Donatella Cortelazzi

Maternal and foetal resistin and adiponectin concentrations in normal and complicated pregnancies

Objective   The aim of this study was to evaluate how resistin and adiponectin (ApN) are involved in maternal energy metabolism and foetal growth.

Fetal Plasma Leptin Concentrations: Relationship with Different Intrauterine Growth Patterns from 19 Weeks to Term

The relationship between in utero fetal growth and fetal leptin concentrations was investigated between 19 and 41 wk in 40 normal (appropriate for gestational age, AGA) fetuses, in 25 intrauterine growth-restricted (IUGR) fetuses, and in 18 fetuses from gestational diabetic mothers (GDM), representing different intrauterine growth patterns. Umbilical venous plasma leptin concentrations were determined at the time of either in utero fetal blood sampling or delivery. Plasma leptin was measurable as early as 19 wk of gestation. A significant difference was observed between umbilical venous and arterial plasma leptin concentrations (0.6 ± 0.6 ng/mL;p < 0.01). In AGA and in IUGR fetuses, significant positive relationships were found between fetal leptin concentrations and both gestational age (p < 0.001) and fetal weight (p < 0.001). Leptin concentrations were significantly higher in AGA than IUGR only after 34 wk (p < 0.05), but leptin per kilogram fetal weight (leptin/kg) was not significantly different. In IUGR with abnormal umbilical arterial Doppler velocimetry and fetal heart rate, leptin/kg significantly higher than in IUGR with normal biophysical and biochemical parameters was found (p < 0.05). Both circulating plasma leptin and leptin/kg were significantly higher in GDM than in normal fetuses (p < 0.001) and correlated with abdominal fat mass measured by ultrasound. No gender differences were observed in any group of fetuses. These findings indicate a clear relationship between fetal leptin concentrations and fetal fat mass. Data in severe IUGR suggest the presence of increased leptin concentrations associated with in utero signs of fetal distress.

Frequent association between MEN 2A and cutaneous lichen amyloidosis.

objective Multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC) are genetic diseases due to activating mutations of the RET proto‐oncogene. Affected patients develop medullary thyroid carcinoma (100%), in an isolated form (FMTC) or in association with phaeochromocytoma (30–50%), and primary hyperparathyroidism (10–20%) (MEN 2A). The presence of cutaneous lichen amyloidosis (CLA) has been anecdotally described in few families harbouring RET proto‐oncogene mutation in codon 634. The aim of the study was to evaluate the incidence of CLA in MEN 2A/FMTC families.

Adjustment of L-T4 substitutive therapy in pregnant women with subclinical, overt or post-ablative hypothyroidism

Objective  Maternal hyperthyrotropinaemia is associated with an increased risk of adverse maternal and neonatal outcomes. Physiological changes during pregnancy require an increased production of thyroid hormones (or an increase in daily substitutive doses of L‐T4 in hypothyroid patients) to meet the maternal and foetal needs. The aim of the study was to evaluate variations of substitutive L‐T4 doses that are able to maintain serum TSH between 0·5 and 2·5 mU/l in pregnant women with subclinical‐ (SH), overt‐ (OH) and post‐ablative (PH) hypothyroidism.

Circulating levels of growth hormone, insulin-like growth factor-I and prolactin in normal, growth retarded and anencephalic human fetuses

We measured growth hormone (GH), insulin-like growth factor-I (IGF-I), and both total and glycosylated prolactin (PRL) levels in 131 blood samples obtained by cordocentesis in normal and abnormal fetuses from 19 to 40 weeks of gestation. In normal fetuses, IGF-I and PRL levels showed a positive correlation and GH a negative correlation with gestational age. A negative relation between GH and IGF-I levels was observed, while PRL did not show any correlation with both GH and IGF-I concentrations. IGF-I increased from 5.6±3 (at 19–22 weeks) to 10.7±5 nmol/l at term; GH decreased from 31±10 to 7.7±4 μg/l and PRL increased from 16±18 to 139±76 μg/l. Glycosylated PRL accounted for about 15% of total PRL, a value similar to that found in normal adults. In 27 fetuses of 27–37 weeks with intra-uterine growth retardation, GH and PRL levels were higher and IGF-I levels lower than in normal fetuses matched for week of gestation. In 8 anencephalic fetuses of 19–26 weeks of gestation, both GH and IGF-I levels were lower, and PRL levels were higher than in matched controls. Altogether these data support the views that a) both GH and PRL secretion are under the hypothalamic control during fetal development, b) the serum GH decrease from midgestation to the end of pregnancy is mediated by the negative feed-back mechanism of increasing IGF-I levels and c) IGF-I production is mainly regulated by fuel supply and only partially by GH.

Anti-iodothyronine autoantibodies in a girl with hyperthyroidism due to pituitary resistance to thyroid hormones

In the present study, we report the uncommon case of a 9.6-yr-old girl with circulating an-ti-T3 autoantibodies (T3-Ab) and hyperthyroidism due to inappropriate secretion of TSH (IST). The diagnosis of IST was based on the findings of normal TSH levels (2.4 mU/L) in the presence of high free T4 (28.2 pmol/L) and free T3 (FT3) levels, as measured by direct measurement methods based on “one-step” analog tracer (28.0 pmo/L) and “two-step” Lisophase® (13.3 pmo/L) techniques. The discrepancy between the two measurements suggested a methodological interference due to T3-Ab in “one-step” technique, being the “two-step” methodology unaffected by the presence of such autoantibodies. T3-Ab were documented by high nonspecific binding of serum to labeled T3 (38.0% vs 4.3 ± 2.1% in controls). The clinical picture of hyperthyroidism, the qualitatively normal TSH responses to TRH and T3 suppression tests, the normal pituitary imaging and the values of some parameters of peripheral thyroid hormone action compatible with hyperthyroidism indicated that the patient was affected by pituitary resistance to thyroid hormones (PRTH). Chronic treatment with dopaminergic agent bromocriptine (7.5 mg/day) did not cause TSH secretion to be suppressed, while the administration of thyroid hormone analog TRIAC (1.4 mg/day) inhibited TSH release (from 2.4 to 0.2 mU/L). As a consequence, circulating thyroid hormone levels normalized and euthyroidism was restored. During TRIAC administration, FT3 levels, measured by “one-step” analog tracer technique, gave spuriously high values due to the methodological interference of T3-Ab (15.2 vs 4.3 pmol/L as measured by “two-step” Lisophase® technique). In conclusion, the present study indicates that a) the levels of circulating free thyroid hormones should be measured by methods unaffected by the presence of anti-iodothyronine autoantibodies in order to prevent either misdiagnosis of IST or, as in the present case, misinterpretation of the efficacy of TSH suppressive treatment, and b) it is mandatory to rule out the presence of such autoantibodies whenever IST is suspected.

Effects of Thyroid Hormones on Cardiac Structure: A Tissue Characterization Study in Patients with Thyroid Disorders Before and After Treatment

Experimental evidence suggests an involvement of thyroid hormones in myocardial nonmyocyte component growth. We evaluated the possible role of thyroid hormones in myocardial remodeling by ultrasonic tissue characterization (videodensitometry) in 8 hyperthyroid patients, in 10 hypothyroid patients, and in 2 patients with thyroid hormone resistance syndrome (RTH), before, 60, and 120 days after treatment (T0, T60, T120), and in 10 age-matched euthyroids. According to a previously described procedure, the derived collagen volume fraction (dCVF%, an echocardiographic index estimating the collagen content) was predicted from the pixel-level frequency distribution width (broadband, Bb) of the selected echocardiographic images. Thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were assessed by immunometric method. QT interval dispersion (QTd) on basal electrocardiogram was measured as a marker of dyshomogeneous ventricular repolarization. At T0, Bb and dCVF% were normal in hyperthyroid and euthyroid patients, and slightly increased in RTH patients, whereas significantly higher values were found in hypothyroids. At T60, a significant reduction in Bb was observed in hypothyroids, with nearly normal dCVF% values. This trend was confirmed at T120 with complete normalization of echoreflectivity. No echoreflectivity changes were observed in hyperthyroid and RTH patients during treatment. QTd was significantly increased in hypothyroids at T0, while no significant differences were found among groups at T60 and T120. Because the different videodeonsitometric myocardial properties observed in hypothyroid versus hyperthyroid patients correspond to an increase of dCVF%, this study suggests that thyroid hormones exert an inhibitory effect on myocardial collagen synthesis in humans.

Serum FSH bioactivity and inhibin levels in patients with gonadotropin secreting and nonfunctioning pituitary adenomas

It has been reported that serum FSH bioactivity and inhibin levels can be used as markers of the presence of true gonadotropin-secreting pituitary adenoma (Gn-oma). To verify this hypothesis, we have investigated the bioactivity of FSH and serum inhibin α-α and α-βA levels in a series of patients with either Gn-oma or nonfunctioning pituitary adenoma (NFPA). Nine patients with Gn-oma (6 men and 3 women), 21 with NFPA (9 men and 12 women) and 30 normal subjects were included in the study. We studied FSH biological activity (FSH-B) by using Sertoli cell aromatase bioassay (SAB) and α-α and α-βA inhibin levels by two noncompetitive immunometric assays (IEMA). In male patients with Gn-oma, serum immunoreactive FSH (FSH-I) and FSH-B levels ranged from 5.1 to 35.5 U/L and from 8.3 to 48 U/L, respectively, FSH B/l ratio being elevated in 2 (2.5 and 4.1; normal male range: 0.3–1.5), while female patients with Gn-oma had serum FSH-I and FSH-B levels ranging from 43.2 to 162 U/L and from 41.2 to 112.8 U/l, respectively, with a normal FSH B/l ratio. In male patients with NFPA, FSH-I and FSH-B levels ranged from 2.7 to 10.7 U/l and from 2.4 to 11.4 U/l while in females they ranged from 3.4 to 67.9 and from 4.6 to 60.8 U/l, respectively. FSH B/l ratio was elevated in 1 male (3.3) and normal in the remaining patients with NFPA. Serum α-α inhibin levels were normal or low in patients with Gn-oma and NFPA, while α-βA inhibin concentrations were slightly elevated in 1 of 6 postmenopausal women (0.9; normal range <0.7 U/ml). The present study confirms and extends previous reports indicating that male patients with Gn-oma may secrete FSH molecules with increased bioactivity. However, this abnormality was also observed in one male patient with NFPA. Moreover, the measurement of inhibin levels does not appear to be a reliable in vivo marker of pituitary tumors of gonadotroph origin, as it was normal or low in almost all patients with either Gn-oma or NFPA.