Identification of microRNAs 758 and 33b as potential modulators of ABCA1 expression in human atherosclerotic plaques.

BACKGROUND AND AIM: Adenosine triphosphate (ATP)-binding cassette (ABC) transporters A1 and G1 are the main transporters involved in macrophage cholesterol efflux. The understanding of the molecular mechanism(s) of their regulation in atherosclerosis is crucial for potential therapeutic approaches. Preclinical studies support a role for microRNAs in the posttranscriptional regulation of these transporters; however, no evidence is still available on human atherosclerosis. Thus, the aim of this study was to investigate the modulation of the ABCA1 and ABCG1 pathway in human atherosclerotic plaques and microRNA involvement in its modulation. METHODS AND RESULTS: Thirty-one human atherosclerotic plaques were obtained from patients undergoing carotid endarterectomy for high-grade (>70%) vessel stenosis, and divided into normocholesterolemic (n = 15) and hypercholesterolemic groups (n = 16) according to the presence/absence of hypercholesterolemia. Both ABCA1 and ABCG1 messenger RNAs (mRNAs) were significantly upregulated in carotid plaques from hypercholesterolemic patients as assessed by real-time polymerase chain reaction (RT-PCR). Despite this result, no difference was found at the protein levels analyzed by Western blot, thus suggesting a strong posttranscriptional modulation. MicroRNA microarray and subsequent validation by RT-PCR showed a significant upregulation of ABCA1-linked miR-758 and miR-33b in plaques from hypercholesterolemic patients. CONCLUSION: We provide evidence of a strong posttranscriptional regulation of ABCA1 and ABCG1 expression in human atherosclerotic plaques from hypercholesterolemic patients. This effect is potentially due to the concomitant increase of miR-33b and miR-758, two well-established regulators of ABCA1 and ABCG1 expression. The identification of miR-33b and miR-758 as putative key regulators of ABCA1 protein expression within human atherosclerotic plaques provides further data for the realization of new anti-atherosclerotic drugs with specific targets based on anti-miRNA technologies.

Care manager to control cardiovascular risk factors in primary care: the Raffaello cluster randomized trial.

BACKGROUND AND AIM: This cluster randomized trial evaluated the efficacy of a disease and care management (D&CM) model in cardiovascular (CVD) prevention in primary care. METHODS AND RESULTS: Eligible subjects had ≥ 1 among: blood pressure ≥ 140/90 mmHg; glycated hemoglobin ≥ 7%; LDL-cholesterol ≥ 160 or ≥ 100 mg/dL (primary or secondary prevention, respectively); BMI ≥ 30; current smoking. The D&CM intervention included a teamwork including nurses as care managers for the implementation of tailored care plans. Control group was allocated to usual-care. The main outcome was the proportion of subjects achieving recommended clinical targets for ≥ 1 of uncontrolled CVD risk factors at 12-month. During 2008-2009 we enrolled 920 subjects in the Abruzzo/Marche regions, Italy. Following the exclusion of L'Aquila due to 2009 earthquake, final analyses included 762 subjects. The primary outcome was achieved by 39.1% (95%CI: 34.2-44.2) and 25.2% (95%CI: 20.9-29.9) of subjects in the intervention and usual-care group, respectively (p < 0.001). The D&CM intervention significantly increased the proportion of subjects who achieved clinical targets for both diabetes and hypertension, with no differences in hypercholesterolemia, smoking status and obesity. CONCLUSIONS: The D&CM intervention was effective in controlling cardiovascular risk factors, in particular hypertension and diabetes. Numbers needed to treat were small. Such intervention may deserve further consideration in clinical practice. REGISTRATION NUMBER: ACTRN12611000813987.

Lower incidence of macrovascular complications in patients on insulin glargine versus those on basal human insulins: a population-based cohort study in Italy.

BACKGROUND AND AIM: The aim of this study was to compare the use of insulin glargine and intermediate/long-acting human insulin (HI) in relation to the incidence of complications in diabetic patients. METHODS AND RESULTS: A population-based cohort study was conducted using administrative data from four local health authorities in the Abruzzo Region (900,000 inhabitants). Diabetic patients without macrovascular diseases and treated with either intermediate/long-acting HI or glargine were followed for 3-years; the incidence of diabetic (macrovascular, microvascular and metabolic) complications was ascertained by hospital discharge claims and estimated using Cox proportional hazard models. Propensity score (PS) matching was also used to adjust for significant differences in the baseline characteristics between the two groups. RESULTS: Overall, 1921 diabetic patients were included: 744 intermediate/long-acting HI and 1177 glargine users. During the 3-year follow-up, 209 (28.1%) incident events of any diabetic complication occurred in the intermediate/long-acting HI and 159 (13.5%) in the glargine group. After adjustment for covariates, glargine users had an HR (95% CI) of 0.57 (0.44-0.74) for any diabetic complication and HRs of 0.61 (0.44-0.84), 0.58 (0.33-1.04) and 0.35 (0.18-0.70) for macrovascular, microvascular and metabolic complications, respectively, compared to intermediate/long-acting HI users. PS analyses supported these findings. CONCLUSIONS: The use of glargine is associated with a lower risk of macrovascular complications compared with traditional basal insulins. However, limitations inherent to the study design including the short length of observation and the lack of data on metabolic control or diabetes duration, do not allow us to consider this association as a proof of causality.

Immunopathogenesis of sarcoidosis and risk of malignancy: a lost truth?

The hypothesis of a relationship between sarcoidosis and malignancy was firstly formulated in 1972 by Brincker. He documented an association of sarcoid reactions or sarcoidosis with 19 lymphomas and associated malignancies. Based on various epidemiological studies, for more than 20 years sarcoidosis has been considered as a condition at increased risk for cancer, particularly lymphoproliferative disorders. The existence of a sarcoidosis-lymphoma syndrome was therefore proposed, highlighting, as a potential mechanism, the uncontrolled lymphocyte proliferation and mitotic activity. A reduced ability to eliminate an antigen and chronic inflammation have been suggested as triggering events. Leading to a reduced tumor immune surveillance, a diminished myeloid dendritic cells (mDC) function, despite up-regulated co-stimulatory and maturation markers, was also raised as potential mechanism. However, some subsequent studies have questioned the presence of a close association between the two entities and have explained those previously published as the result of selection bias and misclassification. Recently, a Swedish population-based cohort study documented a significant overall excess incidence of cancer among sarcoidosis patients, especially those with multiple hospitalizations or admission in older age, emphasizing again a potential neoplastic risk. Therefore, currently, whether these patients have an increased risk of developing malignant lesions is still debated. Larger and unbiased studies are needed before drawing definite conclusions.

MicroRNAs and atherosclerosis: new actors for an old movie.

To date, cardiovascular diseases (CVDs) are the leading causes of morbidity and mortality worldwide. MicroRNAs (miRNAs) are endogenous, short, non-coding RNA sequences able to regulate gene expression principally at the post-transcriptional level. Initially, they were thought to be involved only in developmental timing of worms. Their involvement in human biology was recently discovered and many studies have been performed to demonstrate the role of miRNA in human cancer. Since the first observation in 2005 of their implication in cardiac biology, many studies have demonstrated their role in the genetic modulation of cardiovascular development and in cardiovascular diseases such as cardial remodeling and heart failure, cardiac arrhythmias, cardiac ischaemia, cardiac fibrosis, atherosclerosis and stroke. Thus, the aim of this review is to describe the role of miRNA in atherosclerosis development and evolution and to individuate their role as potential therapeutic target.

Effects of a phytosterol-enriched dairy product on lipids, sterols and 8-isoprostane in hypercholesterolemic patients: a multicenter Italian study.

BACKGROUND AND AIMS: Plant sterols, added to several food sources, lower serum cholesterol concentrations. Plant sterol-induced cholesterol lowering is paralleled by a mild decrease in plasma levels of the antioxidant beta-carotene, the amount of this decrease being considered clinically non-significant. Whether the effect on lipid profile of daily consumption of plant sterol-enriched low-fat fermented milk (FM) is paralleled by a concomitant variation in a reliable marker of the oxidative burden like plasma isoprostane levels is unresolved. METHODS AND RESULTS: The effect of plant sterol consumption on plasma lipid and isoprostane levels of hypercholesterolemic patients was evaluated in a multicenter, randomized double blind study. Hypercholesterolemic patients consumed a FM daily for 6 weeks. Subjects were randomized to receive either 1.6g of plant sterol-enriched FM (n=60) or control FM product (n=56). After 6 weeks of plant sterol-enriched FM consumption, LDL cholesterol was reduced from 166.2+/-2.0 to 147.4+/-2.8 mg/dL (p=0.01). A significant reduction was observed for total cholesterol (from 263.5+/-2.6 to 231.0+/-3.2mg/dL, p=0.01). There was greater LDL cholesterol lowering among hypercholesterolemic patients with higher LDL cholesterol at baseline. We found a reduction of plasma 8-isoprostane in patients taking plant sterol-enriched FM (from 43.07+/-1.78 to 38.04+/-1.14 pg/ml, p=0.018) but not in patients taking the control product (from 42.56+/-2.12 to 43.19+/-2.0 pg/ml, p=NS). Campesterol and beta-sitosterol levels were not influenced by phytosterol consumption. CONCLUSIONS: Daily consumption of low-fat plant sterol dairy product favourably changes lipid profile by reducing LDL-cholesterol, and may also have an anti-oxidative effect through a reduction of plasma isoprostanes.

COX-2 expression in atherosclerosis: the good, the bad or the ugly?

Cyclooxygenase (COX) is the rate limiting enzyme catalyzing the conversion of arachidonic acid into prostanoids, lipid mediators critically implicated in a variety of physiological and pathophysiological processes, including inflammation, vascular and renal homeostasis, and immune responses. Since the early 1990s it has been appreciated that two isoforms of COX exist, referred to as COX-1 and COX-2. Although structurally homologous, COX-1 and COX-2 are regulated by two independent and quite different systems and have different functional roles. In the setting of acute ischemic syndromes it has been recognized that COX pathway plays an important role; however, whereas the function of platelet COX-1 in acute ischemic diseases is firmly established, the role of COX-2 in atherothrombosis remains controversial. The complex role of COX-2 in this setting is also confirmed by the unexpected cardiovascular side effects of long-term treatment with COX-2 inhibitors. In this article, we review the pattern of expression of COX-2 in the cellular players of atherothrombosis, its role as a determinant of plaque vulnerability, the effects of the variable expression of upstream and downstream enzymes in the prostanoid biosynthesis on COX-2 expression and inhibition.

Effect of ischemia and reperfusion on antioxidant enzymes and mitochondrial inner membrane proteins in perfused rat heart.

Experiments were performed to investigate the effects of 60 min severe global ischemia followed by 30 min reperfusion on the antioxidant enzymatic system in the isolated perfused rat heart. Ischemia induced a significant increase of cytoplasmic and mitochondrial selenium-dependent glutathione peroxidase (EC 1.11.1.9) activity. In reperfused hearts, only the mitochondrial form showed a further significant increase. Glutathione reductase (EC 1.6.4.2) was increased in ischemic hearts, whilst the reperfused hearts showed a decrease towards the level found in aerobic hearts. Mitochondrial superoxide dismutase (EC 1.15.1.1) activity was depressed in ischemic as well as in reperfused hearts, though the cytoplasmic form was unmodified. Catalase (EC 1.11.1.6), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glutathione transferase (EC 2.5.1.18) activities were unchanged throughout the experiment. Ischemia and reperfusion induced a significant fall in tissue-reduced glutathione content concomitant with an increase of its oxidized form. We have also studied the mitochondrial inner membrane proteins for both molecular weight, with Coomassie blue, and thiol status, with monobromobimane stain, using a sodium dodecyl sulfate polyacrylamide gel electrophoresis technique. Neither ischemia nor reperfusion effected any relevant modification of the molecular weight of the mitochondrial inner-membrane proteins either in the presence or absence of a reducing agent. However, two of these proteins with an apparent molecular weight of 52,0000 and 12,000 showed a decrease in the monobromobimane stain, probably due to the oxidation of their thiol groups.

Overexpression of functionally coupled cyclooxygenase-2 and prostaglandin E synthase in symptomatic atherosclerotic plaques as a basis of prostaglandin E(2)-dependent plaque instability.

BACKGROUND: Studies have implicated a role for prostaglandin (PG) E(2)-dependent matrix metalloproteinase (MMP) biosynthesis in the rupture of atherosclerotic plaque. Cyclooxygenase-2 (COX-2) and PGE synthase (PGES) are coregulated in nucleated cells by inflammatory stimuli. The aim of this study was to characterize the expression of COX-2 and PGES in carotid plaques and to correlate it with the extent of inflammatory infiltration and MMP activity and with clinical features of patients' presentation. METHODS AND RESULTS: Plaques were obtained from 50 patients undergoing carotid endarterectomy and divided into 2 groups (symptomatic and asymptomatic) according to clinical evidence of recent transient ischemic attack or stroke. Plaques were analyzed for COX-2, PGES, MMP-2, and MMP-9 by immunocytochemistry and Western blot, whereas zymography was used to detect MMP activity. Immunocytochemistry was used to identify CD68+ macrophages, CD3+ T lymphocytes, and HLA-DR+ cells. The percentage of macrophage-rich areas was larger (P<0.0001) in symptomatic plaques. COX-2, PGES, and MMPs were detected in all specimens; enzyme concentration, however, was significantly higher in symptomatic plaques. COX-2, PGES, and MMPs were especially noted in shoulders of symptomatic plaques, colocalizing with HLA-DR+ macrophages. All symptomatic plaques contained activated forms of MMPs. Finally, inhibition of COX-2 by NS-398 was accompanied by decreased production of MMPs that was reversed by PGE(2). CONCLUSIONS: This study demonstrates the colocalization of COX-2 and PGES in symptomatic lesions and provides evidence that synthesis of COX-2 and PGES by activated macrophages is associated with acute ischemic syndromes, possibly through metalloproteinase-induced plaque rupture.

In vivo formation of 8-iso-prostaglandin f2alpha and platelet activation in diabetes mellitus: effects of improved metabolic control and vitamin E supplementation.

BACKGROUND: Diabetes mellitus (DM) is associated with enhanced lipid peroxidation and persistent platelet activation. We tested the hypothesis that the in vivo formation of the F2-isoprostane 8-iso-prostaglandin (PG)F2alpha, a bioactive product of arachidonic acid peroxidation, is enhanced in DM and contributes to platelet activation. METHODS AND RESULTS: Urine samples were obtained from 85 diabetic patients and 85 age- and sex-matched healthy subjects for measurement of immunoreactive 8-iso-PGF2alpha and 11-dehydro-thromboxane B2 (TXM), an in vivo index of platelet activation. Sixty-two had non-insulin-dependent (NID)DM, and 23 had insulin-dependent (ID) DM. Vitamin E supplementation, metabolic control, and cyclooxygenase inhibitors were used to investigate the mechanisms of formation of 8-iso-PGF2alpha in this setting. Urinary 8-iso-PGF2alpha excretion was significantly higher (P=0.0001) in NIDDM patients (419+/-208 pg/mg creatinine; range 160 to 1014) than in age-matched control subjects (208+/-92; 41 to 433). Urinary 8-iso-PGF2alpha was linearly correlated with blood glucose and urinary TXM. 8-iso-PGF2alpha excretion was also significantly (P=0. 0001) higher in IDDM patients (400+/-146; 183 to 702) than in control subjects (197+/-69; 95 to 353). Vitamin E supplementation (600 mg/d for 14 days) was associated with a statistically significant reduction in both urinary 8-iso-PGF2alpha (by 37%) and TXM (by 43%) in 10 NIDDM patients. Improved metabolic control was associated with a significant (P=0.0001) reduction in 8-iso-PGF2alpha and TXM excretion by 32% and 41%, respectively, in 21 NIDDM patients. 8-iso-PGF2alpha was unchanged after 2-week dosing with aspirin and indobufen despite profound suppression of TXM excretion. CONCLUSIONS: We conclude that DM is associated with increased formation of F2-isoprostanes, as a correlate of impaired glycemic control and enhanced lipid peroxidation. This may provide an important biochemical link between impaired glycemic control and persistent platelet activation. These results provide a rationale for dose-finding studies of antioxidant treatment in diabetes.

Effects of vitamin E supplementation on F(2)-isoprostane and thromboxane biosynthesis in healthy cigarette smokers.

BACKGROUND: Increased formation of 8-iso-prostaglandin (PG) F(2alpha) and thromboxane (TX) A(2), potent agonists of platelet and vascular thromboxane (TH)/PGH(2) receptors, has been detected in cigarette smokers. We performed a randomized, double-blind, placebo-controlled study of the effects of vitamin E (300, 600, and 1200 mg/d, each dose for 3 consecutive weeks) on 8-iso-PGF(2alpha) and TXA(2) biosynthesis in 46 moderate cigarette smokers. METHODS AND RESULTS: Urinary immunoreactive 8-iso-PGF(2alpha) and 11-dehydro-TXB(2), plasma vitamin E, and serum TXB(2) were measured by previously validated techniques. Baseline urinary 8-iso-PGF(2alpha) and 11-dehydro-TXB(2) excretion averaged 241+/-78 and 430+/-293 pg/mg creatinine, respectively. Urinary 8-iso-PGF(2alpha) was significantly correlated with 11-dehydro-TXB(2) (r=0.360, n=138, P<0.0001). Baseline plasma vitamin E levels averaged 20.6+/-4.9 micromol/L and were inversely correlated with urinary 11-dehydro-TXB(2) (r=-0.304, P=0.039) but not with 8-iso-PGF(2alpha) (r=-0.227, P=0.129). Vitamin E supplementation caused a dose-dependent increase in its plasma levels that reached a plateau at 600 mg (42.3+/-11.2 micromol/L, P<0. 001). This was not associated with any statistically significant change in urinary 8-iso-PGF(2alpha) or 11-dehydro-TXB(2) excretion. CONCLUSIONS: Supplementation with pharmacological doses of vitamin E has no detectable effects on lipid peroxidation and thromboxane biosynthesis in vivo in healthy subjects with a mild degree of oxidant stress. These findings are consistent with the hypothesis that the basal rate of lipid peroxidation is a major determinant of the response to vitamin E supplementation and have implications for the use of vitamin E in healthy subjects as well as for the design and interpretation of clinical trials of antioxidant intervention.

Increased circulating nitric oxide in young patients with type 1 diabetes and persistent microalbuminuria: relation to glomerular hyperfiltration.

Hyperglycemia has been causally linked to vascular and glomerular dysfunction by a variety of biochemical mechanisms, including a glucose-dependent abnormality in nitric oxide (NO) production and action. NO is a candidate for mediating hyperfiltration and the increased vascular permeability induced by diabetes. Serum nitrite and nitrate (NO2-+ NO3-) concentrations were assessed as an index of NO production in 30 adolescents and young adults with type 1 diabetes, 15 with and 15 without microalbuminuria (albumin excretion rate [AER] between 20 and 200 microg/min), compared with a well-balanced group of healthy control subjects. In all subjects, glomerular filtration rate (GFR) was determined by radionuclide imaging. Our study showed that NO2- + NO3- serum content and GFR values were significantly higher in microalbuminuric diabetic patients than in the other 2 groups. GFR was significantly and positively related to AER levels (r2 = 0.75, P < 0.0001), whereas NO2- + NO3- serum content was independently associated with both AER and GFR values (beta = 2.086, P = 0.05, beta = 1.273, P = 0.0085, respectively), suggesting a strong link between circulating NO, glomerular hyperfiltration, and microalbuminuria in young type 1 diabetic patients with early nephropathy. Interestingly, mean HbA1c, serum concentration was significantly higher in microalbuminuric than in normoalbuminuric diabetic subjects (P < 0.05) and was independently associated with AER values, suggesting a role for chronic hyperglycemia in the genesis of diabetic nephropathy. Moreover, HbA1c serum concentration was significantly and positively related to NO2 + NO3 serum content (r2 = 0.45, P = 0.0063) and GFR values (r2 = 0.57, P = 0.0011), suggesting that chronic hyperglycemia may act through a mechanism that involves increased NO generation and/or action. In conclusion, we suggest that in young type 1 diabetic patients with early nephropathy, chronic hyperglycemia is associated with an increased NO biosynthesis and action that contributes to generating glomerular hyperfiltration and persistent microalbuminuria.

Circadian blood pressure changes and myocardial ischemia in hypertensive patients with coronary artery disease.

OBJECTIVES: We sought to evaluate whether different circadian blood pressure (BP) changes could influence the occurrence of ischemic episodes in untreated and treated hypertensive patients with stable coronary artery disease (CAD). BACKGROUND: In hypertensive patients with CAD the occurrence of myocardial ischemia could be influenced by either high or low BP values. Ambulatory monitoring has shown that circadian BP profile is not uniform in hypertensive patients. METHODS: Twenty-one patients with a nighttime BP fall < 10% ("nondippers"), 35 with a nighttime BP fall between > 10% and < 20% ("dippers") and 14 with a nighttime BP fall > 20% ("overdippers") with CAD underwent simultaneous ambulatory BP and electrocardiographic monitoring before and during drug therapy with nitrates and atenolol or verapamil in a prospective, randomized, open, blinded end point design. RESULTS: Daytime BP was not significantly different among the groups both before and during therapy. Nighttime BP was different by definition. Treatment significantly reduced BP values in each group (p < 0.05). Daytime ischemic episodes did not differ among the groups either before or during therapy. Drug therapy significantly reduced daytime ischemia (p < 0.05). In untreated patients, nighttime ischemia was more frequent in nondippers than in dippers and overdippers (p < 0.05). Drug therapy significantly reduced nocturnal ischemia in nondippers (p < 0.05), had no significant effect in dippers and significantly increased nighttime ischemia in overdippers (p < 0.05). During treatment, nighttime ischemia was more frequent in overdippers than in dippers and nondippers (p < 0.05). The same results were achieved when ischemic episodes were defined with more restrictive criteria (ST segment depression > or = 2 mm). CONCLUSIONS: Circadian BP changes can influence the occurrence of myocardial ischemia in untreated and treated hypertensive patients with CAD. Nocturnal ischemia was found to be more frequent in nondippers among untreated patients and in overdippers among treated patients, potentially suggesting different therapeutic approaches based on circadian BP profile.

Novel determinants of plaque instability.

Arachidonic acid metabolism plays an important role in acute ischemic syndromes affecting the coronary or cerebrovascular territory, as reflected by biochemical measurements of eicosanoid biosynthesis and the results of inhibitor trials in these settings. Two cyclooxygenase (COX)-isozymes have been characterized, COX-1 and COX-2, that differ in terms of regulatory mechanisms of expression, tissue distribution, substrate specificity, preferential coupling to upstream and downstream enzymes and susceptibility to inhibition by the extremely heterogeneous class of COX-inhibitors. While the role of platelet COX-1 in acute coronary syndromes and ischemic stroke is firmly established through approximately 20 years of thromboxane metabolite measurements and aspirin trials, the role of COX-2 expression and inhibition in atherothrombosis is substantially uncertain, because the enzyme was first characterized in 1991 and selective COX-2 inhibitors became commercially available only in 1998. In this review, we discuss the pattern of expression of COX-2 in the cellular players of atherothrombosis, its role as a determinant of plaque 'vulnerability,' and the clinical consequences of COX-2 inhibition. Recent studies from our group suggest that variable expression of upstream and downstream enzymes in the prostanoid biosynthetic cascade may represent important determinants of the functional consequences of COX-2 expression and inhibition in different clinical settings.

Elevated circulating levels of monocyte chemoattractant protein-1 in patients with restenosis after coronary angioplasty.

Inflammation plays a pathogenic role in the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant of monocytes; however, its role in the pathophysiology of restenosis is still unclear. We set out to investigate the role of MCP-1 in restenosis after PTCA. In addition, we tested the hypothesis that MCP-1 exerts its effect, at least in part, by inducing O(2)(-) generation in circulating monocytes. Plasma levels of MCP-1 were measured before and 1, 5, 15, and 180 days after PTCA in 50 patients (30 males and 20 females, aged 62+/-5 years) who underwent PTCA and who had repeated angiograms at 6-month follow-up. Restenosis occurred in 14 (28%) patients. The MCP-1 level was no different at baseline between patients with or without restenosis. However, after the procedure, restenotic patients, compared with nonrestenotic patients, had statistically significant (P<0.0001) elevated levels of MCP-1. In contrast, plasma levels of other chemokines, such as RANTES and interleukin-8, did not differ between the 2 groups after PTCA. Higher MCP-1 throughout the study was correlated with restenosis. Moreover, increased MCP-1 was significantly correlated with increased monocyte activity, as reflected by enhanced O(2)(-) generation. Finally, multivariate regression analysis showed that the MCP-1 plasma level measured 15 days after PTCA was the only statistically significant independent predictor of restenosis (beta=0.688, P<0.0001). This study suggests that MCP-1 production and macrophage accumulation in the balloon-injured vessel may play a pivotal role in restenosis after PTCA. MCP-1 may induce luminal renarrowing, at least in part, by inducing O(2)(-) release in monocytes. Further understanding of the mechanism(s) by which MCP-1 is produced and acts after arterial injury may provide insight into therapies to limit the progression of atherosclerosis and restenosis after balloon angioplasty.

Factors associated with apoptosis in symptomatic and asymptomatic carotid atherosclerotic plaques.

The aim of this study was to investigate the differences that are present between apoptosis in symptomatic (with symptoms of cerebral ischemic attack) and asymptomatic carotid atherosclerotic plaques. The apoptotic process in macrophages and smooth muscle cells was evaluated. Cellular markers and products of immune cells in symptomatic and asymptomatic atherosclerotic plaque and endoarterectomy specimen were analyzed by immunohistochemistry. No statistically significant differences were present regarding the mean SMC actin-positive area. Using double staining of alpha-smooth muscle actin and TUNEL techniques, the number of smooth muscle cells in apoptosis was statistically higher in symptomatic plaque as compared with asymptomatic plaque. Statistically significant differences (p=0.009) were also found in the CD45-positive cells in the inflammatory infiltrate. The CD68-positive macrophages showed statistically significant differences (p=0.0001). Similarly, the double staining with CD68 and TUNEL revealed that apoptotic macrophages were mainly present in asymptomatic plaques rather than symptomatic plaques. Statistically significant differences (p<0.001) were found in the Bcl-2 expression, with higher values in asymptomatic plaques. Our data showed that the increase of the inflammatory cells contributes to plaque instability and that death due to apoptosis of smooth muscle cells in symptomatic plaques could contribute to their destabilization and explains their tendency to fracture.

Relationship between reduced BCL-2 expression in circulating mononuclear cells and early nephropathy in type 1 diabetes.

Microalbuminuria is the earliest clinical evidence of diabetic nephropathy, but the mechanisms linking hyperglycemia and kidney complications are not clear. The aim of this study was to evaluate whether enhanced oxidative stress in patients with microalbuminuria can contribute to diabetic nephropathy development through downregulation of the antiapoptotic gene Bcl-2 that promotes in turn a pro-inflammatory status. We studied 30 patients with type 1 diabetes (15 with and 15 without microalbuminuria) compared to 15 matched healthy controls. Plasma oxidant status, and expression of Bcl-2, activated NF-kB, inducible Nitric Oxide synthase (iNOS), and monocyte chemoattractant protein (MCP)-1 in circulating monocytes were evaluated at baseline and after 8-week oral vitamin E treatment (600 mg b.i.d.). Bcl-2 expression was significantly reduced in microalbuminuric diabetic patients as a consequence of increased oxidant burden secondary to persistent hyperglycemia. Bcl-2 down-regulation was associated with enhanced expression of NF-kB, iNOS and MCP-1, and showed a strong correlation with the albumin excretion rate. Low Bcl-2 expression and high inflammatory status were normalized by vitamin E both in vivo and in vitro. Our study showed that Bcl-2 down-regulation in diabetic patients with poor glycemic control results in the activation of the NF-kB pathway leading to the development of nephropathy. Vitamin E might provide a novel form of therapy for prevention of nephropathy in diabetic patients in which an acceptable glycemic control is difficult to achieve despite insulin therapy.

Increased Na+/Li+ countertransport activity may help to identify type 1 diabetic adolescents and young adults at risk for developing persistent microalbuminuria.

OBJECTIVE: To evaluate whether erythrocyte sodium-lithium countertransport (Na+/Li+ CT) activity may identify adolescents and young adults with childhood-onset of type 1 diabetes to be at greater risk to develop persistent microalbuminuria and incipient diabetic nephropathy. RESEARCH DESIGN AND METHODS: In January 1989, Na+/Li+ CT was measured in 170 normoalbuminuric diabetic adolescents and young adults (age 12-23 years; onset of diabetes before age 18 years; duration of diabetes longer than 7 years). Participants were clinically examined at baseline and biennially thereafter. Na+/Li+ CT activity was measured every 2 years during the 8-year follow-up period. Na+/Li+ CT activity was measured also in parents of diabetic offspring. RESULTS: Over 8 years, 18 (10 male, 8 female) out of 170 patients (10.5%) developed persistent microalbuminuria; no patient developed overt nephropathy. The risk of developing microalbuminuria was higher in children with increased Na+/Li+ CT (using 300 mumol.1 erythrocytes-1.h-1 as the arbitrary cutoff point) (group 1) compared with those with normal Na+/Li+ CT at the beginning of the study (group 2) (18.98 vs. 3.29%, P < 0.01; sensitivity 96.7%; specificity 57.9%). Sex did not influence predictive value, sensitivity, or specificity. Na+/Li+ CT was not significantly correlated with HbA1c or duration of type 1 diabetes. The percentage of offspring with both parents having Na+/Li+ CT activity above the median values was significantly higher in patients in group 1 than in group 2. The odds ratio for the occurrence of microalbuminuria after adjustment for confounding variables (albumin excretion rate [AER], sex, HbA1c, mean blood pressure, cholesterol, triglycerides) in type 1 diabetic adolescents with elevated baseline erythrocyte Na+/Li+ CT was 4.5 (95% CI of 2.1-11.4). CONCLUSIONS: These results confirm those of previous studies and suggest that Na+/Li+ CT may be one of the predictors and risk factors for incipient diabetic nephropathy in adolescents and young adults with onset of diabetes during childhood. Persistently increased Na+/Li+ CT activity may help to identify normotensive, normoalbuminuric patients with type 1 diabetes who are predisposed to develop microalbuminuria and incipient diabetic nephropathy.

Impaired left ventricular diastolic function and vascular postischemic vasodilation associated with microalbuminuria in IDDM patients.

OBJECTIVE: Microalbuminuria is considered an important predictor of cardiovascular events in diabetic patients. In this study, a possible association of microalbuminuria with significant changes in left ventricular (LV) morphology and function and generalized vascular dysfunction was analyzed in insulin-dependent diabetes mellitus (IDDM) patients without hypertension, coronary artery disease, or autonomic dysfunction. RESEARCH DESIGN AND METHODS: Thirty-four young long-term IDDM patients, 16 with and 18 without microalbuminuria, and 20 control subjects were studied. LV systolic function and wall thickness were evaluated by M-mode echocardiography. LV diastolic function was studied using a combined echo-Doppler and phonocardiographic technique. The hyperemic response to forearm ischemia was measured by strain-gauge plethysmography. All patients underwent 24-h ambulatory blood pressure monitoring. RESULTS: LV mass index and wall thickness:radius ratio were significantly higher in microalbuminuric patients. LV relaxation was significantly impaired in both diabetic groups compared with control subjects; moreover, this impairment was significantly greater in microalbuminuric than in normoalbuminuric patients. In microalbuminuric patients, forearm postischemic vasodilation was also significantly lower and mean awake diastolic blood pressure (dBP) was significantly higher than in the other two groups. CONCLUSIONS: Our data suggest that microalbuminuria is associated with significant changes in LV morphology, a more severe impairment of cardiac diastolic function, altered vascular dilatory capacity, and higher daytime dBP. Therefore, microalbuminuric patients should be considered to have a higher risk of cardiovascular complications and be kept under closer surveillance.

Oxidative stress and cardiovascular complications in diabetes: isoprostanes as new markers on an old paradigm.

Long-term vascular complications still represent the main cause of morbidity and mortality in diabetic patients. Although randomized long-term clinical studies comparing the effects of conventional and intensive therapy have demonstrated a clear link between hyperglycemia and the development of complications of diabetes, they have not defined the mechanism through which excess glucose results in tissue damage. Evidence has accumulated indicating that oxidative stress may play a key role in the etiology of diabetic complications. Isoprostanes are emerging as a new class of biologically active products of arachidonic acid metabolism of potential relevance to human vascular disease. Their formation in vivo seems to reflect primarily, if not exclusively, a nonenzymatic process of lipid peroxidation. Enhanced urinary excretion of 8-iso-PGF(2alpha) has been described in association with both type 1 and type 2 diabetes mellitus, and correlates with impaired glycemic control. Besides providing a likely noninvasive index of lipid peroxidation in this setting, measurements of specific F(2) isoprostanes in urine may provide a sensitive biochemical end point for dose-finding studies of natural and synthetic inhibitors of lipid peroxidation. Although the biological effects of 8-iso-PGF(2alpha) in vitro suggest that it and other isoeicosanoids may modulate the functional consequences of lipid peroxidation in diabetes, evidence that this is likely in vivo remains inadequate at this time.