Adela Penesova

Protein array reveals differentially expressed proteins in subcutaneous adipose tissue in obesity.

Objective: Many adipokines, inflammatory cytokines, and other proteins produced by adipose tissue have been shown to be involved in the development of obesity‐related insulin resistance. Nevertheless, new factors that play an important role in these processes are still emerging. Therefore, we screened the level of 120 different proteins in biopsies of subcutaneous adipose tissue (ScAT) of lean and obese subjects.

Adipokine Protein Expression Pattern in Growth Hormone Deficiency Predisposes to the Increased Fat Cell Size and the Whole Body Metabolic Derangements

CONTEXT GH deficiency (GHD) in adults is associated with central adiposity, dyslipidemia, and insulin resistance. OBJECTIVE The objective of the study was to test the hypothesis that GHD might change the spectrum of adipokines and thus influence the adipose tissue and the whole-body metabolic and inflammatory status leading to development of insulin resistance. DESIGN This was a single-center observational study with a cross-sectional design. PARTICIPANTS AND METHODS Protein arrays were used to characterize adipokines expressed in the sc adipose tissue obtained from young GHD adults and compared with age-, gender-, and body mass index (BMI)-matched group of healthy individuals. All subjects underwent an oral glucose tolerance test, euglycemic hyperinsulinemic clamp, and magnetic resonance imaging examination. RESULTS Presence of abdominal obesity, enlarged adipocytes, increased circulating high-sensitivity C-reactive protein, impaired glucose tolerance, and decreased insulin action were found in GHD. Changes in adipokine protein expression due to GHD were highly dependent on the obesity phenotype. Lean GHD individuals (BMI approximately 23 kg/m(2)) had decreased protein levels for stem cell factor and epithelial growth factor, indicating a possible defect in adipocyte differentiation and proliferation. Decrease of vascular endothelial growth factor, stromal cell-derived factor, angiopoietin-2, and brain-derived neurotrophic factor advocated for attenuated angiogenesis and neurogenesis. Presence of obesity (BMI approximately 31 kg/m(2)) eliminated these inhibitory effects. However, adipose tissue expansion in GHD individuals was paralleled by an elevation of adipose tissue proinflammatory cytokines (IL-1beta, interferon-gamma) and chemoattractants (interferon-inducible T cell alpha-chemoattractant, monocyte chemotactic protein-2, monocyte chemotactic protein-3, eotaxin). CONCLUSION Our data demonstrate that GHD modulates adipokine and cytokine protein expression pattern, which might influence the adipose tissue growth and differentiation and predispose to tissue hypoxia, inflammation, and a defect in the whole-body insulin action.

Heart rate variability and catecholamines during hypoglycemia and orthostasis.

The low frequency component of heart rate variability (HRV) is believed to be affected by sympathetic activity, but an evidence for this suggestion remains controversial. This study analyzed association between HRV and plasma catecholamines in response to two distinct conditions activating sympathetic nervous system. Changes in HRV were analysed from ECG recording and plasma norepinephrine and epinephrine levels were measured in response to head-up tilt (60 degrees, 10 min) in 14 healthy volunteers (6 males, mean age 27.2+/-0.8) and in response to insulin-induced hypoglycemia (0.1 IU per kg, i.v. bolus) in 11 healthy volunteers (5 males, mean age 26.6+/-0.9 yr). Normalized low frequency power, low/high frequency ratio, plasma catecholamines increased, whereas normalized high frequency power decreased in response to head-up tilt or hypoglycemia. When analyzed individual time points of orthostatic test, plasma epinephrine correlated positively with low/high frequency ratio and negatively with normalized high frequency at the 3rd min of the head-up tilt. When all data at different time points were pooled significant correlations were found between catecholamines and normalized low frequency power and low/high frequency ratio. In insulin-induced hypoglycemia test plasma epinephrine correlated negatively with normalized high frequency power at the 30th minute. When all data measured at different time points were pooled no significant correlation was found between plasma catecholamines and HRV parameters. In conclusion, the present study shows an increase in low frequency component of HRV in response to orthostasis or hypoglycemia with significant, however inconsistent association to changes in plasma catecholamines.

Subcutaneous adipose tissue zinc-α2-glycoprotein is associated with adipose tissue and whole-body insulin sensitivity.

To examine the regulatory aspects of zinc‐α2‐glycoprotein (ZAG) association with obesity‐related insulin resistance.

Comparison of salivary cortisol and calculated free plasma cortisol during low-dose ACTH test in healthy subjects

OBJECTIVES To compare free plasma cortisol (FPC) with salivary and calculated cortisol. DESIGN AND METHODS FPC, salivary cortisol, free cortisol index (FCI), albumin-derived free cortisol index (FCIalb), Coolens and Dorins cortisol were assayed during repeated low-dose ACTH test in healthy women. RESULTS FPC significantly correlated with its surrogates, the most with FCIalb and salivary cortisol. FPC and salivary cortisol showed the highest method agreement. CONCLUSIONS FCIalb and salivary cortisol are preferred surrogates of FPC.

Sympathetic Nervous System Response to Orthostatic Stress in Female Patients with Rheumatoid Arthritis

Sympathoneural and adrenomedullary impairments have been suggested in patients with rheumatoid arthritis (RA). In the present study, sympathoneural and adrenomedullary responses to orthostasis were evaluated in eight female RA patients and in eight matched healthy controls. The testing consisted of sequence of stabilization period in supine position, legs‐up position, orthostasis, and supine position. In each body position, blood samples were drawn and ECG was recorded. Plasma levels of epinephrine (EPI), norepinephrine (NE) and neuropeptide Y (NPY) were measured and sympathoneural activity was evaluated by analysis of heart rate variability (HRV). Higher baseline NE levels were found in RA patients (P= 0.034), without any difference in response to orthostasis between the study groups. Levels of EPI tended to be lower in RA patients in base line (P= 0.053) and in response to orthostasis (P= 0.079). The RA and control groups did not differ in NPY levels or in HRV parameters considered to reflect sympathetic activity. A subtle tendency to decreased adrenomedullary reactivity but no evidence for abnormal sympathetic responses to orthostasis was found in RA females.

The role of norepinephrine and insulin resistance in an early stage of hypertension.

The interrelationship between activity of sympathetic nervous system and metabolic risk factors in youth with hypertension (HT) has been poorly studied. The aim of our present study was to assess the interrelationship between metabolic risk factors, such as insulin resistance, concentration of plasminogen activator inhibitor (PAI)‐1, and catecholamines in an early stage of HT onset. An oral glucose tolerance test was performed in 17 young males with early‐diagnosed nontreated HT grade 1 and 16 gender‐, age‐, and BMI‐matched normotensive controls. Concentrations of glucose, insulin, epinephrine, norepinephrine, PAI‐1, and plasma renin activity (PRA) were determined in venous plasma. Insulin sensitivity indices (ISIs) proposed by Cederholm, Matsuda, and Gutt were calculated. HT had higher baseline levels of norepinephrine, insulin (P= 0.02), and PAI‐1 (P= 0.04). ISIs were lower in HT subjects (P < 0.001). Baseline concentrations of epinephrine were negatively associated with HDL cholesterol (r=−0.415, P= 0.02), ISI Matsuda (r=−0.361, P= 0.04), ISI Cederholm (r=−0.354, P= 0.04), and ISI Gutt (r=−0.429, P= 0.01), and positively with PRA (r= 0.609, P < 0.0001). Positive association was found between baseline concentrations of norepinephrine and PAI‐1 (r= 0.418, P= 0.02). The sympathetic overactivity, which occurs in the early stage of HT may contribute to reduced insulin sensitivity even in young patients and intensify the undesirable development of metabolic cardiovascular risk factors and progress of the disease.

Increased production of IL-6 and IL-17 in lipopolysaccharide-stimulated peripheral mononuclears from patients with rheumatoid arthritis.

TLR4-mediated inflammatory responses are important for innate immune functions, thus their alterations may participate in the pathogenesis of rheumatoid arthritis (RA). Cortisol is one of the most potent immunomodulatory hormones involved in control of inflammation. In this study, we analyzed TLR4-mediated responses and cortisol effects on the process in peripheral blood mononuclear cells (PBMC) from RA patients. Lipopolysaccharide-stimulated PBMC from 23 female patients and 15 healthy controls were cultured in the presence or absence of cortisol (1 μM) for 24 h. A panel of 17 inflammatory cytokines was analyzed in the cell culture supernatants. Higher (p < 0.05) concentrations of IL-6, IL-17 and MCP-1 were found in lipopolysaccharide-stimulated PBMC from RA patients compared to controls. After normalization of stimulated cytokine secretion to unstimulated cells, a significantly higher (p < 0.05) IL-6 and G-CSF production was found in RA PBMC. Cortisol induced stronger (p < 0.05) suppression of lipopolysaccharide-stimulated secretion of IL-1β, IL-6, IL-17 and G-CSF in RA group compared to controls. The observed higher production of the key inflammatory cytokines by RA PBMC to lipopolysaccharide stimulation supports involvement of TLR4-mediated processes in RA pathogenesis. The higher sensitivity of LPS-stimulated RA PBMC to immunosuppressive effects of cortisol may reflect adaptive processes to chronic inflammation.

Early cognitive impairment along with decreased stress-induced BDNF in male and female patients with newly diagnosed multiple sclerosis

The aim of this study was to evaluate neuroendocrine activation during stress in patients with recently diagnosed multiple sclerosis before starting the immunomodulatory therapy (EDSS score≤2.0). We verified the hypothesis that certain cognitive and affective dysfunction is present already at this early stage of the disease. The sample consisted of 38 subjects, which involved patients who were recently diagnosed multiple sclerosis and age- and sex-matched healthy volunteers. Stroop test served as mental stress model enabling measurement of cognitive performance. Present results showed increased state anxiety, depression scores and poorer performance in the Stroop test in the group of patients compared to healthy subjects. The cognitive dysfunction was particularly evident in male patients with simultaneously decreased concentrations of the brain-derived neurotrophic factor (BDNF) in plasma. The patients at this stage of the disease have not yet developed the hyperactivity of the hypothalamic-pituitary-adrenocortical axis. They showed normal levels of plasma copeptin and reduced aldosterone response to mental stress test in women only. Concentrations of plasma copeptin were higher in men compared to women. Very early stages of multiple sclerosis are accompanied by disturbances in psychological well-being, mild cognitive dysfunction and decreased plasma concentrations of BDNF, particularly in male patients.

Adrenocortical Response to Low‐dose ACTH Test in Female Patients with Rheumatoid Arthritis

Alterations in adrenal steroid production have been suggested in females with rheumatoid arthritis (RA). The aim of the present study was to assess adrenocortical function in RA females. We examined 11 female RA patients (RA: age 30 ± 2 years, BMI 21.0 ± 0.7 kg/m2) and 10 matched healthy controls (C: age 31 ± 1 years, BMI 21.6 ± 0.6 kg/m2). Low‐dose adrenocorticotropic hormone (ACTH) test (i.v. bolus of 1 μg synthetic ACTH) was performed at 10.00 h with blood sampling every 15 min for 90 min. Cortisol, 17‐OH‐progesterone (17OHP), androstenedione (ASD), and dehydroepiandrosterone (DHEA) were assayed in plasma. Baseline cortisol levels were higher in RA patients (RA: 385 ± 38 versus C: 229 ± 28 nmol/L, P= 0.007). In both study groups, ACTH administration increased all the four steroids measured (P < 0.001). Cortisol response to ACTH administration was diminished in RA patients when compared to controls (Δmax: 284 ± 24 in RA versus 424 ± 31 nmol/L in C, P= 0.002). ACTH‐induced maximal rise in plasma DHEA was significantly lower in RA patients when compared to controls (Δmax: 2.59 ± 0.68 in RA versus 5.57 ± 1.25 ng/mL in C, P= 0.015). No significant between‐groups differences were found in responses of ASD or 17OHP. The molar ratio of ASD:cortisol was significantly lower (P < 0.05) in RA patients at base line, but did not differ during ACTH test. After ACTH bolus, the cortisol:17OHP ratio decreased significantly in the RA group (P < 0.001), whereas there was no change in the control group. The present results show decreased secretion of cortisol and DHEA in RA patients in response to ACTH, suggesting a subtle HPA hypofunction at the adrenocortical level.