Francesco Cavagnini

Sympathetic Activation in Obese Normotensive Subjects

Human obesity is characterized by profound alterations in the hemodynamic and metabolic states. Whether these alterations involve sympathetic drive is controversial. In 10 young obese subjects (body mass index, 40.5 +/- 1.2 kg/m2, mean +/- SEM) with normal blood pressure and 8 age-matched lean normotensive control subjects, we measured beat-to-beat arterial blood pressure (Finapres technique), heart rate (electrocardiogram), postganglionic muscle sympathetic nerve activity (microneurography at the peroneal nerve), and venous plasma norepinephrine (high-performance liquid chromatography). The measurements were performed in baseline conditions and, with the exception of plasma norepinephrine, during baroreceptor stimulation and deactivation caused by increases and reductions of blood pressure via intravenous infusions of phenylephrine and nitroprusside. Baseline blood pressure and heart rate were similar in obese and control subjects. Plasma norepinephrine was also similar in the two groups. Muscle sympathetic nerve activity, however, was 38.6 +/- 5.1 bursts per minute in obese subjects and less than half that level in control subjects (18.7 +/- 1.3 bursts per minute), the difference being highly statistically significant (P < .02). Muscle sympathetic nerve activity and heart rate were reduced during phenylephrine infusion and increased during nitroprusside infusion, but the changes were about half as great in obese subjects as in control subjects. Thus, even in the absence of any blood pressure alteration, human obesity is characterized by a marked sympathetic activation, possibly because of an impairment of reflex sympathetic restraint. This may be involved in the high rate of hypertension and cardiovascular complications seen in obesity.

Body Weight Reduction, Sympathetic Nerve Traffic, and Arterial Baroreflex in Obese Normotensive Humans

BACKGROUND Previous studies have shown that sympathetic cardiovascular outflow is increased in obese normotensive subjects and that this increase is associated with a baroreflex impairment. The purpose of this study was to determine whether these abnormalities are irreversible or can be favorably affected by body weight reduction. METHODS AND RESULTS In 20 obese normotensive subjects (age, 31.3+/-1.7 years; body mass index, 37.6+/-0.9 kg/m2, mean+/-SEM), we measured beat-to-beat arterial blood pressure (Finapres technique), heart rate (ECG), postganglionic muscle sympathetic nerve activity (microneurography at a peroneal nerve), and venous plasma norepinephrine (high-performance liquid chromatography) at rest and during baroreceptor stimulation and deactivation induced by increases and reductions of blood pressure via stepwise intravenous infusions of phenylephrine and nitroprusside. Measurements were repeated in 10 subjects after a 16-week hypocaloric diet with normal sodium content (4600 to 5000 J and 210 mmol NaCl/d) and in the remaining 10 subjects after a 16-week observation period without any reduction in the caloric intake. The hypocaloric diet significantly reduced body mass index, slightly reduced blood pressure, and caused a significant and marked decrease in both muscle sympathetic nerve activity (from 50.0+/-5.1 to 32.9+/-4.6 bursts per 100 heart beats, P<.01) and plasma norepinephrine (from 356.2+/-43 to 258.4+/-29 pg/mL, P<.05). This was associated with a significant improvement in the sensitivity of the baroreceptor heart rate (+71.5 +/- 11%, P<.01) and muscle sympathetic nerve activity (+124.5 +/- 22%, P<.001) reflex. Total body glucose uptake also increased significantly (+60.8 +/- 12.0%, P<.05), indicating an increase in insulin sensitivity. All variables remained unchanged in subjects not undergoing caloric restriction. CONCLUSIONS In obese normotensive subjects, a reduction in body weight induced by a hypocaloric diet with normal sodium content exerts a marked reduction in sympathetic activity owing to central sympathoinhibition. This can be due to the consequences of an increased insulin sensitivity but also to a restoration of the baroreflex control of the cardiovascular system with weight loss.

Role of epigenetics in human aging and longevity: genome-wide DNA methylation profile in centenarians and centenarians' offspring.

The role of epigenetics in the modulation of longevity has not been studied in humans. To this aim, (1) we evaluated the DNA methylation from peripheral leukocytes of 21 female centenarians, their 21 female offspring, 21 offspring of both non-long-lived parents, and 21 young women through ELISA assay, pyrosequencing analysis of Alu sequences, and quantification of methylation in CpG repeats outside CpG islands; (2) we compared the DNA methylation profiles of these populations through Infinium array for genome-wide CpG methylation analysis. We observed an age-related decrease in global DNA methylation and a delay of this process in centenarians’ offspring. Interestingly, literature data suggest a link between the loss of DNA methylation observed during aging and the development of age-associated diseases. Genome-wide methylation analysis evidenced DNA methylation profiles specific for aging and longevity: (1) aging-associated DNA hypermethylation occurs predominantly in genes involved in the development of anatomical structures, organs, and multicellular organisms and in the regulation of transcription; (2) genes involved in nucleotide biosynthesis, metabolism, and control of signal transmission are differently methylated between centenarians’ offspring and offspring of both non-long-lived parents, hypothesizing a role for these genes in human longevity. Our results suggest that a better preservation of DNA methylation status, a slower cell growing/metabolism, and a better control in signal transmission through epigenetic mechanisms may be involved in the process of human longevity. These data fit well with the observations related to the beneficial effects of mild hypothyroidism and insulin-like growth factor I system impairment on the modulation of human lifespan.

Effect of protracted treatment with rosiglitazone, a PPARgamma agonist, in patients with Cushing's disease.

Objective  Cushings disease, hypercortisolism due to a pituitary ACTH‐secreting tumour, is a highly morbid illness as yet without effective medical therapy. Recent studies have demonstrated that peroxisome proliferator‐activated receptor gamma (PPARγ) agonists effectively suppress ACTH secretion in a murine tumoral corticotroph cell line, but the few studies conducted so far in patients with ACTH‐secreting pituitary adenomas have yielded variable results.

Prevalence and pathogenesis of sleep apnea and lung disease in acromegaly

Respiratory disorders are common and important complications in acromegaly. Patients suffering from acromegaly display a 1.6–3.3 fold increase in mortality rate, which is due to respiratory disorders in 25% of cases. In these patients, mortality for lung disease is 2–3 fold higher than in the general population. Every portion of the respiratory system may be involved. Deformities of facial bones, edema and hypertrophy of the mucosae and pharyngeal and laryngeal cartilages, enlargement of the tongue and inspiratory collapse of the hypopharinx, all may contribute to respiratory alterations. Nasal polyps, “hormonal rhinitis”, changes of the voice and snoring are common occurrences. Though rarely, a laryngocele may ensue. Pneumomegaly is frequently observed and, as suggested by functional studies, might be due to an increased number rather than volume of the alveoli. An obstructive respiratory syndrome caused by mucosal thickening of the upper airways and bronchi is observed in 25% of female and 70% of male patients. The sleep apnea syndrome (SAS) affects 60–70% of acromegalic patients. SAS may be of obstructive, central or mixed type. Obstructive SAS is the prevailing form in acromegaly. It is due to intermittent obstruction of upper airways with preserved activity of the respiratory center, as testified by the remarkable thoracic and abdominal respiratory efforts. The pathogenesis of the central type of SAS is more complex. Narrowing of the upper airways may induce reflex inhibition of the respiratory center. Moreover, increased GH levels and, possibly, defects in the somatostatinergic pathways, may increase the ventilatory response of the respiratory center to carbon dioxide, thereby leading to respiratory arrest. In the mixed type of SAS, the phenomena underlying the other two forms coexist. Oxygen desaturation concomitant with the apneic episodes accounts for the frequent nocturnal wakening and diurnal drowsiness. Among the clinical correlates of SAS, arterial hypertension is of particular interest due to the close correlation existing between the two disorders. Sleep deprivation related to SAS seems per se to favor the appearance of hypertension. Moreover, short lasting hypoxemia may induce prolonged elevations of blood pressure, mediated by decreased endothelial generation of nitric oxide. Thus, since cardiovascular events are the main cause of mortality in patients with acromegaly, it is reasonable to hypothesize that SAS is involved in the reduced life span of these patients.

Potential Role for Retinoic Acid in Patients with Cushing's Disease

CONTEXT Cushings disease, i.e. cortisol excess due to an ACTH-secreting pituitary adenoma, is a rare disorder with considerable morbidity and mortality but no satisfactory medical treatment as yet. Experimental data have recently shown that retinoic acid restrains ACTH secretion by tumoral corticotropes. OBJECTIVE Our objective was to evaluate the efficacy and safety profile of retinoic acid treatment in patients with Cushings disease. DESIGN This is a prospective, multicenter study. Seven patients with Cushings disease (three men, four postmenopausal women) were started on 10 mg retinoic acid daily and dosage increased up to 80 mg daily for 6-12 months. ACTH, urinary free cortisol (UFC), and serum cortisol as well as clinical features of hypercortisolism and possible side effects of retinoic acid were evaluated at baseline, during retinoic acid administration, and after drug withdrawal. RESULTS A marked decrease in UFC levels was observed in five patients; mean UFC levels on retinoic acid were 22-73% of baseline values and normalization in UFC was achieved in three patients. Plasma ACTH decreased in the first month of treatment and then returned to pretreatment levels in responsive patients whereas no clear-cut pattern could be detected for serum cortisol. Blood pressure, glycemia, and signs of hypercortisolism, e.g. body weight and facial plethora, were ameliorated to a variable extent on treatment. Patients reported only mild adverse effects, e.g. xerophthalmia and arthralgias. CONCLUSIONS Long-term treatment with retinoic acid proved beneficial and well tolerated in five of seven patients with Cushings disease. This represents a novel, promising approach to medical treatment in Cushings disease.

Predictors of morbidity and mortality in acromegaly: an Italian survey

OBJECTIVE To describe demographic and hormonal characteristics, comorbidities (diabetes mellitus and hypertension), therapeutic procedures and their effectiveness, as well as predictors of morbidity and mortality in a nationwide survey of Italian acromegalic patients. DESIGN Retrospective multicenter epidemiological study endorsed by the Italian Society of Endocrinology and performed in 24 tertiary referral Italian centers. The mean follow-up time was 120 months. RESULTS A total of 1512 patients, 41% male, mean age: 45±13 years, mean GH: 31±37 μg/l, IGF1: 744±318 ng/ml, were included. Diabetes mellitus was reported in 16% of cases and hypertension in 33%. Older age and higher IGF1 levels at diagnosis were significant predictors of diabetes and hypertension. At the last follow-up, 65% of patients had a controlled disease, of whom 55% were off medical therapy. Observed deaths were 61, with a standardized mortality ratio of 1.13 95% (confidence interval (CI): 0.87-1.46). Mortality was significantly higher in the patients with persistently active disease (1.93; 95% CI: 1.34-2.70). Main causes of death were vascular diseases and malignancies with similar prevalence. A multivariate analysis showed that older age, higher GH at the last follow-up, higher IGF1 levels at diagnosis, malignancy, and radiotherapy were independent predictors of mortality. CONCLUSIONS Pretreatment IGF1 levels are important predictors of morbidity and mortality in acromegaly. The full hormonal control of the disease, nowadays reached in the majority of patients with modern management, reduces greatly the disease-related mortality.

Effects of Long‐Term Antiepileptic Therapy on the Hypothalamic‐Pituitary Axis in Man

Summary: Effects of long‐term antiepileptic therapy on the hypothalamic ‐pituitary axis were evaluated from the basal and stimulated plasma levels of growth hormone (GH) and prolactin (PRL) and from circadian adrenocorticotropic hormone (ACTH)/cortisol rhythms. Data for patients with well‐controlled epilepsy of mild‐to‐moderate severity were compared with those for normal healthy volunteers. Analysis of the effects of each antiepileptic drug (AED) and of combined AEDs revealed minor abnormalities of stimulated GH secretion in all treated patients. In epileptic men, all individual AEDs (except valproate) and AED polytherapy increased both basal and stimulated plasma levels of PRL. In epileptic women, this effect was more variable and less marked, probably because of early depletion of PRL reserves. Each AED and combined AEDs did not significantly change circadian ACTH/cortisol rhythms in epileptic patients. The effects observed seem not to be related to epilepsy per se. Clinical implications, pathways, and neurotransmitters involved and possible mechanisms of the neuroendocrine effects of long‐term AED therapy are discussed.

Gynaecomastia in men with chronic myeloid leukaemia after imatinib

cKit and platelet-derived growth-factor receptor (PDGFR) are receptor tyrosine kinases expressed in the testis, are involved in testosterone production, and are inhibited by imatinib. We measured hormone concentrations in 38 men receiving imatinib for chronic myeloid leukaemia at baseline and during treatment. Mean follow-up was 23.6 months (SD 7.5). We noted seven cases of gynaecomastia (18%, 95% CI 6-30%). A comparison of hormone concentrations in 21 patients before and during treatment showed that patients who developed gynaecomastia had a reduction in free testosterone concentrations of 29.53 pmol/L (95% CI 11.63-47.43), while patients who did not had a decrease of 6.36 pmol/L (-1.02 to 13.74). In most men with chronic myeloid leukaemia studied here, imatinib was associated with a reduction in the production of testicular hormones and in some, with the development of gynaecomastia.

Delayed Remission after Transsphenoidal Surgery in Patients with Cushing's Disease

BACKGROUND Transsphenoidal surgery (TSS) is the treatment of choice for Cushings disease (CD). Postoperative hypercortisolemia mandates further therapy. OBJECTIVE The aim of the study was to characterize patients without immediate postoperative remission who have a delayed decrease to normal or low cortisol levels without further therapy. DESIGN AND SETTING A retrospective case series was conducted at three tertiary care centers. PATIENTS AND INTERVENTION We reviewed the records of 620 patients (512 females, 108 males; mean age, 38 +/- 13 yr) who underwent transsphenoidal pituitary surgery for CD between 1982 and 2007. RESULTS Outcomes were classified into the following three groups based upon the postoperative pattern of cortisol testing: group IC (immediate control) included 437 of the 620 patients (70.5%) with hypocortisolism and/or cortisol normalization throughout the postoperative follow-up; group NC (no control) included 148 of 620 patients (23.9%) with persistent hypercortisolism; and group DC (delayed control) included 35 of 620 patients (5.6%) who had early elevated or normal UFC levels and developed a delayed and persistent cortisol decrease after an average of 38 +/- 50 postoperative days. The total rate of recurrence was 13% at a median follow-up time of 66 months after TSS; the cumulative rate of recurrence at 4.5 yr was significantly higher in group DC vs. group IC (43 vs. 14%; P = 0.02). CONCLUSIONS Hormonal assessment in the immediate postoperative period after TSS for CD may be misleading because delayed remission can occur in a subset of patients. Expectant management and retesting may spare some patients from unnecessary further treatment. Optimal timing to determine the need for further therapy after TSS remains to be determined.