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.

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.

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.

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.

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.

Serum Irisin, Adropin, and Preptin in Obese Patients 6 Months After Bariatric Surgery

BACKGROUND/OBJECTIVES

The reduction of body mass after bariatric surgery affects energy metabolism and may involve changes in irisin, preptin, and adropin production.

SUBJECTS AND METHODS

Fifty-five morbidly obese patients with a mean body mass index (BMI) of 45.7 ± 5.8 kg/m² were treated with either laparoscopic sleeve gastrectomy(n = 30) or laparoscopic adjustable gastric banding (n = 25). Forty-six (83.6%) were followed-up 6 months after surgery. The control group included 15 healthy non-obese participants. Anthropometric measurements, lipid profiles, HbA1c, and serum irisin, preptin, and adropin were assessed at baseline and on follow-up.

RESULTS

The serum concentrations of all three peptides were higher at 6 months than at baseline but only irisin (p = 0.02) and adropin (p = 0.000001) were significantly higher. The increase in preptin was borderline significant (p = 0.051). Changes of serum concentrations of all three peptides were bidirectional.

CONCLUSION

Body mass reduction resulting from bariatric procedures may change the production of energy regulating peptides, but not always in a favorable manner.

Assessment of Preptin peptide level in the sera of rachitic children and in breast milk of their mothers

BACKGROUND

Preptin is a 34-residue pancreatic hormone that stimulates osteoblast proliferation and reduces osteoblast apoptosis.

RESEARCH AIMS

To measure levels of serum Preptin in rachitic children and in breastmilk of their mothers and to compare with levels in healthy non-rachitic children.

METHODS

Thirty children with rickets and another 30 non-rachitic age and sex matched controls were subjected to detailed history, physical examination including anthropometric measurements, assessment of signs of rickets and laboratory measurement of serum vitamin D, calcium, phosphorus, alkaline phosphatase and Preptin. Mothers' breast milk Preptin were also measured.

RESULTS

Significantly lower serum Preptin (p < 0.001) in rachitic children with a significant negative correlation between serum Preptin and alkaline phosphatase (P < 0.0001). Lower breastmilk Preptin levels in mothers of rachitic children (P < 0.001) with a negative correlation between breastmilk Preptin and both maternal weight and BMI(P < 0.01&P < 0.02). Mothers' milk Preptin is positively correlated with serum Preptin and calcium in non-rachitic children(P < 0.001&0.04), but negatively correlated with their mothers' age (P < 0.01).

CONCLUSION

Preptin may play a role in the etiology of rickets in children. Further studies are recommended to evaluate Preptin role in treatment of rickets in children.

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&gt;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.

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 β 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 L_1-4 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.

Preptin is a new predictor of coronary artery calcification

BACKGROUND

We aimed to assess whether an elevated preptin level is associated with coronary artery calcification (CAC).

METHODS

Two hundred and twenty participants with suspected cardiovascular disease were recruited. CAC was measured using 320-row-detector dynamic volume CT, and the patients were divided into 2 groups: the non-CAC group (with an Agatston score = 0) and the CAC group (with an Agatston score > 0).

RESULTS

The serum preptin level was significantly elevated in the CAC group compared with the non-CAC group. In logistic regression analysis, preptin, as well as age, gender, hypertension history and history of β-blocker use, were independent predictors of a positive CAC score. The highest preptin quintile of patients had a higher CAC level compared with other quintiles. Binary logistic regression analyses showed that the highest preptin quintile had a 2.9-time increased odds ratio of an elevated CAC level than the other 4 quintile patients.

CONCLUSIONS

This study demonstrated that serum preptin was associated with coronary artery calcification.

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.

Three new players in energy regulation: preptin, adropin and irisin

Homeostasis of energy is regulated by genetic factors, food intake, and energy expenditure. When energy input is greater than expenditure, the balance is positive, which can lead to weight gain and obesity. When the balance is negative, weight is lost. Regulation of this homeostasis is multi-factorial, involving many orexigenic (appetite-stimulating) and anorexigenic (appetite-suppressing) peptide hormones. Peripheral tissues are now known to be involved in weight regulation and research on its endocrine characteristics proceeds apace. Preptin with 34 amino acids (MW 3948 Da), adropin with 43 amino acids and a molecular weight of (4999 Da), and irisin with 112 amino acids (12587 Da), are three newly discovered peptides critical for regulating energy metabolism. Preptin is synthesized primarily in pancreatic beta cells, and adropin mainly in the liver and brain, and many peripheral tissues. Irisin, however, is synthesized principally in the heart muscle, along with peripheral tissues, including salivary glands, kidney and liver. The prime functions of preptin and adropin include regulating carbohydrate, lipid and protein metabolisms by moderating glucose-mediated insulin release. Irisin is an anti-obesitic and anti-diabetic hormone regulating adipose tissue metabolism and glucose homeostasis by converting white to brown adipose tissue. This review offers a historical account of these discovery and function of these peptides, including their structure, and physiological and biochemical properties. Their roles in energy regulation will be discussed. Their measurement in biological fluids will be considered, which will lead to further discussion of their possible clinical value.

Concentrations of preptin, salusins and hepcidins in plasma and milk of lactating women with or without gestational diabetes mellitus

This study was undertaken to ascertain whether human milk contains preptin, salusin-alpha (salusin-α) and -beta (salusin-β) and pro-hepcidin and hepcidin-25, and whether there are relationships between plasma and milk preptin, salusin-α and -β and pro-hepcidin and hepcidin-25 concentrations in lactating mothers with and without gestational diabetes mellitus (GDM). Blood was obtained from non-lactating women (n = 12), non-diabetic lactating women (n = 12), and GDM lactating women (n = 12). Colostrum, transitional milk, and mature milk samples were collected just before suckling from healthy and GDM lactating women. Peptides concentrations were determined by ELISA and EIA. Mammary gland tissues were screened immunohistochemically for these peptides. Women with GDM had significantly higher plasma and colostum preptin concentrations than healthy lactating women during the colostral and transitional milk period. Salusin-alpha and -beta levels in milk and plasma were lower in women with GDM. Salusin-α and -β were significantly lower in both plasma and colostrums of GDM than of healthy lactating women. Women with GDM had significantly higher colostum prohepcidin and hepcidin-25 concentrations than healthy lactating women during the colostral period. Plasma prohepcidin was also higher in women with GDM than in healthy lactating women during the colostral period, but plasma prohepcidin and hepcidin-25 levels decreased during mature milk period. Transitional milk pro-hepcidin and hepcidin-25 levels in women with GDM were higher than in healthy lactating women. All these results revealed that the mammary gland produces those peptides, which were present in milk at levels correlating with plasma concentrations.