Human in vivo research on the vascular effects of adenosine

Deciphering the combination mechanisms of Gualou–Xiebai herb pair against atherosclerosis by network pharmacology and HPLC-Q-TOF-MS technology

Introduction: Gualou (Trichosanthes kirilowii Maxim)–Xiebai (Allium macrostemon Bunge) (GLXB) is a well-known herb pair against atherosclerosis (AS). However, the combination mechanisms of GLXB herb pair against AS remain unclear.

Objective: To compare the difference in efficacy between GLXB herb pair and the single herbs and to explore the combination mechanisms of GLXB against AS in terms of compounds, targets, and signaling pathways.

Methods: The combined effects of GLXB were evaluated in AS mice. The main compounds of GLXB were identified via quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS) and UNIFI informatics platforms. The united mechanisms of GLXB in terms of nodes, key interactions, and functional clusters were realized by network pharmacology. At last, the anti-atherosclerotic mechanisms of GLXB were validated using enzyme-linked immunosorbent assay (ELISA) and Western blot in AS mice.

Results: The anti-atherosclerotic effects of the GLXB herb pair (6 g/kg) were more significant than those of Gualou (4 g/kg) and Xiebai (2 g/kg) alone. From the GLXB herb pair, 48 main components were identified. In addition, the GLXB herb pair handled more anti-atherosclerotic targets and more signaling pathways than Gualou or Xiebai alone, whereas 10 key targets of GLXB were found using topological analysis. Furthermore, the GLXB herb pair (6 g/kg) could suppress the inflammatory target levels of IL-6, IL-1β, TNF-α, ALOX5, PTGS2, and p-p38 in AS mice. GLXB herb pair (6 g/kg) could also ameliorate endothelial growth and function by regulating the levels of VEGFA, eNOS, p-AKT, VCAM-1, and ICAM-1 and reducing macrophage adhesion to vascular wall in AS mice. GLXB herb pair (6 g/kg) could improve the blood lipid levels in AS mice. In addition, the regulating effects of GLXB herb pair (6 g/kg) on levels of IL-1β, TNF-α, ALOX5, VEGFA, eNOS, VCAM-1, ICAM-1, and blood lipids were more significant than those of Gualou (4 g/kg) or Xiebai alone (2 g/kg).

Conclusion: The combination mechanisms of the GLXB herb pair were elucidated in terms of components, targets, and signaling pathways, which may be related to suppressing inflammation, regulating vascular endothelial growth/function, and improving blood lipid levels.

Reactive hyperemia: a review of methods, mechanisms, and considerations

Reactive hyperemia is a well-established technique for noninvasive assessment of peripheral microvascular function and a predictor of all-cause and cardiovascular morbidity and mortality. In its simplest form, reactive hyperemia represents the magnitude of limb reperfusion following a brief period of ischemia induced by arterial occlusion. Over the past two decades, investigators have employed a variety of methods, including brachial artery velocity by Doppler ultrasound, tissue reperfusion by near-infrared spectroscopy, limb distension by venous occlusion plethysmography, and peripheral artery tonometry, to measure reactive hyperemia. Regardless of the technique used to measure reactive hyperemia, blunted reactive hyperemia is believed to reflect impaired microvascular function. With the advent of several technological advancements, together with an increased interest in the microcirculation, reactive hyperemia is becoming more common as a research tool and is widely used across multiple disciplines. With this in mind, we sought to review the various methodologies commonly used to assess reactive hyperemia and current mechanistic pathways believed to contribute to reactive hyperemia and reflect on several methodological considerations.

Changes in aortic reactivity associated with the loss of equilibrative nucleoside transporter 1 (ENT1) in mice

Slc29a1 encodes for equilibrative nucleoside transporter subtype 1 (ENT1), the primary mechanism of adenosine transfer across cell membranes. Previous studies showed that tissues isolated from Slc29a1-null mice are relatively resistant to injury caused by vascular ischemia-reperfusion. To determine if there are similar changes in the microvasculature, and investigate underlying mechanism, we examined aortas isolated from wildtype and Slc29a1-null mice. Aorta macrostructure and gene expression were examined histologically and by qPCR, respectively. Wire myography was used to assess the contractile properties of isolated thoracic aortic rings and their response to adenosine under both normoxic and hypoxic conditions. In vivo haemodynamic parameters were assessed using the tail-cuff method. Slc29a1-null mice had significantly (P<0.05) increased plasma adenosine (2.75-fold) and lower blood pressure (~15% ↓) than wild-type mice. Aortas from Slc29a1-null mice were stiffer with a smaller circumference (11% ↓), and had an enhanced contractile response to KCl and receptor-mediated stimuli. Blockade of ENT1 with nitrobenzylthioinosine significantly enhanced (by ~3.5-fold) the response of aorta from wild-type mice to phenylephrine, but had minimal effect on aortas from Slc29a1-null mice. Adenosine enhanced phenylephrine-mediated constriction in the wild-type tissue under both normoxic (11.7-fold) and hypoxic (3.6-fold) conditions, but had no effect on the Slc29a1-null aortic aorta. In conclusion, aortas from Slc29a1-null mice respond to hypoxic insult in a manner comparable to wild-type tissues that have been pharmacologically preconditioned with adenosine. These data also support a role for ENT1 in the regulation of the protective effects of adenosine on contractile function in elastic conduit arteries such as thoracic aorta.

Short-Term Hypoxia Dampens Inflammation in vivo via Enhanced Adenosine Release and Adenosine 2B Receptor Stimulation

Hypoxia and inflammation are closely intertwined phenomena. Critically ill patients often suffer from systemic inflammatory conditions and concurrently experience short-lived hypoxia. We evaluated the effects of short-term hypoxia on systemic inflammation, and show that it potently attenuates pro-inflammatory cytokine responses during murine endotoxemia. These effects are independent of hypoxia-inducible factors (HIFs), but involve augmented adenosine levels, in turn resulting in an adenosine 2B receptor-mediated post-transcriptional increase of interleukin (IL)-10 production. We translated our findings to humans using the experimental endotoxemia model, where short-term hypoxia resulted in enhanced plasma concentrations of adenosine, augmentation of endotoxin-induced circulating IL-10 levels, and concurrent attenuation of the pro-inflammatory cytokine response. Again, HIFs were shown not to be involved. Taken together, we demonstrate that short-term hypoxia dampens the systemic pro-inflammatory cytokine response through enhanced purinergic signaling in mice and men. These effects may contribute to outcome and provide leads for immunomodulatory treatment strategies for critically ill patients.

Ischaemic preconditioning does not alter the determinants of endurance running performance in the heat

PURPOSE

Ischaemic preconditioning (IP) has been shown to be ergogenic for endurance performance in normothermic conditions and alleviate physiological strain under hypoxia, potentially through haemodynamic and/or metabolic mechanisms. Exertional hyperthermia is characterised by competition for blood flow between the muscles and skin, an enhanced metabolic strain and impaired endurance performance. This study investigated the effect of IP on the determinants of endurance performance, through an incremental exercise test in the heat.

METHOD

Eleven males completed two graded exercise tests in the heat (32 °C, 62 % RH) until volitional exhaustion, preceded by IP (4 × 5 min 220 mmHg bilateral upper leg occlusion) or a control (CON) condition (4 × 5-min 50 mmHg bilateral).

RESULT

IP did not improve running speeds at fixed blood lactate concentrations of 2 and 4 mMol L(-1) (p = 0.828), or affect blood glucose concentration throughout the trial [mean (±SD); CON 5.03 (0.94) mMol L(-1), IP 5.47 (1.38) mMol L(-1), p = 0.260). There was no difference in [Formula: see text]O2max [CON 55.5 (3.7) mL kg(-1) min(-1), IP 56.0 (2.6) mL kg(-1) min(-1), p = 0.436], average running economy [CON 222.3 (18.0) mL kg(-1) km(-1), IP 218.9 (16.5) mL kg(-1) km(-1), p = 0.125], or total running time during graded exercise [CON 347 (42) s, IP 379 (68) s, p = 0.166]. The IP procedure did not change muscle temperature [CON ∆ = 0.55 (0.57) °C, IP ∆ = 0.78 (0.85) °C, p = 0.568], but did reduce T CORE during exercise (~-0.1 °C, p = 0.001).

CONCLUSION

The novel application of IP prior to exercise in the heat does not enhance the determinants of endurance performance. For events where IP appears ergogenic, muscle warming strategies are unnecessary as IP does not influence deep muscle temperature.

Upregulation of inducible NO synthase by exogenous adenosine in vascular smooth muscle cells activated by inflammatory stimuli in experimental diabetes

Background

Adenosine has been shown to induce nitric oxide (NO) production via inducible NO synthase (iNOS) activation in vascular smooth muscle cells (VSMCs). Although this is interpreted as a beneficial vasodilating pathway in vaso-occlusive disorders, iNOS is also involved in diabetic vascular dysfunction. Because the turnover of and the potential to modulate iNOS by adenosine in experimental diabetes have not been explored, we hypothesized that both the adenosine system and control of iNOS function are impaired in VSMCs from streptozotocin-diabetic rats.

Methods

Male Sprague–Dawley rats were injected with streptozotocin once to induce diabetes. Aortic VSMCs from diabetic and nondiabetic rats were isolated, cultured and exposed to lipopolysaccharide (LPS) plus a cytokine mix for 24 h in the presence or absence of (1) exogenous adenosine and related compounds, and/or (2) pharmacological agents affecting adenosine turnover. iNOS functional expression was determined by immunoblotting and NO metabolite assays. Concentrations of adenosine, related compounds and metabolites thereof were assayed by HPLC. Vasomotor responses to adenosine were determined in endothelium-deprived aortic rings.

Results

Treatment with adenosine-degrading enzymes or receptor antagonists increased iNOS formation in activated VSMCs from nondiabetic and diabetic rats. Following treatment with the adenosine transport inhibitor NBTI, iNOS levels increased in nondiabetic but decreased in diabetic VSMCs. The amount of secreted NO metabolites was uncoupled from iNOS levels in diabetic VSMCs. Addition of high concentrations of adenosine and its precursors or analogues enhanced iNOS formation solely in diabetic VSMCs. Exogenous adenosine and AMP were completely removed from the culture medium and converted into metabolites. A tendency towards elevated inosine generation was observed in diabetic VSMCs, which were also less sensitive to CD73 inhibition, but inosine supplementation did not affect iNOS levels. Pharmacological inhibition of NOS abolished adenosine-induced vasorelaxation in aortic tissues from diabetic but not nondiabetic animals.

Conclusions

Endogenous adenosine prevented cytokine- and LPS-induced iNOS activation in VSMCs. By contrast, supplementation with adenosine and its precursors or analogues enhanced iNOS levels in diabetic VSMCs. This effect was associated with alterations in exogenous adenosine turnover. Thus, overactivation of the adenosine system may foster iNOS-mediated diabetic vascular dysfunction.

AMPD1 polymorphism and response to regadenoson

AIMS

 AMPD1 c.34C > T (rs17602729) polymorphism results in AMPD1 deficiency. We examined the association of AMPD1 deficiency and variability of hemodynamic response to regadenoson.

SUBJECTS & METHODS

Genotyping for c.34C>T was performed in 267 patients undergoing regadenoson cardiac stress testing.

RESULTS

Carriers of c.34C >T variant exhibited higher relative changes in systolic blood pressure (SBP) compared with wild-type subjects ([%] SBP change to peak: 12 ± 25 vs 5 ± 13%; p = 0.01) ([%] SBP change to nadir: -3 ± 15 vs -7 ± 11%; p = 0.04). Change in heart rate was similar between groups, but side effects were more common in carriers of the variant (+LR = 4.2; p = 0.04).

CONCLUSION

AMPD1 deficiency may be involved in the modulation of regadenoson's systemic effects.

Maternal cigarette, alcohol, and coffee consumption in relation to risk of clubfoot

BACKGROUND

Clubfoot is associated with maternal cigarette smoking in several studies, but it is not clear if this association is confined to women who smoke throughout the at-risk period. Maternal alcohol and coffee drinking have not been well studied in relation to clubfoot.

METHODS

The present study used data from a population-based case-control study of clubfoot conducted in Massachusetts, New York, and North Carolina from 2007 to 2011. Mothers of 646 isolated clubfoot cases and 2037 controls were interviewed about pregnancy events and exposures, including the timing and frequency of cigarette smoking, alcohol intake, and coffee drinking.

RESULTS

More mothers of cases than controls reported smoking during early pregnancy (28.9% vs. 19.1%). Of women who smoked when they became pregnant, those who quit in the month after a first missed period had a 40% increase in clubfoot risk and those who continued to smoke during the next 3 months had more than a doubling in risk, after controlling for demographic factors, parity, obesity, and specific medication exposures. Adjusted odds ratios for women who drank >3 servings of alcohol or coffee per day throughout early pregnancy were 2.38 and 1.77, respectively, but the numbers of exposed women were small and odds ratios were unstable.

CONCLUSIONS

Clubfoot risk appears to be increased for offspring of women who smoke cigarettes, particularly those who continue smoking after pregnancy is recognisable, regardless of amount. For alcohol and coffee drinkers, suggested increased risks were only observed in higher levels of intake.

The effect of eplerenone on adenosine formation in humans in vivo: a double-blinded randomised controlled study

Background

It has been suggested that mineralocorticoid receptor antagonists have direct cardioprotective properties, because these drugs reduce mortality in patients with heart failure. In murine models of myocardial infarction, mineralocorticoid receptor antagonists reduce infarct size. Using gene deletion and pharmacological approaches, it has been shown that extracellular formation of the endogenous nucleoside adenosine is crucial for this protective effect. We now aim to translate this finding to humans, by investigating the effects of the selective mineralocorticoid receptor antagonist eplerenone on the vasodilator effect of the adenosine uptake inhibitor dipyridamole, which is a well-validated surrogate marker for extracellular adenosine formation.

Methods and Results

In a randomised, double-blinded, placebo-controlled, cross-over study we measured the forearm blood flow response to the intrabrachial administration of dipyridamole in 14 healthy male subjects before and after treatment with placebo or eplerenone (50 mg bid for 8 days). The forearm blood flow during administration of dipyridamole (10, 30 and 100 µg·min⁻¹·dl⁻¹) was 1.63 (0.60), 2.13 (1.51) and 2.71 (1.32) ml·dl⁻¹·min⁻¹ during placebo use, versus 2.00 (1.45), 2.68 (1.87) and 3.22 (1.94) ml·dl⁻¹·min⁻¹ during eplerenone treatment (median (interquartile range); P = 0.51). Concomitant administration of the adenosine receptor antagonist caffeine attenuated dipyridamole-induced vasodilation to a similar extent in both groups. The forearm blood flow response to forearm ischemia, as a stimulus for increased formation of adenosine, was similar during both conditions.

Conclusion

In a dosage of 50 mg bid, eplerenone does not augment extracellular adenosine formation in healthy human subjects. Therefore, it is unlikely that an increased extracellular adenosine formation contributes to the cardioprotective effect of mineralocorticoid receptor antagonists.

Trial Registration

ClinicalTrials.gov, NCT01837108

Adenosine A(2A) receptor activation supports an atheroprotective cholesterol balance in human macrophages and endothelial cells

The adenosine A(2A) receptor (A(2A)R) plays an important role in the regulation of inflammatory and immune responses. Our previous work has demonstrated that A(2A)R agonists exhibit atheroprotective effects by increasing expression of reverse cholesterol transport proteins in cultured human macrophages. This study explores the impact of pharmacologic activation/inhibition and gene silencing of A(2A)R on cholesterol homeostasis in both THP-1 human monocytes/macrophages and primary human aortic endothelial cells (HAEC). THP-1 human monocytes/macrophages and HAEC exposed to the A(2A)R-specific agonist ATL313 exhibited upregulation of proteins responsible for cholesterol efflux: the ABCA1 and G1 transporters. Further, activation of A(2A)R led to upregulation of the cholesterol metabolizing enzyme P450 27-hydroxylase, accompanied by intracellular changes in level of oxysterols. We demonstrate that anti-atherogenic properties of A(2A)R activation are not limited to the regulation of lipid efflux in vasculature, but include protection from lipid overload in macrophages, particularly via suppression of the CD36 scavenger receptor. The reduced lipid accumulation manifests directly as a diminution in foam cell transformation. In THP-1 macrophages, either A(2A)R pharmacological blockade or gene silencing promote lipid accumulation and enhance foam cell transformation. Our pre-clinical data provides evidence suggesting that A(2A)R stimulation by ATL313 has the potential to be a viable therapeutic strategy for cardiovascular disease prevention, particularly in patients with elevated risk due to immune/inflammatory disorders.

Targeting adenosine receptors in the development of cardiovascular therapeutics

Adenosine receptor stimulation has negative inotropic and dromotropic actions, reduces cardiac ischemia-reperfusion injury and remodeling, and prevents cardiac arrhythmias. In the vasculature, adenosine modulates vascular tone, reduces infiltration of inflammatory cells and generation of foam cells, and may prevent the development of atherosclerosis as a result. Modulation of insulin sensitivity may further add to the anti-atherosclerotic properties of adenosine signaling. In the kidney, adenosine plays an important role in tubuloglomerular feedback and modulates tubular sodium reabsorption. The challenge is to take advantage of the beneficial actions of adenosine signaling while preventing its potential adverse effects, such as salt retention and sympathoexcitation. Drugs that interfere with adenosine formation and elimination or drugs that allosterically enhance specific adenosine receptors seem to be most promising to meet this challenge.

The chick chorioallantoic membrane imaging method as a platform to evaluate vasoactivity and assess irritancy of compounds

OBJECTIVE

To determine if the chick chorioallantoic membrane (CAM) is a potential alternative that is capable of screening test substances for vasoactivity in terms of vessel diameter changes. The CAM was also evaluated as a tool for irritancy screening.

METHODS

Visual assessment of the CAM for irritancy after the application of the test substance or solvent to its surface was made. An imaging based-in-vivo CAM model was developed by imaging CAM blood vessels in a pre-defined area using a semi-automatic image processing and analysis technique to measure blood vessel diameters. Solvents and drugs such as 70% v/v ethanol, normal saline, 5% w/v glucose monohydrate, glycerin, glucagon, N-methylpyrrolidone, nicotine, glyceryl trinitrate, glucagon, propranolol and caffeine were tested on the CAM.

KEY FINDINGS

Propranolol, nicotine and glycerin were irritants on CAM. Changes in the diameters of fine blood vessels were accurately measured by high resolution image analysis. Vasoconstriction was seen with 70% v/v ethanol while vasodilation was displayed with glucagon and caffeine. The results reflected expected trends with evidence of feedback mechanisms ensuring homeostasis.

CONCLUSION

The CAM model can be applied to assess pharmaceutical and cosmetic formulations in early development work to gain useful insights to potential irritancy and biological effects of components and formulations.

The cardiovascular effects of methylxanthines

In the concentration range that is normally achieved in humans, e.g., after the drinking of coffee or in patients treated with theophylline, the cardiovascular effects of methylxanthines are primarily due to antagonism of adenosine A(1) and A(2) receptors. Inhibition of phosphodiesterases or mobilization of intracellular calcium requires much higher concentrations. In conscious humans, acute exposure to caffeine results in an increase in blood pressure by an increased total peripheral resistance, and a slight decrease in heart rate. This overall hemodynamic response is composed of direct effects of caffeine on vascular tone, on myocardial contractility and conduction, and on the sympathetic nervous system. Caffeine is the most widely consumed methylxanthine, mainly derived from coffee intake. Regular coffee consumption can affect various traditional cardiovascular risk factors, including a slight increase in blood pressure, an increase in plasma cholesterol and homocysteine levels, and a reduced incidence of type 2 diabetes mellitus. Although most prospective studies have not reported an association between coffee consumption and coronary heart disease, these findings do not exclude that the acute hemodynamic and neurohumoral effects of coffee consumption could have an adverse effect in selected patient groups who are more vulnerable for these effects, based on their genetic profile or medication use.

Chronic treatment with cyclosporine affects systemic purinergic parameters, homocysteine levels and vascular disturbances in rats

Vascular disease is a major cause of morbidity and mortality among transplanted recipients and cyclosporine (CsA) treatment has been consistently implicated in this event. In this study we assessed total blood homocysteine levels (tHcy), ecto-nucleotidase activities and adenine nucleotide/nucleoside levels searching for parameters related to the mechanisms of vascular damage induced by chronic CsA treatment in non-transplanted rats. Thirty male Wistar rats were divided in three groups: control group treated with corn oil, CsA 5mg/kg and CsA 15 mg/kg, administered by daily gastric gavage during 8 weeks. CsA 15 mg/kg treatment increased blood levels of tHcy. Both CsA treatments (5mg/kg and 15 mg/kg) decreased adenine nucleotides hydrolysis by ecto-nucleotidases in serum, which negatively correlated with tHcy levels (r: -0.74, r: -0.63 and r: -0.63, p<0.004, for ATP, ADP and AMP, respectively). CsA 15mg/kg induced a statistically significant increase in ADP and decrease in adenosine (ADO) plasma levels compared to control group. THcy levels were positively correlated with plasma ADP levels and negatively correlated with ADO levels (r: 0.84, p<0.0001 and r: -0.68, p<0.0001, respectively). Rats under CsA 15 mg/kg treatment presented cell injury and inflammatory responses in the endothelium and intima layer of the aorta artery. In conclusion, blood ecto-nucleotidases activity, tHcy, and ADP and ADO levels may be implicated in vascular injury induced by CsA treatment.

Real-time optoacoustic monitoring and three-dimensional mapping of a human arm vasculature

We present our findings from a real-time laser optoacoustic imaging system (LOIS). The system utilizes a Q-switched Nd:YAG laser; a standard 128-channel ultrasonic linear array probe; custom electronics and custom software to collect, process, and display optoacoustic (OA) images at 10 Hz. We propose that this system be used during preoperative mapping of forearm vessels for hemodialysis treatment. To demonstrate the real-time imaging capabilities of the system, we show OA images of forearm vessels in a volunteer and compare our results to ultrasound images of the same region. Our OA images show blood vessels in high contrast. Manipulations with the probe enable us to locate and track arteries and veins of a forearm in real time. We also demonstrate the ability to combine a series of OA image slices into a volume for spatial representation of the vascular network. Finally, we use frame-by-frame analysis of the recorded OA video to measure dynamic changes of the crossection of the ulnar artery.

TGF-beta1 inhibits expression and activity of hENT1 in a nitric oxide-dependent manner in human umbilical vein endothelium

AIMS

We studied whether transforming growth factor beta1 (TGF-beta1) modulates human equilibrative nucleoside transporters 1 (hENT1) expression and activity in human umbilical vein endothelial cells (HUVECs). hENT1-mediated adenosine transport and expression are reduced in gestational diabetes and hyperglycaemia, conditions associated with increased synthesis and release of nitric oxide (NO) and TGF-beta1 in this cell type. TGF-beta1 increases NO synthesis via activation of TGF-beta receptor type II (TbetaRII), and NO inhibits hENT1 expression and activity in HUVECs.

METHODS AND RESULTS

HUVECs (passage 2) were used for experiments. Total and hENT1-mediated adenosine transport was measured in the absence or presence of TGF-beta1, NG-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor), S-nitroso-N-acetyl-L,D-penicillamine (SNAP, NO donor), and/or KT-5823 (protein kinase G inhibitor) in control cells and cells expressing a truncated form of TGF-beta1 receptor type II (TTbetaRII). Western blot and real-time PCR were used to determine hENT1 protein abundance and mRNA expression. SLC29A1 gene promoter and specific protein 1 (Sp1) transcription factor activity was assayed. Vascular reactivity was assayed in endothelium-intact or -denuded umbilical vein rings. TGF-beta1 reduced hENT1-mediated adenosine transport, hENT1 protein abundance, hENT1 mRNA expression, and SLC29A1 gene promoter activity, but increased Sp1 binding to DNA. TGF-beta1 effect was blocked by L-NAME and KT-5823 and mimicked by SNAP in control cells. However, TGF-beta1 was ineffective in cells expressing TTbetaRII or a mutated Sp1 consensus sequence. Vasodilatation in response to TGF-beta1 and S-(4-nitrobenzyl)-6-thio-inosine (an ENT inhibitor) was endothelium-dependent and blocked by KT-5823 and ZM-241385.

CONCLUSION

hENT1 is down-regulated by activation of TbetaRII by TGF-beta1 in HUVECs, a phenomenon where NO and Sp1 play key roles. These findings comprise physiological mechanisms that could be important in diseases where TGF-beta1 plasma level is increased as in gestational diabetic mothers or patients with diabetes mellitus.

An association between the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and inflammation markers related to cardiovascular disease

BACKGROUND

Prospective studies have identified many markers of systemic inflammation that are powerful predictors of future cardiovascular events. The methylenetetrahydrofolate reductase (MTHFR) C677T genotype, a common polymorphism that induces hyperhomocysteinaemia, has been proposed as a genetic risk factor for cardiovascular disease. In this work, we evaluated the relationship between the levels of inflammation markers and MTHFR genotype among cardiovascular disease free subjects of the ATTICA study.

METHODS

During 2001-2002, we randomly enrolled for genetic evaluation 574 subjects from Attica region, Greece. In this work, we investigated demographic, lifestyle, clinical, biochemical and genetic information from 322 men (46+/-13 years) and 252 women (45+/-14 years). Among other characteristics, we measured various inflammatory markers levels in relation to C677T MTHFR genotype distribution.

RESULTS

The MTHFR genotypes distribution was: homozygous normal (CC) genotype, 41%; heterozygous (CT), 48%; and homozygous mutant (TT) genotype, 11%. C-reactive protein (CRA), fibrinogen, white blood cell (WBC) counts and amyloid-a levels were higher in TT compared to CC and CT genotypes (p<0.01), in both genders, even after controlling for various potential confounders.

CONCLUSION

The observed association between markers of systemic inflammation with MTHFR genotype may state a hypothesis for a common pathobiological mechanism between inflammation process and MTHFR, which is a key enzyme in homocysteine (Hcy) metabolism.