Effects of simulated altitude (normobaric hypoxia) on cardiorespiratory parameters and circulating endothelial precursors in healthy subjects.

BACKGROUND: Circulating Endothelial Precursors (PB-EPCs) are involved in the maintenance of the endothelial compartment being promptly mobilized after injuries of the vascular endothelium, but the effects of a brief normobaric hypoxia on PB-EPCs in healthy subjects are scarcely studied. METHODS: Clinical and molecular parameters were investigated in healthy subjects (n = 8) in basal conditions (T0) and after 1 h of normobaric hypoxia (T1), with Inspiratory Fraction of Oxygen set at 11.2% simulating 4850 mt of altitude. Blood samples were obtained at T0 and T1, as well as 7 days after hypoxia (T2). RESULTS: In all studied subjects we observed a prompt and significant increase in PB-EPCs, with a return to basal value at T2. The induction of hypoxia was confirmed by Alveolar Oxygen Partial Pressure (PAO2) and Spot Oxygen Saturation decreases. Heart rate increased, but arterial pressure and respiratory response were unaffected. The change in PB-EPCs percent from T0 to T1 was inversely related to PAO2 at T1. Rapid (T1) increases in serum levels of hepatocyte growth factor and erythropoietin, as well as in cellular PB-EPCs-expression of Hypoxia Inducible Factor-1alpha were observed. CONCLUSION: In conclusion, the endothelial compartment seems quite responsive to standardized brief hypoxia, possibly important for PB-EPCs activation and recruitment.

Myocardial deformation in iron overload cardiomyopathy: speckle tracking imaging in a beta-thalassemia major population.

Traditional echocardiography is unable to detect neither the early stages of iron overload cardiomyopathy nor myocardial iron deposition. The aim of the study is to determine myocardial systolic strain indices in thalassemia major (TM), and assess their relationship with T2*, a cardiac magnetic resonance index of the severity of cardiac iron overload. 55 TM cases with recent cardiac magnetic resonance (CMR-T2*) underwent speckle tracking analysis to assess regional myocardial strains and rotation. The results were compared with a normal control group (n = 20), and were subsequently analyzed on the basis of the CMR-T2* values. Two TM groups were studied: TM with significant cardiac iron overload ("low" T2*, ≤20 ms; n = 21), and TM with normal T2* values ("normal" T2*, >20 ms; n = 34). TM patients show significant, uniform decrease in circumferential and radial strain (P < 0.05), and a remarkable reduction in end-systolic rotation, both global, and for all segments (P < 0.001). No significant differences were found between the low- and the normal T2* group either in regional strains and rotation or in standard echocardiographic and CMR parameters. Spearman's correlation coefficient shows no significant correlation between myocardial strains, rotation and cardiac T2* values. In conclusion, our results are in accordance with recent evidence that myocardial iron overload is not the only mechanism underlying iron cardiomyopathy in TM. Strain imaging can predict subclinical myocardial dysfunction irrespective of CMR-T2* values, although it cannot replace CMR-T2* in assessing cardiac iron overload. Finally, it might be useful to appropriately time cardioactive treatment.

Elevated serum procollagen type III peptide in splanchnic and peripheral circulation of patients with inflammatory bowel disease submitted to surgery.

BACKGROUND: In the hypothesis that the increased collagen metabolism in the intestinal wall of patients affected by inflammatory bowel disease (IBD) is reflected in the systemic circulation, we aimed the study to evaluate serum level of procollagen III peptide (PIIIP) in peripheral and splanchnic circulation by a commercial radioimmunoassay of patients with different histories of disease. METHODS: Twenty-seven patients, 17 with Crohn and 10 with ulcerative colitis submitted to surgery were studied. Blood samples were obtained before surgery from a peripheral vein and during surgery from the mesenteric vein draining the affected intestinal segment. Fifteen healthy age and sex matched subjects were studied to determine normal range for peripheral PIIIP. RESULTS: In IBD patients peripheral PIIIP level was significantly higher if compared with controls (5.0 +/- 1.9 vs 2.7 +/- 0.7 microg/l; p = 0.0001); splanchnic PIIIP level was 5.5 +/- 2.6 microg/l showing a positive gradient between splanchnic and peripheral concentrations of PIIIP. No significant differences between groups nor correlations with patients' age and duration of disease were found. CONCLUSIONS: We provide evidence that the increased local collagen metabolism in active IBD is reflected also in the systemic circulation irrespective of the history of the disease, suggesting that PIIIP should be considered more appropiately as a marker of the activity phases of IBD.

Effects of chronic inflammatory bowel diseases on left ventricular structure and function: a study protocol.

BACKGROUND: Experimental evidences suggest an increased collagen deposition in inflammatory bowel diseases (IBD). In particular, large amounts of collagen type I, III and V have been described and correlated to the development of intestinal fibrotic lesions. No information has been available until now about the possible increased collagen deposition far from the main target organ. In the hypothesis that chronic inflammation and increased collagen metabolism are reflected also in the systemic circulation, we aimed this study to evaluate the effects on left ventricular wall structure by assessing splancnic and systemic collagen metabolism (procollagen III assay), deposition (ultrasonic tissue characterization), and cardiac function (echocardiography) in patients with different long standing history of IBD, before and after surgery. METHODS: Thirty patients affected by active IBD, 15 with Crohn and 15 with Ulcerative Colitis, submitted to surgery will be enrolled in the study in a double blind fashion. They will be studied before the surgical operation and 6, 12 months after surgery. A control group of 15 healthy age and gender-matched subjects will also be studied. At each interval blood samples will be collected in order to assess the collagen metabolism; a transthoracic echocardiogram will be recorded for the subsequent determination of cardiac function and collagen deposition. DISCUSSION: From this study protocol we expect additional information about the association between IBD and cardiovascular disorders; in particular to address the question if chronic inflammation, through the altered collagen metabolism, could affect left ventricular structure and function in a manner directly related to the estimated duration of the disease.