Microvascular Density and Circulating Endothelial Progenitor Cells Before and After Treatment with Incretin Mimetics in Diabetic Patients

INTRODUCTION

Glucagon-like peptide 1-receptor agonists (incretin mimetics) and dipeptidyl peptidase-4 inhibitors (incretin enhancers) have been recently introduced in the treatment of diabetes mellitus. In particular, incretin mimetics seems to have ancillary antioxidant/antinflammatory properties that might be involved in endothelial protection.

AIM

To investigate the effect of incretin mimetic therapy (liraglutide, exenatide) given to 11 patients with type 2 diabetes mellitus, on circulating endothelial progenitor cells (EPCs) (bone marrow-derived cells possibly participating in neovascularization and endothelial protection and repair) and capillary density.

METHODS

Four diabetic patients were treated with exenatide (5 μg twice daily for 4 weeks and then 10 μg twice daily for 3 weeks) and 7 with liraglutide (0.6 mg per day for 1 week and then 1.2 mg per day for 3 weeks). Peripheral venous blood samples were obtained before treatment (basal) and after 4 week in patients treated with liraglutide, and after 4 and 7 weeks in patients treated with exenatide, since drug titration is usually longer. EPCs were evaluated by flow cytometry as CD34⁺/KDR⁺ cells. Capillary density was evaluated by videomicroscopy, before and after venous congestion, in the dorsum of the 4th finger.

RESULTS

Patients treated with liraglutide (6 males 1 female, age 54 ± 12 years) showed a decrease in body mass index and blood pressure during treatment, while patients treated with exenatide (3 males 1 female, age 57 ± 6 years) did not show any relevant change. EPCs were significantly increased after treatment with exenatide, but not after treatment with liraglutide. Capillary density was slightly increased only after 4 weeks of treatment with exenatide, however the increase was no longer present at the final evaluation.

CONCLUSIONS

Treatment with exenatide, but not with liraglutide, was able to increase the number of circulating EPCs, possibly through an antioxidative/antiinflammatory effect.

Long-term treatment of acromegaly with lanreotide: evidence of increased serum parathormone concentration

The somatostatin analogue lanreotide is effective in reducing growth hormone levels in patients with acromegaly. Acromegaly is characterized by calcium homeostasis alterations. The aim of our study was to evaluate the effects of lanreotide on bone turnover markers in a group of acromegalic patients and to verify a possible increase of intact parathormone (iPTH) levels in a transient or persistent way. Serum GH, IGF-I and serum and urinary markers of bone metabolism were measured before treatment and on months 3 and 24. In short-term treatment (3 months), lanreotide significantly decreased GH, IGF-I, serum calcium, osteocalcin and alkaline phosphatase levels, but increased iPTH level (49 +/- 16.7 vs pre-treatment 28.3 +/- 7.6 ng/L, p<0.001). During long-term study (24 months) GH and IGF-I were significantly still low; serum calcium and alkaline phosphatase levels returned to pre-treatment levels. iPTH level was significantly still higher compared with pre-treatment (46.4 +/- 9.2 vs 28.3 +/- 7.6 ng/L, p<0.05). No changes were seen in serum albumin, creatinine and vitamin D during short and long term treatment. The changes of most bone markers during lanreotide treatment can be explained by the decrease of GH and IGF-I. The increase of iPTH concentration suggests that lanreotide has ulterior and long-standing actions on calcium homeostasis: intestinal malabsorption of calcium due to the lanreotide could contribute to this "secondary" hyperparathyroidism. The clinical relevance of these long-standing effects needs to be further investigated.

Acromegalic patients show the presence of hypertrophic remodeling of subcutaneous small resistance arteries

Structural alterations of small resistance arteries in patients with essential hypertension (EH) are mostly characterized by inward eutrophic remodeling. However, we have observed the presence of hypertrophic remodeling in patients with renovascular hypertension, as well as in patients with noninsulin-dependent diabetes mellitus, suggesting a relevant effect of humoral growth factors on vascular structure. Growth hormone may stimulate in vitro proliferation of vascular smooth muscle cells. However, no data are presently available about small artery structure in acromegalic patients. Therefore, we have investigated the structure of subcutaneous small arteries in 12 normotensive (NT) subjects, in 12 EH subjects, and in 9 acromegalic patients (APs). All subjects underwent biopsy of the subcutaneous fat; then, small resistance arteries were dissected and mounted on a micromyograph. The normalized internal diameter, media thickness, media-to-lumen ratio, the media cross-sectional area together with remodeling, and growth indices were calculated. Demographic variables were similar in the three groups, except for blood pressure. The media-to-lumen ratio was significantly greater in EH and AP, compared with NT. No difference was observed between EH and AP. The media cross-sectional area was significantly greater in AP compared with EH and with NT. The calculation of remodeling and growth index suggests the presence of eutrophic remodeling in EH (growth index 0%) and of hypertrophic remodeling in AP (growth index 40%). In conclusion, our data suggest the presence of hypertrophic remodeling of subcutaneous small resistance arteries of AP, probably as a consequence of growth-stimulator properties of IGF-1.

Acromegalic Patients Show the Presence of Hypertrophic Remodeling of Subcutaneous Small Resistance Arteries

Structural alterations of small resistance arteries in patients with essential hypertension (EH) are mostly characterized by inward eutrophic remodeling. However, we have observed the presence of hypertrophic remodeling in patients with renovascular hypertension, as well as in patients with noninsulin-dependent diabetes mellitus, suggesting a relevant effect of humoral growth factors on vascular structure. Growth hormone may stimulate in vitro proliferation of vascular smooth muscle cells. However, no data are presently available about small artery structure in acromegalic patients. Therefore, we have investigated the structure of subcutaneous small arteries in 12 normotensive (NT) subjects, in 12 EH subjects, and in 9 acromegalic patients (APs). All subjects underwent biopsy of the subcutaneous fat; then, small resistance arteries were dissected and mounted on a micromyograph. The normalized internal diameter, media thickness, media-to-lumen ratio, the media cross-sectional area together with remodeling, and growth indices were calculated. Demographic variables were similar in the three groups, except for blood pressure. The media-to-lumen ratio was significantly greater in EH and AP, compared with NT. No difference was observed between EH and AP. The media cross-sectional area was significantly greater in AP compared with EH and with NT. The calculation of remodeling and growth index suggests the presence of eutrophic remodeling in EH (growth index 0%) and of hypertrophic remodeling in AP (growth index 40%). In conclusion, our data suggest the presence of hypertrophic remodeling of subcutaneous small resistance arteries of AP, probably as a consequence of growth-stimulator properties of IGF-1.

[Prevalence and aggressiveness of thyroid carcinoma with diameter less than one centimetre in iodine deficiency areas]

BACKGROUND

The introduction of highly sensitive imaging techniques has made it possible to detect many non-palpable thyroid nodules with size less than 1 centimetre. The prevalence of these lesions appears to be high in the general population and increases in iodine deficiency areas. Fine needle aspiration biopsy (FNAB) is considered the most reliable test for the diagnosis of thyroid nodules.

METHODS

From January 1991 to December 2000, 6627 nodules were referred for FNAB to our department. In 4871 (73.5%) euthyroid patients the mean daily urinary excretion of iodine was 73+/-18 micromg/day.

RESULTS

In 2401 nodules (36.2%) the diameter was less than one centimetre. Histologic confirmation of malignancy was available in 187 (89.9%) of 208 operated nodules with diameter more than 1 cm and in 64 (78%) of 82 with diameter less than 1 cm. Logistic regression analysis indicated that a solid hypoechoic feature was a useful criterion to predict malignancy (p<0.001), as well as the presence of calcification (p<0.5) and blurred margins (p<0.5). Lymph node metastases were present in 24.3% of carcinomas with diameter more than 1 cm but, surprisingly, also in 20.3% of those with diameter less than 1 cm. No correlation was seen between diameter of carcinoma nodules and presence of lymph node metastasis.

CONCLUSIONS

These data suggest that the potential malignancy of thyroid nodules is not only correlated to the diameter but to other parameters such as the biological difference of thyroid cancer that could be hypothesized in an iodine deficiency area. In conclusion, FNAB is recommended for nodules with diameter less than 1 centimetre when sonographic findings suggest malignancy such as a hypoechoic pattern, an irregular margin or internal microcalcification.

Pravastatin-associated myopathy. Report of a case

A case of acute inflammatory myopathy associated with the use of pravastatin, a new hydrophilic 3-hydroxy-3 methylglutaril coenzyme A reductase inhibitor, is reported. The patient, a 69-year-old man was affected by non-insulin-dependent diabetes mellitus and hypertension. He assumed pravastatin (20 mg/day) because of hypercholesterolemia. He was admitted with acute myopathy of the lower limbs which resolved in a few days after pravastatin discontinuation. A previously unknown hypothyroidism, probably due to chronic autoimmune thyroiditis, was evidenced. Muscle biopsy (left gastrocnemius) revealed a perimysial and endomysial inflammatory infiltrate with a prevalence of CD4+ lymphocytes. While lovastatin and simvastatin have been associated with toxic myopathy, pravastatin-associated myopathy could represent a distinct, inflammatory entity.

Cardiac involvement in Churg-Strauss syndrome: a follow-up of three cases

Three cases of Churg-Strauss syndrome with myocardial involvement are reported. Cardiac disease is known to be the major cause of death in Churg-Strauss syndrome. Aggressive therapy (steroids and cyclophosphamide) may cure the myocardial dysfunction associated with the disease.

Primary empty sella syndrome and hypogonadotropic hypogonadism in young male patients

Twelve male patients with absence of pubertal development and hypogonadotropic hypogonadism underwent a contrast-enhanced computed tomography of the sellar region and dynamic endocrine testing consisting of insulin-induced hypoglycemia, GnRH and TRH test. In two patients, clinically indistinguishable from the others, the presence of an empty sella turcica was demonstrated. They also showed, in comparison with patients with normal sellar morphology, an absent prolactin response to hypoglycemia with otherwise normal pituitary function. Empty sella, either due to congenital incompetence of the diaphragma sellae or to pituitary shrinkage due to regressive changes by hemorrhage, infarction and possibly autoimmune phenomena, may rarely be associated with hypogonadotropic hypogonadism.

Reversible myocardial impairment in the Churg-Strauss syndrome: report of a case

Heart disease is a major cause of morbidity and mortality in the Churg-Strauss syndrome. However, few clinical follow-ups have been published. In this case report, in which the diagnosis of Churg-Strauss syndrome was made based on histologic criteria and clinical features, heart failure with globally depressed left ventricular function was present. Aggressive therapy (prednisone and cyclophosphamide) was instituted. In the follow-up a prompt clinical response and eventual recovery of the indices of cardiac function as evaluated by echocardiography and radionuclide ventriculography were observed.

[Hypopituitarism secondary to suprasellar giant carotido-ophthalmic aneurysm. Normalization of the hypophyseal function after neurosurgical depression of the aneurysm]

A 49-year-old man presented with a 6-month history of weight loss, muscular weakness, easy fatigue, impotence, decreased visual acuity, campimetry defects. The results of radiologic and endocrine testing disclosed the presence of pituitary dysfunction due to pituitary stalk section caused by a giant suprasellar aneurysm extending into the sellar region. After the neurosurgical decompression of the aneurysm a progressive normalization of all pituitary functions was demonstrated. In this case, the preoperative finding of a preserved pituitary integrity with acute and prolonged endocrine testing demonstrated to be predictable of a recovery of the hypothalamo-pituitary axis after the removal of the mass effect caused by the giant aneurysm.

Effects of the acute subcutaneous administration of synthetic salmon calcitonin in tumoral calcinosis

We examined the effects of the acute administration of salmon calcitonin on phosphate metabolism in tumoral calcinosis. On two different days, 200 MRC U of the synthetic hormone were administered sc to a 38-year-old patient, either as twice daily 100 MRC U injections, or as a continuous sc infusion via a portable pump. Both ways of calcitonin administration elicited a phosphaturic effect and a lowering of serum phosphate level comparable with that observed after an iv infusion of calcitonin. 1,25 dihydroxyvitamin D level, which was in the normal range during a control study, increased after calcitonin administration. In our patient, long term therapy with diet, a phosphate-binding agent and calcitonin prevented the occurrence of new ectopic calcifications. Owing to its phosphaturic activity, synthetic salmon calcitonin may be a useful adjunct to diet and aluminium-containing antacids in long-term management of tumoral calcinosis.

Synthetic salmon calcitonin is not diabetogenic in patients with normal or impaired glucose metabolism

The effects of short term administration of 200 MRC U of synthetic salmon calcitonin (sCT) daily on carbohydrate metabolism were investigated in 10 patients with various bone diseases, 3 of whom had type II diabetes mellitus and 3 of whom had impaired glucose tolerance. Blood glucose levels during the nocturnal postabsorptive period, blood glucose and blood insulin (IRI) levels and the ratio of the area under the insulin curve to the area under the glucose curve (AI/AG) after a mixed meal were determined before and after 15 days of treatment. The values before and after sCT treatment were not significantly different, suggesting that high doses of sCT are not diabetogenic and can be given to patients with impaired glucose tolerance or to diabetics, without any risk of deteriorating metabolic control.