With the increasing use of thyroid ultrasound, the recognition of thyroid nodules in a large proportion of apparently healthy subjects has become common. Because also the papillary thyroid microcarcinomas (PTMC) are being increasingly discovered, it is important to ascertain whether PTMC may exhibit heterogenous clinical features, associated with different aggressiveness. AIM: We retrospectively examined 122 subjects [98 female (80.3%), and 24 male (19.7%)] with thyroid cancer to find potential clinical and pathological findings that could be predictive of clinically aggressive behavior. RESULTS: Twenty of the 31 patients with true incidental cancer (64.5%) in comparison to 20 of the 91 patients with non-incidental cancer (21.9%) had a diameter <10 mm, and this difference was statistically significant (p<0.0001). There was a statistically significant association between size and invasiveness because 19.3% of invasive cancers were <10 mm whereas 44.6% of non-invasive cancers were <10 mm (p=0.005). The relationship between incidental discovery and invasiveness was also evaluated, but the proportion of incidental invasive cancer (19.3%) was not significantly different from that of incidental non-invasive cancer (30.8%). In the multivariate analysis, only size <10 mm (odds ratio=0.35, p=0.013) and papillary vs other histotypes (odds ratio=0.35, p=0.04) were statistically significant protective factors against invasiveness. CONCLUSIONS: a) Incidentally discovered thyroid cancers are more frequently microcarcinomas; b) there appears to be no difference in terms of invasive behavior between incidental and non-incidental thyroid cancer; c) smaller tumor size emerges as a protective factor.

In obese subjects with obstructive sleep apnea (OSA), chronic intermittent hypoxia (CIH) may be linked to systemic and adipose tissue inflammation.

Diabetes and cancer are worldwide chronic diseases with a major impact on the quality and expectancy of life. Metabolic abnormalities observed during the onset and progression of diabetes may have a critical role on the initiation and progression of carcinogenesis. To date, there are no conclusive data on the mechanisms underlying the relationship between diabetes and any type of human cancer. However, recent evidence suggests that both hyperglycemia and hyperinsulinemia in diabetes could elicit cell damage responses, such as glucotoxicity, lipotoxicity and oxidative stress, which participate in the cell transformation process raising the risk of cancer development. In addition, clinical trials have revealed that several anti-diabetes therapies may potentially affect the risk of cancer though largely undefined mechanisms. In this review, we highlight epidemiological and pathophysiological aspects of diabetes, which may influence cancer initiation and progression.

Differences in the inherent properties of adipose tissue-derived stem cells (ASC) may contribute to the biological specificity of the subcutaneous (Sc) and visceral (V) adipose tissue depots. In this study, three distinct subpopulations of ASC, i.e. ASCSVF, ASCBottom, and ASCCeiling, were isolated from Sc and V fat biopsies of non-obese subjects, and their gene expression and functional characteristics were investigated. Genome-wide mRNA expression profiles of ASCSVF, ASCBottom and ASCCeiling from Sc fat were significantly different as compared to their homologous subsets of V-ASCs. Furthermore, ASCSVF, ASCCeiling and ASCBottom from the same fat depot were also distinct from each other. In this respect, both principal component analysis and hierarchical clusters analysis showed that ASCCeiling and ASCSVF shared a similar pattern of closely related genes, which was highly different when compared to that of ASCBottom. However, larger variations in gene expression were found in inter-depot than in intra-depot comparisons. The analysis of connectivity of genes differently expressed in each ASC subset demonstrated that, although there was some overlap, there was also a clear distinction between each Sc-ASC and their corresponding V-ASC subsets, and among ASCSVF, ASCBottom, and ASCCeiling of Sc or V fat depots in regard to networks associated with regulation of cell cycle, cell organization and development, inflammation and metabolic responses. Finally, the release of several cytokines and growth factors in the ASC cultured medium also showed both inter- and intra-depot differences. Thus, ASCCeiling and ASCBottom can be identified as two genetically and functionally heterogeneous ASC populations in addition to the ASCSVF, with ASCBottom showing the highest degree of unmatched gene expression. On the other hand, inter-depot seem to prevail over intra-depot differences in the ASC gene expression assets and network functions, contributing to the high degree of specificity of Sc and V adipose tissue in humans.

Glucagon-like peptide-1 and its analogs may preserve pancreatic beta-cell mass by promoting resistance to cytokine-mediated apoptosis. The mechanisms of TNFalpha-induced apoptosis and of its inhibition by exendin-4 were investigated in insulin-secreting cells. INS-1 and MIN6 insulinoma cells were exposed to 20 ng/ml TNFalpha, with or without pretreatment with 10 nm exendin-4. Treatment with TNFalpha increased c-Jun N-terminal protein kinase (JNK) phosphorylation 2-fold, reduced inhibitor-kappaBalpha (IkappaBalpha) protein content by 50%, induced opposite changes in caspase-3 and Bcl-2 protein content, and increased cellular apoptosis. Moreover, exposure to TNFalpha resulted in increased serine phosphorylation of both insulin receptor substrate (IRS)-1 and IRS-2 and reduced basal and insulin-induced Akt phosphorylation. However, in the presence of a JNK inhibitor, TNFalpha-induced apoptosis was diminished and serine phosphorylation of IRS proteins was prevented. When cells were pretreated with exendin-4, TNFalpha-induced JNK and IRS-1/2 serine phosphorylation was markedly reduced, Akt phosphorylation was increased, caspase-3 and Bcl-2 protein levels were restored to normal, and TNFalpha-induced apoptosis was inhibited by 50%. This was associated with a 2-fold increase in IRS-2 expression levels. A similar ability of exendin-4 to prevent TNFalpha-induced JNK phosphorylation was found in isolated pancreatic human islets. The inhibitory effect of exendin-4 on TNFalpha-induced JNK phosphorylation was abrogated in the presence of the protein kinase A inhibitor H89. In conclusion, JNK activation mediates TNFalpha-induced apoptosis and impairment of the IRS/Akt signaling pathway in insulin-secreting cells. By inhibiting JNK phosphorylation in a PKA-dependent manner, exendin-4 counteracts TNFalpha-mediated apoptosis and reverses the inhibitory events in the IRS/Akt pathway, resulting in promotion of cell survival.

AIMS/HYPOTHESIS: The mechanisms of the protective effects of exendin-4 on NEFA-induced beta cell apoptosis were investigated. METHODS: The effects of exendin-4 and palmitate were evaluated in human and murine islets, rat insulin-secreting INS-1E cells and murine glucagon-secreting alpha-TC1-6 cells. mRNA and protein expression/phosphorylation were measured by real-time RT-PCR and immunoblotting or immunofluorescence, respectively. Small interfering (si)RNAs for Ib1 and Gpr40 were used. Cell apoptosis was quantified by two independent assays. Insulin release was assessed with an insulin ELISA. RESULTS: Exposure of human and murine primary islets and INS-1E cells, but not alpha-TC1-6 cells, to exendin-4 inhibited phosphorylation of the stress kinases, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), and prevented apoptosis in response to palmitate. Exendin-4 increased the protein content of islet-brain 1 (IB1), an endogenous JNK blocker; however, siRNA-mediated reduction of IB1 did not impair the ability of exendin-4 to inhibit JNK and prevent apoptosis. Exendin-4 reduced G-protein-coupled receptor 40 (GPR40) expression and inhibited palmitate-induced phosphorylation of mitogen-activated kinase kinase (MKK)4 and MKK7. The effects of exendin-4 were abrogated in the presence of the protein kinase A (PKA) inhibitors, H89 and KT5720. Knockdown of GPR40, as well as use of a specific GPR40 antagonist, resulted in diminished palmitate-induced JNK and p38 MAPK phosphorylation and apoptosis. Furthermore, inhibition of JNK and p38 MAPK activity prevented palmitate-induced apoptosis. CONCLUSIONS/INTERPRETATION: Exendin-4 counteracts the proapoptotic effects of palmitate in beta cells by reducing GPR40 expression and inhibiting MKK7- and MKK4-dependent phosphorylation of the stress kinases, JNK and p38 MAPK, in a PKA-dependent manner.

Insulin is a major endocrine hormone also involved in the regulation of energy and lipid metabolism via the activation of an intracellular signaling cascade involving the insulin receptor (INSR), insulin receptor substrate (IRS) proteins, phosphoinositol 3-kinase (PI3K) and protein kinase B (AKT). Specifically, insulin regulates several aspects of the development and function of adipose tissue and stimulates the differentiation program of adipose cells. Insulin can activate its responses in adipose tissue through two INSR splicing variants: INSR-A, which is predominantly expressed in mesenchymal and less-differentiated cells and mainly linked to cell proliferation, and INSR-B, which is more expressed in terminally differentiated cells and coupled to metabolic effects. Recent findings have revealed that different distributions of INSR and an altered INSR-A:INSR-B ratio may contribute to metabolic abnormalities during the onset of insulin resistance and the progression to type 2 diabetes. In this review, we discuss the role of insulin and the INSR in the development and endocrine activity of adipose tissue and the pharmacological implications for the management of obesity and type 2 diabetes.

Type 2 diabetes mellitus is increasing in prevalence at alarming rates. Concurrent with its expanding prevalence is the increase in the related risk of morbidity and mortality. Because diabetic patients are prone to cardiovascular disease, treatment strategies should address the cardiovascular risk factors, including blood pressure, lipids, and body weight, in addition to the glycemic aspects of the disease. Newer agents, such as glucagon-like peptide-1 (GLP-1) analogs and dipeptidyl peptidase-4 (DPP-4) inhibitors, have varying degrees of evidence to support their effects on body weight, blood pressure, and lipid levels, beyond glycated hemoglobin reduction. While GLP-1 agonists produce a weight loss, the DPP-4 inhibitors, conversely, appear to have a weight-neutral effect. Substantial evidence demonstrates that both medications produce modest reductions in systolic blood pressure and, in some cases, diastolic blood pressure, and reduce several markers of cardiovascular risk, including C-reactive protein. Moreover, GLP-1 influences endothelial function. The effect of the incretin hormones on serum lipids are either neutral or beneficial, with small, non-significant decreases in LDL cholesterol, increases in HDL cholesterol, and occasionally significant decreases in fasting triglyceride levels. Also, they have positive effects on hepatic steatosis. Although GLP-1 agonists and DPP-4 inhibitors are at present not appropriate for primary treatment of cardiovascular risks factors, the reduction of these parameters is evidently beneficial.

p66Shc, a 66 kDa proto-oncogene Src collagen homologue (Shc) adaptor protein, is classically known as a signalling protein implicated in receptor tyrosine kinase signal transduction. The p66Shc isoform exerts a physiologically relevant, inhibitory signalling effect on the Erk pathway in skeletal muscle myoblasts, which is necessary for actin cytoskeleton polymerization and normal glucose transport responses. More recently, p66Shc has been also identified as a sensor of oxidative stress-induced apoptosis and as a longevity protein in mammals, actions which require Ser36 phosphorylation of the protein and consequent accumulation of intracellular reactive oxygen species. Oxidative stress plays a key role in dysfunction of several organs and tissues, and this is of interest in metabolic diseases such as type 2 diabetes. Thus changes in p66Shc expression and/or function may play an important role in the pathogenesis of type 2 diabetes and potentially serve as an effective target for its treatment.

The small ubiquitin-like modifier-conjugating enzyme UBC9, involved in protein modification through covalent attachment of small ubiquitin-like modifier and other less defined mechanisms, has emerged as a key regulator of cell proliferation and differentiation. To explore the role of UBC9 in adipocyte differentiation, the UBC9 protein levels were examined in differentiating 3T3-L1 cells. UBC9 mRNA and protein levels were increased 2.5-fold at d 2 and then gradually declined to basal levels at d 8 of differentiation. In addition, UBC9 was expressed predominantly in the nucleus of preadipocytes but shifted to cytoplasmic compartments after d 4, after induction of differentiation. UBC9 knockdown was then achieved in differentiating 3T3-L1 preadipocytes using a specific small interfering RNA. Oil-Red-O staining demonstrated accumulation of large triglyceride droplets in approximately 90% of control cells, whereas lipid droplets were smaller and evident in only 30% of cells treated with the UBC9-specific small interfering RNA. CCAAT/enhancer-binding protein (C/EBP)-δ, peroxisome proliferator-activated receptor-γ, and C/EBPα mRNA levels were increased severalfold 2-6 d after induction of differentiation in control cells, whereas the expression of these transcription factors was significantly lower in the presence of UBC9 gene silencing. Adenovirus-mediated overexpression of a catalytically inactive mutant UBC9 protein in 3T3-L1 cells resulted in no changes in expression of adipogenic transcription factors and conversion to mature adipocytes as compared with control. In conclusion, UBC9 appears to play an important role in adipogenesis. The temporal profile of UBC9 induction and its ability to affect C/EBPδ mRNA induction support a role for this protein during early adipogenesis.

The widespread increase in life expectancy is accompanied by an increased prevalence of features of physical frailty. Signs and symptoms may include sarcopenia and osteopenia, reduced exercise capacity, and diminished sense of well-being. The pathogenesis of age-associated sarcopenia and osteopenia is multifactorial, and hormonal decline may be a contributing factor. Aging is associated with a progressive decrease in GH secretion, and more than 30% of elderly people have circulating IGF1 levels below the normal range found in the young. GH acts directly on target tissues, including skeletal muscle and bone among many others, but many effects are mediated indirectly by circulating (liver-derived) or locally produced IGF1. Aging is also associated with reduced insulin sensitivity which, in turn, may contribute to the impairment of IGF1 action. Recent experimental evidence suggests that besides the age-dependent decline in GH and IGF1 serum levels, the dysregulation of GH and IGF1 actions due to impairment of the post-receptor signaling machinery may contribute to the loss of muscle mass and osteopenia. This article will focus on the molecular mechanisms of impaired GH and IGF1 signaling and action in aging, and their role in the pathogenesis of sarcopenia and osteoporosis.

The p66(Shc) protein mediates oxidative stress-related injury in multiple tissues. Steatohepatitis is characterized by enhanced oxidative stress-mediated cell damage. The role of p66(Shc) in redox signaling was investigated in human liver cells and alcoholic steatohepatitis. HepG2 cells with overexpression of wild-type or mutant p66(Shc), with Ser(36) replacement by Ala, were obtained through infection with recombinant adenoviruses. Reactive oxygen species and oxidation-dependent DNA damage were assessed by measuring dihydroethidium oxidation and 8-hydroxy-2'-deoxyguanosine accumulation into DNA, respectively. mRNA and protein levels of signaling intermediates were evaluated in HepG2 cells and liver biopsies from control and alcoholic steatohepatitis subjects. Exposure to H2O2 increased reactive oxygen species and phosphorylation of p66(Shc) on Ser(36) in HepG2 cells. Overexpression of p66(Shc) promoted reactive oxygen species synthesis and oxidation-dependent DNA damage, which were further enhanced by H2O2. p66(Shc) activation also resulted in increased Erk-1/2, Akt and FoxO3a phosphorylation. Blocking of Erk-1/2 activation inhibited p66(Shc) phosphorylation on Ser(36). Increased p66Shc expression was associated with reduced mRNA levels of anti-oxidant molecules, such as NF-E2-related factor 2 and its target genes. In contrast, overexpression of the phosphorylation defective p66(Shc) Ala(36) mutant inhibited p66(Shc) signaling, enhanced anti-oxidant genes, and suppressed reactive oxygen species and oxidation-dependent DNA damage. Increased p66(Shc) protein levels and Akt phosphorylation were observed in liver biopsies from alcoholic steatohepatitis compared to control subjects.

La nostra invenzione riguarda il possibile impiego di una proteina nota, denominata irisina, derivante dal clivaggio di un precursore di membrana chiamato fibronectin type III domain-containing protein 5 (FNDC5), come farmaco per la preservazione della funzionalità e della sopravvivenza delle popolazioni cellulari che compongono l’isola pancreatica, deputata alla produzione di insulina. I risultati sperimentali, da noi ottenuti, dimostrano la capacità dell’irisina di indurre la sintesi e di stimolare la secrezione di insulina glucosio-indotta da parte delle beta-cellule pancreatiche. Inoltre, l’irisina promuove la proliferazione delle beta-cellule e ne riduce la morte indotta dall’esposizione cronica ad acidi grassi saturi. Queste proprietà fanno dell’irisina un valido ausilio nella terapia farmacologica del diabete mellito di tipo 2 e di tutte le condizioni patologiche caratterizzate da alterazioni della funzione secretoria, dalla riduzione del numero delle beta-cellule pancreatiche e da modificazioni della normale architettura/funzione dell’isola pancreatica.