Diabete ed ischemia critica degli arti inferiori. Valutazione degli indicatori sierologici di danno di parete: determinazione quantitativa delle cellule endoteliali circolanti mature

OBIETTIVO : Quantificare le CECs/ml nei pazienti affetti da ischemia critica (IC) degli arti inferiori, eventuali correlazioni tra i fattori di rischio, lo stadio clinico con l’ aumento delle CECs. Valutare i cambiamenti strutturali (calcificazione ed infiltratto infiammatorio) e l’ angiogenesi (numero di capillari /sezione) della parete arteriosa. MATERIALI E METODI: Da Maggio 2006 ad Aprile 2008 in modo prospettico abbiamo arruolato paziente affetti da IC da sottoporre ad intervento chirurgico. In un data base abbiamo raccolto : caratteristiche demografiche, fattori di rischio, stadiazione dell'IC secondo Leriche-Fontaine (L-F), il tipo di intervento chirurgico. Per ogni paziente abbiamo effettuato un prelievo ematico di 2 ml per la quantificazione immunomagnetica delle CECs e prelievo di parete arteriosa. RISULTATI: In modo consecutivo abbiamo arruolato 33 pazienti (75.8% maschi) con età media di 71 aa (range 34-91aa), affetti da arteriopatia ostruttiva cronica periferica al IV stadio di L-F nel 84.8%, da cardiopatia ischemica cronica nel 60.6%, da ipertensione arteriosa nel 72.7% e da diabete mellito di II tipo nel 66.6%. Il valore medio di CECs/ml è risultato significativamente più elevato (p= 0.001) nei soggetti affetti da IC (CECs/ml =531.24 range 107- 3330) rispetto ai casi controllo (CECs/ml = 125.8 range 19-346 ). Le CECs/ml nei pazienti diabetici sono maggiori rispetto alle CECs/ml nei pazienti non diabetici ( 726.7 /ml vs 325.5/ml ), p< 0.05 I pazienti diabetici hanno presentato maggior incidenza di lesioni arteriose complesse rispetto ai non diabetici (66% vs 47%) e minor densità capillare (65% vs 87%). Conclusioni : Le CECs sono un marker sierologico attendibile di danno vascolare parietale, la loro quantità è maggiore nei pazienti diabetici e ipertesi. La minor capacità angiogenetica della parete arteriosa in presenza di maggior calcificazioni ed infiltrato infiammatorio nei diabetici, dimostra un danno istopatologico di parete maggiore .

Impact of long-term corticosteroid therapy on the distribution pattern of lower limb atherosclerosis

OBJECTIVE: Ectopic calcification and mediacalcinosis can be promoted by corticosteroid use. Aim of the present investigation is to describe macrovascular disease features in patients with long-term corticosteroid therapy and symptomatic lower limb peripheral arterial occlusive disease (PAD). METHODS: A consecutive series of 2783 patients undergoing clinical and angiographic work-up of PAD were screened for long-term (>5 years) corticosteroid use (group A). Comparison was performed to a randomly selected age-, sex- and risk factor-matched PAD control cohort from the same series without corticosteroid use (group B). Patients with diabetes mellitus or severe renal failure were excluded. Arterial calcification was evaluated by qualitative assessment on radiographic images. Severity of atherosclerotic lesions was analysed from angiographic images using a semi-quantitative score (Bollinger score). RESULTS: In general, 12 patients (5 males, mean age 78.5 +/- 9.0 years) with 15 ischaemic limbs qualified to be enrolled in group A and were compared to 23 matching control patients (6 2 males, mean age 79.5 +/- 6 years) with 32 ischaemic limbs. Incompressibility of ankle arteries determined by measurement of the ankle-brachial index was seen in 12 limbs (80%) in group A compared to 3 limbs (9%) in group B (p = 0.0009). No significant difference was found comparing group A and B for segmental calcification, whereas comparison of the atherosclerotic burden using the angiographic severity score showed a significantly higher score at the infragenicular arterial level in group A (p = 0.001). CONCLUSION: Findings suggest that the long-term corticosteroid therapy is associated with a distally accentuated, calcifying peripheral atherosclerosis inducing arterial incompressibility. This occlusion pattern is comparable to patients with renal failure or diabetes. Further research is required to support our observations.

Incidental findings in post-mortem CT: Calcified ligamentum arteriosum

This case report describes the incidental finding of a calcified ligamentum arteriosum during post-mortem CT examination. The calcification of the ligament was confirmed at autopsy. Subsequent histological examination revealed the presence of cartilage-like and bone-like tissue as well as extended calcification areas. The importance of not confusing this normal post-mortem CT finding with vessel pathology is being emphasized.

Analysis of coronary bifurcations by intravascular ultrasound and virtual histology

Background Regional differences in shear stress have been identified as reason for early plaque formation in vessel bifurcations. We aimed to investigate regional plaque morphology and composition using intravascular ultrasound (IVUS) and virtual histology (IVUS–VH) in coronary artery bifurcations. Methods We performed IVUS and IVUS–VH studies at coronary bifurcations to analyze segmental plaque burden and composition of different segments in relation to their orientation to the bifurcation. Results A total of 236 patients with a mean age of 59 ± 11 years (69% male) were analyzed. Plaque burden was higher at the contralateral vessel wall facing the bifurcation compared to the ipsilateral vessel wall and this difference was true for proximal and distal segments (proximal: 37 ± 12% and 45 ± 15% for segments at the ipsilateral and contralateral vessel wall, respectively, p < 0.001; distal: 37 ± 10% and 47 ± 15% for segments at the ipsilateral and contralateral vessel wall, respectively, p < 0.001). In addition, these segments exhibited a higher proportion of dense calcium and a lower proportion of fibrous tissue and fibro fatty tissue. Conclusions Segments on the contralateral wall of the bifurcation which have previously been identified as regions with low shear stress not only exhibited a higher plaque burden, but also a higher degree of calcification.

Mitral regurgitation

Mitral regurgitation (MR) involves systolic retrograde flow from the left ventricle into the left atrium. While trivial MR is frequent in healthy subjects, moderate to severe MR constitutes the second most prevalent valve disease after aortic valve stenosis. Major causes of severe MR in Western countries include degenerative valve disease (myxomatous disease, flail leaflet, annular calcification) and ischaemic heart disease, while rheumatic disease remains a major cause of MR in developing countries. Chronic MR typically progresses insidiously over many years. Once established, however, severe MR portends a poor prognosis. The severity of MR can be assessed by various techniques, Doppler echocardiography being the most widely used. Mitral valve surgery is the only treatment of proven efficacy. It alleviates clinical symptoms and prevents ventricular dilatation and heart failure (or, at least, it attenuates further progression of these abnormalities). Valve repair significantly improves clinical outcomes compared with valve replacement, reducing mortality by approximately 70%. Reverse LV remodelling after valve repair occurs in half of patients with functional MR. Percutaneous, catheter-based to mitral valve repair is a novel approach currently under clinical scrutiny, with encouraging preliminary results. This modality may provide a valuable alternative to mitral valve surgery, especially in critically ill patients.

Sodium thiosulfate pharmacokinetics in hemodialysis patients and healthy volunteers

Vascular calcification is a major cause of morbidity and mortality in dialysis patients. Human and animal studies indicate that sodium thiosulfate (STS) may prevent the progression of vascular calcifications. The pharmacokinetics of STS in hemodialysis patients has not been investigated yet.

Infrapopliteal lesion morphology in patients with critical limb ischemia: implications for the development of anti-restenosis technologies

Purpose : To angiographically evaluate infrapopliteal arterial lesion morphology in a consecutive series of patients presenting with critical limb ischemia (CLI) and undergoing infrapopliteal angioplasty. Methods : A prospective analysis was undertaken of a consecutive series of CLI patients undergoing endovascular therapy in a tertiary referral center in the year 2011. Morphological assessment of baseline angiograms obtained prior to revascularization included lesion length, assessment of calcification using a semi-quantitative scoring system, and reference vessel diameter (RVD) measurement. Delta RVDs were assessed subtracting distal RVDs from proximal RVDs. A total of 197 infrapopliteal lesions in 105 CLI patients (n=106 limbs) were assessed. Of these, 136 lesions were treated by endovascular means. Results : The average length of treated lesions was 87.1±43.8 mm in stenoses and 124.0±78.3 mm in chronic occlusions (p<0.001). Mean RVD proximal to the lesions was 1.88 mm whereas it was 1.66 mm distal to the lesions (p≤0.03). Mean arterial calcification was 1.15. Conclusion : This prospective angiographic series underlines the complex nature and extensive longitudinal involvement of infrapopliteal lesions in CLI patients. These findings should be taken into consideration for anti-restenosis concepts in this challenging subgroup of peripheral artery disease patients.

Ocean acidification limits temperature-induced poleward expansion of coral habitats around Japan

Using results from four coupled global carbon cycle-climate models combined with in situ observations, we estimate the effects of future global warming and ocean acidification on potential habitats for tropical/subtropical and temperate coral communities in the seas around Japan. The suitability of coral habitats is classified on the basis of the currently observed regional ranges for temperature and saturation states with regard to aragonite (Ωarag). We find that, under the "business as usual" SRES A2 scenario, coral habitats are projected to expand northward by several hundred kilometers by the end of this century. At the same time, coral habitats are projected to become sandwiched between regions where the frequency of coral bleaching will increase, and regions where Ωarag will become too low to support sufficiently high calcification rates. As a result, the habitat suitable for tropical/subtropical corals around Japan may be reduced by half by the 2020s to 2030s, and is projected to disappear by the 2030s to 2040s. The habitat suitable for the temperate coral communities is also projected to decrease, although at a less pronounced rate, due to the higher tolerance of temperate corals for low Ωarag. Our study has two important caveats: first, it does not consider the potential adaptation of the coral communities, which would permit them to colonize habitats that are outside their current range. Second, it also does not consider whether or not coral communities can migrate quickly enough to actually occupy newly emerging habitats. As such, our results serve as a baseline for the assessment of the future evolution of coral habitats, but the consideration of important biological and ecological factors and feedbacks will be required to make more accurate projections.

Ventricular-arterial coupling in a rat model of reduced arterial compliance provoked by hypervitaminosis D and nicotine

The vitamin D(3) and nicotine (VDN) model is one of isolated systolic hypertension (ISH) in which arterial calcification raises arterial stiffness and vascular impedance. The effects of VDN treatment on arterial and cardiac hemodynamics have been investigated; however, a complete analysis of ventricular-arterial interaction is lacking. Wistar rats were treated with VDN (VDN group, n = 9), and a control group (n = 10) was included without the VDN. At week 8, invasive indexes of cardiac function were obtained using a conductance catheter. Simultaneously, aortic pressure and flow were measured to derive vascular impedance and characterize ventricular-vascular interaction. VDN caused significant increases in systolic (138 +/- 6 vs. 116 +/- 13 mmHg, P < 0.01) and pulse (42 +/- 10 vs. 26 +/- 4 mmHg, P < 0.01) pressures with respect to control. Total arterial compliance decreased (0.12 +/- 0.08 vs. 0.21 +/- 0.04 ml/mmHg in control, P < 0.05), and pulse wave velocity increased significantly (8.8 +/- 2.5 vs. 5.1 +/- 2.0 m/s in control, P < 0.05). The arterial elastance and end-systolic elastance rose significantly in the VDN group (P < 0.05). Wave reflection was augmented in the VDN group, as reflected by the increase in the wave reflection coefficient (0.63 +/- 0.06 vs. 0.52 +/- 0.05 in control, P < 0.05) and the amplitude of the reflected pressure wave (13.3 +/- 3.1 vs. 8.4 +/- 1.0 mmHg in control, P < 0.05). We studied ventricular-arterial coupling in a VDN-induced rat model of reduced arterial compliance. The VDN treatment led to development of ISH and provoked alterations in cardiac function, arterial impedance, arterial function, and ventricular-arterial interaction, which in many aspects are similar to effects of an aged and stiffened arterial tree.

Diagnostic accuracy of 64-slice computed tomography for detecting angiographically significant coronary artery stenosis in an unselected consecutive patient population: comparison with conventional invasive angiography

BACKGROUND: Multislice computed tomography (MSCT) is a promising noninvasive method of detecting coronary artery disease (CAD). However, most data have been obtained in selected series of patients. The purpose of the present study was to investigate the accuracy of 64-slice MSCT (64 MSCT) in daily practice, without any patient selection. METHODS AND RESULTS: Using 64-slice MSCT coronary angiography (CTA), 69 consecutive patients, 39 (57%) of whom had previously undergone stent implantation, were evaluated. The mean heart rate during scan was 72 beats/min, scan time 13.6 s and the amount of contrast media 72 mL. The mean time span between invasive coronary angiography (ICAG) and CTA was 6 days. Significant stenosis was defined as a diameter reduction of > 50%. Of 966 segments, 884 (92%) were assessable. Compared with ICAG, the sensitivity of CTA to diagnose significant stenosis was 90%, specificity 94%, positive predictive value (PPV) 89% and negative predictive value (NPV) 95%. With regard to 58 stented lesions, the sensitivity, specificity, PPV and NPV were 93%, 96%, 87% and 98%, respectively. On the patient-based analysis, the sensitivity, specificity, PPV and NPV of CTA to detect CAD were 98%, 86%, 98% and 86%, respectively. Eighty-two (8%) segments were not assessable because of irregular rhythm, calcification or tachycardia. CONCLUSION: Sixty-four-MSCT has a high accuracy for the detection of significant CAD in an unselected patient population and therefore can be considered as a valuable noninvasive technique.

[Wall calcifications of the left heart atrium]

The chest X-ray of a 61-year-old man with severe aortic and mitral stenosis revealed extensive, circularly arranged calcifications in the wall of the left atrial appendage. He died soon after admission to hospital and autopsy confirmed the atrial calcifications in association with severe mitral stenosis. Although such calcification of the left atrial wall is rare, it can be of importance because it may make the usual surgical approach to mitral valve replacement impossible.

Effects of an aging vascular model on healthy and diseased hearts

The vitamin D(3) and nicotine (VDN) model is a model of isolated systolic hypertension (ISH) due to arterial calcification raising arterial stiffness and vascular impedance similar to an aged and stiffened arterial tree. We therefore analyzed the impact of this aging model on normal and diseased hearts with myocardial infarction (MI). Wistar rats were treated with VDN (n = 9), subjected to MI by coronary ligation (n = 10), or subjected to a combination of both MI and VDN treatment (VDN/MI, n = 14). A sham-treated group served as control (Ctrl, n = 10). Transthoracic echocardiography was performed every 2 wk, whereas invasive indexes were obtained at week 8 before death. Calcium, collagen, and protein contents were measured in the heart and the aorta. Systolic blood pressure, pulse pressure, thoracic aortic calcium, and end-systolic elastance as an index of myocardial contractility were highest in the aging model group compared with MI and Ctrl groups (P(VDN) < 0.05, 2-way ANOVA). Left ventricular wall stress and brain natriuretic peptide (P(VDNxMI) = not significant) were highest, while ejection fraction, stroke volume, and cardiac output were lowest in the combined group versus all other groups (P(VDNxMI) < 0.05). The combination of ISH due to this aging model and MI demonstrates significant alterations in cardiac function. This model mimics several clinical phenomena of cardiovascular aging and may thus serve to further study novel therapies.

Pulp and periodontal healing of laterally luxated permanent teeth: results after 4 years

AIM: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. MATERIAL AND METHODS: Patients presenting with lateral luxation of permanent teeth during 2001-2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root-canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re-examinations were performed after 1, 2, 3, 6, 12 and 48 months. RESULTS: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root-canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4-year re-examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. CONCLUSIONS: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices.

Sodium thiosulfate prevents vascular calcifications in uremic rats

Accelerated vascular calcification is a severe complication of chronic kidney disease contributing to high morbidity and mortality in patients undergoing renal replacement therapy. Sodium thiosulfate is increasingly used for the treatment of soft tissue calcifications in calciphylaxis. Therefore, we determined whether it also prevents development of vascular calcifications in chronic kidney disease. We found that uremic rats treated by thiosulfate had no histological evidence of calcification in the aortic wall whereas almost three-fourths of untreated uremic rats showed aortic calcification. Urinary calcium excretion was elevated and the calcium content of aortic, heart, and renal tissue was significantly reduced in the thiosulfate-treated compared to non-treated animals. Sodium thiosulfate treatment transiently lowered plasma ionized calcium and induced metabolic acidosis. It also lowered bone strength in the treated animals compared to their normal controls. Hence, sodium thiosulfate prevented vascular calcifications in uremic rats, likely by enhancing acid- and/or chelation-induced urinary calcium loss. The negative impact on rat bone integrity necessitates a careful risk-benefit analysis before sodium thiosulfate can be used in individual human patients.

Structural and surface property characterization of titanium dioxide nanotubes for orthopedic implants

This research focused on the to modification of the surface structure of titanium implants with nanostructured morphology of TiO2 nanotubes and studied the interaction of nanotubes with osteoblast cells to understand the parameters that affect the cell growth. The electrical, mechanical, and structural properties of TiO2 nanotubes were characterized to establish a better understanding on the properties of such nanoscale morphological structures. To achieve the objectives of this research work I transformed the titanium and its alloys, either in bulk sheet form, bulk machined form, or thin film deposited on another substrate into a surface of titania nanotubes using a low cost and environmentally friendly process. The process requires only a simple electrolyte, low cost electrode, and a DC power supply. With this simple approach of scalable nanofabrication, a typical result is nanotubes that are each approximately 100nm in diameter and have a wall thickness of about 20nm. By changing the fabrication parameters, independent nanotubes can be fabricated with open volume between them. Titanium in this form is termed onedimensional since electron transport is narrowly confined along the length of the nanotube. My Ph.D. accomplishments have successfully shown that osteoblast cells, the cells that are the precursors to bone, have a strong tendency to attach to the inside and outside of the titanium nanotubes onto which they are grown using their filopodia – cell’s foot used for locomotion – anchored to titanium nanotubes. In fact it was shown that the cell prefers to find many anchoring sites. These sites are critical for cell locomotion during the first several weeks of maturity and upon calcification as a strongly anchored bone cell. In addition I have shown that such a surface has a greater cell density than a smooth titanium surface. My work also developed a process that uses a focused and controllably rastered ion beam as a nano-scalpel to cut away sections of the osteoblast cells to probe the attachment beneath the main cell body. Ultimately the more rapid growth of osteoblasts, coupled with a stronger cell-surface interface, could provide cost reduction, shorter rehabilitation, and fewer follow-on surgeries due to implant loosening.