Leptin and adiponectin mRNA expression from the adipose tissue surrounding the adrenal neoplasia

Relevance of obesity-related organ damage and metabolic syndrome classification in cardiovascular and renal risk stratification in patients with essential hypertension

Introduction

Hypertension is a relevant cardiovascular comorbidity. Adipose tissue represents a metabolically active tissue involved in the regulation of blood pressure and metabolic alterations. In recent decades, several classifications for the metabolic syndrome (MS) have been proposed. Recently, a new syndrome called the "Cardiovascular-kidney-metabolic" (CKM) syndrome was identified, to determine patients at high cardiovascular and metabolic risk. The aim of the study was to compare different classifications in a large population of hypertensive patients.

Materials and methods

Between September 2022 and August 2023, we consecutively enrolled 772 hypertensive patients (407 men; 365 women; mean age 52.2 ± 15.1 years), evaluating anthropometric, biochemical, and instrumental parameters (transthoracic echocardiogram, carotid echo-Doppler, 24-h ambulatory blood pressure monitoring, fundus oculi).

Results

Using different classifications we found MS prevalence: Adult Treatment Panel III (ATP-III) 28.8%, International Diabetes Federation (IDF) 31.5%, CKM 40.7%. CKM Classes 3 and 4 showed higher body mass index and waist circumference compared with other groups. Compared with ATP-III and IDF, CKM Class 4 showed higher 24-h systolic blood pressure, lower percentage of controlled hypertension, increased interventricular septum and posterior wall, reduced ejection fraction, and greater prevalence of hypertensive arterial retinal damage.

Discussion

Visceral obesity and MS are frequent conditions with healthy impact, becoming an important trigger for the development of cardiovascular and metabolic complications. The different MS classifications allow the early identification of patients at high risk of cardiometabolic complications. The new CKM syndrome proves useful to identify individuals at high risk for CKM morbidity and mortality.

Subtype-specific Body Composition and Metabolic Risk in Patients With Primary Aldosteronism

BACKGROUND

Primary aldosteronism (PA) is associated with increased metabolic risks. However, controversy exists as to which subtype of PA has a higher metabolic risk between bilateral and lateralized PA. This study aimed to assess the body composition of 2 PA subtypes, bilateral PA and lateralized PA, according to sex and autonomous cortisol secretion (ACS) and their contribution to comorbidities.

DESIGN AND METHODS

A total of 400 patients with PA (females, n = 210) and 1:10 age- and sex-matched healthy controls (n = 4000) were enrolled. The skeletal muscle area (SMA), subcutaneous fat area, and visceral fat area (VFA) at the third lumbar spine were calculated using abdominal computed tomography-based body composition analysis.

RESULTS

Patients with bilateral PA had higher body mass index (BMI) in both sexes (all P < .05). Hemoglobin A1c level and the prevalence of diabetes were higher in female patients with bilateral PA than in those with lateralized PA (all P < .05). The VFA/BMI ratio was significantly higher in bilateral PA patients than in lateralized PA patients (5.77 ± 2.69 vs 4.56 ± 2.35 in men; 4.03 ± 2.58 vs 2.53 ± 2.05 in women, all P < .001). PA patients with ACS showed decreased SMA compared to those without ACS. Compared with healthy controls, all patients with bilateral PA and female patients with lateralized PA showed significantly higher VFA and VFA/BMI.

CONCLUSIONS

Patients with bilateral PA were more obese and had higher VFA levels than those with lateralized PA. Despite a milder form of PA, this metabolically unfavorable visceral fat distribution may lead to a higher metabolic risk in patients with bilateral PA.

The metabolic phenotype of patients with primary aldosteronism: impact of subtype and sex - a multicenter-study of 3566 Caucasian and Asian subjects

BACKGROUND

Accumulating evidence suggests that primary aldosteronism (PA) is associated with several features of the metabolic syndrome, in particular with obesity, type 2 diabetes mellitus, and dyslipidemia. Whether these manifestations are primarily linked to aldosterone-producing adenoma (APA) or bilateral idiopathic hyperaldosteronism (IHA) remains unclear. The aim of the present study was to investigate differences in metabolic parameters between APA and IHA patients and to assess the impact of treatment on these clinical characteristics.

METHODS

We conducted a retrospective multicenter study including 3566 patients with APA or IHA of Caucasian and Asian origin. We compared the prevalence of metabolic disorders between APA and IHA patients at the time of diagnosis and 1-year post-intervention, with special references to sex differences. Furthermore, correlations between metabolic parameters and plasma aldosterone, renin, or plasma cortisol levels after 1 mg dexamethasone (DST) were performed.

RESULTS

As expected, APA patients were characterized by higher plasma aldosterone and lower serum potassium levels. Only female IHA patients demonstrated significantly worse metabolic parameters than age-matched female APA patients, which were associated with lower cortisol levels upon DST. One-year post-intervention, female adrenalectomized patients showed deterioration of their lipid profile, when compared to patients treated with mineralocorticoid receptor antagonists. Plasma aldosterone levels negatively correlated with the BMI only in APA patients.

CONCLUSIONS

Metabolic alterations appear more prominent in women with IHA. Although IHA patients have worse metabolic profiles, a correlation with cortisol autonomy is documented only in APAs, suggesting an uncoupling of cortisol action from metabolic traits in IHA patients.

Analysis of the miRNA expression from the adipose tissue surrounding the adrenal neoplasia

Background

Primary aldosteronism (PA) is characterized by several metabolic changes such as insulin resistance, metabolic syndrome, and adipose tissue (AT) inflammation. Mi(cro)RNAs (miRNAs) are a class of non-coding small RNA molecules known to be critical regulators in several cellular processes associated with AT dysfunction. The aim of this study was to evaluate the expression of some miRNAs in visceral and subcutaneous AT in patients undergoing adrenalectomy for aldosterone-secreting adrenal adenoma (APA) compared to the samples of AT obtained in patients undergoing adrenalectomy for non-functioning adrenal mass (NFA).

Methods

The quantitative expression of selected miRNA using real-time PCR was analyzed in surrounding adrenal neoplasia, peri-renal, and subcutaneous AT samples of 16 patients with adrenalectomy (11 patients with APA and 5 patients with NFA).

Results

Real-time PCR cycles for miRNA-132, miRNA-143, and miRNA-221 in fat surrounding adrenal neoplasia and in peri-adrenal AT were significantly higher in APA than in patients with NFA. Unlike patients with NFA, miRNA-132, miRNA-143, miRNA-221, and miRNA-26b were less expressed in surrounding adrenal neoplasia AT compared to subcutaneous AT in patients with APA.

Conclusion

This study, conducted on tissue expression of miRNAs, highlights the possible pathophysiological role of some miRNAs in determining the metabolic alterations in patients with PA.

Cerebro-Cardiovascular Risk, Target Organ Damage, and Treatment Outcomes in Primary Aldosteronism

Primary aldosteronism (PA) is the most common type of endocrine hypertension, and numerous experimental and clinical evidence have verified that prolonged exposure to excess aldosterone is responsible for an increased risk of cerebro-cardiovascular events and target organ damage (TOD) in patients with PA. Therefore, focusing on restoring the toxic effects of excess aldosterone on the target organs is very important to reduce cerebro-cardiovascular events. Current evidence convincingly demonstrates that both surgical and medical treatment strategies would benefit cerebro-cardiovascular outcomes and mortality in the long term. Understanding cerebro-cardiovascular risk in PA would help clinical doctors to achieve both early diagnosis and treatment. Therefore, in this review, we will summarize the cerebro-cardiovascular risk in PA, focusing on the TOD of aldosterone, including brain, heart, vascular system, renal, adipose tissues, diabetes, and obstructive sleep apnea (OSA). Furthermore, the various treatment outcomes of adrenalectomy and medical treatment for patients with PA will also be discussed. We hope this knowledge will help improve cerebro-cardiovascular prognosis and reduce the incidence and mortality of cerebro-cardiovascular events in patients with PA.

Cross-Talk Between Nitrosative Stress, Inflammation and Hypoxia-Inducible Factor in Patients with Adrenal Masses

Background

Adrenal masses are the most common of all human tumors. The role of nitrosative stress and inflammation in cancer development has already been demonstrated. However, it is not known whether they are involved in the pathogenesis of adrenal tumors. The aim of the study was to investigate a cross-talk between nitrosative stress, inflammation and hypoxia-inducible factor (HIF-1α) in 75 patients with different types of adrenal masses (non-functional incidentaloma, pheochromocytoma and Cushing's/Conn's adenoma).

Methods

The plasma concentrations of total nitric oxide (NO), S-nitrosothiols, peroxynitrite nitrotyrosine and the activity of serum myeloperoxidase (MPO) were measured spectrophotometrically, whereas concentrations of interleukin 1 beta (IL-1β), tumor necrosis factor α (TNF-α) and hypoxia-inducible factor 1 alpha (HIF-1α) were measured using commercial ELISA kits. The control group consisted of 50 healthy people matched by age and sex to the study group. The number of subjects was determined a priori based on our previous experiment (power of the test = 0.9; α = 0.05).

Results

We found significantly higher nitrosative stress (↑nitric oxide, ↑peroxynitrite, ↑S-nitrosothiols and ↑nitrotyrosine) in the plasma of patients with adrenal tumors, which was accompanied by increased inflammatory (↑myeloperoxidase, ↑interleukin 1 beta and ↑tumor necrosis factor α) and hypoxia (HIF-1α) biomarkers. Peroxynitrite and nitrotyrosine were positively correlated with aldosterone level. Nitrosative stress was also associated with inflammation and HIF-1α. Interestingly, plasma nitrotyrosine and serum MPO differentiated patients with adrenal tumor from healthy individuals with high sensitivity and specificity. Moreover, using multivariate regression analysis, we showed that ONOO^- and IL-1β depended on cortisol level, while ONOO^-, nitrotyrosine and HIF-1α were associated with aldosterone. Unfortunately, none of the assessed biomarkers differentiated between tumor types studied, suggesting that the severity of nitrosative damage and inflammation are similar in patients with incidentaloma, pheochromocytoma, and Cushing's or Conn's adenoma.

Conclusion

Adrenal tumors are associated with increased protein nitration/S-nitrosylation and inflammation.

Insulin sensitivity and pancreatic β-cell function in patients with primary aldosteronism

BACKGROUND

Primary aldosteronism (PA) is associated with an increased risk for dysglycemia. However, the effects of hyperaldosteronism on insulin sensitivity and β-cell function are unclear.

METHODS

Using a cross-sectional study design, we assessed insulin sensitivity and pancreatic β-cell function from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n = 21) and essential hypertension control (EHC) subjects (n = 22). Age, sex, BMI, and mean arterial pressure adjusted measures of insulin sensitivity and β-cell function were compared between the groups.

RESULTS

PA individuals were less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index [QUICKI]: 0.340 ± 0.006 vs. 0.374 ± 0.013, p < 0.001; Matsuda index: 4.14 ± 0.49 vs. 7.87 ± 1.42, p < 0.001; S_I: 11.45 ± 4.85 vs. 21.23 ± 6.11 dL/kg/min per μU/mL, p = 0.02). The hepatic insulin resistance index (HIRI) was higher in PA subjects (PA: 5.61 ± 1.01 vs. EHC: 4.13 ± 0.61, p = 0.002). The insulinogenic index (IGI), an index of β-cell function was higher in the PA cohort (PA: 1.49 ± 0.27 vs. 1.11 ± 0.21 μU/mL/mg/dL, p = 0.03). However, the oral disposition index (DI) was similar between the groups (PA: 4.77 ± 0.73 vs. EHC: 5.46 ± 0.85, p = 0.42), which likely accounts for the similar glucose tolerance between the two cohorts, despite lower sensitivity.

CONCLUSIONS

In summary, insulin sensitivity is significantly lower in PA with an appropriately compensated β-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting β-cell function.

Cardiovascular and metabolic risk factors in patients with subclinical Cushing

PURPOSE

Adrenal incidentalomas (AI) are discovered after work-up unrelated to adrenal gland diseases; up to 30% of AI show subclinical endogenous cortisol excess (SH), frequently associated to hypertension, obesity, metabolic disorders and increased incidence of cardiovascular events (CVEs).

METHODS

We analysed 628 AI patients divided into two groups: 471 non-functional adrenal adenoma (NFA) and 157 SH. All patients underwent complete examinations, 24-h ambulatory blood pressure monitoring, biohumoral parameters and vascular damage markers, such as c-IMT and ankle brachial index. After long-term follow-up, we registered newly onset of CVEs such as myocardial infarction (MI), percutaneous stenting and surgical bypass (PTA/CABG), stroke, overall/cardiovascular mortality. Moreover, SH patients underwent to surgical (SSH) or pharmacological treatment (MSH).

RESULTS

SH patients showed higher prevalence of metabolic syndrome, diabetes mellitus, and previous CVEs respect NFA at baseline. After follow-up MSH group showed higher recurrence of major CV events compared with NFA and SSH (RR 2.27 MSH vs NFA for MI; RR 2.30 MSH vs NFA for PTA/CABG; RR 2.41 MSH vs NFA for stroke). In SSH there was a significant reduction of the number of antihypertensive medications needed to reach target blood pressure levels (2.3 ± 1.0 to 1.5 ± 0.4 drugs). None differences were found in SH patients, distinguished in relation to cortisol plasma levels after dexamethasone suppression test (1.8-5 µg/dL, above 5 µg/dL).

CONCLUSIONS

SH is linked to relevant cardiovascular and metabolic alterations, leading to worsen clinical outcomes. In eligible patients, adrenalectomy is valid and safe option to treat SH, reducing cardiometabolic abnormalities.

Associations Between Metabolic Profiles and Target-Organ Damage in Chinese Individuals With Primary Aldosteronism

Purpose: Patients with primary aldosteronism (PA) have an increased risk of target-organ damage (TOD), but whether metabolic syndrome (MetS) is more prevalent and contributes to TOD in PA patients remains unresolved. We aimed to evaluate the associations between MetS profiles and TOD in Chinese PA individuals. Methods: Metabolic parameters and pre-clinical TOD including left ventricular hypertrophy, estimated glomerular filtration, and microalbuminuria; insulin sensitivity or resistance; and islet β-cell function were assessed by the homeostasis models (HOMA-IR, HOMA-β) and the other surrogate indexes [composite insulin sensitivity index (ISI), modified β-cell function index (MBCI)] determined from the oral glucose tolerance test were compared in PA vs. matched essential hypertension (EH) patients. Results: A total of 109 PA patients and 109 essential hypertension (EH) controls individually matched for sex, age, and office systolic blood pressure and duration of hypertension were studied. The prevalence of MetS and its individual components in PA was significantly lower than in EH [MetS: 28 (25.6%) vs. 54 (49.5%), P < 0.001]. PA patients had a higher composite ISI but a lower HOMA-IR, HOMA-β, and MBCI than EH controls (all P < 0.05). Concerning TOD, PA patients had significantly higher prevalence of microalbuminuria and left ventricular hypertrophy (LVH), and lower levels of estimated glomerular filtration (eGFR) than EH controls (all P < 0.05). On multivariate logistic regression analysis, female gender and elevated plasma aldosterone levels were significantly associated with TOD in PA. However, there were no significant associations between MetS and its individual components and TOD in PA patients. Conclusions: PA patients had a lower MetS prevalence but exhibited more severe TOD than matched EH controls. The study highlights the deleterious effects of aldosterone excess on the development of TOD, whereas MetS or its individual components might be less influential in PA.

Increased UCP1 expression in the perirenal adipose tissue of patients with renal cell carcinoma

Perirenal adipose tissue (PAT) has been implicated in renal cell carcinoma (RCC). The expression of uncoupling protein 1 (UCP1) is higher in PAT compared with that in back subcutaneous adipose tissue (bSAT). The aim of the present study was to determine UCP1 expression in different parts of PAT and to analyze the correlation between UCP1 expression in PAT and RCC. PAT from the upper and lower renal poles and bSAT samples were collected from 50 patients with RCC (RCC group) and 54 patients with renal cysts (control group) who had undergone renal surgery. Both UCP1 mRNA and protein levels were found to be significantly higher and adipocytes appeared to be smaller in the PAT of the RCC group. Furthermore, the RCC group had more multilocular UCP1-positive adipocytes. UCP1 staining in the PAT was significantly stronger in the RCC group, but there was no significant difference in UCP1 staining in the bSAT between the two groups. Furthermore, Fuhrman grade and T stage were higher in the high UCP1 expression group of RCC patients. In conclusion, high UCP1 expression in the PAT may serve as an indicator of poor prognosis in RCC.

Expression of adiponectin receptors 1 and 2 and the leptin receptor in human adrenal tumors

INTRODUCTION

The role of adipokines in neoplasms not related to obesity is unclear. The presence of adiponectin receptors 1 and 2 (AdipoR1 and AdipoR2) as well as the leptin receptor (Ob-R) has been recognized in human adrenal tumors. The authors of the present study were the first to compare the expression of these receptors in histopathologically distinct adrenal tumors.

MATERIAL AND METHODS

The study encompassed tissue specimens of 128 patients with adrenal tumors (28 adrenal cortical adenomas (CA), 35 cortical nodular hyperplasia tumors (CNH), 20 cortical carcinomas (CC), 40 pheochromocytomas (PHEO), 5 malignant pheochromocytomas (PHEOM)) operated on at a single clinical center. The expression of the adiponectin receptors AdipoR1 and AdipoR2 as well as the leptin receptor Ob-R was assessed by immunohistochemistry. The results were correlated with body mass index (BMI) and gender of the patients.

RESULTS

AdipoR1 expression was significantly higher in cortical cancers (p < 0.001) and pheochromocytomas (p < 0.001) as compared to benign cortical tumors. AdipoR2 expression was significantly higher in cortical carcinomas as compared to cortical adenomas and hyperplasia tumors (p = 0.01), and also significantly higher in pheochromocytomas in comparison to adrenocortical cancers (p = 0.004). Leptin receptor expression was absent or minimal in half of nodular hyperplasia tumors and adrenal cortex adenomas. This receptor's expression was significantly higher in adrenocortical cancers (p = 0.038). In pheochromocytomas this receptor was expressed more abundantly than in adrenocortical cancers (p = 0.004).

CONCLUSIONS

These novel findings suggest that adiponectin and leptin receptors could play a regulatory role in human adrenal neoplasms.

Predicting factors related with uncured hypertension after retroperitoneal laparoscopic adrenalectomy for unilateral primary aldosteronism

Although unilateral primary aldosteronism (PA) is the most common surgically correctable cause of hypertension, the cure rate varies widely. The predicting factors related to uncured hypertension are not completely established. This study was designed to determine predicting factors associated with resolution of hypertension after adrenalectomy for PA.The records of unilateral PA patients who had undergone retroperitoneal laparoscopic adrenalectomy were retrospectively reviewed from January 2010 to December 2017 in a single center. Patient demographics and preoperative factors were analyzed, including age, sex, smoking history, family history of hypertension, the presence of diabetes, body mass index (BMI), systolic blood pressure, diastolic blood pressure, biochemical results and tumor characteristics. Univariate and multivariate Logistic regression analysis were used for statistical assessment.126 patients with unilateral PA were enrolled, and the mean age at the time of surgery was 54.2 years. Of these patients, 74 (58.7%) were women, and the mean BMI and duration of hypertension were 26 kg/m and 61 months, respectively. Hypertension was cured in 46% patients, of the patients with uncured hypertension, 91% had improved control of hypertension. In univariate analysis, age (P = .03), BMI (P = .01), duration of hypertension >5 years (P = .03), preoperative antihypertensive agents>2 (P = .02), contralateral abnormalities (P = .03) were the main factors related to uncured hypertension after adrenalectomy. In multivariate regression analysis, uncured hypertension was independently associated with obesity (25.00-29.99: odds ratio [OR], 2.97, P < .02; ≥30: OR, 6.42, P < .01), duration of hypertension >5 years (OR, 6.25, P < .01), preoperative antihypertensive agents >2 (OR, 5.30, P < .001), and contralateral adrenal abnormalities (OR, 8.38, P < .01).The hypertension cure rate of unilateral adrenalectomy in PA is not high. Obesity, duration of hypertension >5 years, preoperative antihypertensive agents >2 and contralateral adrenal abnormalities were independently associated with uncured hypertension.

Impact of body mass index on CT attenuation of adrenal adenoma

OBJECTIVE

To investigate whether lipid metabolism-related factors regulate unenhanced CT attenuation in adrenal adenoma (AA).

MATERIALS AND METHODS

Thirty-six patients with surgically proven AAs were enrolled in this study. The patients' underlying diseases were the following: primary aldosteronism (n = 24), Cushing's syndrome (n = 8), subclinical Cushing's syndrome (n = 3) and non-functioning AA (n = 1). Unenhanced CT attenuation of AAs and liver was measured. Pathologically, clear cell ratio (CCR) constituting each AA was qualitatively assessed. Clinical data including tumor diameter, body mass index (BMI), hemoglobin A1c, triglyceride, total cholesterol, blood cortisol and plasma aldosterone levels were also obtained. Simple and multiple linear regression analyses were performed to evaluate the radiological and clinicopathological factors associated with CT attenuation of AAs for all patients and separately for 25 patients with primary aldosteronism or non-functioning AA.

RESULTS

For all patients, there was a significant correlation between CT attenuation and each of CCR, BMI and blood cortisol levels (p < 0.05). For patients with primary aldosteronism or non-functioning AA, there was also a significant correlation between CT attenuation and CCR or BMI (p < 0.05).

CONCLUSION

In addition to pathological factors, lipid-metabolism-related factors including BMI and blood cortisol levels can affect unenhanced CT attenuation of AA.

Adipokine and cytokine levels in non-functioning adrenal incidentalomas (NFAI)

Due to the fact that overweight or obesity is accompanied by hormonally active adrenal tumors: Cushing Syndrome-(CS) and Subclinical Cushing Syndrome (SCS), it is of high interest the correlation between different adipokines and cytokines secreted by adipose tissue, with metabolic disorders and hormonal activity in this group. Even in non-functioning adrenal incidentalomas (NFAI) elevated risk for cardiovascular disease and metabolic syndrome was demonstrated. The aim of the study was to investigate plasma adiponectin, leptin, resistin, tumor necrosis factor α (TNFα), interleukin 6 (IL6) and monocyte chemoattractant protein 1 (MCP1) levels in patients with NFAIs and healthy subjects. The study included 18 NFAI patients and 18 healthy subjects. The groups were homogeneous in terms of age, sex and body mass index (BMI). Patients with NFAI showed significantly higher circulating levels of pro-inflammatory cytokines compared to healthy controls (MCP 1: p < 0.001; TNFα p = 0.021; IL6 p = 0.012). On the other hand, adiponectin concentration was significantly lower in the NFAI group (p = 0.034). The serum leptin and resistin concentrations did not differ significantly between the two groups. Acquired results were not dependent on glucocorticoid and catecholamine secretion in NFAI patients. Also, there were no clear correlations between BMI and cytokine levels. It is possible that increased risk for cardiovascular and metabolic diseases reported in NFAI patients is at least partially dependent on adipose tissue activity.

Peripherally injected ghrelin and leptin reduce food hoarding and mass gain in the coal tit (Periparus ater)

In birds little is known about the hormonal signals that communicate nutritional state to the brain and regulate appetitive behaviours. In mammals, the peptide hormones ghrelin and leptin elevate and inhibit consumption and food hoarding, respectively. But in birds, administration of both ghrelin and leptin inhibit food consumption. The role of these hormones in the regulation of food hoarding in avian species has not been examined. To investigate this, we injected wild caught coal tits (Periparus ater) with leptin, high-dose ghrelin, low-dose ghrelin and a saline control in the laboratory. We then measured food hoarding and mass gain, as a proxy of food consumption, every 20 min for 2 h post-injection. Both high-dose ghrelin and leptin injections significantly reduced hoarding and mass gain compared with controls. Our results provide the first evidence that hoarding behaviour can be reduced by both leptin and ghrelin in a wild bird. These findings add to evidence that the hormonal control of food consumption and hoarding in avian species differs from that in mammals. Food hoarding and consumptive behaviours consistently show the same response to peripheral signals of nutritional state, suggesting that the hormonal regulation of food hoarding has evolved from the consumption regulatory system.

Expression of adiponectin and leptin receptors in adrenal incidentaloma patients with subclinical hormone secretion

BACKGROUND

The role of adopokines in adrenal tumors' hormonal activity remains unclear. Obesity may induce arterial hypertension, disorders of carbohydrate metabolism, and is a risk factor of cardiovascular disease. In patients with subclinical hormone secretion by the adrenal cortex or medulla the risk of metabolic disease is increased.

OBJECTIVE

Authors of this retrospective study selected 78 patients with subclinical hormone secretion out of all adrenal incidentaloma patients hospitalized in the Department of Endocrinology and Internal Medicine between 1995 and 2014.

METHODS

The analyzed group comprised of 38 subclinical Cushing's syndrome (SCS), 40 incidentally discovered pheochromocytoma (PHEO) and 42 patients operated due to an adrenal tumor without pathological hormonal activity. Expression of adiponectin (AdipoR1, AdipoR2) and leptin (Ob-R) receptors in adrenal tumors was assessed in relation to body mass index (BMI) and hormonal activity.

RESULTS

We found statistically significant negative correlations between BMI and expression of all examined receptors in SCS patients (AdipoR1: p= 0.032; AdipoR2: p< 0.001; leptin Ob-R: p= 0.001). In PHEOs, BMI correlated negatively only with AdipoR2 (p= 0.014).

CONCLUSIONS

Data obtained show that the most significant factor associated with the expression of AdipoR1, AdipoR2 and leptin Ob-R receptors in the adrenal tumor tissue is BMI, not their hormonal activity.

Identification of the Long-Sought Leptin in Chicken and Duck: Expression Pattern of the Highly GC-Rich Avian leptin Fits an Autocrine/Paracrine Rather Than Endocrine Function

More than 20 years after characterization of the key regulator of mammalian energy balance, leptin, we identified the leptin (LEP) genes of chicken (Gallus gallus) and duck (Anas platyrhynchos). The extreme guanine-cytosine content (∼70%), the location in a genomic region with low-complexity repetitive and palindromic sequence elements, the relatively low sequence conservation, and low level of expression have hampered the identification of these genes until now. In vitro-expressed chicken and duck leptins specifically activated signaling through the chicken leptin receptor in cell culture. In situ hybridization demonstrated expression of LEP mRNA in granular and Purkinje cells of the cerebellum, anterior pituitary, and in embryonic limb buds, somites, and branchial arches, suggesting roles in adult brain control of energy balance and during embryonic development. The expression patterns of LEP and the leptin receptor (LEPR) were explored in chicken, duck, and quail (Coturnix japonica) using RNA-sequencing experiments available in the Short Read Archive and by quantitative RT-PCR. In adipose tissue, LEP and LEPR were scarcely transcribed, and the expression level was not correlated to adiposity. Our identification of the leptin genes in chicken and duck genomes resolves a long lasting controversy regarding the existence of leptin genes in these species. This identification was confirmed by sequence and structural similarity, conserved exon-intron boundaries, detection in numerous genomic, and transcriptomic datasets and characterization by PCR, quantitative RT-PCR, in situ hybridization, and bioassays. Our results point to an autocrine/paracrine mode of action for bird leptin instead of being a circulating hormone as in mammals.

Determination of UCP1 expression in subcutaneous and perirenal adipose tissues of patients with hypertension

The objective of this study is to determine the property of human perirenal adipose tissue (PAT) and assess the adipose property of PAT in hypertension. Ninety-four patients, including 64 normotensive patients (T-NP) and 30 hypertensive patients (HP), who underwent renal surgery were included. Expression analysis was performed using quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry in PAT and back subcutaneous adipose tissue (bSAT) depots. Compared with bSAT, PAT adipocytes were smaller, and the expressions of uncoupling protein-1 (UCP1) mRNA and protein were markedly higher, while the mRNA expressions of markers for classic beige and white adipocytes were lower in PAT. Immunohistochemistry analysis showed more multilocular UCP1-positive adipocytes in PAT than in bSAT. UCP1 expressions were lower in PAT in HP than in the T-NP or age- and body mass index-matched NP groups. Bigger unilocular adipocytes with less UCP1 staining in PAT were detected in HP than in NP group, although no such difference was observed in bSAT. PAT acts as a brown-like fat. UCP1 expression of PAT was lower in HP than in normotensive patients. UCP1 expression of PAT may serve as a protective indicator for hypertension.