Expression of obestatin and ghrelin in papillary thyroid carcinoma

Serum and Saliva Levels of Cancer Antigen 15-3, Carcinoembryonic Antigen, Estradiol, Vaspin, and Obestatin as Biomarkers for the Diagnosis of Breast Cancer in Postmenopausal Women

OBJECTIVE

To find suitable biomarkers for diagnosis of Breast cancer in serum and saliva; also, to examine the correlation between salivary and serum concentrations of suitable biomarkers.

METHODS

This case-control study included 30 women with breast cancer as a case group and 30 healthy women as a matched control group. Blood and saliva specimens were collected from all participants. We evaluated serum and salivary cancer antigen 15-3 (CA15-3), carcinoembryonic antigen (CEA), estradiol, vaspin, and obestatin concentrations. Mann-Whitney U testing and Spearman correlation coefficients were used for statistical analysis.

RESULTS

Serum and salivary concentrations of estradiol were significantly higher in patients with breast cancer (BC) than in healthy women (P < .05). Also, serum CEA and salivary obestatin concentrations were significantly higher in BC patients than in the control group (P < .05). However, there was no significant difference between other parameters in patients with BC and controls. We observed a positive correlation between serum and salivary concentrations of CA15-3, as well as a negative correlation between serum and salivary concentrations of vaspin and obestatin.

CONCLUSION

The results of this study demonstrated that concentrations of CEA and estradiol in serum, obestatin in serum and saliva, and estradiol in saliva were significantly different between the 2 groups.

The role of metabolic setting in predicting the risk of early tumour relapse of differentiated thyroid cancer (DTC)

BACKGROUND

The role of insulin resistance and adipocytokines in determining the phenotype and recurrence of differentiated thyroid cancer (DTC) is still unknown. In a previous study, we observed an association between metabolic setting, circulating adipocytokines and thyroid cancer phenotype. The aim of this study was to evaluate the clinical follow-up of patients with DTC and the predictive role of metabolic setting on the risk of tumour relapse.

METHODS

Between September 2016 and January 2017, 57 patients were admitted to our institution to undergo total thyroidectomy because of suspected DTC. Thirty patients with post-surgical histological diagnosis of DTC were included in the study. Each subject underwent pre-surgical analysis of anthropometric parameters, thyroid function and autoimmunity, glucose metabolism, insulin resistance (HOMA-IR) and levels of unacylated and acylated ghrelin, obestatin, leptin and adiponectin. Tumour recurrence at 1 and 3 years from diagnosis was assessed.

RESULTS

Most patients were females (21F, 9M) with a median age at diagnosis of 50.0 (41.0-58.8). At baseline, overweight was found in 7 patients and obesity in 6 cases. Insulin resistance was detected in 14 patients. Overall, 17 patients (56.7%) underwent radioiodine treatment after surgery. During the follow-up, we observed a persistent biochemical disease in one patient whereas tumour relapse was found in six patients at 1 year from diagnosis (lymph node metastases) and in one patient at 3 years from diagnosis (lung metastases). Independently from age, sex, stage of disease and the presence of lymph node metastasis at diagnosis, higher BMI, leptin and insulin levels as well as HOMA-IR were associated with a higher risk of tumour relapse (p < 0.05 for all).

CONCLUSIONS

Our results highlight a possible role for BMI, leptin and insulin resistance as predictors of early DTC relapse.

Circulating adipokines and metabolic setting in differentiated thyroid cancer

The associative link relating insulin resistance (IR) and adipokines to the occurrence and phenotype of differentiated thyroid cancer (DTC) is unknown. The aim of this study was to evaluate the relationship between IR and adipokines in DTC patients, as compared with carriers of benign thyroid diseases (BTD) and healthy controls. This observational study enrolled 77 subjects phenotyped as DTC (N = 30), BTD (N = 27) and healthy subjects (N = 20). Each subject underwent preoperative analysis of anthropometric parameters, thyroid function and autoimmunity, insulin resistance (HOMA-IR) and levels of unacylated (UAG) and acylated ghrelin (AG), obestatin, leptin and adiponectin. Multivariate regression models were used to test the predictive role of metabolic correlates on thyroid phenotypes and DTC extension. The three groups showed similar age, gender distribution, smoking habit, BMI and thyroid parameters. Obestatin was significantly higher in DTC group compared to BTD (P < 0.05) and control subjects (P < 0.0001). DTC and BTD groups showed higher levels of UAG (P < 0.01) and AG (P < 0.05). Leptin levels were comparable between groups, whereas adiponectin levels were lower in DTC compared to BTD group (P < 0.0001) and controls (P < 0.01). In parallel, HOMA-IR was higher in DTC than BTD (P < 0.05) and control group (P < 0.01). Stepwise multivariable regression analysis showed that obestatin and UAG were independent predictors of DTC (P = 0.01 for both). In an analysis restricted to the DTC group, obestatin levels were associated with the absence of lymph node metastases (P < 0.05). Our results highlight a potential association between metabolic setting, circulating adipokines and thyroid cancer phenotype.

Comparison of irisin hormone expression between thyroid cancer tissues and oncocytic variant cells

Objective: The incidence of thyroid cancer has been continuously increasing. The main objective of this study was to investigate irisin expression in various thyroid pathologies and to compare these expression patterns with irisin expression in healthy thyroid tissues. Methods: The study groups consisted of 20 cases each of control thyroid tissue, Hashimoto's thyroiditis, thyroid papillary carcinoma, oncocytic papillary carcinoma, follicular thyroid carcinoma, oncocytic follicular thyroid carcinoma, medullary thyroid carcinoma, anaplastic thyroid carcinoma. Irisin expression was evaluated using immunohistochemistry. Irisin levels in thyroid tissue supernatants were measured using ELISA. Results: Patients with HT showed increased irisin expression compared with controls (p<0.05). In addition, mild immunoreactivity was observed in the thyroid tissues of patients with papillary carcinoma while significantly increased irisin immunoreactivity was observed tissues of patients with oncocytic papillary carcinoma (p<0.05). There was no difference in irisin immunoreactivity in thyroid tissues between patients with follicular carcinoma and controls. However, irisin immunoreactivity was higher in tissues of patients with oncocytic follicular carcinoma than in tissues of patients with follicular carcinoma (p<0.05). No irisin immunoreactivity was observed in tissues of patients with medullary carcinoma, a malignant tumor the thyroid; however, irisin expression was significantly increased in tissues of patients with anaplastic carcinoma compared with that in tissues of controls (p<0.05). Furthermore, in all thyroid tissues with irisin expression, irisin immunoreactivity was observed in follicular cells, indicating that irisin is produced by these cells. Conclusion: Irisin is a novel potential immunohistochemical marker for differentiating oncocytic variants of papillary and FTCs from papillary and follicular thyroid cancers.

The Role of Adipokines in the Establishment and Progression of Head and Neck Neoplasms

Adipokines constitute a family of protein factors secreted by white adipose tissue (WAT), that regulate the functions of WAT and other sites. Leptin, adiponectin and resistin, are the main adipokines present in serum and saliva, targeting several tissues and organs, including vessels, muscles, liver and pancreas. Besides body mass regulation, adipokines affect glucose homeostasis, inflammation, angiogenesis, cell proliferation and apoptosis, and other crucial cell procedures. Their involvement in tumor formation and growth is well established and deregulation of adipokine and adipokine receptors' expression is observed in several malignancies including those located in the head and neck region. Intracellular effects of adipokines are mediated by a plethora of receptors that activate several signaling cascades including Janus kinase/ Signal transducer and activator of transcription (JAK/ STAT pathway), Phospatidylinositol kinase (PI3/ Akt/ mTOR) and Peroxisome proliferator-activated receptor (PPAR). The present review summarizes the current knowledge on the role of adipokines family members in carcinogenesis of the head and neck region. The diagnostic and prognostic significance of adipokines and their potential role as serum and saliva biomarkers are also discussed.

Serum ghrelin levels in papillary thyroid carcinoma

OBJECTIVE

Ghrelin plays a role in several processes of cancer progression, and numerous cancer types express ghrelin and its receptor. We aimed to investigate serum levels of ghrelin in patients with papillary thyroid carcinoma (PTC) and its association with the prognostic factors in PTC.

MATERIALS AND METHODS

We enrolled 54 patients with thyroid cancer (7 male, 47 female) and 24 healthy controls (6 male, 18 female) in the study. We compared demographic, anthropometric, and biochemical data, and serum ghrelin levels between the groups. Serum ghrelin levels were measured using as enzyme-linked immunosorbent assay.

RESULTS

Ghrelin levels were similar between the groups, but plasma ghrelin levels were significantly higher in tumors larger than 1 cm diameter compared with papillary microcarcinomas. Serum ghrelin levels also correlated with tumor size (r = 0.499; p < 0.001). Body mass index, thyroid-stimulating hormone, and HOMA-IR levels were similar between the groups. There were no statistically significant differences regarding average age and other prognostic parameters including lymph node invasion, capsule invasion, multifocality and surgical border invasion between patients with microcarcinoma and tumors larger than 1 cm.

CONCLUSION

In our study, no significant difference in serum ghrelin levels was determined between patients with papillary thyroid cancer and healthy controls however, serum ghrelin levels were higher in tumors larger than 1 cm compared to in those with thyroid papillary microcarcinoma.

Obestatin stimulates glucose-induced insulin secretion through ghrelin receptor GHS-R

Orexigenic hormone ghrelin and anorexic hormone obestatin are encoded by the same preproghrelin gene. While it is known that ghrelin inhibits glucose-stimulated insulin secretion (GSIS), the effect of obestatin on GSIS is unclear. Ghrelin's effect is mediated by its receptor Growth Hormone Secretagogue Receptor (GHS-R), but the physiologically relevant receptor of obestatin remains debatable. Here we have investigated the effect of obestatin on GSIS in vitro, in vivo and ex vivo, and tested whether obestatin regulates insulin secretion through GHS-R. We found that under hyperglycemic condition, obestatin augments GSIS in rat insulinoma cells (INS-1) and in pancreatic islets from ghrelin -/- mice. Surprisingly, obestatin-induced GSIS was absent in β-cells in which GHS-R was suppressed. Obestatin-induced insulin secretion was abolished in the circulation of Ghsr -/- mice, and in pancreatic islets isolated from Ghsr -/- mice. We also found that obestatin-induced GSIS was attenuated in islets isolated from β-cell-specific Ghsr knockout MIP-Cre/ERT;Ghsrf/f mice. Our data collectively demonstrate that obestatin is a potent insulin secretagogue under hyperglycemic condition, and obestatin's effect on insulin secretion is mediated by GHS-R in pancreatic β-cells. Our findings reveal an intriguing insight that obestatin and ghrelin have opposing effects on insulin secretion, and both are mediated through ghrelin receptor GHS-R.

Mechanisms in endocrinology: the crosstalk between thyroid gland and adipose tissue: signal integration in health and disease

Obesity and thyroid diseases are common disorders in the general population and they frequently occur in single individuals. Alongside a chance association, a direct relationship between 'thyroid and obesity' has been hypothesized. Thyroid hormone is an important determinant of energy expenditure and contributes to appetite regulation, while hormones and cytokines from the adipose tissue act on the CNS to inform on the quantity of energy stores. A continuous interaction between the thyroid hormone and regulatory mechanisms localized in adipose tissue and brain is important for human body weight control and maintenance of optimal energy balance. Whether obesity has a pathogenic role in thyroid disease remains largely a matter of investigation. This review highlights the complexity in the identification of thyroid hormone deficiency in obese patients. Regardless of the importance of treating subclinical and overt hypothyroidism, at present there is no evidence to recommend pharmacological correction of the isolated hyperthyrotropinemia often encountered in obese patients. While thyroid hormones are not indicated as anti-obesity drugs, preclinical studies suggest that thyromimetic drugs, by targeting selected receptors, might be useful in the treatment of obesity and dyslipidemia.

Ghrelin gene products in acute and chronic inflammation

Ghrelin gene products--the peptides ghrelin, unacylated ghrelin, and obestatin--have several actions on the immune system, opening new perspectives within neuroendocrinology, metabolism and inflammation. The aim of this review is to summarize the available evidence regarding the less known role of these peptides in the machinery of inflammation and autoimmunity, outlining some of their most promising therapeutic applications.

Is association between thyroid hormones and gut peptides, ghrelin and obestatin, able to suggest new regulatory relation between the HPT axis and gut?

BACKGROUND

Ghrelin and obestatin are important appetite- and energy-regulating peptides, secreted by the stomach. These gut peptides and thyroid hormones are involved in metabolism regulation. Although subclinical thyroidism is common, to date, very few studies have been reported about gut hormones in thyroid dysfunction, and their results are controversial. The purpose of this study was to investigate ghrelin and obestatin in patients with subclinical hypo- and hyperthyroidism. Moreover, is association between thyroid hormones and gut peptides able to suggest new regulatory relation between the HPT axis and gut?

MATERIALS AND METHODS

The study group included 70 subclinical hypo- and hyperthyroid subjects (in equal groups) and 35 healthy euthyroid controls. Serum values of ghrelin, obestatin, free T3, free T4, thyroid-stimulating hormone and the ratio of ghrelin to obestatin were measured in all participants.

RESULTS

Ghrelin and obestatin both decreased in subclinical hypothyroid subjects (320±81ng/l and 44.3±11.7ng/l, respectively) compared to the control group (487±110ng/l and 58.5±10.3ng/l, respectively). On the other hand, ghrelin and obestatin both increased in subclinical hyperthyroid subjects (750±289ng/l and 71.1±27.3ng/l, respectively) compared to the control group. In addition, ghrelin and obestatin showed strong correlations with TSH, FT3 and FT4.

CONCLUSION

This study shows that gut hormones are significantly associated with thyroid hormones. Thus, there may be a cross talk between the HPT axis and gut. We would like to consider new regulatory relation for description of the found data.

Individual plasma ghrelin changes in the same patients in hyperthyroid, hypothyroid and euthyroid state

Ghrelin is a multifunctional peptide of widespread expression. Since it has been shown to influence energy homeostatis, its potential role in thyroid dysfunction may have clinical significance. In this study, plasma ghrelin changes have been analyzed in the same patients in three different thyroid states for the first time. The study group consisted of 16 patients who had been diagnosed with hyperthyroidism, were treated with radioiodine, developed hypothyroidism after treatment, and finally became euthyroid on l-thyroxine substitution. In the initial state of hyperthyroidism plasma ghrelin levels correlated negatively with fT3 and fT4. In hypothyroidism ghrelin concentration increased significantly (p<0.05). Although the mean value of plasma ghrelin tended to decrease in the euthyroid state, the individual difference between hypothyroidism and euthyroidism was not significant. Plasma ghrelin in euthyroidism was still significantly higher than in hyperthyroidism (p<0.05), and correlated positively with ghrelin levels in hyperthyroidism and hypothyroidism. In our opinion, plasma ghrelin fluctuations may reflect metabolic changes in patients with thyroid dysfunction. Moreover, it cannot be excluded that in thyroid disorders ghrelin acts as a compensatory factor, helping to balance metabolic disturbances.

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.

The ghrelin axis--does it have an appetite for cancer progression?

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHSR), is a peptide hormone with diverse physiological roles. Ghrelin regulates GH release, appetite and feeding, gut motility, and energy balance and also has roles in the cardiovascular, immune, and reproductive systems. Ghrelin and the GHSR are expressed in a wide range of normal and tumor tissues, and a fluorescein-labeled, truncated form of ghrelin is showing promise as a biomarker for prostate cancer. Plasma ghrelin levels are generally inversely related to body mass index and are unlikely to be useful as a biomarker for cancer, but may be useful as a marker for cancer cachexia. Some single nucleotide polymorphisms in the ghrelin and GHSR genes have shown associations with cancer risk; however, larger studies are required. Ghrelin regulates processes associated with cancer, including cell proliferation, apoptosis, cell migration, cell invasion, inflammation, and angiogenesis; however, the role of ghrelin in cancer is currently unclear. Ghrelin has predominantly antiinflammatory effects and may play a role in protecting against cancer-related inflammation. Ghrelin and its analogs show promise as treatments for cancer-related cachexia. Further studies using in vivo models are required to determine whether ghrelin has a role in cancer progression.

Effects of Acute Recombinant Human TSH on Serum Ghrelin Levels

Recent findings showed the presence of a reciprocal relationship between thyroid hormones and ghrelin, although the exact mechanism is not known.

DESIGN

Our study is addressed to evaluate the effect of acute exogenous rhTSH administration on serum ghrelin levels in athyreotic patients on replacement l-thyroxine therapy. The study group included 50 patients (16 males and 34 females) submitted to total thyroidectomy and 131-iodine remnant ablation for differentiated thyroid cancer on l-thyroxine therapy. Mean age was 47.5 ± 16.5 years and mean BMI was 25.6 ± 5.01 kg/m(2). rhTSH was administrated at the dosage of 0.9 mg i.m. once daily for two consecutive days. Blood samples were taken between 08.00 and 09.00 after a overnight fasting for measurement of TSH, FT3, FT4, and ghrelin before the first administration of rhTSH and for measurement of TSH and ghrelin 24, 48, 72, and 96 h after the first administration of rhTSH.

RESULTS

Mean ± SD values of basal TSH were 0.54 ± 0.77 μU/ml without significant difference between females and males. As expected, after rhTSH administration TSH concentrations increased at 24 and 48 h with peak TSH values ranging from 20.20 to 313 μU/ml (mean ± SD 98.4 ± 66.7 μU/ml). Mean ± SD values of basal ghrelin were 1085 ± 373 pg/ml without significant difference between males and females. After rhTSH administration ghrelin concentrations decreased significantly (p < 0.01) at 24 h (mean ± SD 934 ± 314 pg/ml p < 0.01) and returned to pre-treatment levels at 96 h.

CONCLUSION

Our study demonstrates that acute exogenous TSH administration has a suppressive effect on ghrelin secretion independent from changes in thyroid status.

A novel human ghrelin variant (In1-ghrelin) and ghrelin-O-acyltransferase are overexpressed in breast cancer: potential pathophysiological relevance

The human ghrelin gene, which encodes the ghrelin and obestatin peptides, contains 5 exons (Ex), with Ex1-Ex4 encoding a 117 amino-acid (aa) preproprotein that is known to be processed to yield a 28-aa (ghrelin) and/or a 23-aa (obestatin) mature peptides, which possess biological activities in multiple tissues. However, the ghrelin gene also encodes additional peptides through alternative splicing or post-translational modifications. Indeed, we previously identified a spliced mRNA ghrelin variant in mouse (In2-ghrelin-variant), which is regulated in a tissue-dependent manner by metabolic status and may thus be of biological relevance. Here, we have characterized a new human ghrelin variant that contains Ex0-1, intron (In) 1, and Ex2 and lacks Ex3-4. This human In1-ghrelin variant would encode a new prepropeptide that conserves the first 12aa of native-ghrelin (including the Ser3-potential octanoylation site) but has a different C-terminal tail. Expression of In1-variant was detected in 22 human tissues and its levels were positively correlated with those of ghrelin-O-acyltransferase (GOAT; p = 0.0001) but not with native-ghrelin expression, suggesting that In1-ghrelin could be a primary substrate for GOAT in human tissues. Interestingly, levels of In1-ghrelin variant expression in breast cancer samples were 8-times higher than those of normal mammary tissue, and showed a strong correlation in breast tumors with GOAT (p = 0.0001), ghrelin receptor-type 1b (GHSR1b; p = 0.049) and cyclin-D3 (a cell-cycle inducer/proliferation marker; p = 0.009), but not with native-ghrelin or GHSR1a expression. Interestingly, In1-ghrelin variant overexpression increased basal proliferation of MDA-MB-231 breast cancer cells. Taken together, our results provide evidence that In1-ghrelin is a novel element of the ghrelin family with a potential pathophysiological role in breast cancer.

The expanding roles of the ghrelin-gene derived peptide obestatin in health and disease

Obestatin is a 23 amino acid, ghrelin gene-derived peptide hormone produced in the stomach and a range of other tissues throughout the body. While it was initially reported that obestatin opposed the actions of ghrelin with regards to appetite and food intake, it is now clear that obestatin is not an endogenous ghrelin antagonist, but it is a multi-functional peptide hormone in its own right. In this review we will discuss the controversies associated with the discovery of obestatin and explore emerging central and peripheral roles of obestatin, which includes adipogenesis, pancreatic homeostasis and cancer.

Ghrelin in obesity and endocrine diseases

Ghrelin shows orexigenic effect through its action on the hypothalamic appetite-regulating pathways, while in the periphery ghrelin increases adipose tissue accumulation and has a diabetogenic effect on the liver and pancreas. Adenosine monophosphate-activated protein kinase (AMPK) has been suggested as one of the mediators of ghrelin's effects. Plasma ghrelin levels are dependent on body mass index as well as food intake patterns. Ghrelin levels are in general reduced in obese individuals and in subjects with insulin resistance. In contrast to other forms of obesity, patients with Prader-Willi syndrome (PWS) display high levels of ghrelin, reduced visceral adiposity and relative hypoinsulinemia. Relationships between obesity and common genomic variants of GHRL and GHS-R genes have been studied. Ghrelin may have a role in the weight-reducing effect of bariatric surgery; however, this is a much debated issue. Altered ghrelin levels have also been observed in Cushing's syndrome and thyroid disease probably due to the secondary insulin resistance in these subjects.

WITHDRAWN: Ghrelin in obesity and endocrine diseases

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.mce.2011.02.011. The duplicate article has therefore been withdrawn.