The anti-inflammatory effects of exercise training promote atherosclerotic plaque stabilization in apolipoprotein E knockout mice with diabetic atherosclerosis.

Physical exercise is the cornerstone of cardiovascular disease treatment. The present study investigated whether exercise training affects atherosclerotic plaque composition through the modification of inflammatory-related pathways in apolipoprotein E knockout (apoE(-/-)) mice with diabetic atherosclerosis. Forty-five male apoE(-/-) mice were randomized into three equivalent (n=15) groups: control (CO), sedentary (SED), and exercise (EX). Diabetes was induced by streptozotocin administration. High-fat diet was administered to all groups for 12 weeks. Afterwards, CO mice were euthanatized, while the sedentary and exercise groups continued high-fat diet for 6 additional weeks. Exercising mice followed an exercise program on motorized-treadmill (5 times/week, 60 min/session). Then, blood samples and atherosclerotic plaques in the aortic root were examined. A considerable (P<0.001) regression of the atherosclerotic lesions was observed in the exercise group (180.339 ± 75.613 x10(3)µm(2)) compared to the control (325.485 ± 72.302 x10(3)µm(2)) and sedentary (340.188 ± 159.108 x 10(3)µm(2)) groups. We found decreased macrophages, matrix metalloproteinase-2 (MMP-2), MMP-3, MMP-8 and interleukin-6 (IL-6) concentrations (P<0.05) in the atherosclerotic plaques of the exercise group. Compared to both control and sedentary groups, exercise training significantly increased collagen (P<0.05), elastin (P<0.001), and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) (P<0.001) content in the atherosclerotic plaques. Those effects paralleled with increased fibrous cap thickness and less internal elastic lamina ruptures after exercise training (P<0.05), while body-weight and lipid parameters did not significantly change. Plasma MMP-2 and MMP-3 concentrations in atherosclerotic tissues followed a similar trend. From our study we can conclude that exercise training reduces and stabilizes atherosclerotic lesions in apoE-/- mice with diabetic atherosclerosis. A favorable modification of the inflammatory regulators seems to explain those beneficial effects.

Exercise ameliorates serum MMP-9 and TIMP-2 levels in patients with type 2 diabetes.

AIM: This study assessed the impact of regular exercise on inflammatory markers (high-sensitivity C-reactive protein [hsCRP], fibrinogen), and matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), in patients with type 2 diabetes mellitus (T2DM). PATIENTS: Fifty overweight patients with T2DM were randomly assigned to two groups: (A) an exercise group (EXG, n=25), with self-controlled exercise for at least 150 min/week and one additional supervised exercise session/week; and (B) a control group (COG, n=25), with no exercise instructions. All participants were taking oral antidiabetic drugs, and none had diabetic complications. Clinical parameters, exercise capacity (VO(2 peak)), ventilatory threshold (VT), insulin resistance indices (fasting insulin, HOMA-IR, HOMA%S), hsCRP, fibrinogen, MMP-2, MMP-9, TIMP-1 and TIMP-2 were assessed at baseline and after 16 weeks. RESULTS: No significant changes were found in body mass index, waist/hip ratio, insulin-resistance indices, MMP-2 and TIMP-1 throughout the study in either group (P>0.05). Compared with controls, the EXG showed a significant decrease in systolic and mean blood pressure, total and LDL cholesterol, and HbA(1c) (P<0.05). Also, exercise significantly suppressed levels of fibrinogen (P=0.047), hsCRP (P=0.041) and MMP-9 (P=0.028), and the MMP-9-to-TIMP-1 ratio (P=0.038), whereas VO(2 peak) (P=0.011), VT (P=0.008) and plasma TIMP-2 levels (P=0.022) were considerably upregulated in the EXG vs. COG. Standard multiple-regression analyses revealed that MMP-9 changes were independently associated with fibrinogen and HbA(1c) changes, while fibrinogen changes independently predicted TIMP-2 alterations with exercise. CONCLUSION: Mostly self-controlled exercise of moderate intensity ameliorated serum levels of pro- and anti-atherogenic markers in patients with T2DM, with no effects on body weight. These data offer further insight into the cardioprotective mechanisms of exercise in patients with T2DM.

Visfatin (nampt) and ghrelin as novel markers of carotid atherosclerosis in patients with type 2 diabetes.

OBJECTIVE: Visfatin (nampt) and ghrelin are the most recently identified adipocytokines, but their role in atherosclerosis is poorly clarified. In our study we investigated their association with advanced carotid atherosclerosis and carotid intima-media thickness (CIMT) in patients with type 2 diabetes mellitus (T2DM). METHODS: 122 patients (50 males) with T2DM, aged 55-70 were enrolled. Sixty-four age- and sex-matched healthy individuals served as controls (group A). CIMT was assayed in all participants by ultrasound. Among diabetic patients, 47 appeared with carotid plaques (group B), while 75 without plaques (group C). Anthropometric parameters, blood pressure, glycemic and lipid profile, high-sensitivity CRP (hsCRP), insulin resistance (HOMA-IR), fibrinogen, nampt and ghrelin were measured. RESULTS: Diabetic patients had a higher mean-CIMT, increased body-mass index, worse lipid profile, elevated blood pressure and higher levels of white blood cells count, nampt and hsCRP with respect to controls (p<0.01). Among diabetic patients, groups B and C were comparable in anthropometric, glycemic and lipid parameters. Serum nampt was significantly higher in group B rather than in groups A and C (p<0.05). On the other hand, ghrelin levels were considerably lower only in diabetic patients with carotid atherosclerosis compared with healthy individuals. In univariate analysis, mean-CIMT correlated with age (r=0.312; p=0.003), nampt (r=0.341; p<0.001) and ghrelin (r=-0.421; p=0.002) and the latter associations remained significant in multiple regression analysis. CONCLUSIONS: High nampt and low ghrelin serum levels are significantly associated with advanced carotid atherosclerosis in patients with T2DM. Moreover these adipocytokines are independently associated with CIMT, implicating their role as novel atherosclerotic biomarkers and providing another important link between adiposity and atherosclerosis.

Beneficial changes of serum calcification markers and contralateral carotid plaques echogenicity after combined carotid artery stenting plus intensive lipid-lowering therapy in patients with bilateral carotid stenosis.

OBJECTIVES/DESIGN: In symptomatic patients treated with ipsilateral carotid artery stenting (CAS) plus intensive lipid lowering, we assessed the changes of osteopontin (OPN), osteoprotegerin (OPG) and the Gray-Scale Median (GSM) score contralateral to symptomatic carotid stenosis. MATERIALS/METHODS: Forty-six symptomatic patients (group A) with significant carotid stenosis (North American Symptomatic Carotid Endarterectomy Trial (NASCET): >70%) underwent ipsilateral CAS. Those patients had simultaneously contralateral low-grade carotid stenosis (NASCET: 30-69%). Group B included 67 symptomatic patients with low-grade bilateral carotid stenosis (NASCET: 30-69%), but without indications for revascularisation. All patients were treated with atorvastatin (10-80mg) to target low-density lipoprotein (LDL)<100mgdl(-1). Blood samples and plaques' GSM score contralateral to brain infarct were assayed at baseline and after 6 months. RESULTS: At baseline, there were no significant differences between groups (p>0.05). Six-month atorvastatin treatment equivalently improved lipid profile in both groups (p<0.05). The parameters hsCRP, OPN and OPG were significantly down-regulated within both groups, but to a greater extent in group A (p<0.05). Besides this, contralateral GSM score was significantly improved from baseline in both groups (p<0.01), but that increment was more pronounced in group A (vs. group B; p=0.041). These changes were inversely correlated with changes in OPN (p=0.014), OPG (p=0.011) and LDL (p=0.041). CONCLUSION: Ipsilateral CAS plus intensive lipid-lowering therapy was associated with enhanced contralateral carotid plaque stability and attenuated inflammatory burden and calcification inhibitors to a greater extent than atorvastatin therapy alone in patients with bilateral carotid stenosis.

Intensive lipid-lowering therapy ameliorates novel calcification markers and GSM score in patients with carotid stenosis.

OBJECTIVES/DESIGN: Carotid plaque echogenicity quantified by the Gray-Scale Median (GSM) score has been associated with plaque vulnerability. The aim of this study was to assess whether intensive lipid-lowering treatment with atorvastatin in patients with carotid artery stenosis ameliorates novel vascular calcification inhibitors, such as osteopontin (OPN) and osteoprotegerin (OPG), and improves GSM score. METHODS: Ninety-seven patients with carotid stenosis (>40%), but without indication for intervention, were treated for 6 months with atorvastatin (10mg-80mg) to target LDL<100mg/dl. Fifty-two age-and sex-matched healthy individuals served as the control group. Blood samples and GSM were obtained at the beginning and after 6 months. RESULTS: Systolic blood pressure, hsCRP, fibrinogen, OPN and OPG levels differed significantly between patients with carotid stenosis and healthy controls at baseline (p<0.05). Atorvastatin treatment improved lipid profile and significantly reduced hsCRP (p=0.002), WBC count (p=0.041), OPN (p<0.001) and OPG levels (p<0.001). GSM score increased considerably after atorvastatin therapy (from 58.33+/-24.38 to 79.33+/-22.3; p<0.001) and that effect appeared related to OPN (p=0.001), OPG (p=0.013) and LDL (p=0.01) reduction. CONCLUSIONS: In patients with carotid stenosis, intensive lipid-lowering therapy with statins attenuates serum OPN and OPG levels and enhances carotid plaque echogenicity, outlining their beneficial effects on plaque stability.

Dietary L-aspartate and L-glutamate inhibit fatty streak initiation in cholesterol-fed rabbit.

BACKGROUND AND AIM: Low-density lipoprotein (LDL) oxidation is a potential atherogenic agent, and protecting LDL from oxidation prevents atherogenesis. It has been shown that L-aspartate and L-glutamate decrease lipid peroxidation after reoxygenation by means of the initiation of the cardiopulmonary bypass circuit (CPB), when supplemented to the CPB prime, and so they may protect against atherogenesis. The aim of this study was to evaluate the effect of the dietary administration of L-aspartate and L-glutamate on fatty streak onset in cholesterol-fed rabbit. METHODS AND RESULTS: Male New Zealand white rabbits were fed for four weeks with either a high-cholesterol plus corn oil diet (control group) or the same diet supplemented with 12.5 mM L-aspartate and 12.5 mM L-glutamate in drinking water (Asp + Glu group). The mononuclear cells adhering to the endothelium and the intimal foam cells of the thoracic aorta were used to quantify the extent of atherosclerosis. Total serum cholesterol and lipid peroxidation activity, measured as thiobarbituric acid reactive substances (TBARS), were determined 0, 1 and 4 weeks after a 2-week adaptation period. There were no between-group differences in body weight or food intake during the intervention. Serum TBARS were significantly increased in both groups during the experimental period but without any statistical difference between groups. At the end of the dietary intervention, there was a ten-fold increase in total serum cholesterol concentration in both groups vs baseline. The numbers of adherent mononuclear cells and intimal foam cells were both significantly lower in the Asp + Glu group. CONCLUSIONS: Our results suggest that dietary supplementation with L-aspartate and L-glutamate seems to protect the arterial wall from atherogenesis in an experimental animal.

A morphometric study of the structural characteristics of the aorta in pigs using an image analysis method.

The objective of this study was to evaluate multiple structural characteristics, in addition to vasa vasorum density, in different aortic regions. The aorta of healthy Landrace pigs was divided into four thoracic and three abdominal segments. Transverse sections were reserved for morphometric analysis. Image analysis showed the aortic diameter, the thickness of the media, the number of elastic lamellae and the thickness of elastic membranes being reduced with increased distance from the heart (P < 0.05). The average thickness of lamellar units remained constant in the thoracic, but increased in the abdominal aorta (P < 0.05). The number of lamellar units, contained in the avascular zone of the media, and the density of vasa vasorum decreased peripherally (P < 0.05), still the average thickness of the avascular zone was invariant. In conclusion, the anatomical properties of the vessel wall alter through the aorta, being optimal for the varying stresses to which the aorta is subjected along its length. The distinct aortic parts may exhibit inherent morphological features, responsible for the various pathological processes that affect the aorta.

Effect of impaired vasa vasorum flow on the structure and mechanics of the thoracic aorta: implications for the pathogenesis of aortic dissection.

OBJECTIVE: To investigate the alterations of structure and mechanical properties of the aortic wall, resulting from impairment of vasa vasorum flow. METHODS: Eight healthy Landrace pigs were subjected to interruption of vasa vasorum flow to the upper segment of their descending thoracic aorta. Under sterile conditions, the periaortic tissue was excised and the contiguous intercostal arteries were ligated. Ten sham-operated pigs were used as controls. Fifteen days postoperatively, the animals were sacrificed and their upper descending thoracic aortas were removed. Histology, and collagen and elastin content determination by image analysis technique were performed. Mechanical analysis of aortic strips was carried out with a uniaxial tension device and stress-strain curves were obtained. RESULTS: In contrast to normal aortic walls of the control group, histology of the avascular aortas revealed severe ischemic necrosis of the outer media along with abnormal straightening of the elastin and collagen fibers, without significant collagen and elastin content changes. The borderline between the outer ischemic and inner non-ischemic media was sharp, and an outset of dissection was observed at this point. Mechanical analysis showed that at the same level of strain, the ischemic aorta was significantly stiffer at both low (P=0.03) and high strains (P=0. 003). CONCLUSIONS: Impairment of blood supply to the thoracic aorta leads to abnormal morphology of elastin and collagen fibers of the outer media, resulting in increased aortic stiffness under a wide range of stresses. In the clinical setting, decreased vasa vasorum flow, reportedly occurring in arterial hypertension, may increase the stiffness of the outer media of the thoracic aorta and produce interlaminar shear stresses, contributing to the development of aortic dissection.

Doxorubicin cardiotoxicity and serum lipid increase is prevented by dextrazoxane (ICRF-187).

This study is related to the serious side effects of Doxorubicin-cardiotoxicity and serum lipid caused by the drug's cumulative effect. Studies were performed on experimental animals treated with intensive administration of Doxorubicin. Seventy five wistar rats were divided in two equal groups A and B. Group A was used for doxorubicin administration and B for doxorubicin and dextrazoxane. The drugs were administered weekly for twelve weeks at doses 0.2 mg/100 g BW for doxorubicin and 1.5 mg/100 g BW for dextrazoxane. Histological examination of the cardiac muscle, large vessels, liver and other organs and biochemical examination for serum lipids and liver enzymes were performed on certain weeks. Comparison of the findings of the two groups showed a) a reduction in doxorubicin cardiotoxicity by dextrazoxane and b) the addition of dextrazoxane to doxorubicin resulted in lowering the increase of serum lipids produced by doxorubicin. c) In vitro tests by chemiluminescence showed that dextrazoxane acts as a scavenger of oxygen free radicals.

Inhibition of adriamycin cardiotoxicity by 5-fluorouracil: a potential free oxygen radical scavenger.

Adriamycin (ADR), a broad spectrum anticancer agent, has a limit to total dose used, due to cumulative cardiotoxicity. This side effect has been tested in the present study in combined administration with 5-fluorouracil a cytotoxic drug that often is applied together with ADR in cancer treatment. The study was performed on Wistar rats, and the experiment consisted of weekly administration for 12 weeks of adriamycin alone, of 5-fluorouracil alone, a combination of both, and a control group (normal saline) in separate groups comprising 42 animals each. The histology of the cardiac muscle, large vessels and liver, biochemistry of serum cholesterol, triglycerides and HDL-C and oxygen free radical production were examined. It was found that addition of 5-FU to the ADR administration reduced significantly the cardiac lesions, delayed and reduced the increase of serum lipids, produced by ADR alone and oxygen free radical production was also reduced, indicating that 5-fluorouracil is acting as a scavenger of free radicals.

An increase of serum lipids after cumulative doses of doxorubicin and epirubicin in experimental animals.

A wide range of pharmacological actions has been attributed to the anthracyclins. In this study we examined their effect on serum lipids in experimental animals in parallel with histological alterations. Three Wistar rat groups were injected with doxorubicin, epirubicin or normal saline once a week for 12 weeks. Total serum lipids, cholesterol, triglycerides, HDL-cholesterol, transaminases, proteins and alkaline phosphatase were assayed weekly. A proportion of the animals were sacrificed at the same time points and the cardiac muscle, large vessels, liver and abdominal muscle were stained and examined under light microscopy. Serum lipids were found to increase gradually, starting after 8 weeks of drug administration, until the end of the experiment. Tissue damage was noted in the cardiac muscle, abdominal muscle and large vessels, also following an increasing trend. Doxorubicin had a more pronounced effect than epirubicin on both serum lipid increase and tissue destruction. These alterations may contribute to anthracyclin-related cardiac damage.

Low-dose heparin treatment does not inhibit SW480 human colon cancer growth and metastasis in vivo.

We investigated heparin effects on the biological behavior of SW480 human colon adenocarcinoma cells in vivo. Tumor growth, pathological features, metastatic potential and karyotype, were studied after the twelve week low-dose heparin treatment of nude mice subcutaneously injected with SW480 cells. A non statistically significant increase in tumor growth was observed (0.05 < p < 0.1, compared to the control group). No differences in tumor histology and karyotype were detected. Two of the six heparin-treated animals exhibited an increase in tumor vascularization. Metastasis to the lungs and liver was not inhibited. These results do not support the role of heparin in the prevention of the in vivo growth and metastasis of SW 480 colon cancer cells.

In vitro effects of heparin on SW480 tumor cell-matrix interaction.

We investigated the in vitro effects of heparin on the growth and interaction of SW480 colon adenocarcinoma cells with the extracellular matrix proteins laminin, fibronectin and collagen IV. Cell adhesion assays were performed in wells precoated with the proteins mentioned. Tumor cell migration and invasiveness were assayed in Transwell cell culture chambers. SW480 cell adhesion to the matrix proteins and migration to laminin/fibronectin precoated filters were inhibited by heparin in a dose- dependent manner, whereas cell growth and invasion through collagen IV gel were not affected. Our results suggest that heparin influences the SW480 cell-matrix interaction in vitro and inhibits crucial steps of the metastatic process in an experimental model.

Medial necrosis and acute alterations in aortic distensibility following removal of the vasa vasorum of canine ascending aorta.

OBJECTIVE: It is known that the outer layers of the thoracic aorta receive substantial blood flow through vasa vasorum. This study was undertaken to test the hypothesis that removal of vasa vasorum flow will alter the elastic properties of the ascending aorta. METHODS: Distensibility of the ascending aorta was determined before and 30 min after careful removal of the periaortic fat network which contains the vasa vasorum in 10 acutely instrumented dogs (experimental group) and the results were compared with those obtained from six weight matched sham operated control dogs. Aortic distensibility was measured using the formula: distensibility = 2 x pulsatile changes in aortic diameter divided by (diastolic aortic diameter x pulse pressure). Aortic pressures were measured directly from the ascending aorta by a pressure gauge. Aortic diameters were simultaneously determined by an elastic air filled ring connected to a transducer. The efficacy of the technique for the interruption of vasa vasorum blood supply to the aortic wall was proved in six additional animals by histology of transverse blocks of aortic wall from the area of interest. Histology was performed before vasa vasorum removal in two animals, 30 min after vasa vasorum removal in another two, and 15 d after vasa vasorum removal in the remainder. RESULTS: At baseline, there was no difference in the measured variables between the two groups. Aortic distensibility decreased significantly in the experimental group after vasa vasorum removal by 0.90(SEM 0.17) 10(-6).cm2.dyn-1 (p < 0.001), while it remained unchanged in the control group during the experiment. Complete removal of vasa vasorum of the ascending aorta was found in experimental group animals which were killed 30 min after operation, while ischaemic medial necrosis was observed in those killed 15 d after operation. CONCLUSIONS: Vasa vasorum removal led to an acute decrease in the distensibility of the ascending aorta. Lack of blood supply to the outer part of the aortic wall is most likely to have accounted for these findings.

Mechanism of growth retardation following chronic administration of beta-adrenoceptor antagonists to developing rats.

A total of 112 3-week old Wistar rats were separated into eight groups: control groups I-IV (n = 62) and propranolol-treated groups V-VIII (n = 50). Propranolol hydrochloride (100 mg/kg) was present in the rats' drinking water until 26 weeks of age and growth rates of all groups were monitored daily until 53 days of age and thereafter every third day throughout the study. Chronic oral propranolol administration produced growth retardation (P less than 0.05) in both sexes that was reversible when treatment was discontinued. Organ weights were generally smaller in propranolol-treated rats; on the other hand, the ratio of most organ weights per 100 g of body weight was greater in propranolol-treated rats (especially females). The radio-immunological determination of plasma growth hormone showed increased concentrations of growth hormone in propranolol-treated rats (P less than 0.05), whereas hypothalamic somatostatin content was not significantly changed. The results showed that the retarded growth rate following chronic oral propranolol administration to growing rats was independent of changes in plasma growth hormone and hypothalamic somatostatin concentrations, and that retardation was entirely reversible when the beta-adrenoceptor antagonist was discontinued.

Pharmacokinetic interaction in beagle dogs of antiplatelet drugs: acetylsalicylic acid, dipyridamole and calcium dobesilate.

In clinical practice, the co-administration of antiplatelet drugs, such as acetylsalicylic acid (ASA) and dipyridamole (DP) and calcium dobesilate, is often recommended in order to obtain secondary prophylaxis against certain ischaemic diseases. Therefore the possible pharmacokinetic interactions between these three drugs were studied after a single-dose in beagle dogs. The plasma concentrations of ASA, DP and CaDb were measured by HPLC. It was found that the DP and CaDb kinetics were unaffected by concurrent intake of ASA, DP or CaDb. However, concurrent DP or CaDb improved the bioavailability of ASA, particularly the increased Cmax and (AUC).

Creatine kinase (CK-BB) determination in cerebrospinal fluid after acute experimental head injury.

Early changes of the activity of enzymes such as creatine kinase in the cerebrospinal fluid (CSF) or serum are often investigated after head injuries to assess the extent of brain damage and establish a reliable prognosis. The purpose of the present study was to determine levels of creatine kinase isoenzyme CK-BB in the CSF of rats after experimental head injuries. External head injuries of different severity were inflicted on rats, immediately after which CSF was collected for isoenzyme activity determination. It was found that the levels of CK-BB were significantly elevated immediately after the head injury and that the greater the degree of external cranial injury inflicted, the higher the isoenzyme activity was. The results seem to provide evidence that CK-BB activity is an early indicator of brain damage and that its level may reflect the extent of cerebral damage involved.

Pentoxifylline in the treatment of experimental peritonitis in rats.

The objective of this study was to determine the effect of pentoxifylline on the clinical and pathologic course of experimentally induced peritonitis in rats. This drug is a methyxanthine derivative that has vasodilating properties and may decrease platelet aggregation. Peritonitis was induced in 40 Wistar rats by creating a closed ileal loop 4 cm long 5 cm from the ileocecal valve. The animals were divided into two groups of 20 animals each. The first group served as controls, while each animal of the second group received 17 mg/kg/day of pentoxifylline intramuscularly from the day of operation until 30 days postoperatively. The survival rate was significantly increased in the group receiving pentoxifylline and adhesion or abscess formation was considerably reduced. We concluded that the administration of pentoxifylline prolongs significantly the survival of animals with experimental peritonitis and reduces the development of adhesions and abscesses in the peritoneal cavity. This beneficial effect may be attributed to decreased fibrinogen deposits and increased fibrinolytic activity within the peritoneal cavity, thus rendering the bacteria more susceptible to cellular and noncellular clearing mechanisms.

The effect of heparin upon fibrinopurulent peritonitis in rats.

The effect of heparin upon the clinical and pathologic course of experimentally induced peritonitis in the rat was studied. Peritonitis was induced in 40 rats by creating a closed ileal loop 4 centimeters long at a distance of 5 centimeters from the ileocecal valve. The rats were divided into two groups of 20 each. The first group served as the control group while each rat of the second group received 30 units of heparin subcutaneously per day postoperatively. Survival was drastically increased in the group receiving heparin (p = 0.001). Adhesion or abscess formation was considerably reduced in this group. The results of peritoneal cultures showed decreased incidence of Escherichia coli and clostridia in the heparin-treated group. Blood cultures also showed decreased incidence of both aerobes and anaerobes in the treated group. It is concluded from this that the administration of heparin significantly prolongs survival time of animals with peritonitis and reduces the development of adhesions and abscesses in the peritoneal cavity. This beneficial effect could be attributed to decreased fibrinogen deposits within the peritoneal cavity, thus rendering the bacteria more susceptible to cellular and noncellular clearing mechanisms.