Visfatin plasma concentrations in patients with hyperthyroidism and hypothyroidism before and after control of thyroid function

Alterations in serum concentrations of visfatin and betatrophin in dogs with hypothyroidism

BACKGROUND

Hypothyroidism in dogs is associated with obesity and altered lipid and carbohydrate metabolism. The adipokines, visfatin, and betatrophin, affect glucose tolerance. Betatrophin is involved in lipid regulation.

HYPOTHESIS

Visfatin and betatrophin serum concentrations are altered in hypothyroid dogs.

ANIMALS

Dogs with naturally occurring hypothyroidism (n = 25) and healthy dogs (n = 25).

METHODS

Insulin, visfatin, and betatrophin serum concentrations were measured in all dogs and 19 of the hypothyroid dogs after 30 days of thyroxine treatment. Body condition score (BCS) was determined (1-9 scale).

RESULTS

Visfatin concentrations were lower in hypothyroid compared with healthy dogs (mean, 95% confidence interval [CI]; 2.0 ng/mL, 1.2-3.3 vs 5.1 ng/mL, 3.3-7.8; P = .004) and increased post-treatment (3.1 ng/mL, 1.9-4.9 vs 2.6 ng/mL, 1.6-4.1; P = .05). Betatrophin concentrations were lower in lean to normal (body condition score [BCS], 3-5) hypothyroid dogs compared to lean to normal healthy dogs (52 pg/mL, 9-307 vs 597 pg/mL, 216-1648; P = .03), but were not different between overweight (BCS, 6-9) hypothyroid and healthy dogs (341 pg/L, 168-695 vs 178 pg/mL, 77-415; P = .26), and decreased post-treatment in overweight dogs (206 pg/mL, 87-488 vs 268 pg/mL, 112-640; P = .004). Visfatin concentrations were higher in overweight compared with lean to normal dogs (4.7 ng/mL, 3.3-6.6 vs 2.2 ng/mL, 1.2-4.2; P = .04). Betatrophin concentrations were positively correlated with BCS (r = .47, P = .02) and insulin concentrations (r = .48, P = .03) in hypothyroid dogs and negatively correlated with BCS (r = -.47, P = .02) and thyroid stimulating hormone concentrations (r = -.56, P = .01) in healthy dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Hypothyroidism in dogs is associated with alterations in visfatin and betatrophin concentrations that partially resolve with thyroxine treatment.

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.

Adipocytokines in Graves' orbitopathy and the effect of high-dose corticosteroids

Graves' orbitopathy (GO) is a serious, progressive eye condition seen in patients with autoimmune thyroid disease. GO is characterized by inflammation and swelling of soft orbital tissues. Adipose tissue produces cytokine mediators called adipokines. The present study focuses on the relationship between serum levels of selected adipokines in patients with GO, comparing them with the control group, and uniquely describes the effect of high-dose systemic corticosteroids (HDSC) on their levels. For the purposes of this study, we collected blood samples before and after the treatment with HDSC from 60 GO patients and 34 control subjects and measured serum levels of adiponectin, AIF-1, A-FABP and FGF-21. Levels of adiponectin significantly differed among the three study groups (ANOVA p = 0.03). AIF-1 levels were also significantly different among the study groups (ANOVA p < 0.0001). AIF-1 was significantly associated with the presence of GO after adjusting for clinical factors (age, sex, smoking and BMI) and level of TSH (odds ratio 1.003, p < 0.01). This finding could enforce targeting macrophages in treatment strategies for GO since AIF-1 is considered as a marker of their activation.

The Association Between Three Adipocytokines (Adiponectin, Resistin and Visfatin) And Thyroid Status in Patients With Type 2 Diabetes Mellitus and Autoimmune Thyroiditis

Autoimmune thyroiditis (AIT) and type 2 diabetes mellitus (DM2) are the most common endocrinological diseases worldwide. Relation between these diseases explains several hypotheses. One of them is influence of some adipocytokines. This study evaluated association between three adipocytokines (adiponectin, resistin and visfatin) and thyroid and glycid status in patients with DM2 and AIT compared to the control group (CG). The group consisted of four subgroups: patients with DM2 without thyreopathies, patients with AIT on substitution therapy without diabetes and prediabetes, patients with DM2 and AIT on substitution therapy and healthy subjects as the CG. We investigated parameters of thyroid and glucose metabolism and serum levels of three adipocytokines. The mean level of resistin in the group of patients with diabetes and thyroiditis was significantly higher than in patients with thyroiditis without diabetes and than in the CG. We found a weak negative correlation between visfatin and fasting glucose levels in patients with thyroiditis without diabetes. We detected a weak negative correlation between resistin and glycated haemoglobin and a weak negative correlation between visfatin and thyroid gland volume in patients with diabetes without thyroiditis. In the CG we determined a weak positive correlation between visfatin and free thyroxin. Our results are consistent with several studies, which confirmed association between AIT and adipocytokines.

Effect of restoration of euthyroidism on visfatin concentrations and body composition in women

Dysregulation of thyroid function has known impact on body metabolism, however, data regarding metabolic outcome after restoration of thyroid function is limited. Therefore, the aim of the study was to investigate the effect of restoration of euthyroidism on serum visfatin, and its associations with insulin resistance and body composition. This is an observational study with consecutive enrollment. Forty-nine hyperthyroid (median age of 34 years) and 44 hypothyroid women (median age of 46 years) completed the study. Laboratory parameters and body composition analysis were assessed before and after the therapy. In the hyperthyroid group, visfatin concentrations increased (P < 0.0001), while glucose concentrations decreased (P < 0.0001). Total body mass and fat mass in the trunk and limbs significantly increased during the treatment. In the hypothyroid group, significant weight loss resulted from decrease of fat and muscle masses in trunk and limbs. Visfatin serum concentrations positively correlated with total fat mass (r = 0.19, P = 0.01) and insulin concentrations (r = 0.17, P = 0.018). In conclusion, restoration of thyroid function is not associated with beneficial changes in body composition, especially among hyperthyroid females.

Role of Nampt overexpression in a rat model of Hashimoto's thyroiditis and its mechanism of action

The present study was designed to investigate the role of nicotinamide phosphoribosyltransferase (Nampt) overexpression in a rat model of Hashimoto's thyroiditis (HT) and its mechanism of action. A rat model of HT was constructed, and the HT rats were injected with an adenoviral expression vector carrying the Nampt gene. The expression of Nampt and Toll-like receptor 4 (TLR4) in thyroid tissues was examined using immunohistochemistry (IHC), RT-qPCR and western blot analyses. Serum anti-thyroglobulin antibodies (TGAb) and anti-thyroid peroxidase antibodies (TPOAb) were measured using chemiluminescence method. Hematoxylin and eosin (H&E) and IHC staining of the rat thyroid tissues showed destroyed thyroid follicles and monocyte infiltration, as well as increased Nampt expression in the thyroid tissues of rats with HT. Furthermore, it was found that Nampt overexpression led to increased severity of inflammatory infiltration in thyroid tissues and increased levels of TPOAb in the serum of HT rats; however, the serum TGAb level was not affected by Nampt overexpression. In addition, Nampt overexpression promoted TLR4 expression in HT rats. In conclusion, it was demonstrated that Nampt was strongly expressed in the capillary region of HT rats thyroid tissues. The Nampt mRNA level was increased but the Nampt protein level was decreased in the thyroid tissues of rats with HT. Nampt overexpression has a promotive effect on HT progression, and this effect was related to TLR4. This study suggests that inhibition of Nampt activity may be valuable in the treatment of HT.

Visfatin level in children and adolescents with autoimmune thyroiditis

BACKGROUND

This study aims to assess the levels of visfatin in children and adolescents with autoimmune thyroiditis (AIT) and its relationship with disease-related variables.

METHODS

The study included 84 children and adolescents with AIT and 84 healthy subjects. Measurements of fasting glucose, insulin, thyroid-stimulating hormone (TSH), free thyroxin (FT4), antithyroid peroxidase antibodies (TPOAb) and antithyroglobulin antibody (TgAb) were completed, with assessment of visfatin levels.

RESULTS

Overt hypothyroidism was diagnosed in 58 cases, while subclinical hypothyroidism was diagnosed in 26 of the studied patients. Total studied cases, overt and subclinical subgroups had significantly higher levels of TSH, HOMA-IR, TPOAb, TgAb and visfatin and significantly lower FT4 level compared with the control. Spearman correlation analysis revealed that visfatin was correlated positively with BMI, homeostasis model assessment (HOMA-IR), TSH and TPOAb, while inversely correlation with FT4. In logistic regression analysis, visfatin was correlated only with TPOAb.

CONCLUSIONS

This preliminary study provides evidence of significantly higher level of visfatin in children and adolescents with AIT. Visfatin might have a potential role in the pathogenesis of AIT, which needs to be validated by measuring immunological responses in children and adolescents with AIT.

Nicotinamide phosphoribosyltransferase leukocyte overexpression in Graves' opthalmopathy

To investigate the role of NAMPT/visfatin in euthyroid patients with Graves' disease without (GD) and with Graves' ophthalmopathy (GO), we analyzed NAMPT leukocyte expression and its serum concentration. This was a single-center, cross-sectional study with consecutive enrollment. In total, 149 patients diagnosed with Graves' disease were enrolled in the study. We excluded subjects with hyper- or hypothyroidism, diabetes mellitus, other autoimmune disorders, active neoplastic disease, and infection. The control group was recruited among healthy volunteers adjusted for age, sex, and BMI with normal thyroid function and negative thyroid antibodies. Serum levels of visfatin, TSH, FT4, FT3, antibodies against TSH receptor (TRAb), antithyroperoxidase antibodies, antithyroglobulin antibodies, fasting glucose, and insulin were measured. NAMPT mRNA leukocyte expression was assessed using RT-qPCR. NAMPT/visfatin serum concentration was higher in GD (n = 44) and GO (n = 49) patients than in the control group (n = 40) (p = 0.0275). NAMPT leukocyte expression was higher in patients with GO (n = 30) than in GD patients (n = 27) and the control group (n = 29) (p < 0.0001). Simple linear regression analysis revealed that NAMPT/visfatin serum concentration was significantly associated with GD (β = 1.5723; p = 0.021). When NAMPT leukocyte expression was used as a dependent variable, simple regression analysis found association with TRAb, fasting insulin level, HOMA-IR, GD, and GO. In the stepwise multiple regression analysis, we confirmed the association between higher serum NAMPT/visfatin level and GD (coefficient = 1.5723; p = 0.0212), and between NAMPT leukocyte expression and GO (coefficient = 2.4619; p = 0.0001) and TRAb (coefficient = 0.08742; p = 0.006). Increased NAMPT leukocyte expression in patients with GO might suggest a presently undefined role in the pathogenesis of GO.

The relationship between serum adipocytokines and Graves' ophthalmopathy: A hospital-based study

Adipocytokines are thought to be associated with inflammatory disorders and autoimmune diseases. However, limited information is available on the relationship between serum adipocytokine levels, Graves' disease (GD), and Graves' ophthalmopathy (GO). The present study examined the relationship between serum adipocytokine levels and GD and GO. A total of 80 patients with GD participated in this study. The medical records of patients were reviewed retrospectively. GO activity was assessed using the clinical activity score (CAS). GO severity was assessed by the modified NOSPECS classification and included soft tissue involvement, proptosis, and extraocular muscle involvement. Serum adiponectin, leptin, resistin, and retinol-binding protein 4 (RBP-4) levels were measured using commercially available enzyme-linked immunosorbent assays. The prevalence of GO was 36.3%. Serum adiponectin, leptin, and resistin levels were significantly higher in patients with GO than in those without GO. The CAS was positively correlated with serum adiponectin and leptin levels. The total eye score was positively correlated with serum adiponectin, leptin, resistin, and RBP-4 levels. A multivariate analysis revealed that serum leptin and resistin levels were associated with the presence of GO after adjusting for clinical factors. Free thyroxine was negatively correlated with serum leptin level. These results suggest that adipocytokines, such as leptin and resistin, may play a role in inflammatory and autoimmune processes of GD and GO. Future studies with larger numbers of patients are required to establish relationships between serum adipocytokines levels and GO and ascertain the role of adipocytokines in GD and GO.

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.

Circulating Visfatin in Hypothyroidism Is Associated with Free Thyroid Hormones and Antithyroperoxidase Antibodies

We hypothesized that regulation of visfatin in hypothyroidism might be altered by coexisting chronic autoimmune thyroiditis. This is a prospective case-control study of 118 subjects. The autoimmune study group (AIT) consisted of 39 patients newly diagnosed with hypothyroidism in a course of chronic autoimmune thyroiditis. The nonautoimmune study group (TT) consisted of 40 patients thyroidectomized due to the differentiated thyroid cancer staged pT1. The control group comprised 39 healthy volunteers adjusted for age, sex, and BMI with normal thyroid function and negative thyroid antibodies. Exclusion criteria consisted of other autoimmune diseases, active neoplastic disease, diabetes mellitus, and infection, which were reported to alter visfatin level. Fasting blood samples were taken for visfatin, TSH, free thyroxine (FT4), free triiodothyronine (FT3), antithyroperoxidase antibodies (TPOAb), antithyroglobulin antibodies (TgAb), glucose, and insulin levels. The highest visfatin serum concentration was in AIT group, and healthy controls had visfatin level higher than TT (p = 0.0001). Simple linear regression analysis revealed that visfatin serum concentration was significantly associated with autoimmunity (β = 0.1014; p = 0.003), FT4 (β = 0.05412; p = 0.048), FT3 (β = 0.05242; p = 0.038), and TPOAb (β = 0.0002; p = 0.0025), and the relationships were further confirmed in the multivariate regression analysis.

Serum visfatin concentration in acutely ill and weight-recovered patients with anorexia nervosa

Visfatin is a recently described protein that is thought to regulate the process of adipocyte differentiation. Findings suggest that visfatin may be actively involved in the control of weight regulatory networks. However, to what extent and which role it plays in eating disorders is still poorly understood, as mixed results have been reported. The aim of the current study was to investigate serum visfatin concentrations on a cross sectional sample between acute anorexia nervosa patients (n=44), weight recovered patients (n=13) and healthy controls (n=46) and a longitudinal sample of acute patients (n=57) during weight recovery at three different time-points. Results did not show significant differences in visfatin between the three groups; however, acute patients showed a higher visfatin/BMI-SDS ratio than controls and recovered patients. Longitudinal results revealed an increase of visfatin levels during therapy. Our results suggest that high ratios of visfatin/BMI-SDS could be a state marker in acute anorexia nervosa, displaying a compensatory mechanism of the individual to maintain normal visfatin levels under malnourished conditions.

Visfatin, Leptin, and TNF-α: Interrelated Adipokines in Insulin-Resistant Clinical and Subclinical Hypothyroidism

PURPOSE

This study is designed to evaluate the interrelationships among adipokines-visfatin, leptin, and tumor necrosis factor-α (TNF-α)- and insulin resistance (IR) in overt (n = 40) and subclinic hypothyroid (n = 25) patients and compare our findings with sex and body mass index-matched healthy controls (n = 25).

METHODS

Serum visfatin, leptin, and TNF-α levels were measured by enzyme-linked immunosorbent assay and C-reactive protein by immunoturbidimetry. Thyroid status (TSH, FT3, FT4) and lipid status (triglyceride, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, total cholesterol) parameters were measured. IR was determined by homeostatic model assessment (HOMA-IR) and McAuley (McA) indices.

RESULTS

HOMA-IR (p < 0.05) and McA indices (p < 0.01) revealed the presence of IR in overt hypothyroid patients. C-reactive protein, TNF-α, leptin, and visfatin levels were significantly higher (p < 0.01, p < 0.01, p < 0.001, and p < 0.001) in overt hypothyroid patients than euthyroid control group. Subclinic hypothyroid patients were observed to have significantly higher leptin and visfatin levels (p < 0.05) than euthyroid control group. In overt hypothyroid patients, we found plasma visfatin to be significantly positively correlated with HOMA-IR index (r = 0.336, p < 0.05) and body mass index (r = 0.445, p < 0.01) and negatively correlated with McA index (r = -0.574, p < 0.01).

CONCLUSION

This study demonstrates the presence of IR in overt hypothyroid patients by HOMA and McA indices. Increased levels of visfatin, leptin, and TNF-α in overt and subclinic hypothyroid patients and the correlations among these adipokines highlighten their crucial role in the IR-associated disorders.

Adipocytokines in thyroid dysfunction

Adipocytokines are important mediators of interorgan crosstalk in metabolic regulation. Thyroid diseases have effects on metabolism and inflammation. The mechanism of these effects is not clear. Recently, there are several reports suggesting this interrelation between adipocytokines and thyroid dysfunction. In this review, we summarize this relation according to the literature.

Association between novel adipocytokines adiponectin, vaspin, visfatin, and thyroid: An experimental and clinical update

Adipose tissue secretes a variety of active biological substances, called adipocytokines, that act in an autocrine, paracrine, and endocrine manner. They have roles in appetite control, thermogenesis, and thyroid and reproductive functions. All these molecules may lead to local and generalized inflammation, mediating obesity-associated vascular disorders including hypertension, diabetes, atherosclerosis, and insulin resistance. Thyroid dysfunction is associated with changes in body weight, thermogenesis, and energy expenditure. The connections between cardiovascular risk factors such as dyslipidemia, impaired glucose tolerance, insulin resistance, atherosclerosis, and thyroid dysfunction have been reported in several studies. The adipocytokines serve as causative or protective factors in the development of these disorders in the states of thyroid dysfunction. Abnormal levels of adipocytokines (adiponectin (ADP), leptin, resistin, vaspin, and visfatin) in hypo- and hyperthyroidism have been reported with controversial results. This review aims to update the implication of novel adipokines ADP, vaspin, and visfatin in thyroid dysfunction.

Insulin action in hyperthyroidism: a focus on muscle and adipose tissue

Hyperthyroidism leads to an enhanced demand for glucose, which is primarily provided by increased rates of hepatic glucose production due to increased gluconeogenesis (in the fasting state) and increased Cori cycle activity (in the late postprandial and fasting state). Adipose tissue lipolysis is increased in the fasting state, resulting in increased production of glycerol and nonesterified fatty acids. Under these conditions, increased glycerol generated by lipolysis and increased amino acids generated by proteolysis are used as substrates for gluconeogenesis. Increased nonesterified fatty acid levels are necessary to stimulate gluconeogenesis and provide substrate for oxidation in other tissues (such as muscle). In the postprandial period, insulin-stimulated glucose uptake by the skeletal muscle has been found to be normal or increased, mainly due to increased blood flow. Under hyperthyroid conditions, insulin-stimulated rates of glycogen synthesis in skeletal muscle are decreased, whereas there is a preferential increase in the rates of lactate formation vs. glucose oxidation leading to increased Cori cycle activity. In hyperthyroidism, the Cori cycle could be considered as a large substrate cycle; by maintaining a high flux through it, a dynamic buffer of glucose and lactate is provided, which can be used by other tissues as required. Moreover, lipolysis is rapidly suppressed to normal after the meal to facilitate the disposal of glucose by the insulin-resistant muscle. This ensures the preferential use of glucose when available and helps to preserve fat stores.