Widespread vascular production of C-reactive protein (CRP) and a relationship between serum CRP, plaque CRP and intimal hypertrophy

OBJECTIVES

Evidence of local vascular production and a relationship between serum hsCRP levels and tissue expression of CRP in subjects with vascular disease would support a direct role for CRP in atherosclerosis.

METHODS AND RESULTS

Vascular tissue from subjects undergoing coronary artery bypass grafting surgery (CABGS) (n=28) and carotid endarterectomy (CEA) (n=25) were studied. Histological samples were assessed for intima-media ratio (IMR) and CRP by immunohistochemistry. CRP mRNA was quantified by real-time polymerase chain reaction. CRP mRNA was seen in all plaques, non-atherosclerotic artery and atrium but no difference in mRNA expression was seen between plaque and non-atherosclerotic tissue. Serum hsCRP correlated with IMR (r=0.64, p=0.001) in non-atherosclerotic arteries and with plaque CRP staining (r=0.57, p=0.009) independent of age, BMI, lipids, diabetes and blood pressure. In a separate patient series, serum hsCRP was measured in aortic and coronary sinus blood from subjects undergoing CABGS or angiography (n=54). There was a coronary circulation hsCRP gradient ([mean+/-S.E.M.] aortic CRP 4.3mg/l+/-0.8 versus coronary sinus 5.8+/-1.2mg/l, p<0.05).

CONCLUSIONS

Widespread vascular CRP mRNA expression, a correlation between serum hsCRP, intimal hypertrophy and plaque CRP, and a coronary hsCRP gradient suggest vascular secretion may contribute to serum CRP levels.

Program for Aboriginal and Torres Strait Islander People in the Goulburn-Murray Region: Development and Risk Factor Screening at Indigenous Community Organisations

The Heart Health Project was developed in partnership between Aboriginal health and social organisations in the Goulburn-Murray region and university departments. The aims included screening for cardiovascular disease (CVD) risk factors, and evaluating community-directed interventions. We describe the development of the Heart Health Project and the results of risk factor screening among employees (n=66) of Aboriginal organisations during 2003-04. Screening identified few new cases of overt hypertension, diabetes or hypercholesterolaemia, but did find a large proportion of the survey sample who smoked, had evidence of periodontal disease or who had ?high normal? levels of risk factors at a relatively young age, placing them at risk of developing overt disease. Barriers to diet and exercise behaviours thought to protect against CVD were documented. While appropriate planning made clinical follow-up relatively straightforward, effective referral of at-risk people to primary prevention programs was more difficult. The barriers to making diet and exercise changes need consideration in designing interventions for primary prevention of CVD, as does the importance of promoting heart health in a culturally relevant way. This can be achieved through community direction but long-term support for partnerships and intervention programs is required.

A Collaborative Cardiovascular Health Program for Aboriginal and Torres Strait Islander People in the Goulburn-Murray Region: Development and Risk Factor Screening at Indigenous Community Organisations

The Heart Health Project was developed in partnership between Aboriginal health and social organisations in the Goulburn-Murray region and university departments. The aims included screening for cardiovascular disease (CVD) risk factors, and evaluating community-directed interventions. We describe the development of the Heart Health Project and the results of risk factor screening among employees (n=66) of Aboriginal organisations during 2003-04. Screening identified few new cases of overt hypertension, diabetes or hypercholesterolaemia, but did find a large proportion of the survey sample who smoked, had evidence of periodontal disease or who had "high normal" levels of risk factors at a relatively young age, placing them at risk of developing overt disease. Barriers to diet and exercise behaviours thought to protect against CVD were documented. While appropriate planning made clinical follow-up relatively straightforward, effective referral of at-risk people to primary prevention programs was more difficult. The barriers to making diet and exercise changes need consideration in designing interventions for primary prevention of CVD, as does the importance of promoting heart health in a culturally relevant way. This can be achieved through community direction but long-term support for partnerships and intervention programs is required.

Severe combined hyperlipidaemia and retinal lipid infiltration in a patient with Type 2 diabetes mellitus

Severe combined hyperlipidaemia has occasionally been associated with infiltration of tissues in addition to arteries and the skin. We report a woman with Type 2 diabetes mellitus (DM) and severe combined hyperlipidaemia who developed retinal lipid infiltration, resulting in blindness. A 61-year-old woman with a 15-year history of Type 2 DM was admitted following a two-week history of progressive visual loss. Examination identified lipid infiltration into the retina. Phenotypically she had severe combined hyperlipidaemia with elevated IDL cholesterol and a broad beta band on lipoprotein electrophoresis, raising the possibility of familial dysbetalipoproteinaemia. However, gene sequencing analysis indicated that the patient was homozygous for the E3/E3 allele of the ApoE gene with no mutations detected in either the coding region or intron-exon boundaries. Her lipid profile improved following dietary therapy and gemfibrozil treatment, but this had little effect on either her fundal appearances or her visual acuity. Type 2 DM plays a vital role both in allowing expression of severe combined hyperlipoproteinaemia, in addition to serving as a risk factor for complications such as tissue infiltration.

Exercise frequency and arterial compliance in non-diabetic and type 1 diabetic individuals

BACKGROUND

The role of exercise in preventing cardiovascular disease (CVD) has been well documented. To determine whether this benefit could be related to effects on vascular endothelial function and vessel wall elasticity, thereby preserving arterial compliance, we examined the relationship between habitual exercise and arterial compliance as measured by pulse wave analysis.

DESIGN

A cross-sectional study of healthy volunteers and patients with type 1 diabetes.

METHODS

Non-diabetic individuals not taking cholesterol or blood pressure-lowering medication (n=176) and patients with type 1 diabetes (n=105), aged 17-70 years, were recruited. Small and large artery compliance and other haemodynamic variables were measured using the PulseWave CR-2000 cardiovascular profiling system. A questionnaire was completed to assess the frequency of physical activity.

RESULTS

In multivariate analysis, undertaking three or more episodes of vigorous activity per week was associated with having a 1 unit greater small artery compliance, independent of age, sex, height, diabetes status and blood pressure. The effect was especially marked in non-diabetic women.

CONCLUSIONS

The results support other findings that regular physical activity protects against CVD, through the preservation of vascular compliance.

Blood pressure and hypertension for Australian Aboriginal and Torres Strait Islander people

BACKGROUND

Reliable, large-scale, population-based data on blood pressure for Australian Aboriginal and Torres Strait Islander populations are limited. This present study aims to describe the blood pressure levels and to explore the clinical risk factors for hypertension among Australian Aboriginal and Torres Strait Islander peoples.

DESIGN

A cross-sectional population survey was conducted in isolated communities in northern and central Australia.

METHODS

Australian Aboriginal people (n = 1088) and Torres Strait Islanders (n = 606) aged 15 years and over were examined between 1993 and 1997. Blood pressure, body mass index, plasma glucose and urinary albumin-creatinine ratio were measured. The association of systolic, diastolic and pulse blood pressure to age was determined and independent associations of hypertension with other clinical variables were tested using logistic regression. Comparisons with results from other Australian data (including AusDiab) were made.

RESULTS

Systolic blood pressure and pulse pressure increased in a linear manner with age but mean diastolic blood pressure leveled off at around 50 years and decreased thereafter, suggestive of arterial stiffening. The age-standardized prevalence of hypertension (blood pressure > or = 140/90 mmHg or medication) for subjects aged 25-54 years was 27%, compared with 9% in non-Indigenous Australians in the Northern Territory and Queensland (AusDiab Survey). Older age, male sex, higher body mass index, albumin-creatinine ratio and diabetes were independently associated with hypertension.

CONCLUSIONS

Elevated blood pressure is a public health concern for indigenous people, which again highlights health differentials in Australia. Early detection and management of high blood pressure should be assigned a high priority in Indigenous communities.

Differential association of C-reactive protein with adiposity in men and women in an Aboriginal community in northeast Arnhem Land of Australia

OBJECTIVE

To examine the relationship between C-reactive protein (CRP), adiposity and other metabolic abnormalities in an Aboriginal community in Northern Australia.

DESIGN

Cross-sectional analysis of data obtained between 2001 and 2003 from 379 Aboriginal people residing in a geographically isolated community.

RESULTS

Mean (95% CI) CRP in women and men was 4.06 cholesterol (3.53, 4.66) mg/l and 3.42 (2.94, 3.97) mg/l, respectively (P=NS). The prevalence of the metabolic syndrome (US National Cholesterol Education [corrected] Program (NCEP) definition) was significantly higher for women than men (41 vs 18%, chi (2)=20.94, P<0.001). C-reactive protein correlated strongly with adiposity in women (waist circumference, waist to hip ratio and body mass index; r>/=0.514, P<0.01) but much less strongly in men (r</=0.221, P<0.05). In a multivariate stepwise linear regression model, waist circumference was the strongest independent predictor explaining 35% of CRP concentration variance in women, but only 5.4% in men (WHR). Incremental increases in CRP concentration across four BMI categories were significant in women (P (linear trend)<0.001) but not in men.

CONCLUSIONS

High CRP levels in the surveyed population are consistent with the high prevalence of vascular disease morbidity and mortality in Aboriginal Australians. The relationship of CRP with increasing body fat was strong and consistent in women but not in men. Prospective studies are needed to elucidate the role of CRP (if any) as a predictive marker for cardiovascular events in this high-risk population.

Traditional risk factor assessment does not capture the extent of cardiovascular risk in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is associated with accelerated atherosclerosis. However, the degree of endothelial dysfunction and its relationship to traditional and novel cardiovascular risk factors have not been examined in SLE.

METHODS

In a case-control design, 35 patients with clinically stable SLE and 35 control subjects matched for age, sex, body mass index and smoking status were studied. Arterial elasticity, lipid profile, homocysteine, measures of inflammation and oxidative stress were determined.

RESULTS

Among traditional vascular risk factors, there was a nonsignificant trend towards lower blood pressure in the control subjects, whereas low-density lipoprotein (LDL) cholesterol levels were significantly lower in the SLE group (2.5 vs 3.3 mmol/L, P < 0.001). Patients with SLE had significantly lower small artery elasticity (SAE; 4.9 vs 7.0 ml/mmHg x 100, P < 0.001) and higher plasma homocysteine (11.4 vs 8.3 mmol/L, P = 0.002) than control subjects. Levels of serum sVCAM-1 (614 vs 494 ng/mL, P = 0.002), oxidized LDL (144 vs 97, P < 0.001) and CD40 ligand (4385 vs 1373 pg/ml, P = 0.001) were significantly higher in SLE. Oxidized LDL levels, older age at SLE diagnosis and higher disease damage scores correlated inversely with SAE but not traditional risk factors.

CONCLUSION

Impaired endothelial function as shown by decreased SAE, and an adverse profile of novel proatherogenic and prothrombotic vascular disease risk factors were prevalent in clinically quiescent SLE. These findings show the vulnerability of patients with SLE for atherosclerosis, and emphasize that assessments based on traditional risk factors alone may be inadequate.

The metabolic syndrome and changing relationship between blood pressure and insulin with age, as observed in Aboriginal and Torres Strait Islander peoples

AIMS

To determine the prevalence of the metabolic syndrome (MS) among Aboriginal and Torres Strait Islander peoples. A further objective was to investigate the relationships between fasting insulin and blood pressure (BP) within these groups with increasing age.

METHODS

A cross-sectional population-based study included 369 Torres Strait Islanders (residing in Torres Strait and Far North Queensland), and 675 Aborigines from central Australia. Data necessary for classification of MS was collected, including fasting and 2-h glucose and insulin, urinary albumin and creatinine, anthropometric measurements, BP, serum lipids.

RESULTS

The ATPIII criteria classified 43% of Torres Strait Islanders and 44% of Aborigines with MS, whereas 32 and 28%, respectively, had the MS according to WHO criteria. Agreement between the two criteria was only modest (kappa coefficient from 0.28 to 0.57). Factor analyses indicated no cluster including both insulin and BP in either population. Significant correlations (P < 0.05) [adjusted for gender, body mass index (BMI) and waist circumference] were observed between BP and fasting insulin: a positive correlation for Torres Strait Islanders aged 15-29 years, and an inverse correlation for Aborigines aged 40 years and older.

CONCLUSION

Torres Strait Islanders and Aborigines had very high prevalences of the MS. Specific population characteristics (high prevalences of central obesity, dyslipidaemia, renal disease) may make the WHO definition preferable to the ATPIII definition in these population groups. The poor agreement between criteria suggests a more precise definition of the metabolic syndrome that is applicable across populations is required. This study showed an inverse relationship with age for the correlation of BP and fasting insulin.

Plasma low-molecular weight fluorescence in type 1 diabetes mellitus

Characteristic tissue fluorescence is associated with advanced glycation end product (AGE) accumulation in experimental diabetes models, but its utility in patients with type 1 diabetes remains to be established. We studied 148 patients with type 1 diabetes and 77 healthy age-matched control subjects. Low-molecular weight (LMW) fluorophore levels were estimated in plasma samples obtained after an overnight fast. Intra- and interassay coefficients of variation were 4.7% and 6.4%, respectively. LMW fluorophore levels were significantly higher in patients with diabetes than in control subjects (6.3 +/- 0.6 AU/mL vs. 4.1 +/- 0.3; P = 0.007). However, all of this difference came from patients with microvascular complications (n = 67, 7.5 +/- 1.3). There was no significant difference in LMW fluorescence between complication-free patients (4.4 +/- 0.2) and control subjects (P > 0.05). On multivariate analysis, LMW fluorophores correlated with measures of renal function (P < 0.05) but not with diabetes per se. In addition, there was no correlation between LMW fluorophores and the markers of oxidative stress or systemic inflammation. Longitudinal and interventional studies are required to determine whether the association between LMW fluorophores and nephropathy is cause or effect.

Oxidized LDL and small LDL particle size are independently predictive of a selective defect in microcirculatory endothelial function in type 2 diabetes

AIM

To explore the associations of LDL (low-density lipoprotein) particle size and oxidized LDL with endothelium-dependent function of the forearm microcirculation in diabetes.

METHODS

Endothelium-dependent function was examined in 43 middle-aged men and women with type 2 diabetes and 10 age-matched controls. All received aspirin to inhibit endothelial cyclo-oxygenase. Forearm blood flow (FBF) was measured using venous occlusion plethysmography with separate administration of acetylcholine (ACh) and bradykinin (BK) into the brachial artery. Endothelium-independent function was assessed using sodium nitroprusside (SNP). N(G)-monomethyl-L-arginine (L-NMMA) was co-infused with ACh (ACh + L-NMMA) and BK (BK + L-NMMA) to assess non-NO-mediated contributions to endothelium-dependent function.

RESULTS

Subjects with diabetes had impaired endothelium-dependent and endothelium-independent function compared with controls (p < 0.01 for ACh, BK and SNP). In multivariate regression analysis, LDL size (r = 0.41 and p = 0.007), oxidized LDL (r = -0.41 and p = 0.007) and duration of diabetes (r = -0.37 and p = 0.02) predicted FBF response to ACh independently of age, gender and systolic blood pressure. There were no associations between LDL size, oxidized LDL, duration of diabetes and FBF response to BK, SNP, ACh + L-NMMA or BK + L-NMMA.

CONCLUSION

In type 2 diabetes, small dense LDL particles, duration of diabetes and oxidized LDL may independently contribute to endothelial dysfunction of the microcirculation. These disturbances may occur via a selective defect, because ACh and BK activate endothelial NO synthase via different G-protein signal transduction pathways.

Systemic and vascular inflammation is elevated in early IgA and type 1 diabetic nephropathies and relates to vascular disease risk factors and renal function

BACKGROUND

Inflammation is implicated in cardiovascular disease (CVD) and mortality in end-stage renal failure (ESRF). Its importance in early renal disease is yet to be defined.

METHODS

Serum levels of systemic and vascular inflammatory markers in early IgA nephropathy (IgAN) and control subjects were measured and related to renal function and vascular risk factors. A parallel study in type 1 diabetes mellitus subjects with (T1DM Nx) and without nephropathy (T1DM No Nx) was performed.

RESULTS

Fifty-one IgAN patients aged 46+/-2 years (mean+/-SEM), calculated creatinine clearance (CrCl) 88+/-5 ml/min, were compared with 51 matched control subjects. Forty-six T1DM Nx patients aged 40+/-2 years, CrCl 84+/-5 ml/min, and 73 T1DM No Nx patients aged 38+/-2 years were also compared. High sensitivity C-reactive protein (hsCRP) was elevated in IgAN, T1DM Nx and T1DM No Nx patients compared with controls [4.2+/-0.6 (P < 0.001), 4.1+/-0.6 (P < 0.001), 2.6+/-0.4 (P < 0.05) vs 1.6+/-0.3 mg/l]. Levels in T1DM Nx patients were higher than in T1DM No Nx patients (P < 0.05). Inflammation and vascular dysfunction as measured by pulse pressure (PP) were related. HsCRP correlated with PP in IgAN and T1DM Nx (r = 0.47, P = 0.001; r = 0.40, P < 0.05). PP was the strongest independent predictor of hsCRP in IgAN (T = 2.45, P < 0.001), while body mass index (T = 7.83, P < 0.001) was the strongest predictor in T1DM Nx. Endothelial cell adhesion molecules were increased in T1DM Nx > IgAN > T1DM No Nx vs controls: soluble vascular adhesion molecule-1 (sVCAM-1) 760+/-30 (P < 0.001) > 663+/-34 (P = 0.001) > 601+/-21 (P < 0.05) vs 536+/-15 ng/ml; soluble intracellular adhesion molecule-1 (sICAM-1) 320+/-8 (P < 0.001) > 313+/-13 (P < 0.001) > 307+/-8 (P < 0.001) vs 244+/-6 ng/ml. sVCAM-1 levels were higher in T1DM Nx than in T1DM No Nx, P < 0.001. In IgAN and T1DM Nx, hsCRP correlated with sICAM-1 (r = 0.33, P = 0.017; r = 0.37; P = 0.017). sVCAM-1 was related to renal function in IgAN and T1DM Nx: serum cystatin C (r = 0.63, P < 0.001: r = 0.425, P = 0.002), and urine protein:creatinine ratio in IgAN (r = 0.48; P = 0.001).

CONCLUSIONS

Systemic and vascular markers of inflammation are increased in early renal disease and relate to renal dysfunction and cardiovascular risk factors. Inflammation may be a common process in various renal diseases and may link and accelerate renal dysfunction and CVD.

Expression of GLUT12 in the fetal membranes of the human placenta

The aim of this study was to characterize the expression of the novel glucose transporter GLUT12 in the fetal membranes of the human placenta. RT-PCR and Western blotting of extracts of amnion and choriodecidua from four normal term placentas identified GLUT12 mRNA and protein expression. In all four samples the signals for GLUT12 were markedly stronger in the choriodecidua than in the amnion, whereas the signals for GLUT1, a glucose transporter know to be expressed in fetal membranes, were similar for the two tissues. In further studies, paraffin sections of fetal membranes were analyzed by immunohistochemistry with GLUT12 and GLUT1-specific polyclonal antibodies. GLUT12 immunoreactivity was localized predominantly to the trophoblast cells in the chorion and to a lesser extent to decidual cells and to epithelial and fibroblast cells of the amnion. GLUT1 was localized to chorionic trophoblast cells and amniotic epithelial and fibroblast cells. GLUT12 expression was predominantly cytoplasmic, whereas GLUT1 was associated with the membrane of the cells. These results show that GLUT12 is expressed in cells of human fetal membranes and suggest that GLUT12 may play a role in the facilitation of glucose transport into these cells.

Oxidative stress and high-density lipoprotein function in Type I diabetes and end-stage renal disease

In a cross-sectional study, oxidative stress in high vascular disease risk groups, ESRD (end-stage renal disease) and Type I diabetes, was assessed by measuring plasma protein carbonyls and comparing antioxidant capacity of HDL (high-density lipoprotein) as pertaining to PON1 (paraoxonase 1) activity and in vitro removal of LPO (lipid peroxides). ESRD subjects on haemodialysis (n=22), Type I diabetes subjects (n=20) without vascular complications and healthy subjects (n=23) were compared. Plasma protein carbonyls were higher in ESRD patients [0.16 (0.050) nmol/mg of protein; P=0.001; value is mean (SD)] relative to subjects with Type I diabetes [0.099 (0.014) nmol/mg of protein] and healthy subjects [0.093 (0.014) nmol/mg of protein]. Plasma PON1 activity, with and without correction for HDL-cholesterol, was lower in diabetes but did not differ in ESRD compared with healthy subjects. Plasma PON1 activity, without correction for HDL, did not differ between the three groups. In ESRD, plasma PON1 activity and plasma protein carbonyl concentrations were inversely related (r=−0.50, P<0.05). In an in vitro assay, LPO removal by HDL in ESRD subjects was greater than HDL from healthy subjects (P<0.01), whereas HDL from patients with Type I diabetes was less effective (P<0.01). Efficacy of LPO removal was unrelated to plasma PON1 activity, in vitro glycation or mild oxidation, but was impaired by marked oxidation and glycoxidation. Protein carbonyl levels are increased in ESRD but not in complication-free Type I diabetes. HDL antioxidant function is increased in ESRD, perhaps a compensatory response to increased oxidative stress, but is lower in Type I diabetes. HDL dysfunction is related to glycoxidation rather than glycation or PON1 activity.

Molecular and cellular regulation of glucose transporter (GLUT) proteins in cancer

Malignant cells are known to have accelerated metabolism, high glucose requirements, and increased glucose uptake. Transport of glucose across the plasma membrane of mammalian cells is the first rate-limiting step for glucose metabolism and is mediated by facilitative glucose transporter (GLUT) proteins. Increased glucose transport in malignant cells has been associated with increased and deregulated expression of glucose transporter proteins, with overexpression of GLUT1 and/or GLUT3 a characteristic feature. Oncogenic transformation of cultured mammalian cells causes a rapid increase of glucose transport and GLUT1 expression via interaction with GLUT1 promoter enhancer elements. In human studies, high levels of GLUT1 expression in tumors have been associated with poor survival. Studies indicate that glucose transport in breast cancer is not fully explained by GLUT1 or GLUT3 expression, suggesting involvement of another glucose transporter. Recently, a novel glucose transporter protein, GLUT12, has been found in breast and prostate cancers. In human breast and prostate tumors and cultured cells, GLUT12 is located intracellularly and at the cell surface. Trafficking of GLUT12 to the plasma membrane could therefore contribute to glucose uptake. Several factors have been implicated in the regulation of glucose transporter expression in breast cancer. Hypoxia can increase GLUT1 levels and glucose uptake. Estradiol and epidermal growth factor, both of which can play a role in breast cancer cell growth, increase glucose consumption. Estradiol and epidermal growth factor also increase GLUT12 protein levels in cultured breast cancer cells. Targeting GLUT12 could provide novel methods for detection and treatment of breast and prostate cancer.

Lipoproteins and diabetic microvascular complications

Risk factors for the microvascular complications (nephropathy and retinopathy) of Type 1 and Type 2 diabetes mellitus and the associated accelerated atherosclerosis include: age, diabetes duration, genetic factors, hyperglycaemia, hypertension, smoking, inflammation, glycation and oxidative stress and dyslipoproteinaemia. Hypertriglyceridaemia, low HDL and small dense LDL are common features of Type 2 diabetes and Type 1 diabetes with poor glycaemic control or renal complications. With the expansion of knowledge and of clinical and research laboratory tools, a broader definition of 'lipid' abnormalities in diabetes is appropriate. Dyslipoproteinaemia encompasses alterations in lipid levels, lipoprotein subclass distribution, composition (including modifications such as non-enzymatic glycation and oxidative damage), lipoprotein-related enzymes, and receptor interactions and subsequent cell signaling. Alterations occur in all lipoprotein classes; chylomicrons, VLDL, LDL, HDL, and Lp(a). There is also emerging evidence implicating lipoprotein related genotypes in the development of diabetic nephropathy and retinopathy. Lipoprotein related mechanisms associated with damage to the cardiovascular system may also be relevant to damage to the renal and ocular microvasculature. Adverse tissue effects are mediated by both alterations in lipoprotein function and adverse cellular responses. Recognition and treatment of lipoprotein-related risk factors, supported by an increasing array of assays and therapeutic agents, may facilitate early recognition and treatment of high complication risk diabetic patients. Further clinical and basic research, including intervention trials, is warranted to guide clinical practice. Optimal lipoprotein management, as part of a multi-faceted approach to diabetes care, may reduce the excessive personal and economic burden of microvascular complications and the related accelerated atherosclerosis.

'Lipoproteins, glycoxidation and diabetic angiopathy'

The chronic vascular complications of diabetes (nephropathy, retinopathy and accelerated atherosclerosis) are a major cause of morbidity and premature mortality. In spite of the more widespread availability of intensive diabetes management, approximately one in three people with diabetes develop aggressive complications and over 70% die of atherosclerosis-related diseases. Genetic and acquired factors are likely to be contributory. Potential mediators of vascular damage may include the interrelated processes of lipoprotein abnormalities, glycation, oxidation and endothelial dysfunction. Lipoprotein abnormalities encompass alterations in lipid concentrations, lipoprotein composition and subclass distribution and lipoprotein-related enzymes. Nonenzymatic glycation and oxidative damage to lipoproteins, other proteins and to vascular structures may also be deleterious. As atherosclerosis is a chronic condition commencing in youth, and because clinical events may be silent in diabetes, surrogate measures of vascular disease are important for early identification of diabetic patients with or at high risk of vascular damage, and for monitoring efficacy of interventions. The increasing array of biochemical assays for markers and mediators of vascular damage, noninvasive measures of vascular health, and therapeutic options should enable a reduction in the excessive personal and economic burden of vascular disease in type 1 and type 2 diabetes.

Paraoxonase activity in Greek migrants and Anglo-Celtic persons in the Melbourne Collaborative Cohort Study: relationship to dietary markers

BACKGROUND

Greek migrants to Australia have low all-cause and cardiovascular disease (CVD) mortality. This may be partly due to maintenance of a traditional Mediterranean diet and its interaction with CVD risk factors. The enzyme paraoxonase-1 (PON1) is thought to contribute to the anti-atherogenic properties of high density lipoproteins (HDL) by metabolizing lipid peroxides. PON1 activity is subject to modulation by dietary and genetic factors.

AIMS

To determine PON1 activity in Greek migrants and Anglo-Celtic subjects recruited from the Melbourne Collaborative Cohort Study, and its relationship to coronary risk factors and dietary markers.

METHODS

Greek (n = 127) and Anglo-Celtic (n = 128) participants in the MCCS were recruited. By design, there were approximately equal numbers of men and women and of diabetic and non-diabetic subjects. Subjects were screened for glucose tolerance, dyslipidaemia, hypertension and coronary heart disease. Plasma markers of diet (carotenoids, retinol, tocopherol, homocysteine) and inflammation (C-reactive protein) were assessed. Serum PON1 activity was determined spectrophotometrically using two substrates: paraoxon (paraoxonase) and phenylacetate (arylesterase).

RESULTS

PON1 activity was significantly higher in the presence of hyperlipidaemia but otherwise did not vary by ethnicity, presence of coronary heart disease, diabetes, hypertension or smoking. Among subjects with the high activity phenotype (defined by the ratio of paraoxonase:arylesterase activity), paraoxonase activity correlated directly with circulating diet-derived carotenoid concentrations for Greeks, and inversely with homocysteine and C-reactive protein for Anglo-Celtics. No such associations were seen among subjects with the low activity phenotype.

CONCLUSIONS

The data suggest that dietary modulation of atherosclerotic risk may vary according to PON1 phenotype.

Comparison of arterial assessments in low and high vascular disease risk groups

BACKGROUND

An increasing number of arterial function assessments are available, including small and large arterial elasticity (SAE/C2, LAE/C1), endothelial function as measured by flow mediated dilation (FMD), carotid intima-medial thickness (IMT), ankle brachial index (ABI), pulse pressure (PP), and pulse wave velocity (PWV). We have consecutively performed these measures in subjects with low and high vascular disease risks to assess the interrelationships.

METHODS AND RESULTS

Twenty healthy subjects (HS) and 20 older subjects with type 2 diabetes mellitus (DM) were studied with all techniques at a single sitting by a single operator. In HS, C2 correlated with FMD (R = 0.577, P = .008), PWV (R = 0.522, P = .046), and ABI (R = 0.463, P = .04). There was no significant correlation of C1 and FMD or blood pressure (BP) measurements. In DM, C2 correlated with FMD (R = 0.443, P = .05), systolic BP (R = -0.553, P = .01), PP (R = -0.601, P = .005), and systemic vascular resistance (R = -0.577, P = .008). There was no significant correlation between anthropometric measures and arterial function measures in either group. The IMT was not correlated with any measure of arterial function in either group.

CONCLUSIONS

C2 assessed by pulse wave analysis correlated with endothelial function measured by FMD in young apparently healthy subjects and older subjects with type 2 diabetes. Systolic BP and PP correlated with C2 and FMD in older diabetic subjects but not healthy subjects. The interrelationships between arterial function measures are different in high and low risk populations. This variability needs to be considered when applying these techniques to individuals in different populations.

Coaching patients On Achieving Cardiovascular Health (COACH): a multicenter randomized trial in patients with coronary heart disease

BACKGROUND

Disease management programs in which drugs are prescribed by dietitians or nurses have been shown to improve the coronary risk factor profile in patients with coronary heart disease. However, those disease management programs in which drugs are not prescribed by allied health professionals have not improved coronary risk factor status. The objective of the Coaching patients On Achieving Cardiovascular Health (COACH) study was to determine whether dietitians or nurses who did not prescribe medications could coach patients with coronary heart disease to work with their physicians to achieve the target levels for their total cholesterol (TC) and other risk factors.

METHODS

Multicenter randomized controlled trial in which 792 patients from 6 university teaching hospitals underwent a stratified randomization by cardiac diagnosis within each hospital: 398 were assigned to usual care plus The COACH Program and 394 to usual care alone. Patients in The COACH Program group received regular personal coaching via telephone and mailings to achieve the target levels for their particular coronary risk factors. There was one coach per hospital. The primary outcome was the change in TC (DeltaTC) from baseline (in hospital) to 6 months after randomization. Secondary outcomes included measurement of a wide range of physical, nutritional, and psychological factors. The analysis was performed by intention to treat.

RESULTS

The COACH Program achieved a significantly greater DeltaTC than usual care alone: the mean DeltaTC was 21 mg/dL (0.54 mmol/L) (95% confidence interval [CI], 16-25 mg/dL [0.42-0.65 mmol/L]) in The COACH Program vs 7 mg/dL (0.18 mmol/L) (95% CI, 3-11 mg/dL [0.07-0.29 mmol/L]) in the usual care group (P<.0001). Thus, the reduction in TC from baseline to 6 months after randomization was 14 mg/dL (0.36 mmol/L) (95% CI, 8-20 mg/dL [0.20-0.52 mmol/L]) greater in The COACH Program group than in the usual care group. Coaching produced substantial improvements in most of the other coronary risk factors and in patient quality of life.

CONCLUSIONS

Coaching, delivered as The COACH Program, is a highly effective strategy in reducing TC and many other coronary risk factors in patients with coronary heart disease. Coaching has potential effectiveness in the whole area of chronic disease management.

Low plasma concentrations of diet-derived antioxidants in association with microalbuminuria in Indigenous Australian populations

Microalbuminuria is a risk factor for renal and cardiovascular diseases. Oxidant stress may contribute to vascular disease risk by promoting damage to renal and vascular tissues. This study examined the associations of plasma levels of diet-derived antioxidants with albuminuria in Australian population groups at high risk of renal and cardiovascular disease. Data on microalbuminuria and diet-derived plasma antioxidants were drawn from results of cross-sectional community-based risk factor surveys of Aboriginal and Torres Strait Islander peoples (n =698, 15 years and older). Prevalence of microalbuminuria ranged from 17-21%. After adjustment for age, gender, body mass index, diabetes, smoking status, plasma lipids and blood pressure, microalbuminuria was associated with significantly lower plasma concentrations of lycopene (-29%; P <0.001), beta-carotene (-22%; P <0.001), alpha-carotene (-22%; P <0.001) and cryptoxanthin (-17%; P <0.001) compared with normalbuminuric persons. Significant associations of microalbuminuria with plasma concentrations of alpha-tocopherol, retinol, lutein plus zeaxanthin and homocysteine were absent. The data are consistent with a protective effect of diets rich in carotenoids on vascular endothelium and/or renal tissues, and support the need for interventions to address affordable food supplies and dietary quality among Indigenous Australians.