Relationship of nonalcoholic hepatic steatosis to overnight low-dose dexamethasone suppression test in obese individuals

Possible, probable, and certain hypercortisolism: A continuum in the risk of comorbidity

Hypercortisolism may be considered as a continuum in terms of both hormonal and cardiometabolic abnormalities. It ranges from cases with "normal" hormonal profile and low to intermediate risk of comorbidity to florid cases with clear clinical and hormonal evidence of glucocorticoid excess and clearly increased cardiometabolic risk. Even in patients with nonfunctioning adrenal incidentaloma (NFAI), defined as adrenal incidentaloma with normal results on the currently available hormonal test for evaluation of hypercortisolism, cardiometabolic and mortality risk is higher than in the general population without adrenal lesions. Mild hypercortisolism or autonomous cortisol secretion (ACS) is a term used for patients with adrenal incidentaloma and pathological dexamethasone suppression test (DST) results, but without specific clinical signs of hypercortisolism. It is widely known that this condition is linked to higher prevalence of several cardiometabolic comorbidities, including diabetes, hypertension, osteoporosis and metabolic syndrome, than in patients with NFAI or without adrenal tumor. In case of overt Cushing's syndrome, cardiovascular risk is extremely high, and standard mortality ratio is high, cardiovascular disease being the leading cause of death. The present review summarizes the current evidence for a detrimental cardiometabolic profile in patients with possible (NFAI), probable (ACS) and certain hypercortisolism (overt Cushing's syndrome).

Ectopic lipid metabolism in anterior pituitary dysfunction

Over the past decades, adapted lifestyle and dietary habits in industrialized countries have led to a progress of obesity and associated metabolic disorders. Concomitant insulin resistance and derangements in lipid metabolism foster the deposition of excess lipids in organs and tissues with limited capacity of physiologic lipid storage. In organs pivotal for systemic metabolic homeostasis, this ectopic lipid content disturbs metabolic action, thereby promotes the progression of metabolic disease, and inherits a risk for cardiometabolic complications. Pituitary hormone syndromes are commonly associated with metabolic diseases. However, the impact on subcutaneous, visceral, and ectopic fat stores between disorders and their underlying hormonal axes is rather different, and the underlying pathophysiological pathways remain largely unknown. Pituitary disorders might influence ectopic lipid deposition indirectly by modulating lipid metabolism and insulin sensitivity, but also directly by organ specific hormonal effects on energy metabolism. In this review, we aim to I) provide information about the impact of pituitary disorders on ectopic fat stores, II) and to present up-to-date knowledge on potential pathophysiological mechanisms of hormone action in ectopic lipid metabolism.

Comorbidities in Mild Autonomous Cortisol Secretion - A Clinical Review of Literature

Mild autonomous cortisol secretion (mACS) is a state of cortisol excess usually associated with existence of adrenal incidentaloma. Because of the lack of symptoms of the disease, the biochemical evaluation is the most important to determine a diagnosis. However, scientific societies have different diagnostic criteria for mACS, which makes the treatment of this disease and using results of original papers in daily practice more difficult. Chronic hypercortisolemic state, even if mild, may lead to diseases that are mostly connected with overt Cushing's syndrome. Some of them can cause a higher mortality of patients with mACS and those problems need to be addressed. In this review we describe the comorbidities associated with mACS: cardiovascular disorders, arterial hypertension, diabetes mellitus, insulin resistance, dyslipidemia, obesity, metabolic syndrome, non-alcoholic fatty liver disease, vertebral fractures and osteoporosis. The point of this paper is to characterise them and determine if and how these conditions should be managed. Two databases - PubMed and Web of Science were searched. Even though the evidence are scarce, this is an attempt to lead clinicians through the problems associated with this enigmatic condition.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD often occurs associated with endocrinopathies. Evidence suggests that endocrine dysfunction may play an important role in NAFLD development, progression, and severity. Our work aimed to explore and summarize the crosstalk between the liver and different endocrine organs, their hormones, and dysfunctions. For instance, our results show that hyperprolactinemia, hypercortisolemia, and polycystic ovary syndrome seem to worsen NAFLD’s pathway. Hypothyroidism and low growth hormone levels also may contribute to NAFLD’s progression, and a bidirectional association between hypercortisolism and hypogonadism and the NAFLD pathway looks likely, given the current evidence. Therefore, we concluded that it appears likely that there is a link between several endocrine disorders and NAFLD other than the typically known type 2 diabetes mellitus and metabolic syndrome (MS). Nevertheless, there is controversial and insufficient evidence in this area of knowledge.

NAFLD Aggravates Septic Shock Due to Inadequate Adrenal Response and 11β-HSDs Dysregulation in Rats

Background: Non-alcoholic fatty liver disease (NAFLD) is linked with metabolic syndrome. Previous studies showed that obesity may disrupt adrenal function and adversely affect its counter-regulations against shock. This study hence evaluated adrenal function abnormalities in NAFLD with shock. Methods: Sprague-Dawley rats were fed with regular chow-diet (control) or high fat diet (HFD, 60% energy derived from fat). Blood tests were performed at the end of the 4th, 6th and 8th week, respectively. Experiments were performed at the end of the 8th week. Results: HFD rats developed NAFLD. HFD rats had 27% and 51% increase in plasma corticosterone at the 6th and 8th week in usual status. However, HFD rats had 5 times more reduction of mean arterial pressure in response to lipopolysaccharide-induced sepsis as compared to control rats. The corticosterone increment ratio was also lower in HFD rats, even after ACTH administration. 11β-HSD system tended to generate more corticosterone in HFD rats under hemodynamic stable status without shock and the trend was lost in HFD rats with septic shock. Conclusion: Rats with NAFLD had profound septic shock due to inadequate corticosterone response. This is, at least partly, due to 11β-HSDs dysregulation in sepsis.

Effects of Mifepristone on Nonalcoholic Fatty Liver Disease in a Patient with a Cortisol-Secreting Adrenal Adenoma

Cushing syndrome (CS), a complex, multisystemic condition resulting from prolonged exposure to cortisol, is frequently associated with nonalcoholic fatty liver disease (NAFLD). In patients with adrenal adenoma(s) and NAFLD, it is essential to rule out coexisting endocrine disorders like CS, so that the underlying condition can be properly addressed. We report a case of a 49-year-old woman with a history of hypertension, prediabetes, dyslipidemia, biopsy-confirmed steatohepatitis, and benign adrenal adenoma, who was referred for endocrine work-up for persistent weight gain. Overt Cushing features were absent. Biochemical evaluation revealed nonsuppressed cortisol on multiple 1-mg dexamethasone suppression tests, suppressed adrenocorticotropic hormone, and low dehydroepiandrosterone sulfate. The patient initially declined surgery and was treated with mifepristone, a competitive glucocorticoid receptor antagonist. In addition to improvements in weight and hypertension, substantial reductions in her liver enzymes were noted, with complete normalization by 20 weeks of therapy. This case suggests that autonomous cortisol secretion from adrenal adenoma(s) could contribute to the metabolic and liver abnormalities in patients with NAFLD. In conclusion, successful management of CS with mifepristone led to marked improvement in the liver enzymes of a patient with long-standing NAFLD.

The impact of cortisol in steatotic and non-steatotic liver surgery

The intent of this study was to examine the effects of regulating cortisol levels on damage and regeneration in livers with and without steatosis subjected to partial hepatectomy under ischaemia–reperfusion. Ultimately, we found that lean animals undergoing liver resection displayed no changes in cortisol, whereas cortisol levels in plasma, liver and adipose tissue were elevated in obese animals undergoing such surgery. Such elevations were attributed to enzymatic upregulation, ensuring cortisol production, and downregulation of enzymes controlling cortisol clearance. In the absence of steatosis, exogenous cortisol administration boosted circulating cortisol, while inducing clearance of hepatic cortisol, thus maintaining low cortisol levels and preventing related hepatocellular harm. In the presence of steatosis, cortisol administration was marked by a substantial rise in intrahepatic availability, thereby exacerbating tissue damage and regenerative failure. The injurious effects of cortisol were linked to high hepatic acethylcholine levels. Upon administering an α7 nicotinic acethylcholine receptor antagonist, no changes in terms of tissue damage or regenerative lapse were apparent in steatotic livers. However, exposure to an M3 muscarinic acetylcholine receptor antagonist protected livers against damage, enhancing parenchymal regeneration and survival rate. These outcomes for the first time provide new mechanistic insight into surgically altered steatotic livers, underscoring the compelling therapeutic potential of cortisol–acetylcholine–M3 muscarinic receptors.

The effect of cortisol in rat steatotic and non-steatotic liver transplantation from brain-dead donors

In the present study, we examined the effects of cortisol on steatotic and non-steatotic liver grafts from brain-dead donors and characterized the underlying mechanisms involved. Non-steatotic liver grafts showed reduced cortisol and increased cortisone levels in association with up-regulation of enzymes that inactivate cortisol. Conversely, steatotic liver grafts exhibited increased cortisol and reduced cortisone levels. The enzymes involved in cortisol generation were overexpressed, and those involved in cortisol inactivation or clearance were down-regulated in steatotic liver grafts. Exogenous administration of cortisol negatively affected hepatic damage and survival rate in non-steatotic liver transplantation (LT); however, cortisol treatment up-regulated the phosphoinositide 3-kinase (PI3K)-protein kinase C (PKC) pathway, resulting in protection against the deleterious effects of brain-dead donors on damage and inflammatory response in steatotic LT as well as in increased survival of recipients. The present study highlights the differences in the role of cortisol and hepatic mechanisms that regulate cortisol levels based on the type of liver. Our findings suggest that cortisol treatment is a feasible and highly protective strategy to reduce the adverse effects of brain-dead donor livers in order to ultimately improve liver graft quality in the presence of steatosis, whereas cortisol treatment would not be recommended for non-steatotic liver grafts.

Glucocorticoids and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the global obesity and metabolic disease epidemic and is rapidly becoming the leading cause of liver cirrhosis and indication for liver transplantation worldwide. The hallmark pathological finding in NAFLD is excess lipid accumulation within hepatocytes, but it is a spectrum of disease ranging from benign hepatic steatosis to steatohepatitis through to fibrosis, cirrhosis and risk of hepatocellular carcinoma. The exact pathophysiology remains unclear with a multi-hit hypothesis generally accepted as being required for inflammation and fibrosis to develop after initial steatosis. Glucocorticoids have been implicated in the pathogenesis of NAFLD across all stages. They have a diverse array of metabolic functions that have the potential to drive NAFLD acting on both liver and adipose tissue. In the fasting state, they are able to mobilize lipid, increasing fatty acid delivery and in the fed state can promote lipid accumulation. Their action is controlled at multiple levels and in this review will outline the evidence base for the role of GCs in the pathogenesis of NAFLD from cell systems, rodent models and clinical studies and describe interventional strategies that have been employed to modulate glucocorticoid action as a potential therapeutic strategy.

Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.

Non-alcoholic fatty liver disease in common endocrine disorders

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of disease spanning from simple benign steatosis to steatohepatitis with fibrosis and scarring that can eventually lead to cirrhosis. Its prevalence is rising rapidly and is developing into the leading indication for liver transplantation worldwide. Abnormalities in endocrine axes have been associated with NALFD, including hypogonadism, hypothyroidism, GH deficiency and hypercortisolaemia. In some instances, correction of the endocrine defects has been shown to have a beneficial impact. While in patients with type 2 diabetes the association with NAFLD is well established and recognised, there is a more limited appreciation of the condition among common endocrine diseases presenting with hormonal excess or deficiency. In this review, we examine the published data that have suggested a mechanistic link between endocrine abnormalities and NAFLD and summarise the clinical data endorsing these observations.

11β-Hydroxysteroid dehydrogenase 1: translational and therapeutic aspects

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts the inactive glucocorticoid cortisone and its active form cortisol. It is widely expressed and, although bidirectional, in vivo it functions predominantly as an oxoreductase, generating active glucocorticoid. This allows glucocorticoid receptor activation to be regulated at a prereceptor level in a tissue-specific manner. In this review, we will discuss the enzymology and molecular biology of 11β-HSD1 and the molecular basis of cortisone reductase deficiencies. We will also address how altered 11β-HSD1 activity has been implicated in a number of disease states, and we will explore its role in the physiology and pathologies of different tissues. Finally, we will address the current status of selective 11β-HSD1 inhibitors that are in development and being tested in phase II trials for patients with the metabolic syndrome. Although the data are preliminary, therapeutic inhibition of 11β-HSD1 is also an exciting prospect for the treatment of a variety of other disorders such as osteoporosis, glaucoma, intracranial hypertension, and cognitive decline.

Hepatic 11beta-HSD1 mRNA expression in fatty liver and nonalcoholic steatohepatitis

CONTEXT

Nonalcoholic fatty liver disease represents the hepatic manifestation of the metabolic syndrome. Nonalcoholic steatohepatitis (NASH) is the progressive form of liver injury. The pathophysiology that leads to NASH is not well understood.

OBJECTIVE

We hypothesize that an altered cortisol metabolism in the liver may be a pathogenetic factor.

DESIGN AND PATIENTS

75 patients (28 men, 47 women) underwent liver biopsy for elevation in liver enzymes. Histological diagnosis identified normal liver in eight, fatty liver in 20, NASH grade 1 in 22, grade 2 in nine, grade 3 in three patients, and other forms of hepatitis or cirrhosis in 13 patients. We quantified hepatic 11beta-hydroxysteroid dehydrogenase type1 (11beta-HSD1) and hexose-6-phosphate-dehydrogenase (H6PDH) mRNA expression by real-time PCR. In addition, analysis of 24 h urinary excretion of cortisol metabolites using GCMS was performed and compared with healthy controls.

RESULTS

11beta-HSD1 mRNA expression correlated significantly (R2= 0.809; P < 0.001) with H6PDH mRNA expression, negatively with waist-to-hip ratio in women (R2= 0.394; P= 0.005), but not with urinary (THF + 5alpha-THF)/THE ratio, total cortisol metabolite excretion, age, BMI, degree of fatty liver or NASH stages. Total cortisol metabolite excretion was increased in patients with fatty liver or NASH compared with healthy controls.

CONCLUSIONS

Our data suggest that expression of hepatic 11beta-HSD1 and H6PDH are closely interlinked. 11beta-HSD1 gene expression does not seem to be involved in the pathogenesis of fatty liver or NASH. However, those patients showed an increased 5alpha- and 5beta-reduction of cortisol leading to an increased cortisol turnover rate and an activation of the HPA axis.

The pituitary-adrenal axis and body composition

The activity of the pituitary-adrenal axis can profoundly impact on body composition. This is dramatically seen in Cushing's syndrome (CS) but changes in body composition are also implicated in depression and alcoholic pseudocushing's. The pathophysiological mechanisms underlying these changes remain poorly understood. Changes to body composition in CS include increased fat mass, decreased bone mass, thinning of the skin and reduced lean mass. Why these tissues are affected so dramatically is unclear. Additionally, the change in body composition between individuals varies considerably for reasons which are only now becoming evident. This paper reviews the phenotypic changes with altered pituitary-adrenal axis activity and discusses the mechanisms involved. The primary focus is on adipose, bone, muscle and skin since the most dramatic changes are seen in these tissues.

Non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease: an open question

AIMS

To review available data concerning the basic science and epidemiological-clinical evidence for an association of NAFLD and cardiovascular disease.

DATA SYNTHESIS

Non-alcoholic fatty liver disease (NAFLD) defines alcohol-like hepatic histological lesions seen in the non-alcoholic, insulin resistant patient representing the hepatic counterpart of the metabolic syndrome. Along with insulin resistance, additional genetic, endocrine and vascular changes together with environmental stimuli--which are also involved in the pathogenesis of atherosclerosis--play a prominent role in the development and progression of NAFLD. Clinical and epidemiological studies seem to indicate that NAFLD is associated with an increased risk for cardiovascular disease but further studies are needed to confirm the available data. The mainstay of NAFLD treatment is based on the correction of the same metabolic changes that predispose to atherosclerosis.

CONCLUSIONS

Non-invasive evaluation of risk for cardiovascular events is recommended in all individuals presenting with NAFLD and conversely, the presence of NAFLD should always be looked for in subjects with features belonging to the metabolic syndrome. Further studies are needed on the mechanisms linking fatty liver and vascular diseases.

Cushing’s syndrome in a clinic population with diabetes

BACKGROUND

A recent report has suggested that occult Cushing's syndrome (CS) may be present in a significant number of patients with type 2 diabetes mellitus. The aim of this study was to determine whether any patients in our clinic population with diabetes had this condition.

METHODS

One hundred and seventy-one consecutive overweight attendees at the diabetic clinic were enrolled in a study to assess the presence of occult CS. The initial screen was with the 1 mg overnight dexamethasone suppression test and follow-up testing, where indicated was with a 24 h collection for urine-free cortisol.

RESULTS

Thirty-one of 171 patients had a positive result from the overnight dexamethasone suppression test. Follow-up testing with 24 h urine-free cortisol reduced the number of patients with positive results to 3. Two of these were shown to have alcoholic pseudo-CS. The third patient has had several high urine-free cortisol results, in the presence of normal scans of pituitary and adrenals. He has no stigmata of CS and is being observed.

CONCLUSION

Based on the results of our study, there would appear to be little value in screening type 2 diabetics for CS, in the absence of clinical suspicion.

Cortisol clearance and associations with insulin sensitivity, body fat and fatty liver in middle-aged men

AIMS/HYPOTHESIS

The regulation of cortisol metabolism in vivo is not well understood. We evaluated the relationship between cortisol metabolism and insulin sensitivity, adjusting for total and regional fat content and for non-alcoholic fatty liver disease.

MATERIALS AND METHODS

Twenty-nine middle-aged healthy men with a wide range of BMI were recruited. We measured fat content by dual-energy X-ray absorptiometry and magnetic resonance imaging (MRI), liver fat by ultrasound and MRI, the hypothalamic-pituitary-adrenal axis by adrenal response to ACTH(1-24), unconjugated urinary cortisol excretion, corticosteroid-binding globulin, and cortisol clearance by MS. We assessed insulin sensitivity by hyperinsulinaemic-euglycaemic clamp and by OGTT.

RESULTS

Cortisol clearance was strongly inversely correlated with insulin sensitivity (M value) (r = -0.61, p = 0.002). Cortisol clearance was increased in people with fatty liver compared with those without (mean+/-SD: 243 +/- 10 vs 158 +/- 36 ml/min; p = 0.014). Multiple regression modelling showed that the relationship between cortisol clearance and insulin sensitivity was independent of body fat. The relationship between fatty liver and insulin sensitivity was significantly influenced by body fat and cortisol clearance.

CONCLUSIONS/INTERPRETATION

Cortisol clearance is strongly associated with insulin sensitivity, independently of the amount of body fat. The relationship between fatty liver and insulin sensitivity is mediated in part by both fatness and cortisol clearance.

Associations between liver histology and cortisol secretion in subjects with nonalcoholic fatty liver disease

OBJECTIVES

To assess associations between the activity of hypothalamo-pituitary-adrenal (HPA) axis and liver histology in patients with nonalcoholic fatty liver disease (NAFLD).

DESIGN AND PATIENTS

In a cross-sectional study, we enrolled 50 consecutive, overweight, NAFLD patients and 40 control subjects who were comparable for age, sex and body mass index (BMI).

MEASUREMENTS

NAFLD (by liver biopsy), HPA axis activity (by 24-hour urinary free cortisol [UFC] excretion and serum cortisol levels after 1 mg dexamethasone), insulin resistance (by homeostasis model assessment: HOMA-IR), and metabolic syndrome (MetS) features.

RESULTS

NAFLD patients had markedly higher (P < 0.001) 24-h UFC (149 +/- 24 vs. 90 +/- 16 nmol/day) and postdex suppression cortisol concentrations (32 +/- 10 vs. 16 +/- 7 nmol/l) than controls. The MetS and its individual components were more frequent among NAFLD patients. The marked differences in urinary/serum cortisol concentrations that were observed between the groups were little affected by adjustment for age, sex, BMI, waist circumference, systolic blood pressure, triglycerides, homeostasis model assessment for insulin resistance score and presence of diabetes. Importantly, 24-h UFC and postdex cortisol concentrations strongly correlated to hepatic necroinflammatory grade (P < 0.01) and fibrosis stage (P < 0.001) among NAFLD patients. By logistic regression analysis, 24-h UFC (odds ratio (OR) 1.80, 95%CI 1.3-2.8) or postdex cortisol concentrations (OR 1.95, 95%CI 1.4-3.1) independently predicted the severity of hepatic fibrosis, but not necroinflammation, after adjustment for potential confounders.

CONCLUSIONS

These results suggest that NAFLD patients have a subtle, chronic overactivity in the HPA axis (that is closely associated with the severity of liver histopathology) leading to subclinical hypercortisolism that might be implicated in the development of NAFLD.