not differ between PAI and controls. However, NKCC was significantly reduced in PAI (12.0 ± 1.5% vs 21.1 ± 2.6%, P < 0.0001). Phenotypically, the percentage of NK cells expressing the activating receptors NKG2D and NKp46 was significantly lower in PAI, as was the surface density of NKG2D (all P < 0.0001). Intracellular granzyme B expression was significantly increased in NK cells from PAI patients (P < 0.01).
Conclusions
Adrenal insufficiency is associated with significantly decreased NKCC, thereby potentially compromising early recognition and elimination of virally infected cells. This potential impairment in anti-viral immune defense may contribute to the increased rate of respiratory infections and ultimately mortality in PAI.