Suna Aydin

Ghrelin is present in human colostrum, transitional and mature milk.

Ghrelin and its mRNA have recently been found in numerous human tissues including breast. The aim of this study was to compare the ghrelin levels in colostrum, mature and transitional milk and plasma in lactating women with plasma samples from non-lactating women. Venous blood samples were obtained from 17 healthy lactating women aged 22-35 years and from 16 age-matched controls. Colostrum, transitional and mature milk samples were collected just before suckling. The level of bioactive ghrelin was determined by RIA. Comparison of ghrelin values for lactating women showed significantly lower concentrations in colostrum (70.3 +/- 18 pg/ml), transitional milk (83.8 +/- 18pg/ml) and mature milk (97.3 +/- 13 pg/ml) than in the corresponding plasma samples (first day 95 +/- 16 pg/ml, 10th day 111 +/- 13 pg/ml and 15th day 135 +/- 16 pg/ml). The plasma concentrations were lower in the lactating than in the non-lactating women. Thus, the ghrelin levels in colostrum, transitional and mature milk were elavated concomitantly with increasing plasma ghrelin after delivery. The origin of milk ghrelin is not known, but it probably comes from the plasma.

A comparison of leptin and ghrelin levels in plasma and saliva of young healthy subjects

In the last 10 years, saliva has been increasingly used as a diagnostic fluid and in predictions of disease progression. Leptin and ghrelin are synthesized in several tissues including the salivary glands. The action of ghrelin is antagonistic to that of leptin. This study was undertaken to measure and compare the saliva ghrelin-leptin and plasma ghrelin-leptin levels in healthy young subjects. In 30 healthy subjects, after an overnight fast, saliva and plasma leptin levels were measured using the ELISA method while saliva and plasma immunoreactive ghrelin levels were measured using a commercial radioimmunoassay (RIA). The latter uses 125I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin (Phoenix, Europe, Karlsruhe, Germany). The results of this investigation revealed that saliva leptin levels (6.19+/-2.10 microg/l) were lower than plasma levels (7.39+/-3.23 microg/l) while saliva ghrelin levels (188.5+/-84.7 pg/ml) were higher than plasma levels (126.4+/-38.5 pg/ml), when male and female subjects were considered together. Saliva leptin levels (5.93+/-1.94 microg/l) were lower than plasma levels (6.22+/-2.92 pg/ml) while saliva ghrelin levels (190.3+/-80.2 pg/ml) were higher than plasma levels (120.4+/-35.7 pg/ml) in young males. Saliva leptin levels (6.47+/-2.29 microg/l) were lower than plasma levels (8.73+/-3.14 microg/l) while saliva ghrelin levels (183.2+/-90.2 pg/ml) were higher than plasma levels (129.3+/-42.8 pg/ml) in young females, and both saliva and plasma leptin levels were slightly lower in male subjects in comparison with female subjects. Also, Immunohistochemistry study indicated that ghrelin positivity was found in ductus epithelium of salivary gland. We have demonstrated for the first time that saliva ghrelin levels were higher than in plasma while saliva leptin levels were almost the same as in plasma. Measurements of ghrelin and leptin in saliva is non-invasive, simple, and generally much preferred by patients and thus may be an acceptable alternative to plasma sampling.

Cardiac, skeletal muscle and serum irisin responses to with or without water exercise in young and old male rats: cardiac muscle produces more irisin than skeletal muscle.

Irisin converts white adipose tissue (WAT) into brown adipose tissue (BAT), as regulated by energy expenditure. The relationship between irisin concentrations after exercise in rats compared humans after exercise remains controversial. We therefore: (1) measured irisin expression in cardiac and skeletal muscle, liver, kidney, peripheral nerve sheath and skin tissues, as also serum irisin level in 10 week-old rats without exercise, and (2) measured tissue supernatant irisin levels in cardiac and skeletal muscle, and in response to exercise in young and old rats to establishing which tissues produced most irisin. Young (12 months) and old rats (24 months) with or without 10min exercise (water floating) and healthy 10 week-old Sprague-Dawley rats without exercise were used. Irisin was absent from sections of skeletal muscle of unexercised rats, the only part being stained being the perimysium. In contrast, cardiac muscle tissue, peripheral myelin sheath, liver, kidneys, and skin dermis and hypodermis were strongly immunoreactivity. No irisin was seen in skeletal muscle of unexercised young and old rats, but a slight amount was detected after exercise. Strong immunoreactivity occurred in cardiac muscle of young and old rats with or without exercise, notably in pericardial connective tissue. Serum irisin increased after exercise, being higher in younger than older rats. Irisin in tissue supernatants (cardiac and skeletal muscle) was high with or without exercise. High supernatant irisin could come from connective tissues around skeletal muscle, especially nerve sheaths located within it. Skeletal muscle is probably not a main irisin source.

Today's and yesterday's of pathophysiology: Biochemistry of metabolic syndrome and animal models

During the past 20 y, there has been much interest in sugars and especially fructose in relation to human health. Over the past decade, considerable scientific debate and controversy have arisen about the potential health effects of sucrose, high-fructose corn syrup (HFCS), and fructose itself. HFCS increasingly has been used as a sweetener in thousands of food products and soft drinks, leading to the development of obesity, diabetes, dyslipidemia, and metabolic syndrome (MetS) in both rodents and humans, which is associated with an increase in body weight. There is a need for detailed research on the mechanism underlying MetS that could lead to a remedy. This review will first systematically present a definition of MetS, its history, prevalence, and comparative diagnostic criteria. We will then consider fructose and its effects on human health, the diet-induced obesity model (various fat contents), the hypercholesterolemic model, the diabetes model, the hypertensive model, the MetS or insulin resistance model, and biomarkers related to MetS, in light of contemporary data using multiple databases (PubMed, MEDLINE, and OVID).

A comprehensive immunohistochemical examination of the distribution of the fat-burning protein irisin in biological tissues.

Irisin was first identified in skeletal muscle cells, but its precise location has not yet been demonstrated, and there is limited information about irisin protein in other human and rat tissues. The present immunohistochemical study was undertaken to screen skeletal muscle and other tissues for irisin immunoreactivity. İrisin staining was found in the brain (neurons and neuroglia), cardiac and skeletal muscle (fibers) and skin (sebaceous glands) tissues in male rats. In both human adult and fetal skeletal muscle, the most intense immunohistochemical staining was in the perimysium and endomysium, in the peripheral nerve (epineurium) and axon and nerve sheaths spreading among the cells, in the sarcoplasma and subendomysium. Irisin was also demonstrated in the testis (seminiferous tubules, some spermatogenic cells in fetal and Leydig cells in fetal and adult testis, ductus epididymis in fetal human epididymis); pancreas (islets of Langerhans, serous acini cells, intralobular and intralobular ducts cells); liver (hepatocytes; Kupffer cells and sinusoidal endothelial cells); spleen (subcapsular region and periarterial lymphatic sheets); the stomach (gastric parietal cells, tunica muscularis cells). We conclude that the fat-burning protein irisin locally produced in peripheral and central tissues could act as a gatekeeper of metabolic energy regulation in those tissues, since this myokine converts white into brown adipose tissue, enhancing energy expenditure.

Alterations of irisin concentrations in saliva and serum of obese and normal-weight subjects, before and after 45 min of a Turkish bath or running

The purpose of this study was to ascertain (1) whether human saliva contains irisin and whether its level correlates with serum irisin concentration, (2) whether salivary glands, eccrine glands and sebaceous glands in human skin produce irisin, (3) how the changes in saliva and serum irisin concentrations after the Turkish bath at 47 ± 3°C compare with the changes caused by moderate exercise in obese and normal weight subjects. Seven obese male subjects and seven normal weight subjects were enrolled for Turkish bath. Seven obese male subjects and seven normal weight subjects were also enrolled for moderate outdoor exercise, and thirteen male normal weight subjects neither exercised nor showered at the Turkish bath. From each participant, 1.5 ml of saliva and 5 ml blood were collected simultaneously before and after the moderate exercise and Turkish bath. Salivary glands and eccrine and sebaceous glands in the skin were screened immunohistochemically for irisin while serum and saliva irisin were measured with an ELISA. Submandibular glands, eccrine glands and sebaceous glands in the human skin showed strong irisin immunoreactivity. Human saliva contained irisin and its level was significantly higher than the serum levels in both obese and normal weight subjects. However, irisin concentrations were more markedly increased in both saliva and serum samples from subjects who had showered at a Turkish bath than in obese subjects who had exercised or in normal weight subjects. Human submandibular glands, eccrine sweat glands and sebaceous glands synthesize irisin.

Irisin: a potentially candidate marker for myocardial infarction.

Myocardial infarction (MI) causes energy depletion through imbalance between coronary blood supply and myocardial demand. Irisin produced by the heart reduces ATP production by increasing heat generation. Energy depletion affects irisin concentration in circulation and cardiac tissues, suggesting an association with MI. We examined: (1) irisin expression immunohistochemically in rat heart, skeletal muscle, kidney and liver in isoproterenol (ISO)-induced MI, and (2) serum irisin concentration by ELISA. Rats were randomly allocated into 6 groups (n=6), (i) control, (ii) ISO (1h), (iii) ISO (2h), (iv) ISO (4h), (v) ISO (6h), and (vi) ISO (24h), 200mg ISO in each case. Rats were decapitated and the blood and tissues collected for irisin analysis. Blood was centrifuged at 1792 g for 5 min. Tissues were washed with saline and fixed in 10% formalin for histology. Serum irisin levels gradually decreased from 1h to 24h in MI rats compared with controls, the minimum being at 2h, increasing again after 6h. Cardiac muscle cells, glomerular, peritubular renal cortical interstitial cells, hepatocytes and liver sinusoidal cells and perimysium, endomysium and nucleoi of skeletal muscle were irisin positive, but its synthesis decreased 1-4h after MI. At all time-points, irisin increased near myocardial connective tissue, with production in skeletal muscle, liver and kidney recovering after 6h, although slower than controls. Unique insight into the pathogenesis of MI is shown, and the gradually decrease of serum irisin might be a diagnostic marker for MI.

Copeptin, adropin and irisin concentrations in breast milk and plasma of healthy women and those with gestational diabetes mellitus.

Copeptin, adropin and irisin are polypeptide hormones implicated in energy homostasis and diabetes. The purposes of this study were (1) to compare the copeptin, adropin and irisin concentrations between colostrum, transitional and mature milk and plasma in lactating women with and without GDM and (2) to compare these values with those from non-lactating women. Venous blood samples were obtained before suckling from 15 healthy lactating women aged 26-30 years, 15 lactating women with GDM aged 26-32 years, and 14 age-matched controls aged 25-31 years. Colostrum, transitional milk and mature milk samples were collected just before suckling. The concentration of copeptin was determined by EIA while the concentrations of adropin and irisin were determined by ELISA. The levels of copeptin, adropin and irisin in the colostrum were significantly higher than those in transitional and mature milk samples from healthy women; also, transitional milk had higher copeptin, adropin and irisin concentrations than mature milk. The amounts of copeptin in the colostrum and transitional milk were significantly higher than in mature milk samples from women with GDM, while the amounts of adropin and irisin were significantly lower. The relative concentrations of copeptin, adropin and irisin in the plasma samples from these groups of women were similar to those in the colostrum, transitional and mature milk samples, but the latter concentrations were higher than those in the plasma. These peptides could influence the regulation of metabolic pathways and the postnatal growth and development of different organs in the newborn.

Deficiency of a new protein associated with cardiac syndrome X; called adropin.

The pathophysiology of cardiac syndrome X (CSX) is still unclear, but most patients with CSX have endothelial dysfunction. It has been shown that adropin uniquely effects the regulation of endothelial function. The purpose of the study was to evaluate the role of adropin in CSX. Eighty-six consecutive cardiac syndrome X-diagnosed patients and 86 age-sex matched healthy subjects were enrolled into the study. Serum adropin levels, nitrite/nitrate levels were measured in each subject. The adropin levels were significantly lower in patients with CSX than healthy subjects (1.7 ± 0.8 ng/mL and 3.4 ± 1.8 ng/mL, respectively; P < 0.001). The BMI values of patients with CSX were significantly higher than control subjects (28.1 ± 2.4 kg/m(2) and 26.0 ± 3.7 kg/m(2) , respectively; P < 0.001). Plasma nitrite/nitrate levels were lower in patients with CSX than control subjects (15.9 ± 1.6 μmol/L vs. 25.4 ± 2.8 μmol/L, respectively; P < 0.001), and they have a significantly positive correlation with plasma adropin levels (r = 0.463, P < 0.001). In the multiple linear regression analysis, nitrite/nitrate levels, BMI, and adropin were found to be independent risk factors for CSX. A ROC curve is used to identify the ability of adropin levels to predict the cardiac syndrome X. The area under the ROC curve was 0.854 for adropin levels (P = 0.0001). The sensitivity and specificity values of adropin levels were 90.7 and 70.9%, respectively (cut-off value 2.73). In conclusion, lower serum adropin levels were associated with CSX. Adropin is an independent risk factor for CSX.

Plasma adropin levels predict endothelial dysfunction like flow-mediated dilatation in patients with type 2 diabetes mellitus.

Objective This study investigated the role of plasma adropin levels to show endothelial dysfunction in individuals with type 2 diabetes mellitus and to compare these with flow-mediated dilatation. Methods A total of 92 individuals with diagnosed type 2 diabetes mellitus were included and divided into 2 groups according to their brachial flow-mediated dilatation. The endothelial dysfunction group consisted of 46 participants with flow-mediated dilatation change of less than 7%, whereas 46 participants with flow-mediated dilatation change of more than 7% were accepted as the nonendothelial dysfunction group. Venous blood samples were taken from all study participants, and plasma adropin levels were measured using an enzyme-linked immunosorbent assay kit. Results The mean flow-mediated dilatation values were 13.2% ± 4.9% in the nonendothelial dysfunction group, and 3.5% ± 3.4% in the endothelial dysfunction group. Mean hemoglobin A1c levels were significantly higher in the endothelial dysfunction group than in the nonendothelial dysfunction group (8.7% ± 1.9% vs 7.9% ± 1.6%, respectively; P < 0.038). Mean plasma adropin levels were 3.04 ± 0.79 ng/mL in the endothelial dysfunction group and 4.67 ± 1.43 ng/mL in the nonendothelial dysfunction group; P < 0.001. Plasma adropin levels showed no correlation with body mass index (r = −0.072, P = 0.497) but were positively correlated with flow-mediated dilatation values (r = 0.537, P < 0.001). In the linear regression analysis, adropin and hemoglobin A1c were independent risk factors for endothelial dysfunction in individuals with type 2 diabetes mellitus. Conclusion Adropin is a new marker for use in demonstrating endothelial dysfunction.