The release of the adipocytokine visfatin is regulated by glucose and insulin

Diurnal rythm of Nampt is gender and weight dependent

RESEARCH AIM

Nicotinamide phosphoribosyltransferase (Nampt) is an adipocytokine that is elevated in obesity, type 2 diabetes and increased levels are associated with inflammatory processes. Nampt serum concentrations have been suggested to follow a diurnal rhythm peaking in the afternoon in lean males. However, no data exists regarding the effects of gender and body weight.

MATERIAL AND METHODS

We measured Nampt serum levels over 24 h in a cohort of healthy individuals living with either normal weight or obesity. Furthermore, effects of meals, oral glucose tolerance test and physical exercise on Nampt concentrations were evaluated. Correlation analyses to other hormonal- and lab parameters and anthropometric measurements were performed.

RESULTS

Nampt showed a diurnal rhythm with increased levels at daytime and a peak in the early afternoon. This diurnal rhythm was significant for all groups but obese males. The Nampt amplitude, measured both relatively and absolutely, was significantly higher in females than in males. Meals did not influence Nampt serum levels, whereas physical exercise and an OGTT did significantly influence Nampt serum levels.

CONCLUSION

In conclusion, we found gender specific differences in Nampt amplitude and coefficient variation with both being higher in females. The circadian rhythm of Nampt was independent of gender in healthy lean individuals, whereas it was disturbed in men with obesity.

Role of the intracerebroventricular injection of the visfatin and its interaction with neuropeptide Y and nitric systems on food intake in neonatal chicken

Visfatin play an essential role in the central regulation of appetite in birds. This study aimed to determine role of intracerebroventricular (ICV) injection of the visfatin on food intake and its possible interaction with neuropeptide Y (NPY) and nitric oxide system in neonatal broiler chicken. In experiment 1, neonatal chicken received ICV injection visfatin (1, 2 and 4 µg). In experiment 2, chicken received ICV injection of B5063 (NPY1 receptor antagonist 1.25 µg), visfatin (4 µg) and co-injection of the B5063 + Visfatin. In experiments 3-6, SF22 (NPY2 receptor antagonist 1.25 µg), SML0891 (NPY5 receptor antagonist 1.25 µg), L-NAME (nitric oxide synthase inhibitor, 100 nmol) and L-arginine (Precursor of nitric oxide, 200 nmol) were injected instead of B5063. Then the amount of cumulative food was measured at 30, 60 and 120 min after injection. Obtained data showed, injection visfatin (2 and 4 µg) increased food intake compared to control group (P < 0.05). Co-injection of the B5063 + Visfatin decreased visfatin-induced hyperphagia compared to control group (P < 0.05). Co-injection of the L-NAME + Visfatin amplified visfatin-induced hyperphagia compared to control group (P < 0.05). The result showed that visfatin has hyperphagic role and this effect mediates via NPY1 and nitric oxide system in neonatal chicken.

Bone marrow stem cell-derived β-cells: New issue for diabetes cell therapy

This investigation aimed to establish the promising role of insulin-producing cells (IPCs) growing from bone marrow-mesenchymal stem cells (BM-MSCs) in relieving hyperglycemia induced in rats. BM-MSCs were differentiated into IPCs using three different protocols. The efficiency of BM-MSCs differentiation into IPCs in vitro was confirmed by detecting IPCs specific gene expression (Foxa-2, PDX-1 and Ngn-3) and insulin release assay. The in vivo study design included 3 groups of male Wistar rats; negative control group, diabetic group and IPCs-transfused group (5 ×106 cells of the most functional IPCs/rat). One month after IPCs infusion, serum glucose, insulin, c-peptide and visfatin levels as well as pancreatic glucagon level were quantified. Gene expression analysis of pancreatic Foxa-2 and Sox-17, IGF-1 and FGF-10 was done. Additionally, histological investigation of pancreatic tissue sections was performed. Our data clarified that, the most functional IPCs are those generated from BM-MSCs using differentiation protocol 3 as indicated by the significant up-regulation of Foxa-2, PDX-1 and Ngn-3 gene expression levels. These findings were further emphasized by releasing of a significant amount of insulin in response to glucose load. The transplantation of the IPCs in diabetic rats elicited significant decline in serum glucose, visfatin and pancreatic glucagon levels along with significant rise in serum insulin and c-peptide levels. Moreover, it triggered significant up-regulation in the expression levels of pancreatic Foxa-2, Sox-17, IGF-1 and FGF-10 genes versus the untreated diabetic counterpart. The histopathological examination of pancreatic tissue almost assisted the biochemical and molecular genetic analyses. These results disclose that the cell therapy holds potential to develop a new cure for DM based on the capability of BM-MSCs to generate β-cell phenotype using specific protocol.

The cytokine trio - visfatin, placental growth factor and fractalkine - and their role in myocardial infarction with non-obstructive coronary arteries (MINOCA)

Myocardial infarction with nonobstructive coronary arteries (MINOCA) remains a puzzling clinical entity. It is characterized by clinical evidence of myocardial infarction (MI) with normal or near-normal coronary arteries in angiography. Given the complex etiology including multiple possible scenarios with varied pathogenetic mechanisms, profound investigation of the plausible biomarkers of MINOCA may bring further pathophysiological insights and novel diagnostic opportunities. Cytokines have a great diagnostic potential and are used as biomarkers for many diseases. An unusual trio of visfatin, placental growth factor (PlGF) and fractalkine (CX3CL1) can directly promote vascular dysfunction, inflammation and angiogenesis through the activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling. They are redundant in physiological processes and become overexpressed in the pathomechanisms underlying MINOCA. The knowledge about their concentration might serve as a valuable diagnostic and/or therapeutic tool for assessing vascular endothelial function. Here we analyze the current knowledge on visfatin, PlGF and CX3CL1 in the context of MINOCA and present the novel clinical implications of their combined expression as predictors or indicators of this condition.

Visfatin in the porcine pituitary gland: expression and regulation of secretion during the oestrous cycle and early pregnancy

Visfatin is a multifunctional protein which, besides the control of energy homeostasis, seems to be also involved in the regulation of female fertility through the influence on the endocrine hypothalamus-pituitary-gonadal axis, including the pituitary. The aim of this study was to investigate the expression of visfatin mRNA and protein in the anterior (AP) and posterior pituitary lobes of the pig during the oestrous cycle and early pregnancy. In AP, we also examined colocalisation of visfatin with pituitary tropic hormones. Moreover, we aimed to evaluate the in vitro effects of GnRH, FSH, LH, and insulin on visfatin protein concentration and secretion in AP cells during the cycle. The study showed that visfatin is present in all types of porcine pituitary endocrine cells and its expression is reliant on stage of the cycle or pregnancy. GnRH, FSH, LH and insulin stimulated visfatin secretion by AP cells on days 17 to 19 of the cycle, while on days 2 to 3 visfatin release was enhanced only by LH. Summarising, visfatin is locally produced in the pituitary in a way dependent on hormonal milieu typical for reproductive status of pigs. Further research is required to clarify the role of visfatin in the pituitary gland.

Adipokines as Clinically Relevant Therapeutic Targets in Obesity

Adipokines provide an outstanding role in the comprehensive etiology of obesity and may link adipose tissue dysfunction to further metabolic and cardiovascular complications. Although several adipokines have been identified in terms of their physiological roles, many regulatory circuits remain unclear and translation from experimental studies to clinical applications has yet to occur. Nevertheless, due to their complex metabolic properties, adipokines offer immense potential for their use both as obesity-associated biomarkers and as relevant treatment strategies for overweight, obesity and metabolic comorbidities. To provide an overview of the current clinical use of adipokines, this review summarizes clinical studies investigating the potential of various adipokines with respect to diagnostic and therapeutic treatment strategies for obesity and linked metabolic disorders. Furthermore, an overview of adipokines, for which a potential for clinical use has been demonstrated in experimental studies to date, will be presented. In particular, promising data revealed that fibroblast growth factor (FGF)-19, FGF-21 and leptin offer great potential for future clinical application in the treatment of obesity and related comorbidities. Based on data from animal studies or other clinical applications in addition to obesity, adipokines including adiponectin, vaspin, resistin, chemerin, visfatin, bone morphogenetic protein 7 (BMP-7) and tumor necrosis factor alpha (TNF-α) provide potential for human clinical application.

Hormonal regulation of visfatin and adiponectin system in quail muscle cells

Visfatin and adiponectin are two adipokines known to regulate energy homeostasis and stress response within different peripheral tissues. Their role and regulation in highly metabolically active tissue such as the muscle is of particular interest. As modern poultry exhibit insulin resistance, obesity, and hyperglycemia along with a lack of insight into the regulation of these avian adipokines, we undertook the present work to determine the regulation of visfatin and adiponectin system by cytokines and obesity-related hormones in a relevant in vitro model of avian muscle, quail muscle (QM7) cells. Cells were treated with pro-inflammatory cytokine IL-6 (5 and 10 ng/mL) and TNFα (5 and 10 ng/mL), as well as leptin (10 and 100 ng/mL) and both orexin-A and orexin-B (ORX-A/B) (5 and 10 ng/mL). Results showed significant increases in visfatin mRNA abundance under both cytokines (IL-6 and TNFα), and down regulation with ORX-B treatment. Adiponectin expression was also upregulated by pro-inflammatory cytokines (IL-6 and TNFα), but down regulated by leptin, ORX-A, and ORXB. High doses of IL-6 and TNFα up regulated the expression of adiponectin receptors AdipoR1 and AdipoR2, respectively. Leptin and orexin treatments also down regulated both AdipoR1 and AdipoR2 expression. Taken together, this is the first report showing a direct response of visfatin and the adiponectin system to pro-inflammatory and obesity-related hormones in avian muscle cells.

Expression and regulation of visfatin/NAMPT in the porcine corpus luteum during the estrous cycle and early pregnancy

Visfatin/NAMPT creates a hormonal link between energy metabolism and female reproduction. A recent study documented visfatin expression in the ovary and its action on follicular cells; however, the expression of visfatin in luteal cells is still unknown. The aim of this study, therefore, was to investigate the transcript and protein expression of visfatin as well as its immunolocalization in the corpus luteum (CL) and to examine the involvement of extracellular signal-regulated kinases (ERK1/2) in the regulation of visfatin level in response to LH, insulin, progesterone (P₄), prostaglandin E₂ (PGE₂) and F_2α (PGF_2α). Corpora lutea were harvested from gilts on days 2-3, 10-12 and 14-16 of the estrous cycle and on days 10-11, 12-13, 15-16 and 27-28 of pregnancy. The current study demonstrated that visfatin expression depends on hormonal status related to the phase of the estrous cycle or early pregnancy. Visfatin was immunolocalized to the cytoplasm of small and large luteal cells. Moreover, visfatin protein abundance was increased by P₄, and decreased by both prostaglandins, while LH and insulin have modulatory effects, depending on the phase of the cycle. Interestingly, LH, P₄ and PGE₂ effects were abolished in response to the inhibition of ERK1/2 kinase. Thus, this study demonstrated that expression of visfatin in the porcine CL is determined by the endocrine status related to the estrous cycle and early pregnancy and by the action of LH, insulin, P₄ and prostaglandins via activation of the ERK1/2 pathway.

Type 2 Diabetes Mellitus Coincident with Clinical and Subclinical Thyroid Dysfunctions Results in Dysregulation of Circulating Chemerin, Resistin and Visfatin

The alterations of circulating adipocytokines have been reported in thyroid diseases or type 2 diabetes mellitus (T2DM), but such data in T2DM coincident with clinical and subclinical thyroid-dysfunctions are limited, and remain to be investigated. We studied the changes in serum chemerin, resisitin and visfatin in T2DM patients with thyroid dysfunctions, and their association with inflammatory and insulin resistance-markers. A total of 272 female and male Iranian participants were selected and divided into six groups: the euthyroid group, T2DM, T2DM coincident with clinical and sub clinical hypothyroidism (SC-HO, and C-HO), and T2DM coincident with clinical and sub clinical hyperthyroidism (SC-HR, C-HR).Demographic characteristics, serum levels of adipocytokines, thyroid hormones, inflammatory factors (IL1-β, IL-6 and CRP) and insulin resistance-markers were determined in all participants. T2DM patients with clinical thyroid dysfunctions showed higher levels of circulating resistin, visfatin, chemerin and inflammatory factors, compared with the T2DM group and T2DM coexisted with subclinical thyroid diseases. No significant differences were observed in circulating adipocytokines and inflammatory markers between T2DM coexisting with subclinical thyroid diseases and those without thyroid dysfunctions. Our results revealed that clinical thyroid dysfunction in T2DM patients was associated with elevated levels of circulating resistin, chemerin, visfatin and inflammatory factors, while no such alteration was detected in T2DM coincident with subclinical thyroid dysfunction.

Correlation of salivary visfatin levels in obese and NON-OBESE population with periodontal status

Background

Visfatin is an inflammatory adipokine that has been linked to obesity and plays a key function in immune response modulation. It's also been proposed that it's a pro-inflammatory marker for periodontitis. Hence, the aim of the present study was to assess the salivary Visfatin levels in obese and non-obese population and correlate with the periodontal status.

Materials and methods

A total of 40 individuals aged between 21 and 35 years (Group 1: n = 20, non-obese and Group 2: n = 20, obese) were enrolled in this case-control study. Clinical parameters such as periodontal probing depth (PPD) and clinical attachment level (CAL) were recorded. Body Mass Index (BMI) was recorded. Unstimulated salivary samples were collected and the samples were assayed for Visfatin using human Visfatin ELISA kit. The results were analysed using SPSS Software, Version 23.0. Unpaired t-test and Mann-Whitney U test was used to compare the clinical parameters and salivary Visfatin level between both the groups. Also, Spearman's rank correlation test was done for correlation of BMI with salivary Visfatin levels and clinical parameters.

Results

The salivary Visfatin level was higher in group 2 (33.1070 ± 0.81 ng/mL) as compared to group 1 (22.2310 ± 1.33 ng/mL). Moderate positive statistically significant association was found between BMI and Visfatin (r = 0.738, p = 0.000). Also when Visfatin and PPD and CAL were correlated, moderate positive statistically significant association was found (r = 0.625, p = 0.000 and r = 0.630, p = 0.000).

Conclusion

The present study suggests that there exists a positive correlation between BMI and salivary Visfatin and BMI and periodontal parameters including probing depth and clinical attachment level. This illustrates that salivary Visfatin may be a potential marker for periodontal inflammation in obese population.

Role of visfatin in obesity-induced insulin resistance

The growing worldwide burden of insulin resistance (IR) emphasizes the importance of early identification for improved management. Obesity, particularly visceral obesity, has been a key contributing factor in the development of IR. The obesity-associated chronic inflammatory state contributes to the development of obesity-related comorbidities, including IR. Adipocytokines, which are released by adipose tissue, have been investigated as possible indicators of IR. Visfatin was one of the adipocytokines that attracted attention due to its insulin-mimetic activity. It is released from a variety of sources, including visceral fat and macrophages, and it influences glucose metabolism and increases inflammation. The relationship between visfatin and IR in obesity is debatable. As a result, the purpose of this review was to better understand the role of visfatin in glucose homeostasis and to review the literature on the association between visfatin levels and IR, cardiovascular diseases, and renal diseases in obesity.

Visfatin is negatively associated with coronary artery lesions in subjects with impaired fasting glucose

It is not determined whether serum visfatin levels are related to the presence and severity of coronary artery disease (CAD) in non-diabetic subjects. In this study, a total of 65 consecutive non-diabetic participants who underwent coronary angiography were enrolled. Serum visfatin and fasting glucose, as well as the serum total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride, were measured in all participants before the procedure. The extent of coronary artery lesions was determined by Gensini score. Serum visfatin levels were significantly lower in patients with CAD compared to participants with normal coronary arteries. Inversely, the circulating levels of fasting glucose were found to be elevated in patients with CAD compared with the control subjects. Multivariable logistic regression analysis demonstrated that visfatin and impaired fasting glucose (IFG) were independently associated with the presence of CAD in non-diabetics. No significant relationship was found between serum visfatin and fasting glucose levels in IFG subjects. However, there was a negative association between visfatin concentrations and Gensini score in participants with IFG. Both circulating visfatin concentrations and IFG are independently associated with CAD in non-diabetics. Serum visfatin levels are negatively related to the angiographic severity of CAD in subjects with IFG.

Adipose Tissue Secretion Pattern Influences β-Cell Wellness in the Transition from Obesity to Type 2 Diabetes

The dysregulation of the β-cell functional mass, which is a reduction in the number of β-cells and their ability to secure adequate insulin secretion, represents a key mechanistic factor leading to the onset of type 2 diabetes (T2D). Obesity is recognised as a leading cause of β-cell loss and dysfunction and a risk factor for T2D. The natural history of β-cell failure in obesity-induced T2D can be divided into three steps: (1) β-cell compensatory hyperplasia and insulin hypersecretion, (2) insulin secretory dysfunction, and (3) loss of β-cell mass. Adipose tissue (AT) secretes many hormones/cytokines (adipokines) and fatty acids that can directly influence β-cell function and viability. As this secretory pattern is altered in obese and diabetic patients, it is expected that the cross-talk between AT and pancreatic β-cells could drive the maintenance of the β-cell integrity under physiological conditions and contribute to the reduction in the β-cell functional mass in a dysmetabolic state. In the current review, we summarise the evidence of the ability of the AT secretome to influence each step of β-cell failure, and attempt to draw a timeline of the alterations in the adipokine secretion pattern in the transition from obesity to T2D that reflects the progressive deterioration of the β-cell functional mass.

The Correlation of Prediabetes and Type 2 Diabetes With Adiposity in Adults

Background

Fat metabolism is associated with prediabetes and type 2 diabetes mellitus (T2DM). The aim of this study was to evaluate the detailed correlation of diabetes status with adiposity among adults.

Methods

Briefly, 28,429 adults aged ≥18 years from both sexes in the National Health and Nutrition Examination Survey (NHANES) 1999–2018 were included in this study. Multivariable linear regression models were used to examine associations of prediabetes and diabetes status, disease duration of T2DM, serum glucose, glycohemoglobin (HbA1c) with total percent fat (TPF), and fat mass distribution.

Results

After adjusting for sociodemographic covariates, health behaviors, hypertension, hypercholesterolemia, there were direct associations of prediabetes and T2DM status with TPF, trunk fat mass, android fat mass, gynoid fat mass and android to gynoid ratio compared with non-diabetes. But the fat mass decreased with the increase of the disease duration in patients with T2DM. Besides, when stratifying by diabetes status, we found direct associations of serum glucose and HbA1c with TPF, trunk fat mass, android fat mass, gynoid fat mass, and android to gynoid ratio in non-diabetic and prediabetic participants. But in patients with T2DM, inverse associations of serum glucose and HbA1c with fat mass were observed.

Conclusions

This study indicated that adults with prediabetes and T2DM had significantly higher TPF, trunk fat mass, android fat mass, gynoid fat mass, and android to gynoid ratio compared with those without diabetes. Moreover, fat mass decreased as the disease duration increased in patients with T2DM. The associations of serum glucose and HbA1c with TPF and fat mass distribution in patients with T2DM were opposite to the relationships observed in non-diabetic and prediabetic participants.

Obesity: A Chronic Low-Grade Inflammation and Its Markers

As the prevalence of obesity continues to rise, the world is facing a major public health concern. Obesity is a complex disease associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation. Of multifactorial etiology, it is often used as a measurement of morbidity and mortality. There remains much unknown regarding the association between obesity and inflammation. This review seeks to compile scientific literature on obesity and its associated inflammatory markers in chronic disease and further discusses the role of adipose tissue, macrophages, B-cells, T-cells, fatty acids, amino acids, adipokines, and hormones in obesity. Data were obtained using PubMed and Google Scholar. Obesity, inflammation, immune cells, hormones, fatty acids, and others were search words used to acquire relevant articles. Studies suggest brown adipose tissue is negatively associated with body mass index (BMI) and body fat percentage. Researchers also found the adipose tissue of lean individuals predominantly secretes anti-inflammatory markers, while in obese individuals more pro-inflammatory markers are secreted. Many studies found that adipose tissue in obese individuals showed a shift in immune cells from anti-inflammatory M2 macrophages to pro-inflammatory M1 macrophages, which was also correlated with insulin resistance. Obese individuals generally present with higher levels of hormones such as leptin, visfatin, and resistin. With obesity on the rise globally, it is predicted that severe obesity will become most common amongst low-income adults, black individuals, and women by 2030, making the need for intervention urgent. Further investigation into the association between obesity and inflammation is required to understand the mechanism behind this disease.

Measuring visfatin levels in saliva: an alternative approach to gestational diabetes screening

Objective

Oral glucose tolerance testing (OGTT) is the current recommended approach for the diagnosis of gestational diabetes mellitus (GDM). Visfatin is a type of novel adipokine of interest that mostly participates in glucose metabolism and inflammatory processes. We aim to identify a screening technique for GDM using salivary visfatin levels and to establish this technique's value as a screening method compared to OGTT.

Methods

This is a cross-sectional case-control study. The cohort was formed from the saliva samples of pregnant patients in their 24^th through 28^th weeks of gestation. Patients were divided into two groups depending on their GDM status. OGTT and visfatin test results were compared and subjected to further analysis to establish a cutoff value for visfatin testing.

Results

ELISA results indicated a significant difference between patients with GDM compared to patients without GDM; the values were 18.89 ± 9.59 and 12.44 ± 8.75, respectively (p: 0.007). A cutoff value of 10.5 ng/mL can be used to detect GDM with 78% sensitivity and 51% specificity.

Conclusion

Salivary visfatin levels were significantly higher in patients with GDM. The existence of a differential in the concentration of visfatin in saliva can be utilized to develop a new screening method for GDM.

Understanding the Pancreatic Islet Microenvironment in Cystic Fibrosis and the Extrinsic Pathways Leading to Cystic Fibrosis Related Diabetes

Cystic fibrosis (CF) is an autosomal recessive chronic condition effecting approximately 70 000 to 100 000 people globally and is caused by a loss-of-function mutation in the CF transmembrane conductance regulator. Through improvements in clinical care, life expectancy in CF has increased considerably associated with rising incidence of secondary complications including CF-related diabetes (CFRD). CFRD is believed to result from β-cell loss as well as insufficient insulin secretion due to β-cell dysfunction, but the underlying pathophysiology is not yet fully understood. Here we review the morphological and cellular changes in addition to the architectural remodelling of the pancreatic exocrine and endocrine compartments in CF and CFRD pancreas. We consider also potential underlying proinflammatory signalling pathways impacting on endocrine and specifically β-cell function, concluding that further research focused on these mechanisms may uncover novel therapeutic targets enabling restoration of normal insulin secretion.

Visfatin level and gestational diabetes mellitus: a systematic review and meta-analysis

It is reported that elevated visfatin level is associated with gestational diabetes mellitus (GDM). However, the relationship between visfatin level and GDM remains controversial. The aim of our study was to systematically review available literature linking visfatin to GDM for a comprehensive understanding of the relationship between circulating visfatin level and GDM in human. PubMed, The Cochrane Library and Web of Science were searched for studies published up to July 2020. Standard mean difference with 95% confidence interval was calculated to evaluate the relationship between visfatin level and GDM using the Review Manager 5.3 and Stata 12.0. The evidence indicated that no significant difference was observed in the level of circulating visfatin between the women with GDM and normal glucose tolerance, suggesting circulating visfatin level is not independently related to GDM. Nevertheless, visfatin is involved in the development of GDM in obese women.

Contributions of white and brown adipose tissues to the circadian regulation of energy metabolism

The term energy metabolism comprises the entirety of chemical processes associated with uptake, conversion, storage, and breakdown of nutrients. All these must be tightly regulated in time and space to ensure metabolic homeostasis in an environment characterized by cycles such as the succession of day and night. Most organisms evolved endogenous circadian clocks to achieve this goal. In mammals, a ubiquitous network of cellular clocks is coordinated by a pacemaker residing in the hypothalamic suprachiasmatic nucleus. Adipocytes harbor their own circadian clocks, and large aspects of adipose physiology are regulated in a circadian manner through transcriptional regulation of clock-controlled genes. White adipose tissue (WAT) stores energy in the form of triglycerides at times of high energy levels that then serve as fuel in times of need. It also functions as an endocrine organ, releasing factors in a circadian manner to regulate food intake and energy turnover in other tissues. Brown adipose tissue (BAT) produces heat through nonshivering thermogenesis, a process also controlled by the circadian clock. We here review how WAT and BAT contribute to the circadian regulation of energy metabolism. We describe how adipose rhythms are regulated by the interplay of systemic signals and local clocks and summarize how adipose-originating circadian factors feed-back on metabolic homeostasis. The role of adipose tissue in the circadian control of metabolism becomes increasingly clear as circadian disruption leads to alterations in adipose tissue regulation, promoting obesity and its sequelae. Stabilizing adipose tissue rhythms, in turn, may help to combat disrupted energy homeostasis and obesity.

Non-canonical roles of NAMPT and PARP in inflammation

Nicotinamide adenine dinucleotide (NAD⁺) is the most important hydrogen carrier in cell redox reactions. It is involved in mitochondrial function and metabolism, circadian rhythm, the immune response and inflammation, DNA repair, cell division, protein-protein signaling, chromatin remodeling and epigenetics. Recently, NAD⁺ has been recognized as the molecule of life, since, by increasing NAD⁺ levels in old or sick animals, it is possible to improve their health and lengthen their lifespan. In this review, we summarize the contribution of NAD⁺ metabolism to inflammation, with special emphasis in the major NAD⁺ biosynthetic enzyme, nicotinamide phosphoribosyl transferase (NAMPT), and the NAD⁺-consuming enzyme, poly(ADP-ribose) polymerase (PARP). The extracurricular roles of these enzymes, i.e. the proinflammatory role of NAMPT after its release, and the ability of PARP to promote a novel form of cell death, known as parthanatos, upon hyperactivation are revised and discussed in the context of several chronic inflammatory diseases.

Adipose Tissue Immunomodulation: A Novel Therapeutic Approach in Cardiovascular and Metabolic Diseases

Adipose tissue is a critical regulator of systemic metabolism and bodily homeostasis as it secretes a myriad of adipokines, including inflammatory and anti-inflammatory cytokines. As the main storage pool of lipids, subcutaneous and visceral adipose tissues undergo marked hypertrophy and hyperplasia in response to nutritional excess leading to hypoxia, adipokine dysregulation, and subsequent low-grade inflammation that is characterized by increased infiltration and activation of innate and adaptive immune cells. The specific localization, physiology, susceptibility to inflammation and the heterogeneity of the inflammatory cell population of each adipose depot are unique and thus dictate the possible complications of adipose tissue chronic inflammation. Several lines of evidence link visceral and particularly perivascular, pericardial, and perirenal adipose tissue inflammation to the development of metabolic syndrome, insulin resistance, type 2 diabetes and cardiovascular diseases. In addition to the implication of the immune system in the regulation of adipose tissue function, adipose tissue immune components are pivotal in detrimental or otherwise favorable adipose tissue remodeling and thermogenesis. Adipose tissue resident and infiltrating immune cells undergo metabolic and morphological adaptation based on the systemic energy status and thus a better comprehension of the metabolic regulation of immune cells in adipose tissues is pivotal to address complications of chronic adipose tissue inflammation. In this review, we discuss the role of adipose innate and adaptive immune cells across various physiological and pathophysiological states that pertain to the development or progression of cardiovascular diseases associated with metabolic disorders. Understanding such mechanisms allows for the exploitation of the adipose tissue-immune system crosstalk, exploring how the adipose immune system might be targeted as a strategy to treat cardiovascular derangements associated with metabolic dysfunctions.

Nasser S, Younis N, Bhagani H, Al-Dhaheri Y, Pintus G, Eid AA, El-Yazbi AF, Eid AH. Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.

Can adipokine visfatin be a novel marker of pregnancy-related disorders in women with obesity?

Overweight and obesity have become a dangerous disease requiring multiple interventions, treatment and preventions. In women of reproductive age, obesity is one of the most common medical conditions. Among others, obese state is characterized by low-grade systemic inflammation and enhanced oxidative stress. Increased maternal body mass index might amplify inflammation and reactive oxygen species production, which is associated with unfavourable clinical outcomes that affect both mother and child. Intrauterine growth retardation, preeclampsia, or gestational diabetes mellitus are examples of the hampered maternal and foetoplacental unit interactions. Visfatin is the obesity-related adipokine produced mainly by the visceral adipose tissue. Visfatin affects glucose homeostasis, as well as the regulation of genes related to oxidative stress and inflammatory response. Here, we review visfatin interactions in pregnancy-related disorders linked to obesity. We highlight the possible predictive and prognostic value of visfatin in diagnostic strategies on gravidas with obesity.

Nicotinamide Mononucleotide: A Promising Molecule for Therapy of Diverse Diseases by Targeting NAD+ Metabolism

NAD+, a co-enzyme involved in a great deal of biochemical reactions, has been found to be a network node of diverse biological processes. In mammalian cells, NAD+ is synthetized, predominantly through NMN, to replenish the consumption by NADase participating in physiologic processes including DNA repair, metabolism, and cell death. Correspondingly, aberrant NAD+ metabolism is observed in many diseases. In this review, we discuss how the homeostasis of NAD+ is maintained in healthy condition and provide several age-related pathological examples related with NAD+ unbalance. The sirtuins family, whose functions are NAD-dependent, is also reviewed. Administration of NMN surprisingly demonstrated amelioration of the pathological conditions in some age-related disease mouse models. Further clinical trials have been launched to investigate the safety and benefits of NMN. The NAD+ production and consumption pathways including NMN are essential for more precise understanding and therapy of age-related pathological processes such as diabetes, ischemia–reperfusion injury, heart failure, Alzheimer’s disease, and retinal degeneration.

Circulating Adipokine Levels in Nonobese Women With Polycystic Ovary Syndrome and in Nonobese Control Women: A Systematic Review and Meta-Analysis

Levels of circulating adipokines in nonobese polycystic ovary syndrome (PCOS) patients have been reported in many studies. However, the results are inconsistent. The aim of this meta-analysis is to assess whether the levels of circulating adipokines are changed in nonobese PCOS relative to nonobese healthy controls. To identify eligible studies, a literature research was performed in the PubMed, Embase, and Web of Science databases without restricting by region, journal, or language. A total of 81 studies met the eligibility criteria. The meta-analysis showed that the circulating level of adiponectin (standardized mean difference [SMD]: -0.95; 95% CI: -1.36 to -0.53) was significantly decreased in nonobese PCOS patients. In contrast, the circulating levels of chemerin (SMD: 1.13; 95% CI: 0.08 to 2.18), leptin (SMD: 0.47; 95% CI: 0.13 to 0.81), resistin (SMD: 0.45; 95% CI: 0.03 to 0.88), and visfatin (SMD: 1.38; 95% CI: 0.68 to 2.09) were significantly increased in nonobese PCOS patients. There were no significant changes in the circulating levels of apelin (SMD: 0.32; 95% CI: -1.34 to 1.99), irisin (SMD: 1.01; 95% CI: -0.68 to 2.70), omentin (SMD: -0.37; 95% CI: -1.05 to 0.31), or vaspin (SMD: 0.09; 95% CI: -0.14 to 0.32). Thus, scientific evidence suggests that the circulating adipokine levels are altered in nonobese PCOS patients compared to nonobese healthy controls. Therefore, independent of the degree of obesity, dysregulated circulating adipokine levels might play important roles in the occurrence and development of PCOS.

The Relationship Between Serum Visfatin Levels and Metabolic Parameters According To Different Body Mass Indexes

Aim: The aim of this study was to investigate the relationship between body mass index and serum visfatin and metabolic parameters in subjects with different body mass indexes. Methods: Patients enrolled in this study were applied a questionnaire including their personal information, dietary habits and status of physical activities. Their length and body weight were measured, body mass indexes were calculated, and body fat percentage and waist circumference were measured. In addition, routine biochemical parameters (total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, fasting blood glucose, fasting insulin) and serum visfatin levels of patients were measured, and they were evaluated according to their body mass indexes. Results: Serum visfatin levels of patients were not found to be correlated with their age, gender and waist circumference, but a moderate negative correlation was determined with body fat percentage. Also there was a negative correlation between body mass indexes and serum visfatin level. While there was no statistically significant relation between serum visfatin level and cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol as well as VLDL-cholesterol, a negative correlation was found between serum visfatin and fasting glucose and fasting insulin levels. Conclusion: Serum visfatin levels resulted lower in patients with high body mass indexes. Negative correlation between serum visfatin levels and fasting blood glucose as well as fasting blood insulin indicates that serum visfatin levels may be associated with the mechanism of insulin resistance in obesity. Keywords: visfatin, body mass index, metabolic profile

Possible interaction between visfatin, periodontal infection, and other systemic diseases: A brief review of literature

Gingivitis and periodontitis are common bacterial infections caused by a variety of microorganisms. Despite the microorganisms’ roles as etiologic agents, inflammation-induced substances also have crucial parts in the loss of connective tissue and the supporting alveolar bone. Visfatin is a pleiotropic mediator, which acts as growth factor, cytokine, and pre-B-cell colony-enhancing factor. A positive correlation was detected between the serum/plasma levels of visfatin and inflammatory disorders such as diabetes mellitus and cardiovascular disease. In addition, the visfatin level was higher in saliva and the gingival crevicular fluid (GCF) of subjects with periodontal disease. This review defined current, predictable patterns of possible interaction of visfatin with periodontal infection and other systemic diseases, using PubMed and Medline databases searching for articles written in English. Peer-reviewed articles were targeted using the following keywords: “visfatin,” “periodontal disease,” “inflammatory mediator,” and “biomarker.” Available full-text articles were read, and related articles were also scrutinized, while a hand search was also performed. Search was confined to human studies, and articles written in English and published between 1985 and 2016 were selected. It was concluded that periodontal infection and other systemic diseases could be related to the levels of visfatin in GCF, saliva, and serum as a biomarker of these diseases.

Placental expressions and serum levels of adiponectin, visfatin, and omentin in GDM

AIMS

Adiponectin, visfatin, and omentin have been shown to be associated with insulin sensitivity and might have a role in the pathophysiology of gestational diabetes mellitus (GDM). This study aimed to (1) compare adiponectin, visfatin, and omentin mRNA expressions in placenta and their serum levels between normal pregnancy (NP) and GDM class A1 (GDMA1) pregnancy and (2) determine correlations between placental gene expressions as well as serum levels with maternal and neonatal clinical parameters in all, NP, and GDM subjects.

METHODS

NP subjects (n = 37), who had normal medical history during their pregnancies without diagnosis of any abnormalities and GDMA1 subjects (n = 37), who were diagnosed since they had antenatal care, were recruited when they were in labor with a gestational age of at least 34 weeks. Clinical parameters and serum adiponectin, visfatin, and omentin levels were measured in the delivery room.

RESULTS

GDMA1 subjects had higher serum visfatin and plasma glucose levels, but lower serum omentin levels (p  < 0.05 all) compared to controls, with comparable levels of placental adiponectin, visfatin, and omentin expressions, plasma insulin, and indices of insulin sensitivity and insulin resistance. Serum visfatin was negatively correlated with neonatal weight and length in the GDM group (p  < 0.05 all). Serum omentin was negatively correlated with pre-pregnancy body mass index and waist circumference only in the NP group (p  < 0.05 all). Serum adiponectin was negatively correlated with maternal age and HOMA-IR in the NP group (p  < 0.05 all) and with placental weight and serum omentin in the GDM group (p  < 0.05 all).

CONCLUSIONS

In conclusion, in GDMA1, increased serum visfatin, which has insulin-mimetic effect, might be associated with a compensatory mechanism that improves the impaired insulin function. Decreased serum omentin in GDMA1, which is normally found in visceral obesity, might lead to insulin resistance and contribute to the pathophysiology of GDM.

Adipokine levels and their association with insulin resistance and fetal outcomes among the newborns of Indian gestational diabetic mothers

OBJECTIVES

To investigate the cord blood levels of adipokine and to assess their association with the fetal insulin resistance and fetal outcomes in newborns of gestational diabetic women (GDM). Methods: This cross-sectional study was performed in 40 GDM women and 40 healthy pregnant women (HPW) in the Department of Obstetrics and Gynecology at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) hospital in Puducherry, India, during the period from May 2016 to December 2017. Cord blood samples were collected at delivery from GDM and HPW groups. Cord plasma biochemical parameters such as insulin, C-peptide, adiponectin, leptin, resistin, and visfatin concentrations were measured. Leptin/adiponectin ratio (L/A), homeostasis model assessment of insulin resistance (HOMA2-IR), insulin sensitivity (HOMA2-%S) and beta cell function (HOMA2-%B) were calculated. The pregnancy outcomes such as birth weight (BW), Ponderal index and Apgar scores of the baby were measured. Results: The BW and Ponderal index of the baby were found to be significantly higher in GDM newborns compared to HPW newborns. Cord plasma insulin, C-peptide, HOMA2 -IR, visfatin, leptin, and L/A ratio were significantly higher whereas adiponectin level was lower in GDM compared to HPW. A significant positive correlation was observed between L/A ratio and fetal HOMA2-IR. Conclusion: Altered adipokine levels with increased L/A ratio was observed among the new-borns of Indian gestational diabetic mothers. There was an association between increased L/A ratio, insulin resistance and increased Ponderal index among the new-borns.

Visfatin as a predictor for growth of fetus and infant

Objective:

Visfatin is an adipocytokine that functions as an enzyme and a growth factor to investigate the relationship between serum visfatin and the fetus’s anthropometric markers up to a year after birth.

Materials and Methods:

Forty-one eligible pregnant women in their first trimester were divided and matched in terms of body mass index (BMI) before pregnancy into normal and higher than normal BMI groups, A and B. Serum visfatin levels were measured during 6-12 and 15-20 weeks of gestation using ELISA.

Results:

The infants were followed up for a mean duration of 10.19±2.83 months. In group A, there was a strong positive relationship between birth head circumference and the first (p₁=0.054, r₁=0.580) and second trimester visfatin levels (p₂=0.051, r₂=0.530). In group B, second trimester visfatin levels correlated negatively with birth length (p=0.015, r=-0.523) and infant’s head circumference (p₂=0.050, r₂=-0.392). In a separate study on group B, visfatin levels in the first and second trimesters showed a significant negative correlation with infant’s weight. A significant correlation was observed between the first and second trimesters visfatin level with infant’s height in both groups, such that this relationship was positive in group A and negative in group B. Linear regression analysis revealed that first and second trimester visfatin levels were significant independent predictors of infant’s weight in group B and infant’s height in both groups. Second trimester visfatin level was a significant predictor of birth height in group B.

Conclusion:

Maternal serum visfatin level shows a relationship with fetal and infant anthropometric indicators, with different effects in the two groups, suggesting visfatin dysfunction in the overweight group before pregnancy.

The role of extracellular and intracellular Nicotinamide phosphoribosyl-transferase in cancer: Diagnostic and therapeutic perspectives and challenges

Nicotinamide phosphoribosyl-transferase (Nampt) or pre-B cell colony-enhancing factor or visfatin represents a pleiotropic molecule acting as an enzyme, a cytokine and a growth factor. Intracellular Nampt plays an important role in cellular bioenergetics and metabolism, particularly NAD biosynthesis. NAD biosynthesis is critical in DNA repair, oncogenic signal transduction, transcription, genomic integrity and apoptosis. Although its insulin-mimetic function remains a controversial issue, extracellular Nampt presents proliferative, anti-apoptotic, pro-inflammatory, pro-angiogenic and metastatic properties. Nampt is upregulated in many malignancies, including obesity-associated cancers, and is associated with worse prognosis. Serum Nampt may be a potential diagnostic and prognostic biomarker in cancer. Pharmacologic agents that neutralize Nampt or medications that decrease Nampt levels or downregulate signaling pathways downstream of Nampt may prove to be useful anti-cancer treatments. In particular, Nampt inhibitors as monotherapy or in combination therapy have displayed anti-cancer activity in vivo and in vitro. The aim of this review is to explore the role of Nampt in cancer pathophysiology as well as to synopsize the mechanisms underlying the association between extracellular and intracellular Nampt, and malignancy. Exploring the interplay of cellular bioenergetics, inflammation and adiposopathy is expected to be of importance in the development of preventive and therapeutic strategies against cancer.

Assessment of Salivary Adipokines Resistin, Visfatin, and Ghrelin as Type 2 Diabetes Mellitus Biomarkers

Type 2 diabetes mellitus (T2DM) is emerging as a metabolic epidemic worldwide. Pathologically, dysregulation of many biological pathways precedes hyperglycemia and the clinical diagnosis of T2DM. Changing trajectories along the process of T2DM development necessitates frequent measurement of biomarkers for early identification of at-risk individuals and successful prevention. Increase in circulating inflammatory adipokines has been suggested as predictive of T2DM. Human saliva is an easily accessible biospecimen amenable for painless frequent collection and possesses nearly 50% of serum proteome. In this study, we measured the adipokines resistin, visfatin, TNF-α, and ghrelin as markers for T2DM in unstimulated whole saliva (UWS) using specific assay kits. Resistin and visfatin concentrations were significantly higher in T2DM saliva. Although the concentration of acylated or unacylated ghrelin was lower in diabetic saliva, the decrease was not significant. Since resistin and visfatin are biomarkers integral to T2DM pathology, their salivary assessments may receive clinical acceptance.

NAMPT-Mediated NAD Biosynthesis as the Internal Timing Mechanism: In NAD+ World, Time Is Running in Its Own Way

The biological age of organisms differs from the chronological age and is determined by internal aging clock(s). How cells estimate time on a scale of 24 hours is relatively well studied; however, how biological time is measured by cells, tissues, organs, or organisms in longer time periods (years and decades) is largely unknown. What is clear and widely agreed upon is that the link to age and age-related diseases is not chronological, as it does not depend on a fixed passage of time. Rather, this link depends on the biological age of an individual cell, tissue, organ, or organism and not on time in a strictly chronological sense. Biological evolution does not invent new methods as often as improving upon already existing ones. It should be easier to evolve and remodel the existing (circadian) time clock mechanism to use it for measurement or regulation of longer time periods than to invent a new time mechanism/clock. Specifically, it will be demonstrated that the circadian clock can also be used to regulate circannual or even longer time periods. Nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD+) levels, being regulated by the circadian clock, might be the missing link between aging, cell cycle control, DNA damage repair, cellular metabolism and the aging clock, which is responsible for the biological age of an organism. The hypothesis that NAMPT/NAD+/SIRT1 might represent the time regulator that determines the organismal biological age will be presented. The biological age of tissues and organs might be regulated and synchronized through eNAMPT blood secretion. The "NAD World 2.0" concept will be upgraded with detailed insights into mechanisms that regulate NAD⁺-mediated aging clock ticking, the duration and amplitude of which are responsible for the aging rate of humans.

Nicotinamide is an inhibitor of SIRT1 in vitro, but can be a stimulator in cells

Nicotinamide (NAM), a form of vitamin B3, plays essential roles in cell physiology through facilitating NAD+ redox homeostasis and providing NAD+ as a substrate to a class of enzymes that catalyze non-redox reactions. These non-redox enzymes include the sirtuin family proteins which deacetylate target proteins while cleaving NAD+ to yield NAM. Since the finding that NAM exerts feedback inhibition to the sirtuin reactions, NAM has been widely used as an inhibitor in the studies where SIRT1, a key member of sirtuins, may have a role in certain cell physiology. However, once administered to cells, NAM is rapidly converted to NAD+ and, therefore, the cellular concentration of NAM decreases rapidly while that of NAD+ increases. The result would be an inhibition of SIRT1 for a limited duration, followed by an increase in the activity. This possibility raises a concern on the validity of the interpretation of the results in the studies that use NAM as a SIRT1 inhibitor. To understand better the effects of cellular administration of NAM, we reviewed published literature in which treatment with NAM was used to inhibit SIRT1 and found that the expected inhibitory effect of NAM was either unreliable or muted in many cases. In addition, studies demonstrated NAM administration stimulates SIRT1 activity and improves the functions of cells and organs. To determine if NAM administration can generate conditions in cells and tissues that are stimulatory to SIRT1, the changes in the cellular levels of NAM and NAD+ reported in the literature were examined and the factors that are involved in the availability of NAD+ to SIRT1 were evaluated. We conclude that NAM treatment can hypothetically be stimulatory to SIRT1.

The relationship between circulating visfatin/nicotinamide phosphoribosyltransferase, obesity, inflammation and lipids profile in elderly population, determined by structural equation modeling

BACKGROUND

The available literature suggests that circulating visfatin/Nicotinamide Phosphoribosyltransferase (NAMPT) level variability in humans is related to obesity, insulin resistance, inflammation, and lipid profile. The aim of the study was to assess the relationship between circulating visfatin/NAMPT, obesity, insulin resistance, inflammation, and lipid profile in a large population-based, elderly cohort, applying structural equation modeling.

MATERIALS AND METHODS

The analysis included 2983 elderly participants of the PolSenior study with assessed total blood count, fasting concentrations of lipids, glucose, insulin, hs-CRP, interleukin-6, and visfatin/NAMPT (by ELISA), and calculated HOMA-IR.

RESULTS

The circulating visfatin/NAMPT levels were higher in obese compared to normal weight subjects, in those with hs-CRP above 3 mg/L, with low serum HDL cholesterol, and in insulin resistant subjects. Based on results of the exploratory factor analysis, a baseline model of mutual relationship between four latent and measured variables was created and a final model was developed by maintaining only two significant categories. The important variables for 'latent inflammation' proved to be hs-CRP and IL-6 serum levels. In the case of 'nutritional status', important variables were BMI, waist circumference, and to a lesser extent insulin resistance. Additionally, the residual correlation between those two constructs was also statistically significant.

CONCLUSION

The structural equation modeling provided support for the existence of a link between nutritional status, inflammation and circulating visfatin/NAMPT level. This indicates that circulating visfatin/NAMPT can be considered as a novel surrogate marker of systemic inflammation associated with fat depot, especially visceral, in the elderly population.

Extracellular nicotinamide phosphoribosyltransferase, a new cancer metabokine

In this review, we focus on the secreted form of nicotinamide phosphoribosyltransferase (NAMPT); extracellular NAMPT (eNAMPT), also known as pre-B cell colony-enhancing factor or visfatin. Although intracellular NAMPT is a key enzyme in controlling NAD metabolism, eNAMPT has been reported to function as a cytokine, with many roles in physiology and pathology. Circulating eNAMPT has been associated with several metabolic and inflammatory disorders, including cancer. Because cytokines produced in the tumour micro-environment play an important role in cancer pathogenesis, in part by reprogramming cellular metabolism, future improvements in cancer immunotherapy will require a better understanding of the crosstalk between cytokine action and tumour biology. In this review, the knowledge of eNAMPT in cancer will be discussed, focusing on its immunometabolic function as a metabokine, its secretion, its mechanism of action and possible roles in the cancer micro-environment.

Histopathologic Evaluation of Nonalcoholic Fatty Liver Disease in Hypothyroidism-Induced Rats

It is speculated that thyroid hormones may be involved in nonalcoholic fatty liver disease (NAFLD) pathogenesis. A literature scan, however, demonstrated conflicting results from studies investigating the relationship between hypothyroidism and NAFLD. Therefore, our study aims to evaluate NAFLD, from the histopathologic perspective, in hypothyroidism-induced rats. Wistar rats were divided into 2 groups: the experimental group consumed water containing methimazole 0.025% (MMI, Sigma, USA) for 12 weeks and the control group consumed tap water. At the end of week 12, serum glucose, ALT, AST, triglyceride, HDL, LDL, TSH, fT4, fT3, visfatin, and insulin assays were performed. Sections were stained with hematoxylin-eosin and "Oil Red-O" for histopathologic examination of the livers. In our study, we detected mild hepatosteatosis in all hypothyroidism-induced rats. There was statistically significant difference with respect to obesity between the two groups (p < 0.001). The mean fasting blood glucose was 126.25 ± 23.4 mg/dL in hypothyroidism-induced group and 102.63 ± 15.51 mg/dL in the control group, with a statistically significant difference between the groups (p = 0.032). The two groups did not differ statistically significantly with respect to visfatin levels (p > 0.05). In conclusion, we found that hypothyroidism-induced rats had mild hepatosteatosis as opposed to the control group histopathologically. Our study indicates that hypothyroidism can cause NAFLD.

Pancreatic regulation of glucose homeostasis

In order to ensure normal body function, the human body is dependent on a tight control of its blood glucose levels. This is accomplished by a highly sophisticated network of various hormones and neuropeptides released mainly from the brain, pancreas, liver, intestine as well as adipose and muscle tissue. Within this network, the pancreas represents a key player by secreting the blood sugar-lowering hormone insulin and its opponent glucagon. However, disturbances in the interplay of the hormones and peptides involved may lead to metabolic disorders such as type 2 diabetes mellitus (T2DM) whose prevalence, comorbidities and medical costs take on a dramatic scale. Therefore, it is of utmost importance to uncover and understand the mechanisms underlying the various interactions to improve existing anti-diabetic therapies and drugs on the one hand and to develop new therapeutic approaches on the other. This review summarizes the interplay of the pancreas with various other organs and tissues that maintain glucose homeostasis. Furthermore, anti-diabetic drugs and their impact on signaling pathways underlying the network will be discussed.

Effect of Metformin, Acarbose and Their Combination on the Serum Visfatin Level in Nicotinamide/Streptozocin-Induced Type 2 Diabetic Rats

BACKGROUND

Diabetes mellitus is a chronic metabolic disease with life-threatening complications. Metformin and acarbose are two oral antidiabetic drugs.

OBJECTIVES

This experimental study was designed and carried out at the Arak University of Medical Sciences in Arak, Iran, to investigate the effects of these drugs (both alone and in combination) on glycemic control, lipid profile, and serum visfatin levels in nicotinamide/streptozotocin type 2 diabetic rats.

MATERIALS AND METHODS

Type 2 diabetes was induced in 30 male Wistar rats by the administration of streptozotocin (STZ) (60 mg/kg body weight) intraperitoneally (IP) 15 minutes after the IP administration of nicotinamide (110 mg/kg body weight). After one week, the diabetic rats were randomly divided into four groups. Three diabetic groups were treated with 150 mg/kg/day of metformin, acarbose (40 mg/100 g of diet), or a combination of the two for six weeks, respectively. Biochemical parameters, including fasting blood glucose, glycated hemoglobin, lipid profile, insulin, and visfatin were assessed and compared with those of the control diabetic group.

RESULTS

The data showed metformin, acarbose, and acarbose + metformin downregulated visfatin levels in diabetic rats, but only the reduction in metformin-treated rats was significant (162 ± 21.7, 195.66 ± 6.45 (ng/l), P = 0.001). Fasting blood glucose and glycated hemoglobin decreased significantly in all treated rats, specifically in the treated group that received the two drugs in combination. The serum insulin level was also reduced in all treated groups, and it was significant in the acarbose (P < 0.05) and the combination therapy groups (P < 0.05). The lipid profile improved in all treated groups.

CONCLUSIONS

Compared with acarbose or metformin monotherapy, the addition of acarbose to metformin had superior antihyperglycemia efficacy and provided an efficacious and safe alternative for the treatment of type 2 diabetic rats. Acarbose/metformin reduced the fasting blood glucose and glycated hemoglobin without significant changes in serum visfatin levels.

The comparison of serum vaspin and visfatin concentrations in obese and normal weight women

BACKGROUND AND OBJECTIVES

There is evidence based studies which show that plasma level of visfatin and vaspin in patients with type 2 diabetes mellitus elevate in comparison with healthy people. But there is no consistency in plasma visfatin and vaspin concentration between studies done on obese people. For this reason, the aim of this study is to investigate the serum level concentrations of visfatin and vaspin in obese women compared to normal weight women.

MATERIALS AND METHODS

The participants of this study consist of 43 women aged 20-50, and 43 healthy women with normal weight as a control group. They were matched for age and physical activity. 24h food recall was used to collect dietary information from subjects. Moreover, blood sampling was taken to measure the blood levels of sugar, lipid profile, vaspin and visfatin.

RESULTS

The mean serum level of visfatin was not statistically different between obese and normal weight women. But, the obese women had statistically higher mean serum level of vaspin than normal women (p=0.04). We found no relations between serum levels of vaspin with serum concentration of visfatin. Also, serum levels of these two adipokines were not related to the serum concentrations of fasting glucose, total cholesterol, low-density lipoprotein cholesterol and triglyserides and high-density lipoprotein cholesterol. Also, there was a significant positive relationship between carbohydrate intake and serum visfatin level in women participating to this study (p=0.018, r=0.257).

CONCLUSION

The results of this study demonstrated that the level of serum vaspin was significantly higher in obese women. But there were no differences in serum levels of visfatin in comparison to normal weight women. Meanwhile this study demonstrated a positive relationship between serum levels of visfatin with dietary intake of carbohydrate, but no relationship between serum level of visfatin and vaspin in women participating in this study.

The role of visfatin (PBEF/Nampt) in pregnancy complications

Visfatin (PBEF/Nampt) is an adipocytokine that exerts pleiotropic effects within the human body, particularly affecting its metabolism and immunity. Visfatin was originally identified as being secreted by peripheral blood lymphocytes acting as a pre-B-cell colony-enhancing factor (PBEF). However, it was subsequently reported to be expressed in almost every tissue of the human body, with visceral fat deposits being the main source of visfatin. In addition to its secreted form, visfatin may also be found intracellularly where it functions as a nicotinamide phosphoribosyltransferase (Nampt). Visfatin maternal plasma concentrations increase during pregnancy, suggesting its important role in this complicated process. Alterations in visfatin level also take place in patients during pregnancy complications. This review focuses on the ones that most commonly occur in connection with visfatin: preterm labor, pre-eclampsia and gestational diabetes mellitus. The review aims to provide a better understanding of the role of visfatin during pregnancy and the causes of its alteration in maternal plasma, highlighting the potential use of visfatin as a diagnostic marker of pregnancy complications in the future.

Physiological and pathophysiological roles of NAMPT and NAD metabolism

Nicotinamide phosphoribosyltransferase (NAMPT) is a regulator of the intracellular nicotinamide adenine dinucleotide (NAD) pool. NAD is an essential coenzyme involved in cellular redox reactions and is a substrate for NAD-dependent enzymes. In various metabolic disorders and during ageing, levels of NAD are decreased. Through its NAD-biosynthetic activity, NAMPT influences the activity of NAD-dependent enzymes, thereby regulating cellular metabolism. In addition to its enzymatic function, extracellular NAMPT (eNAMPT) has cytokine-like activity. Abnormal levels of eNAMPT are associated with various metabolic disorders. NAMPT is able to modulate processes involved in the pathogenesis of obesity and related disorders such as nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) by influencing the oxidative stress response, apoptosis, lipid and glucose metabolism, inflammation and insulin resistance. NAMPT also has a crucial role in cancer cell metabolism, is often overexpressed in tumour tissues and is an experimental target for antitumour therapies. In this Review, we discuss current understanding of the functions of NAMPT and highlight progress made in identifying the physiological role of NAMPT and its relevance in various human diseases and conditions, such as obesity, NAFLD, T2DM, cancer and ageing.

Correlations of serum visfatin and metabolisms of glucose and lipid in women with gestational diabetes mellitus

Aims/Introduction

Visfatin is a newly discovered adipocytokine hormone, which exerts an insulin‐like effect by binding to the insulin receptor‐1. However, the role of visfatin in human gestational diabetes mellitus (GDM) remains controversial. The purpose of the present study was to investigate the correlation between serum visfatin and metabolism of glucose and lipid in GDM.

Materials and Methods

This was a prospective study. A total of 38 GDM patients and 35 age‐ and body mass index‐matched controls were studied between January 2012 and October 2013. Fasting serum levels of visfatin, fasting plasma glucose, hemoglobin A1c and lipid profile were measured. Two‐tailed t‐tests and Pearson's correlation coefficient were used to analyze the data.

Results

Perinatal visfatin levels were negatively correlated with fasting plasma glucose, insulin resistance index and triglycerides in controls (r = −0.47, −0.51, −0.57, respectively; P < 0.05), and positively correlated with high‐density lipoprotein cholesterol (r = 0.32, P < 0.05). A positive correlation with visfatin level only appeared in weight gain and body mass index in women with GDM (r = 0.36, 0.45, respectively; P < 0.05).

Conclusions

Visfatin appears to be involved in glucose and lipid metabolism regulation and insulin resistance, suggesting a role in GDM pathogenesis.