Antioxidant Defense Capacity Is Reduced in Thyroid Stem/Precursor Cells Compared to Differentiated Thyrocytes.

There is much evidence linking oxidative stress to thyroid cancer, and stem cells are thought to play a key role in the tumor-initiating mechanism. Their vulnerability to oxidative stress is unexplored. This study aimed to comparatively evaluate the antioxidant capacity of stem/precursor thyroid cells and mature thyrocytes. Human stem/precursor cells and mature thyrocytes were exposed to increasing concentrations of menadione, an oxidative-stress-producing agent, and reactive oxygen species (ROS) production and cell viability were measured. The expression of antioxidant and detoxification genes was measured via qPCR as well as the total antioxidant capacity and the content of glutathione. Menadione elevated ROS generation in stem/precursor thyroid cells more than in mature thyrocytes. The ROS increase was inversely correlated (p = 0.005) with cell viability, an effect that was partially prevented by the antioxidant curcumin. Most thyroid antioxidant defense genes, notably those encoding for the glutathione-generating system and phase I detoxification enzymes, were significantly less expressed in stem/precursor thyroid cells. As a result, the glutathione level and the total antioxidant capacity in stem/precursor thyroid cells were significantly decreased. This reduced antioxidant defense may have clinical implications, making stem/precursor thyroid cells critical targets for environmental conditions that are not detrimental for differentiated thyrocytes.

Risk for Coexistent Autoimmune Diseases in Familial and Sporadic Type 1 Diabetes is Related to Age at Diabetes Onset.

OBJECTIVE: Type 1 diabetes (T1D) is frequently associated with other autoimmune diseases (AIDs). Although most of T1D patients are sporadic cases (S-T1D), 10% to 15% have a familial form (F-T1D) involving 2 or more first-degree relatives. This study evaluated the effect of T1D family aggregation and age onset on AIDs occurrence. METHODS: In this observational, cross-sectional, case-control, single center study, we enrolled 115 F-T1D and 115 S-T1D patients matched for gender, age, T1D age onset, and duration. With respect to T1D age onset (before or after 18 years), both groups were further subdivided into young- or adult-onset F-T1D and young- or adult-onset S-T1D. The presence of organ-specific antibodies and/or overt AIDs was evaluated. RESULTS: The F-T1D group had a higher percentage of AIDs (29.8% vs 18.4%, P = .04) and a significant earlier onset of AIDs at Cox regression analysis (P = .04) than the S-T1D group. Based on multivariate analysis, the adult-onset F-T1D subgroup had the highest prevalence of both additional organ-specific antibodies (60.5%) and overt AIDs (34.9%), whereas the adult S-T1D subgroup was the least frequently involved (29.1% and 12.7%, respectively). In F-T1D patients, offsprings develop T1D and AIDs earlier than their parents do. CONCLUSIONS: In T1D patients, familial aggregation and adult-onset of T1D increase the risk for coexistent AIDs. These clinical predictors could guide clinicians to address T1D patients for the screening of T1D-related AIDs.

Insulin Receptor Isoforms Differently Regulate Cell Proliferation and Apoptosis in the Ligand-Occupied and Unoccupied State.

The insulin receptor (IR) presents two isoforms (IR-A and IR-B) that differ for the α-subunit C-terminal. Both isoforms are expressed in all human cells albeit in different proportions, yet their functional properties-when bound or unbound to insulin-are not well characterized. From a cell model deprived of the Insulin-like Growth Factor 1 Receptor (IGF1-R) we therefore generated cells exhibiting no IR (R-shIR cells), or only human IR-A (R-shIR-A), or exclusively human IR-B (R-shIR-B) and we studied the specific effect of the two isoforms on cell proliferation and cell apoptosis. In the absence of insulin both IR-A and IR-B similarly inhibited proliferation but IR-B was 2-3 fold more effective than IR-A in reducing resistance to etoposide-induced DNA damage. In the presence of insulin, IR-A and IR-B promoted proliferation with the former significantly more effective than the latter at increasing insulin concentrations. Moreover, only insulin-bound IR-A, but not IR-B, protected cells from etoposide-induced cytotoxicity. In conclusion, IR isoforms have different effects on cell proliferation and survival. When unoccupied, IR-A, which is predominantly expressed in undifferentiated and neoplastic cells, is less effective than IR-B in protecting cells from DNA damage. In the presence of insulin, particularly when present at high levels, IR-A provides a selective growth advantage.

Increased Thyroid Cancer Incidence in Volcanic Areas: A Role of Increased Heavy Metals in the Environment?

Thyroid cancer incidence is significantly increased in volcanic areas, where relevant non-anthropogenic pollution with heavy metals is present in the environment. This review will discuss whether chronic lifelong exposure to slightly increased levels of metals can contribute to the increase in thyroid cancer in the residents of a volcanic area. The influence of metals on living cells depends on the physicochemical properties of the metals and their interaction with the target cell metallostasis network, which includes transporters, intracellular binding proteins, and metal-responsive elements. Very little is known about the carcinogenic potential of slightly increased metal levels on the thyroid, which might be more sensitive to mutagenic damage because of its unique biology related to iodine, which is a very reactive and strongly oxidizing agent. Different mechanisms could explain the specific carcinogenic effect of borderline/high environmental levels of metals on the thyroid, including (a) hormesis, the nonlinear response to chemicals causing important biological effects at low concentrations; (b) metal accumulation in the thyroid relative to other tissues; and (c) the specific effects of a mixture of different metals. Recent evidence related to all of these mechanisms is now available, and the data are compatible with a cause-effect relationship between increased metal levels in the environment and an increase in thyroid cancer incidence.

Efficacy of Botulinum Toxin A for Treating Cramps in Diabetic Neuropathy.

OBJECTIVE: Muscle cramps occur in >50% of diabetic patients and reduce the quality of life. No effective treatment is available. We evaluated the clinical effectiveness of botulinum toxin A (BTX-A) injections for treating cramps in diabetic patients with neuropathy. METHODS: This single-center, double-blind, placebo-controlled perspective study investigated the efficacy and safety of BTX-A intramuscular injection for treating calf or foot cramps refractory to common pharmacological drugs. Fifty diabetic patients with peripheral neuropathy and cramps were randomly assigned to 2 matched groups. BTX-A (100 or 30 units) or saline was injected on each side into the gastrocnemius or the small flexor foot muscles. Changes in pain intensity (primary outcome) and cramp frequency were evaluated over the course of 20 weeks after BTX-A administration. Cramp interference in daily life and the electrophysiological cramp threshold frequency were also measured. The treatment was repeated 5 months after first injection in 19 responders. RESULTS: All outcome measures improved significantly after BTX-A compared with placebo. The changes with respect to baseline were already significant after 1 week and persisted up to week 14. Only 5 of 25 (20%) patients were nonresponders (<50% decrease of the primary outcome). The responses to a second BTX-A injection provided results similar to the first administration. Mild pain at the injection site (4/25 cases) was the only adverse event, and it disappeared within 2 to 3 days. INTERPRETATION: Local BTX-A infiltration is an efficacious and safe procedure for obtaining a sustained amelioration of muscle cramps associated with diabetic neuropathy. Ann Neurol 2018;84:682-690.

Impact of unhealthy childhood and unfavorable parents' characteristics on adiposity in schoolchildren.

BACKGROUND: Childhood obesity is encouraged by low physical activity (PA), time spent using screens (screen time, ST), and by sugar-sweetened beverage consumption (SSBc). It is also influenced by unfavorable parents' characteristics, such as a high body mass index (BMI) and low education level (EL). Our aim was to evaluate the overall and specific influence of these factors on childhood adiposity. MATERIAL AND METHODS: Anthropometric parameters including BMI z-score, waist circumference (WC), waist to height ratio (WtHR), and fat mass were measured in a cohort of 1702 schoolchildren (6.0-14.5 years, mean 10.7 ± 1.8) and questionnaires concerning children's PA, ST, and SSBc, and parent's BMI and EL were administered to parents. RESULTS: Overweight/obesity prevalence was higher (P < .0001) in males (57%) than in females (43%). Less physically active children (28.9%) had a higher prevalence of overweight/obesity and higher BMI z-score, WC, WtHR, and fat mass relative to more physically active children (P < .05). PA was negatively associated with the BMI z-score (r = 0.18, P < .0001) and fat mass percentage (r = 0.18, P < .0001). Children with more ST had higher WC and WtHR than non-ST viewers (P < .05) but not BMI. Moreover, SSBc did not influence the anthropometric parameters. At multivariate analysis, male gender, less PA, and parental risk factors (parent's overweight/obesity and low/medium EL) were independently associated with overweight and obesity among childhood with a progressively increasing odds ratio (1.65, 1.40, and 1.80, respectively). CONCLUSIONS: Male gender, behavioral risk factors (particularly low PA), and parent's characteristics are important correlates of obesity in children.

Differentiated thyroid cancer in children: Heterogeneity of predictive risk factors.

OBJECTIVE: To correlate clinical and pathological characteristics at diagnosis with patient long-term outcomes and to evaluate ongoing risk stratifications in a large series of paediatric differentiated thyroid cancers (DTC). STUDY DESIGN: Retrospective analysis of clinical and pathological prognostic factors of 124 paediatric patients with DTC (age at diagnosis <19 years) followed up for 10.4 ± 8.4 years. Patients with a follow-up >3 years (n = 104) were re-classified 18 months after surgery on the basis of their response to therapy (ongoing risk stratification). RESULTS: Most patients had a papillary histotype (96.0%), were older than 15 years (75.0%) and were diagnosed because of clinical local symptoms (63.7%). Persistent/recurrent disease was present in 31.5% of cases during follow-up, but at the last evaluation, only 12.9% had biochemical or structural disease. The presence of metastases in the lymph nodes of the lateral compartment (OR 3.2, 95% CI, 1.28-7.16, P = 0.01) was the only independent factor associated with recurrent/persistent disease during follow-up. At the last evaluation, biochemical/structural disease was associated with node metastases (N1a, N1b) by univariate but not multivariate analysis. Ongoing risk stratification compared to the initial risk classification method better identified patients with a lower probability of persistent/recurrent disease (NPV = 100%). CONCLUSIONS: In spite of the aggressive presentations at diagnosis, paediatric patients with DTC show an excellent response to treatment and often a favourable outcome. N1b status should be considered a strong predictor of persistent/recurrent disease which, as in adults, is better predicted by ongoing risk stratification.

Seasonal variations in TSH serum levels in athyreotic patients under L-thyroxine replacement monotherapy.

BACKGROUND: Whether serum TSH undergoes seasonal fluctuations in euthyroid and hypothyroid residents of temperate climates is controversial. METHODS: Monthly TSH and thyroid hormone levels were cross-sectionally analysed in a large cohort of euthyroid subjects (n=11 806) and L-thyroxine (L-T4)-treated athyreotic patients (n=3 934). Moreover, in a small group (n=119) of athyreotic patients treated with an unchanged dosage of L-T4 monotherapy, hormones were measured both in the coldest and in the hottest seasons of the same year (longitudinal study). RESULTS: No seasonal hormone change was observed in the euthyroid subjects except for a small FT3 increase in winter (+2.9%, P<.001). In contrast, the L-T4-treated athyreotic patients had significantly higher serum TSH values in the cold season when the FT4 values were significantly lower. The differences were more notable in the longitudinal series (TSH, 0.80 vs. 0.20 mU/L and FT4, 16.3 vs. 17.8 pmol/L in December-March vs. June-September, respectively). In these patients also serum FT3 values significantly decreased in winter (in the longitudinal series, 3.80 in winter vs 4.07 pmol/L in summer). Regression analysis showed that in athyreotic subjects, a greater FT4 change is required to obtain a TSH change similar to that of euthyroid controls and that this effect is more pronounced in the summer. CONCLUSION: Athyreotic patients undergoing L-T4 monotherapy have abnormal seasonal variations in TSH. These changes are secondary to the FT4 and FT3 serum decreases in winter, which occur in spite of the constant treatment. The underlying mechanisms are unclear, but in some cases, these changes may be clinically relevant.

The changing epidemiology of thyroid cancer: why is incidence increasing?

PURPOSE OF REVIEW: Thyroid cancer incidence is increasing worldwide. Causes are highly debated. RECENT FINDINGS: Thyroid cancer increase has been associated to socioeconomic status, better access to healthcare and rising use of thyroid imaging. Therefore, the rise could be apparent because of the useless identification of a large reservoir of subclinical papillary lesions that will never affect patient health (overdiagnosis).However, not all epidemiological and clinical data support this hypothesis. The increasing number of large tumors, the increasing thyroid cancer-related mortality in spite of earlier treatment and the changes in thyroid cancer molecular profile suggest a true increase. Recently increased and thyroid-specific environmental carcinogens could be responsible, such as radiation (mostly medical radiation), increased iodine intake and chronic lymphocytic thyroiditis and environmental pollutants such as nitrates, heavy metals and other compounds largely used in the industrialized society. Possible mechanisms await further investigation. SUMMARY: The increased incidence of thyroid cancer is the likely result of two coexisting processes: increased detection (apparent increase) and increased number of cases (true increase) due to unrecognized thyroid-specific carcinogens.To identify causal factors and to differentiate stationary cancers from those that will progress are major urgent requirements for both clinical and scientific purposes.

Efficacy of real-time continuous glucose monitoring on glycaemic control and glucose variability in type 1 diabetic patients treated with either insulin pumps or multiple insulin injection therapy: a randomized controlled crossover trial.

BACKGROUND: The aim of this study was to determine the efficacy of real-time continuous glucose monitoring in T1D patients treated with insulin pump therapy or multiple daily insulin therapy. METHODS: Twenty adult patients (ten insulin pump therapy and ten multiple daily insulin) with poor glycaemic control (HbA1c > 8.0%) were randomized into two groups for 6 months: the continuous glucose monitoring arm (using real-time continuous glucose monitoring) and the SMBG arm. After 2 months of wash-out, the participants crossed over. The primary outcome was HbA1c reduction. The secondary outcomes were hypoglycaemia and hyperglycaemia risk assessment (area under the curve < 70 mg/dL/day and AUC > 200 mg/dL/day, respectively) and glucose variability. RESULTS: Fourteen patients (eight multiple daily insulin, six insulin pump therapy) used continuous glucose monitoring appropriately (at least 40% of the time). In these patients, the improvement in glycaemic control was more evident during the real-time continuous glucose monitoring period (7.76% ± 0.4 vs 8.54% ± 0.4, p < 0.05) than during the self-monitoring of blood glucose period (8.42% ± 0.4 vs 8.56% ± 0.5, p = 0.2). Better results with continuous glucose monitoring were observed in patients using multiple daily insulin with greater improvement in both glycaemic control (7.71% ± 0.2 vs 8.58% ± 0.2, p < 0.05) and glucose variability and with a marked reduction in the risk of both hypoglycaemia and hyperglycaemia. CONCLUSIONS: Appropriate use of real-time continuous glucose monitoring improved glycometabolic control in T1D patients. The effects of continuous glucose monitoring were more evident in patients under multiple daily insulin treatment, compared with insulin pump therapy. Glucose variability, in addition to glycaemic control, was improved in compliant diabetic patients.

Biological effects of insulin and its analogs on cancer cells with different insulin family receptor expression.

Hyperinsulinemia is a likely cause of the increased cancer incidence and mortality in diabetic patients, but its role is difficult to define in vivo. Previous in vitro studies testing the mitogenic potential of insulin and its analogs provided incomplete and sometimes contradictory results. To better evaluate cancer cell responsiveness to insulin, to its analogs and to IGF-I, we measured under identical experimental conditions cell proliferation, invasiveness, and foci formation in six cancer cell lines with different insulin receptor family expression levels. The cancer cells studied have a different expression of insulin receptor (IR), its isoforms (IR-A and IR-B), and of the IGF-I receptor. The data indicate that insulin stimulates proliferation in all cancer cell lines, invasiveness in some, and foci formation in none. Cancer cell responses to insulin (and IGF-I) are not related to receptor expression levels; moreover, hormone-stimulated proliferation and invasiveness are not correlated. IGF-I is a more potent stimulator than insulin in most but not all cancer cell lines. Insulin analogs including M1 and M2 Glargine metabolites stimulate cancer cells similar to insulin. However, exceptions occur for specific analogs in particular cancer cells. In conclusion, in vitro insulin is an effective growth factor for all cancer cells but the biological response to insulin cannot be predicted on the basis of receptor expression levels. In the clinical setting, these observations should be taken in account when deciding treatment for diabetic patients who are at risk of undiscovered cancer or survivors of oncological diseases.

Insulin autoimmune syndrome (Hirata Disease) in European Caucasians taking α-lipoic acid.

OBJECTIVE: Lipoic acid (LA) is a widely used nutritional supplement and is sometimes used as an adjuvant treatment for diabetic neuropathy and other conditions. Insulin autoimmune syndrome (IAS, Hirata disease) is a rare cause of spontaneous hypoglycaemia, extremely high serum insulin levels and high titres of autoantibodies against endogenous insulin despite no prior exposure to exogenous insulin. In Japanese individuals, IAS is associated with the human leucocyte antigen (HLA) HLA-DRB1*04:06 allele and often occurs upon exposure to sulphhydryl-containing compounds including LA. Only one case has been reported in Caucasians. We now report six Caucasian patients taking LA with IAS and describe a unique HLA subtype in these patients. RESEARCH DESIGN AND METHODS: Six Caucasian patients (M = 3; F = 3), median age 63 years, presented with spontaneous episodes of fasting and postabsorptive hypoglycaemia associated with mainly neuroglycopenic symptoms. No patient was treated with insulin or had an insulinoma. Hypoglycaemic symptoms appeared 30 and 120 days after taking lipoic acid (LA; 600 mg/day). Case histories and standard laboratory analyses were utilized. RESULTS: Discontinuation of LA resulted in a reduction in hypoglycaemic episodes. All patients were treated with oral or iv glucose and prednisone (12.5-25 mg/day). HLA analysis revealed the HLA-DRB1*04:03 allele in five patients, while the HLA-DRB1*04:06 allele was present in one patient. CONCLUSIONS: This is the first report of LA-related IAS in Caucasians who possess the HLA-DRB1*04:03 allele, implicating this allele in the genetic susceptibility to IAS in Caucasians. The greater occurrence of the HLA-DRB1*04:03 allele in Caucasian and other populations, combined with the growing use of LA in developed countries, may be a future predictor of additional cases of IAS.

Reactivation of p53 mutants by prima-1 [corrected] in thyroid cancer cells.

Most undifferentiated thyroid carcinomas express p53 mutants and thereafter, are very resistant to chemotherapy. p53 reactivation and induction of massive apoptosis (Prima-1) is a compound restoring the tumor-suppressor activity of p53 mutants. We tested the effect of Prima-1 in thyroid cancer cells harboring p53 mutations. Increasing doses of Prima-1 reduced viability of thyroid cancer cells at a variable extent (range 20-80%). Prima-1 up-regulated p53 target genes (p21(WAF1) , BCL2-associated X protein (Bax), and murine double minute 2 (MDM2)), in BC-PAP and Hth-74 cells (expressing D259Y/K286E and K286E p53 mutants) but had no effect in SW1736 (p53 null) and TPC-1 (expressing wild-type p53) thyroid cancer cells. Prima-1 also increased the cytotoxic effects of either doxorubicin or cisplatin in thyroid cancer cells, including the chemo-resistant 8305C, Hth-74 and BC-PAP cells. Moreover, real-time PCR and Western blot indicated that Prima-1 increases the mRNA of thyroid-specific differentiation markers in thyroid cancer cells. Fluorescence-activated cell sorting analysis revealed that Prima-1 effect on thyroid cancer cells occurs via the enhancement of both cell cycle arrest and apoptosis. Small interfering RNA experiments indicated that Prima-1 effect is mediated by p53 mutants but not by the p53 paralog p73. Moreover, in C-643 thyroid cancer cells, forced to ectopically express wild-type p53, Prima-1 prevented the dominant negative effect of double K248Q/K286E p53 mutant. Finally, co-IP experiments indicated that in Hth-74 cells Prima-1 prevents the ability of p53 mutants to sequestrate the p53 paralog TAp73. These in vitro studies imply that p53 mutant reactivation by small compounds may become a novel anticancer therapy in undifferentiated thyroid carcinomas.

The role of membrane glycoprotein plasma cell antigen 1/ectonucleotide pyrophosphatase phosphodiesterase 1 in the pathogenesis of insulin resistance and related abnormalities.

Insulin resistance is a major feature of most patients with type 2 diabetes mellitus (T2D). A number of laboratories have observed that PC-1 (membrane [corrected] glycoprotein plasma cell antigen 1; also termed [corrected] ectonucleotide pyrophosphatase phosphodiesterase 1 or ENPP1) [corrected] is either overexpressed or overactive in muscle, adipose tissue, fibroblasts, and other tissues of insulin-resistant individuals, both nondiabetic and diabetic. Moreover, PC-1 (ENPP1) overexpression [corrected] in cultured cells in vitro and in transgenic mice in vivo, [corrected] impairs insulin stimulation of insulin receptor (IR) activation and downstream signaling. PC-1 binds to the connecting domain of the IR alpha-subunit that is located in residues 485-599. The connecting domain transmits insulin binding in the alpha-subunit to activation of tyrosine kinase activation in the beta-subunit. When PC-1 is overexpressed, it inhibits insulin [corrected]induced IR beta-subunit tyrosine kinase activity. In addition, a polymorphism of PC-1 (K121Q) in various ethnic populations is closely associated with insulin resistance, T2D, and cardio [corrected] and nephrovascular diseases. The product of this polymorphism has a 2- to 3-fold increased binding affinity for the IR and is more potent than the wild-type PC-1 protein (K121K) in inhibiting the IR. These data suggest therefore that PC-1 is a candidate protein that may play a role in human insulin resistance and T2D by its overexpression, its overactivity, or both.

Levels of histone acetylation in thyroid tumors.

Histone acetylation is a major mechanism to regulate gene transcription. This post-translational modification is modified in cancer cells. In various tumor types the levels of acetylation at several histone residues are associated to clinical aggressiveness. By using immunohistochemistry we show that acetylated levels of lysines at positions 9-14 of H3 histone (H3K9-K14ac) are significantly higher in follicular adenomas (FA), papillary thyroid carcinomas (PTC), follicular thyroid carcinomas (FTC) and undifferentiated carcinomas (UC) than in normal tissues (NT). Similar data have been obtained when acetylated levels of lysine 18 of H3 histone (H3K18ac) were evaluated. In this case, however, no difference was observed between NT and UC. When acetylated levels of lysine 12 of H4 histone (H4K12ac) were evaluated, only FA showed significantly higher levels in comparison with NT. These data indicate that modification histone acetylation is an early event along thyroid tumor progression and that H3K18 acetylation is switched off in the transition between differentiated and undifferentiated thyroid tumors. By using rat thyroid cell lines that are stably transfected with doxycyclin-inducible oncogenes, we show that the oncoproteins RET-PTC, RAS and BRAF increase levels of H3K9-K14ac and H3K18ac. In the non-tumorigenic rat thyroid cell line FRTL-5, TSH increases levels of H3K18ac. However, this hormone decreases levels of H3K9-K14ac and H4K12ac. In conclusion, our data indicate that neoplastic transformation and hormonal stimulation can modify levels of histone acetylation in thyroid cells.

Maternal Diabetes Impairs Insulin and IGF-1 Receptor Expression and Signaling in Human Placenta.

Background: Maternal high blood glucose during pregnancy increases the risk for both maternal and fetal adverse outcomes. The mechanisms underlying the regulator effects of hyperglycemia on placental development and growth have not been fully illustrated yet. The placenta expresses high amounts of both insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R). It has been reported that the placenta of diabetic women has structural and functional alterations and the insulin/IGF system is likely to play a role in these changes. The aim of the present study was to measure the content of IR and IGF-1R and their phosphorylation in the placenta of women with type 1 diabetes mellitus (T1D) or with gestational diabetes mellitus (GDM) compared to women with normal glucose tolerance (NGT) during pregnancy. Methods: Placental tissues were obtained from 80 Caucasian women with a singleton pregnancy. In particular, we collected placenta samples from 20 T1D patients, 20 GDM patients and 40 NGT women during pregnancy. Clinical characteristics and anthropometric measures of all women as well as delivery and newborn characteristics were recorded. Patients were also subdivided on the basis of peripartum glycemia either ≥90 mg/dl or <90 mg/dl, regardless of the diagnosis. Results: In T1D patients, a higher rate of adverse outcomes was observed. Compared to the GDM women, the T1D group showed significantly higher average capillary blood glucose levels at the third trimester of pregnancy and at peripartum, and higher third-trimester HbA1c values. In both T1D and GDM women, HbA1c values during pregnancy correlated with glucose values in the peripartum period (R-squared 0.14, p=0.02). A positive correlation was observed between phosphorylation of placental IR and the glucose levels during the third trimester of GDM and T1D pregnancy (R-squared 0.21, p=0.003). In the placenta of T1D patients, IGF-1R phosphorylation and IR isoform A (IR-A) expression were significantly increased (p=0.006 and p=0.040, respectively), compared to the NGT women. Moreover, IGF-1R phosphorylation was significantly increased (p<0.0001) in the placenta of patients with peripartum glucose >90 mg/dl, while IR-A expression was increased in those with peripartum blood glucose higher than 120 mg/dl (p=0.046). Conclusions: To the best of our knowledge, our study represents the first one in which an increased maternal blood glucose level during pregnancy is associated with an increased IGF-1R phosphorylation and IR-A expression in the placenta. Both these mechanisms can promote an excessive fetal growth.

Thyroid Stem Cells But Not Differentiated Thyrocytes Are Sensitive to Slightly Increased Concentrations of Heavy Metals.

Thyroid cancer incidence is markedly increased in volcanic areas where residents are biocontaminated by chronic lifelong exposure to slightly increased metals in the environment. Metals can influence the biology of living cells by a variety of mechanisms, depending not only on the dose and length of exposure but also on the type and stage of differentiation of target cells. We explored the effect of five heavy metals (Cu, Hg, Pd, W and Zn) at nanomolar concentrations (the biocontamination level in residents of the volcanic area in Sicily where thyroid cancer is increased) on stimulating the proliferation of undifferentiated (thyrospheres) and differentiated human thyroid cells. Thyrosphere proliferation was significantly increased after exposure to each individual metal and a greater stimulating effect was observed when a mixture of the examined metals was used. No effect was seen in differentiated thyrocytes. For all metals, the dose-response curve followed a biphasic pattern that is typical of hormesis. Thyrosphere growth concerned the size rather than number, except with the metal mixture. An altered morphology was also observed in metal-treated thyrospheres. Metal-induced proliferation was due to activation of the ERK1/2 pathway, as confirmed by growth inhibition when ERK1/2 signaling was blocked. These studies show that stem/precursor thyroid cells are sensitive to small increases in environmental metal concentrations that are harmless for differentiated thyrocytes.

Heavy Metals in the Environment and Thyroid Cancer.

In recent decades, the incidence of thyroid cancer has increased more than most other cancers, paralleling the generalized worldwide increase in metal pollution. This review provides an overview of the evidence supporting a possible causative link between the increase in heavy metals in the environment and thyroid cancer. The major novelty is that human thyroid stem/progenitor cells (thyrospheres) chronically exposed to different metals at slightly increased environmentally relevant concentrations show a biphasic increase in proliferation typical of hormesis. The molecular mechanisms include, for all metals investigated, the activation of the extracellular signal-regulated kinase (ERK1/2) pathway. A metal mixture, at the same concentration of individual metals, was more effective. Under the same conditions, mature thyrocytes were unaffected. Preliminary data with tungsten indicate that, after chronic exposure, additional abnormalities may occur and persist in thyrocytes derived from exposed thyrospheres, leading to a progeny population of transformation-prone thyroid cells. In a rat model predisposed to develop thyroid cancer, long-term exposure to low levels of metals accelerated and worsened histological signs of malignancy in the thyroid. These studies provide new insight on metal toxicity and carcinogenicity occurring in thyroid cells at a low stage of differentiation when chronically exposed to metal concentrations that are slightly increased, albeit still in the "normal" range.