Plasma and aqueous levels of subfatin, preptin and betatrophin in patients with diabetic retinopathy.

AIM: To examine subfatin, preptin and betatrophin levels in plasma and aqueous in patients with diabetes mellitus (DM) (with and without retinopathy). MATERIAL AND METHOD: Sixty patients, who were similar in terms of age and gender, and were scheduled for operation due to cataract, were included in the study. The patients were divided into three groups as Group C (20 weeks without diabetes and comorbidity), Group DM (20 patients with DM but no retinopathy) and Group DR (20 patients with diabetic retinopathy). The preoperative body mass index (BMI), fasting plasma glucose, HbA1c, lipid profile levels of all patients in the groups were examined. Blood samples were also taken for plasma subfatin, preptin and betatrophin levels. At the beginning of the cataract surgery, 0.1 ml of aqueous fluid was taken from the anterior chamber. Plasma and aqueous subfatin, preptin and betatrophin levels were analyzed by ELISA (enzyme-linked immunosorbent assays) method. RESULTS: In our study results, there was a significant difference in BMI, fasting plasma glucose and hemoglobin A1c levels (p < 0.05 for all parameters). Plasma and aqueous subfatin levels were higher in Group DR compared to Group C (p < 0.001, p = 0.036, respectively). Plasma and aqueous preptin levels were higher in group DR and group DM than in group C (p = 0.001, p = 0.002, p < 0.001, p = 0.001, respectively). Plasma and aqueous betatrophin levels were higher in Group DR compared to group C (p = 0.001, p = 0.010, respectively). CONCLUSION: Subfatin, preptin and betatrophin molecules may have an important role in the pathogenesis of diabetic retinopathy.

Effects of exercise training on serum preptin, undercarboxylated osteocalcin and high molecular weight adiponectin in adults with metabolic syndrome.

NEW FINDINGS: What is the central question of this study? Are the advantages of aerobic interval exercise, resistance exercise and concurrent exercise on the metabolic profile mediated in part through preptin and undercarboxylated osteocalcin (ucOCN)? What is the main finding and its importance? Glucose was significantly lowered after concurrent exercise and aerobic interval exercise, but serum preptin and insulin were significantly lowered in all three training groups. By contrast, ucOCN and high molecular weight adiponectin increased significantly in all three training groups. These findings support the possible cross-talk between bone, pancreatic ß-cells and energy metabolism in humans and suggest that preptin and ucOCN may potentially serve as markers of exercise-induced improvement of metabolism. ABSTRACT: Preptin is a peptide hormone that plays an important role in the development of obesity by regulation of carbohydrate metabolism. Undercarboxylated osteocalcin (ucOCN) is also linked to the regulation of body energy in that it modulates fat and glucose metabolism. This research aimed to examine the impact of aerobic interval, resistance and concurrent exercise on serum preptin, ucOCN and high molecular weight adiponectin (HMW-APN) in obese adults with metabolic syndrome (MetS). Forty-four obese men with MetS were randomized to receive aerobic interval exercise (AIEX, n = 10), resistance exercise (REX, n = 10), or concurrent aerobic interval and resistance exercise (CEX, n = 10), or to act as a non-exercise control (CON, n = 10) three times a week for 12 weeks. Preptin was reduced more after AIEX and CEX than after REX (89.1% and 87.1% versus 9.6%; P = 0.028 and 0.030, respectively). ucOCN increased significantly only in the CEX (27.5%, P = 0.009) and AIEX (25%, P = 0.025) groups, but HMW-APN increased significantly in all three training groups (AIEX 145.1%, P < 0.001; CEX 137%, P < 0.001; and REX 59.8%, P = 0.041). After the intervention, the improvement of peak oxygen uptake ( V̇O2peak ) in the AIEX group (73%) was greater than in the CEX (29.3%) and REX (3.8%) groups. On the other hand, CEX exhibited a greater reduction in glucose, insulin, insulin resistance index and HbA1c than did AIEX and REX. Our study indicates that the reduction in glucose after exercise training (especially AIEX and CEX) may be, somewhat, linked to decreased preptin and raised ucOCN and HMW-APN.

Preptin promotes proliferation and osteogenesis of MC3T3-E1 cells by upregulating ß-catenin expression.

Preptin, an oligopeptide secreted by pancreatic ß-cell, plays a significant role in glycometabolism and bone metabolism. Preptin strengthens proliferation and differentiation of osteoblasts, but the mechanism is unclear. Here, we explored the role of the Wnt/ß-catenin signaling pathway which is well known to affect bone development and remodelling in the function of preptin. We found that preptin promoted the cell proliferative activity and osteoblastic differentiation in osteoblast-like MC3T3-E1 cells in a dose-independent manner, as evidenced by elevation in osteogenic genes, alkaline phosphatase activity and alizarin red staining in a dose-independent manner. Additionally, our findings demonstrated that the ß-catenin expression level and runt-related transcription factor 2, which is the key downstream target of this pathway, were increased. The Wnt/ß-catenin signalling pathway antagonist DKK1 abrogated the proliferative effect and differentiation function of preptin in MC3T3-E1 cells. These data indicated that preptin may be a potential therapeutic target for the treatment of osteoporosis and that osteogenic impact of preptin in MC3T3-E1 cells might be mediated by the Wnt/ß-catenin signalling pathway. © 2019 IUBMB Life, 9999(9999):1-9, 2019.

Investigation of the relation between bone mass density and serum preptin levels in pre- and postmenopausal women.

Preptin is a peptide hormone co-secreted with insulin and amylin from pancreatic ß cells. It has been demonstrated to have osteogenic effects both in vitro and in vivo. In the present study, serum preptin levels were measured in pre- and postmenopausal women with similar body mass indexes (BMIs) to elucidate its link with bone mineral density (BMD). Sixty women (30 premenopausal and 30 postmenopausal) with low bone mineral density were studied. The BMD scores, serum preptin levels and serum estradiol levels were measured. The correlation between serum preptin and estradiol levels with BMD was assessed. Serum preptin and estradiol levels were significantly lower in the postmenopausal women than the premenopausal subjects [2102.27 ± 918.66 vs. 2667.30 ± 940.41 ng/L (P < 0.05) and 39.32 ± 31.74 vs. 99.24 ± 49.24 pg/ml (P < 0.001), respectively]. The serum preptin levels had weak positive (albeit statistically significant) correlations with estradiol (r = 0.271, P = 0.036), femur neck BMD (r = 0.233, P = 0.035) and total hip BMD (r = 0.287, P = 0.031), but no correlation was observed between serum preptin levels and L1-4 lumbar spine BMD (r = 0.136, P = 0.474). The findings of the present study suggest that serum preptin levels in women decrease after menopause and have a positive correlation with estradiol, femoral and total hip BMDs.

Patatin-like phospholipase domain containing 3-gene (adiponutrin), preptin, kisspeptin and amylin regulates oocyte developmental capacity in PCOS.

This study was planned to test whether follicular fluid (FF) levels of patatin-like phospholipase domain containing 3-gene (PNPLA3:adiponutrin), preptin, kisspeptin, and amylin change in polycystic ovarian syndrome (PCOS). A total of 40 infertile volunteers undergoing IVF/ICSI were included in the study. They were divided into two groups as PCOS (n=20) and control group without PCOS (n=20). The controls were recruited from subjects with a poor ovarian response. The PCOS and control participants were matched according to their body mass index (BMI). Each group of participants underwent ovarian stimulation with GnRH antagonist protocol. Blood and FF samples of one dominant follicle were obtained from each subject during the oocyte pick-up. FF and serum levels of PNPLA3, preptin, kisspeptin and amylin were measured through ELISA. Amylin and adiponutrin median values were not different according to study groups (p>0.05). FF-preptin median values in the control group were similar to the serum preptin values of control and PCOS groups (Z=0.970, p=1.000 and Z=2.631, p=0.051, respectively). Medians of the serum preptin in control and PCOS groups were the same (Z=1.649; p=0.595). FF-preptin median values of PCOS group were significantly lower than the preptin median values of the control group. Serum preptin levels were positively correlated with HOMA-IR, but not with pregnancy rates and the number of retrieved oocytes. Serum kisspeptin levels were negatively correlated with the number of retrieved oocytes and pregnancy rates. While amylin and adiponutrin have no role in the folliculogenesis, kisspeptin and preptin work together for regulating follicle developmental capacity in PCOS.

Preptin in women with polycystic ovary syndrome.

INTRODUCTION: Polycystic ovary syndrome (PCOS) patients, frequently develop metabolic complications, such as insulin resistance (IR), impaired carbohydrate metabolism, dyslipidemia, obesity. Among the new markers responsible for metabolic disorders, preptin seems to be of great significance. MATERIAL: One hundred and thirty-four women aged 17-45 were enrolled. PCOS was diagnosed in 73 women on the basis of ESHRE-ASRM criteria. Non-PCOS group consisted of 61 women with regular menstruation matched for nutritional status. METHODS: All women underwent anamnesis, physical examination, anthropometric measurements, the abdominal ultrasound examination, and dual energy X-ray absorptiometry (DXA). Serum adropin levels were determined by ELISA. Biochemical and hormonal (testosterone, androstenedione, LH, FSH, estradiol) measurements were also performed. Insulin resistance indices (HOMA, QUICKI, Matsuda) and free androgen index (FAI) were calculated with the test results according to the standard formula. For all comparisons, statistical significance was defined by p ≤ .05. RESULTS: Serum preptin levels were significantly higher in the PCOS group. No significant correlations between preptin level and metabolic and hormonal markers were observed. The logistic regression analysis demonstrated that serum preptin level was an independent factor differentiating the two groups. CONCLUSIONS: Serum preptin levels were significantly higher in women with PCOS compared with controls. This peptide might be an independent predictor of PCOS in the future.

Investigation of the irisin, preptin and adropin levels in the blood serum of Alburnus tarichi.

Irisin, preptin and adropin are three newly discovered peptides that play critical roles in regulating energy homeostasis in various vertebrates.The purposes of this study were to measure the serum concentrations of preptin, adropin and irisin in the Alburnus tarichi and to investigate the relationship of these peptides to the weight, gender and length of this the fish, which will provide useful information for future biotechnology purposes aimed at improvements in aquaculture production. This study used 12 adult A. tarichi (6 female and 6 male) obtained from Van Lake (Van, Turkey). The serum irisin, preptin and adropin levels were measured using a commercially available enzyme-linked immunosorbent assay (ELISA) kit to determine correlations between the levels of these three hormones and fish body weight and length.  No statistically significant correlations were detected between the serum irisin, adropin and preptin levels and A. tarichi body weight (p = 0.921, r = -0.031; p = 0.08, r = 0.519; p = 0.461, r = -0.235, respectively) or length (p = 0.901, r = -0.040; p = 0.105, r = 0.490; p = 0.236, r = -0.369, respectively).Thus, serum levels of these hormones are independent of fish gender, body weight and length.

Serum Preptin and Amylin Values in Psoriasis Vulgaris and Behçet's Patients.

BACKGROUND: Insulin resistance is found in both psoriasis and Behçet's disease. No study has yet explored whether preptin and amylin, two hormones associated with insulin resistance, are involved in the insulin resistance observed in patients with psoriasis and Behçet's disease. OBJECTIVES: We aimed to explore how the amounts of preptin and amylin change in psoriasis and Behçet's disease and whether they are involved in the etiopathology of these two diseases, by comparing hormone levels in patients and healthy controls. METHODS: The study registered 30 patients with psoriasis, 30 patients with Behçet's disease, and 30 healthy volunteers (as a control group). Fasting blood sugar, triglyceride, LDL, VLDL, HDL, total cholesterol, HbA1c, C-peptide, insulin, and serum preptin and amylin levels were measured in all subjects. RESULTS: Serum preptin and amylin levels were significantly lower in the patients with psoriasis and Behçet's disease than in the control group (P < 0.001, P = 0.004, and P = 0.008, respectively). A comparison of the serum preptin and amylin levels between the patients with psoriasis and Behçet's disease did not reveal a statistically significant difference. Serum insulin level and The homeostasis model assessment of insulin resistance (HOMA-IR) index were significantly lower in the psoriasis patient group relative to the control group (P = 0.02 and P = 0.03, respectively), while the values for the Behçet's disease group did not differ significantly from those for the control group CONCLUSIONS: Serum levels of preptin and amylin were significantly lower in patients with psoriasis and Behçet's disease, indicating that these hormones may be a factor for development of metabolic syndrome in these two diseases.

Effect of Boric Acid on Metabolic Peptides and Some Biochemical Parameters in Experimental Diabetic Rats.

Boron (B) is an element that has recently been wondered and researched in many fields, especially due to its effects on energy metabolism. The aim of this study is to evaluate the effect of boric acid (BA) on newly discovered energy metabolism peptides that have not been studied before. In this study, the effects of 15 mg/kg of BA were evaluated in 24 Wistar rats. Groups were named as control group, 15 mg/kg BA group, streptozotocin (STZ)-induced experimental diabetic group, and STZ-induced experimental diabetic + 15 mg/kg BA administered group (STZ+15 mg/kg BA). Serum asprosin, nesfatin-1, preptin, insulin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), aspartate transaminase (AST), alanine transaminase (ALT), and glucose analyses were performed. In this study, the increase in glucose, TG, TC, LDL-C levels, and AST, ALT activities in STZ-induced groups were reduced with BA administration. While HDL-C level significantly decreased in the STZ group, the level approached the control group values after BA administration (p<0.001). As for peptides, although there was a statistically significant increase after 15 mg/kg BA administration, these levels did not approach the control group values (p<0.001). According to the findings, STZ-induced diabetes mellitus and the biochemical processes that develop accordingly change correlatively. This study showed that BA is effective in energy metabolism.

Irisin, adropin, and preptin as biomarkers of energy dysregulation in depressive disorder.

OBJECTIVE: Lack of energy, fatigue, debility are often seen in depression and hardly respond to treatment. Finding some biomarkers for these symptoms may be important for diagnosis and treatment. We aimed to investigate the possible relationship between depression and energy-related molecules irisin, adropin and preptin. METHODS: There were 117 patients with depression and 59 healthy volunteers included in the study. Sociodemographic characteristics and clinical features of groups were evaluated, and depressed patients were divided into subtypes, then irisin, adropin, preptin levels were compared between depressive patients and healthy controls and between subtypes. Depression severity, quality of life, functionality and the relations with irisin, adropin and preptin levels and associations between depression subtypes were evaluated. RESULTS: Irisin, adropin, and preptin levels were lower in depression, positively correlated with quality of life, and negatively correlated with depression severity and functional impairment. Depression subtypes showed no difference in irisin, adropin and preptin levels. CONCLUSIONS: We found decreased serum irisin, adropin and preptin levels in depression. Our results may support investigation of irisin, adropin and preptin as biomarkers for depression but it might be more meaningful to evaluate these biomarkers in a long-term follow-up.

The potential anti-osteoporotic effect of exercise-induced increased preptin level in ovariectomized rats.

Osteoporosis increases bone fragility and fractures. Preptin hormone is regulated by moderate exercise training and increases bone formation. Therefore, this study was conducted to see how estradiol administration and moderate exercise training affected osteoporotic changes in ovariectomized (OVX) rats. To achieve this aim, 36 healthy adult female Wistar albino rats were randomized into Sham, OVX, ovariectomized estradiol-treated (OVX + E) (OVX + E rats were treated using subcutaneous estradiol benzoate 2.5 µg/kg body weight/day), ovariectomized practicing moderate exercise training, ovariectomized estradiol-treated and practiced a moderate exercise training, and ovariectomized alendronate-treated (OVX + Alen) (OVX + Alen rats were treated orally with alendronate 3 mg/kg body weight/week) groups. Alendronate was used as a standard anti-osteoporotic drug. Moderate exercise training, including therapy with estradiol and alendronate for OVX rats began on the fourth week and lasted for six weeks. Results showed that OVX rats had estrogen and preptin deficiency in serum. These deficiencies were associated with a significant increase in bone resorption biomarkers (urinary deoxypyridinoline and hydroxyproline), and bone formation biomarkers (serum osteocalcin and bone-specific alkaline phosphatase). Also, serum pro-inflammatory cytokines (tumor necrosis factor alpha and interleukin-6) were increased, while bone osteopontin (OPN) expression was decreased. Subsequently, the osteoporotic alterations were verified based on histopathological changes. From the results, estradiol therapy and moderate exercise training significantly improved these findings to the same extent as that of the standard alendronate treatment. Therefore, through their anti-inflammatory properties, increasing bone OPN expression, and regulating serum preptin; estradiol therapy and moderate exercise training can reduce osteoporotic alterations in OVX rats. Thus, combined estradiol therapy and moderate exercise training could be a promising potential therapeutic protocol to reduce postmenopausal osteoporosis. Also, targeting serum preptin and bone osteopontin regulation could have a critical role in the treatment of postmenopausal osteoporosis.

Preptin: A New Bone Metabolic Parameter?

Preptin is a 34-aminoacid peptide derived from the E-peptide of pro-insulin-like growth factor 2 (pro-IGF2) that is co-secreted with insulin and upregulates glucose-mediated insulin secretion. High serum preptin levels were described in conditions associated with insulin resistance, such as polycystic ovary syndrome and type 2 diabetes mellitus (T2M). Insulin and also IGF2 are known to be anabolic bone hormones. The "sweet bone" in T2M usually associates increased density, but altered microarchitecture. Therefore, preptin was proposed to be one of the energy regulatory hormones that positively impacts bone health. Experimental data demonstrate a beneficial impact of preptin upon the osteoblasts. Preptin also appears to regulate osteocalcin secretion, which in turn regulates insulin sensitivity. Preptin is greatly influenced by the glucose tolerance status and the level of physical exercise, both influencing the bone mass. Clinical studies describe low serum preptin concentrations in osteoporosis in both men and women, therefore opening the way towards considering preptin a potential bone anabolic therapy. The current review addresses the relationship between preptin and bone mass and metabolism in the experimental and clinical setting, also considering the effects of preptin on carbohydrate metabolism and the pancreatic-bone loop.

Maternal serum preptin levels in the pathogenesis and diagnosis of Gestational diabetes mellitus.

Background: Gestational diabetes mellitus (GDM) is a metabolic disorder that occurs during pregnancy that increases both maternal and fetal mortality and morbidity. It was investigated whether there is a change in circulating levels of preptin, a new peptide secreted from pancreatic beta cells, due to GDM in pregnant women. The relationship between serum preptin levels with insulin and other metabolic parameters was also evaluated in these subjects. Methods: Eighty-five patients diagnosed as GDM and 89 healthy pregnant women with 75 mg oral glucose tolerance test (OGTT) was assessed in terms of serum preptin levels. Results: The serum preptin levels of the GDM group were significantly higher than those of the control group (p=0.001; p < 0.01). For the cutoff value of preptin measurement of 335.3 ng/L, the sensitivity was 97.65%, specificity was 87.64%, positive predictive value was 88.3% and negative predictive value was 97.5%. The risk of developing the disease is 294.273 times higher in patients with preptin level of 335.3 and above. Conclusions: We think that the reason for the increase in serum preptin levels in GDM is probably the response to glucose. The current results indicate that preptin plays an important role in elucidating the pathology of GDM. In addition, the search for a practical marker for the diagnosis of GDM suggests that the measurement of preptin level is promising.

Circulating serum preptin levels in women with polycystic ovary syndrome: A systematic review and meta-analysis.

Background: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder with complex pathogenesis and metabolic complications, such as insulin resistance. Among the new markers, preptin seems to play a significant role in metabolic disorders. Objective: This meta-analysis was conducted to determine the relationship between circulating preptin levels and PCOS. Materials and Methods: A systematic review and meta-analysis was performed to identify relevant articles in electronic databases such as PubMed, Web of Science, Scopus, Cochrane, EMBASE, and the Google Scholar search engine, using a predefined search strategy. A random-effects model was used to combine standard mean difference (SMD) and 95% CI to compare results between groups. Meta-regression and subgroup analysis were also performed to reveal the sources of heterogeneity. Results: The meta-analysis encompassed a total of 8 studies and 582 participants. The results indicate a statistically significant association between PCOS and serum preptin levels, with a pooled standardized mean difference (SMD = 1.35; 95% CI]: 0.63-2.08; p < 0.001). Further analysis suggested a significant difference in serum preptin levels between women with PCOS and higher homeostatic model assessment for insulin resistance ratio (SMD = 2.40; 95% CI: 1.17-3.63; p < 0.001) within the subgroup. Conclusion: Our meta-analysis shows that increased serum preptin levels are associated with PCOS, suggesting that preptin may be related to the pathogenesis of PCOS and may be recognized as a novel diagnostic biomarker for PCOS. However, further studies are needed to confirm our results.

Evaluating the energy regulatory hormones of nesfatin-1, irisin, adropin and preptin in multiple sclerosis.

BACKGROUND: Nesfatin-1, irisin, adropin and preptin were originally introduced as energy regulatory hormones. However, the results of studies revealed that these hormones may also have important roles in inflammation, immune function and neurological impairment. Multiple sclerosis (MS) is a chronic autoimmune disease, characterized by progressive inflammation, demyelination, and axonal loss in the central nervous system. We aimed to evaluate nesfatin-1, irisin, adropin and preptin hormones in patients with MS accompanied by inflammation and central nervous system dysfunction. MATERIALS AND METHODS: A total of 110 subjects (65 patients with relapsing-remitting MS and 45 healthy individuals as control group) were included in this study. Venous blood samples were collected between 7:30 a.m. and 9:00 a.m. Serum concentrations of all markers were measured by enzyme linked immunoassay methods. The unpaired t-test was used to investigate between-group differences. RESULTS: The nesfatin-1, irisin, adropin and preptin levels were found to be significantly lower in the MS group compared to the control group (p < 0.05). CONCLUSION: In the present study, circulating nesfatin-1, irisin, adropin and preptin levels were decreased in patients with MS. However, the pathogenesis of MS and the underlying molecular mechanism of these hormones in MS have still not been elucidated. Further investigations with larger sample sizes and longer periods are required to obtain satisfactory information. In conclusion, the energy regulatory hormones of nesfatin-1, irisin, adropin and preptin may have potential for the development of new therapeutic targets for treatment of inflammatory diseases.

Review of Novel Potential Insulin Resistance Biomarkers in PCOS Patients-The Debate Is Still Open.

Research on proteins and peptides that play roles in metabolic regulation, which may be considered potential insulin resistance markers in some medical conditions, such as diabetes mellitus, obesity and polycystic ovarian syndrome (PCOS), has recently gained in interest. PCOS is a common endocrine disorder associated with hyperandrogenemia and failure of ovulation, which is often accompanied by metabolic abnormalities, including obesity, dyslipidemia, hyperinsulinemia, and insulin resistance. In this review, we focus on less commonly known peptides/proteins and investigate their role as potential biomarkers for insulin resistance in females affected by PCOS. We summarize studies comparing the serum fasting concentration of particular agents in PCOS individuals and healthy controls. Based on our analysis, we propose that, in the majority of studies, the levels of nesfastin-1, myonectin, omentin, neudesin were decreased in PCOS patients, while the levels of the other considered agents (e.g., preptin, gremlin-1, neuregulin-4, xenopsin-related peptide, xenin-25, and galectin-3) were increased. However, there also exist studies presenting contrary results; in particular, most data existing for lipocalin-2 are inconsistent. Therefore, further research is required to confirm those hypotheses, as well as to elucidate the involvement of these factors in PCOS-related metabolic complications.

New Peptides as Potential Players in the Crosstalk Between the Brain and Obesity, Metabolic and Cardiovascular Diseases.

According to the World Health Organization report published in 2016, 650 million people worldwide suffer from obesity, almost three times more than in 1975. Obesity is defined as excessive fat accumulation which may impair health with non-communicable diseases such as diabetes, cardiovascular diseases (hypertension, coronary artery disease, stroke), and some cancers. Despite medical advances, cardiovascular complications are still the leading causes of death arising from obesity. Excessive fat accumulation is caused by the imbalance between energy intake and expenditure. The pathogenesis of this process is complex and not fully understood, but current research is focused on the role of the complex crosstalk between the central nervous system (CNS), neuroendocrine and immune system including the autonomic nervous system, adipose tissue, digestive and cardiovascular systems. Additionally, special attention has been paid to newly discovered substances: neuropeptide 26RFa, preptin, and adropin. It was shown that the above peptides are synthesized both in numerous structures of the CNS and in many peripheral organs and tissues, such as the heart, adipose tissue, and the gastrointestinal tract. Recently, particular attention has been paid to the role of the presented peptides in the pathogenesis of obesity, metabolic and cardiovascular system diseases. This review summarizes the role of newly investigated peptides in the crosstalk between brain and peripheral organs in the pathogenesis of obesity, metabolic, and cardiovascular diseases.

Is Preptin a New Bone Metabolism Parameter in Hemodialysis Patients?

BACKGROUND: Preptin is a bone-anabolic pancreatic peptide hormone. Its role in bone metabolism has been studied in rats and in patients with diabetes, but its levels and significance in bone metabolism in hemodialyzed (HD) patients is unknown. METHODS: The relationships between preptin and anthropometric and biochemical parameters related to bone metabolism were studied in 73 patients on chronic hemodialysis (48 males, 25 females; mean age of 57 years; HD vintage of 69.7 months). Of these subjects, 36 patients had diabetes or impaired glucose tolerance (DM/IGT), and 37 patients had normal glucose tolerance (NGT). Dual-energy X-ray absorptiometry of the femoral neck and lumbar spine were also performed. RESULTS: No differences were observed in preptin levels between DM/IGT and NGT HD patients. Preptin was positively correlated with HD vintage (r = 0.312, p = 0.007). Negative correlations between preptin and bone mineral density (BMD), T-score, and Z-score in the lumbar spine (L2-L4) were observed (r = -0.319, p = 0.009; r = -0.341, p = 0.005; r = -0.375, p = 0.002). Preptin was positively correlated with parathormone (PTH) levels (r = 0.379, p < 0.001) and osteocalcin levels (r = 0.262, p = 0.027). CONCLUSIONS: The results indicate that preptin may reflect on bone and mineral metabolism disturbances seen in HD patients. The significant correlation of preptin with PTH and osteocalcin suggests that preptin may be important in indirect measurement of bone turnover in HD patients.

The effect of thyroid dysfunction and treatment on adropin, asprosin and preptin levels in rats.

OBJECTIVES: Thyroid hormones have important roles in normal development and energy regulating mechanisms as well as signaling mechanisms that affect energy consumption through central and peripheral pathways. The aim of this study was to determine the effects of thyroid dysfunction on adropin, asprosin and preptin levels in rat. METHODS: The study was performed on the 38 male Wistar-albino rats. Experiment groups were designed as follows. 1-Control, 2-Hypothyroidism; To induce hypothyroidism PTU was applied by intraperitoneal as 10 mg/kg/day for 2 weeks. 3-Hypothyroidism + Thyroxine; Previously animals were made with hypothyroidism by 1 week PTU application and then 1 week l-thyroxine was given by intraperitoneal as 1.5 mg/kg/day. 4-Hyperthyroidism; Rats were made with hyperthyroidism by 3 weeks l-thyroxine (0.3 mg/kg/day). 5-Hyperthyroidism + PTU; Animals were made hyperthyroisim by l-thyroxine as groups 4, then 1 week PTU was applied to treatment of hiperthyrodism. At the end of supplementation animals were sacrificed and blood samples were collected for FT3, FT4, adropin, asprosin, preptin analysis. RESULTS: FT3 ve FT4 levels were reduced significantly in hypothyroidism while increased in hyperthyroidism (p<0.001). Hipothyrodism led to reduces adropin, asprosin and preptin levels. And also hyperthyroidism reduced adropin and preptin levels (p<0.001). CONCLUSIONS: The results of study show that experimental hypothyroidism and hyperthyroidism lead to significantly change to adropin, asprosin and preptin levels. However, correction of thyroid function caused to normals levels in asprosin and preptin.

Swim therapy-induced tissue specific metabolic responses in male rats.

Swim therapy in the form of moderate physical activity has general health benefits. Regular exercise prevents the progression of chronic diseases affecting the different bodily systems. The metabolic alterations associated with following such lifestyle remain not fully understood. The aim of the present study was to elucidate the metabolic changes following prolonged swim therapy. Twenty-four Sprague Dawley rats were divided into sedentary and exercise groups. Our results revealed that regular exercise significantly increased the serum levels of growth hormone (GH), glucagon and corticosterone. A reduction in the circulating levels of irisin and insulin hormones, and glucose were noticed alongside with an upregulation in the mRNA expression levels of FNDC5, PGC-1α, GLUT-4 and preptin receptors with downregulation in the expression of Enho gene in the heart of exercised rats. Liver of the exercised rats showed elevation in the transcriptional levels of Enho gene, PPARα, and preptin with reduction in the transcriptional levels of preptin receptors. Exercise induced an increase in the pancreatic mRNA of Enho gene, preptin and preptin receptors, and a reduction in FNDC5, PPARα and PGC-1α. An elevation in the gastrocnemius muscle PGC-1α mRNA expression and a decline in the soleus muscle Enho mRNA were found. Exercise diminishes the activities of SOD, CAT and GPx in the gastrocnemius muscle, liver and pancreas. Myogenin expression increased in all examined skeletal muscles. This study takes into account the complex crosstalk between different signaling pathways in skeletal muscles, heart, liver and pancreas as well as the metabolic alterations in response to regular exercise.