Matrix metalloproteinases and cardiovascular disease

The Predictive Role of Plasma Biomarkers in the Evolution of Aortopathies Associated with Congenital Heart Malformations

Dilatation of the aorta is a constantly evolving condition that can lead to the ultimate life-threatening event, acute aortic dissection. Recent research has tried to identify quantifiable biomarkers, with both diagnostic and prognostic roles in different aortopathies. Most studies have focused on the bicuspid aortic valve, the most frequent congenital heart disease (CHD), and majorly evolved around matrix metalloproteinases (MMPs). Other candidate biomarkers, such as asymmetric dimethylarginine, soluble receptor for advanced glycation end-products or transforming growth factor beta have also gained a lot of attention recently. Most of the aortic anomalies and dilatation-related studies have reported expression variation of tissular biomarkers. The ultimate goal remains, though, the identification of biomarkers among the serum plasma, with the upregulation of circulating MMP-1, MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), asymmetric dimethylarginine (ADMA), soluble receptor for advanced glycation end-products (sRAGE) and transforming growth factor beta (TGF-β) being reported in association to several aortopathies and related complications in recent research. These molecules are apparently quantifiable from the early ages and have been linked to several CHDs and hereditary aortopathies. Pediatric data on the matter is still limited, and further studies are warranted to elucidate the role of plasmatic biomarkers in the long term follow-up of potentially evolving congenital aortopathies.

Vessel stiffness, calcification and osteoporosis. Common pathogenetic components

Atherosclerosis and osteoporosis until recently were regarded as the diseases of modern society, and their simultaneous development was explained just by the increased chances with longevity. Currently, there are studies showing evidence on these diseases in ancient populations, regardless the age and gender. The diseases found in younger age, with the early Egyptian civilization, witness on the common genetic and behavioral risk factors and pathogenetic components, than simple age-related chance. Scientific publications show more and more data on common properties of these diseases and pathogenetic mechanisms. High risk of premature death from atherosclerosis and osteoporosis complications facilitates the search for individual and general predictors of the disorders with the aim of on-time prevention. Treatment of atherosclerosis and osteoporosis presentation events in one patient demands for a range of medications that leads to polypragmasia. The review is focused on common mechanisms of vascular stiffness development, calcification and bone density decrease. Profound understanding might make it to open novel targets for one drug to both diseases, with decreased rate of complications.

Enzyme-responsive Drug Delivery Systems

One major challenge in the pharmaceutical industry is how to deliver drugs locally and specifically to a target area. One way to accomplish this is to develop drug delivery vehicles that respond to biomarkers or other cues that are indicative of a disease state. Over the past several years, enzymes have become key targets for bio-recognition due to their role in both healthy and diseased tissues. This has led to the development of drug delivery vehicles that release their cargo via either carrier degradation, shape change, or bond cleavage due to enzymes over-expressed at the disease site. This chapter will focus on the use of both oxidoreductases and hydrolases as triggers for enzyme-responsive drug delivery systems.

Samul-Tang Regulates Cell Cycle and Migration of Vascular Smooth Muscle Cells against TNF-α Stimulation

Samul-Tang (SMT), consisting of four medicinal herbs, is a well-known herbal prescription treating hematological disorders related symptoms. Our previous study demonstrated that SMT attenuated inflammation of vascular endothelial cells. In condition of retained vascular dysfunction, vascular inflammation is initiated and results in activation of smooth muscle cells (SMCs). Activated SMCs lose control of cell cycle regulation and migrate into intima, resulting in formation of atheroma. Here, we further investigated whether SMT suppresses proliferation and migration of SMCs. SMT showed antiproliferative effects on SMCs by suppressing [³H]-thymidine incorporation against TNF-α stimulation. Underlying mechanisms of antiproliferative effects were found to be resulting from cell cycle regulation. SMT downregulated expression of cyclin D1-CDK4 and cyclin E-CDK2 complexes and upregulated p21^waf1/cip1 and p27^kip1. SMT also suppressed migration of SMCs against TNF-α stimulation. This is thought to have resulted from suppressing MMP2 and MMP9 expressions and ROS production. In summary, SMT attenuates abnormal migration of vascular smooth muscle cells via regulating cell cycle and suppressing MMPs expression and ROS production. Our study suggests that SMT, a traditionally used herbal formula, protects vascular smooth muscle cells and might be used as an antiatherosclerotic drug.

Prognostic role of matrix metalloproteinases in bladder carcinoma: a systematic review and meta-analysis

Recent studies have shown that matrix metalloproteinases (MMPs) might be a biomarker for predicting outcomes of bladder cancer. However, the prognostic value of overexpression of MMPs in bladder cancer is debatable and the studies are inconsistent. Therefore, this meta-analysis was performed to clarify the specific association and prognostic value of overexpression of MMPs in bladder carcinoma. Relevant studies were identified by searching PubMed, EMBASE, and the Web of Science. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for disease-specific survival (DSS), overall survival (OS), disease/recurrence-free survival (DFS/RFS), and progression/metastasis-free survival (PFS/MFS) were analyzed to determine the prognostic value of MMPs. In total, eighteen applicable studies were included in this meta-analysis. We found that high expression of MMPs significantly correlated with a poor DSS and OS (HR=1.66; 95% CI = 1.38–2.01 and HR= 1.67; 95%CI= 1.26–2.22). MMPs also predicted tumor progression and metastasis with a pooled HR of 3.03 (95% CI 1.98–4.64). However, high MMPs expression had no pivotal impact on DFS/RFS (HR= 1.21; 95% CI= 0.96–1.53). With the purpose of better understanding the prognostic role of MMPs in patients wirh bladder carcinoma, we carried out this systematic review and meta-analysis.

Knowledge-transfer learning for prediction of matrix metalloprotease substrate-cleavage sites

Matrix Metalloproteases (MMPs) are an important family of proteases that play crucial roles in key cellular and disease processes. Therefore, MMPs constitute important targets for drug design, development and delivery. Advanced proteomic technologies have identified type-specific target substrates; however, the complete repertoire of MMP substrates remains uncharacterized. Indeed, computational prediction of substrate-cleavage sites associated with MMPs is a challenging problem. This holds especially true when considering MMPs with few experimentally verified cleavage sites, such as for MMP-2, -3, -7, and -8. To fill this gap, we propose a new knowledge-transfer computational framework which effectively utilizes the hidden shared knowledge from some MMP types to enhance predictions of other, distinct target substrate-cleavage sites. Our computational framework uses support vector machines combined with transfer machine learning and feature selection. To demonstrate the value of the model, we extracted a variety of substrate sequence-derived features and compared the performance of our method using both 5-fold cross-validation and independent tests. The results show that our transfer-learning-based method provides a robust performance, which is at least comparable to traditional feature-selection methods for prediction of MMP-2, -3, -7, -8, -9 and -12 substrate-cleavage sites on independent tests. The results also demonstrate that our proposed computational framework provides a useful alternative for the characterization of sequence-level determinants of MMP-substrate specificity.

Matrix-metalloproteinases as targets for controlled delivery in cancer: An analysis of upregulation and expression

While commonly known for degradation of the extracellular matrix, matrix metalloproteinases (MMPs) exhibit broad potential for use in targeting of bioactive and imaging agents in cancer treatment. MMPs are upregulated at all stages of expression in cancers. A comprehensive analysis of published literature on expression of all MMP subtypes at the genetic, protein, and activity levels in normal and diseased tissues indicate targeting applicability in a variety of cancers. This expression significantly increases at advanced cancer stages, providing an improved opportunity for controlled release in higher-stage patients. Since MMPs are integral at every stage of metastasis, MMP roles in cancer are discussed with a focus on MMP distribution and mobility within cells and tumors for cancer targeting applications. Several strategies for MMP utilization in targeting - such as matrix degradation, MMP cleavage, MMP binding, and MMP-induced environmental changes - are addressed.

Gelatinases A and B and Antioxidant Enzyme Activity in the Early Phase of Acute Myocardial Infarction

Oxidative stress plays important roles in the pathophysiology of acute myocardial infarction (AMI). The aim of this study was to investigate the correlation of the oxidative stress status and matrix metalloproteinase activity in AMI patients in comparison to controls. This study included 136 subjects: 68 patients with AMI (42 males/26 females; mean age 58.5 ± 10.5 years) and 68 controls (37 males/29 females; mean age 60.2 ± 12.4 years). Gelatinases A and B were assayed using gelatin zymography, enzyme activities were obtained spectrophotometrically. Gelatinase A and B activities were increased in the AMI patients' group compared to the control. Activities of serum superoxide dismutase (SOD) and xanthine oxidase (XO) were significantly higher in AMI patients (106.53 ± 23.45 U/l, P < 0.001 and 158.18 ± 29.59 U/l, P < 0.001) than in the control group (55.99 ± 10.79 U/l and 79.81 ± 7.93 U/l). The activity of catalase (CAT) in the sera of AMI patients was lower (271.31 ± 7.53 U/l, P < 0.005) than in the control group (305.94 ± 97.28 U/l). Plasma glutathione peroxidase (GPx) and glutathione reductase (GR) in AMI patients were significantly higher (582.47 ± 184.81 U/l, P < 0.001 and 59.64 ± 21.88 U/l, P < 0.001) than in the control group (275.32 ± 104.69 U/l and 47.71 ± 20.05 U/l). The present findings demonstrate activation of gelatinases A and B and oxidative stress markers in the early stage of AMI. Gelatinases, detected at high levels in AMI patients only, indicate their noticeable predisposition for becoming additional biomarkers of the early phase of AMI.

Association study for the role of Matrix metalloproteinases 2 and 3 gene polymorphisms in dental caries susceptibility

OBJECTIVE

Various exogenous and endogenous risk factors have been described as contributing to dental caries susceptibility. In the last decade it has been established that both pro and active forms of host derived Matrix metalloproteinases (MMPs) are present in the oral cavity. MMPs role in caries development has been hypothesized. The aim of this study was to analyse MMP2 (rs2287074) and MMP3 (rs679620) single nucleotide polymorphisms (SNPs) and their role in caries susceptibility.

DESIGN

The two SNPs were analysed by PCR- restriction fragment length polymorphism (RFLP) in a sample of 102 ethnic Bulgarian volunteers (42 males and 60 females), all students in Sofia Medical University.

RESULTS

Statistical analysis of the MMP2 SNP showed significant differences for the genotype frequencies between the caries free (CF, DMFT=0) and low caries experience (LCE, DMFT≤5) groups. Analysis for the non-synonymous MMP3 SNP found significant differences between both CF vs caries experience groups (LCE+ high caries experience (HCE, DMFT≥5)) and LCE vs HCE groups. The presence of allele G decreased the risk of HCE about 4 times.

CONCLUSIONS

MMP2 and MMP3 genes are likely to be involved in caries susceptibility in our population. However, as dental caries is a multifactorial disorder and several genes are likely to have influence on it, it is reasonable to expect that SNPs, even those proven to be functional like rs679620, potentially play a significant, but not major role in the disease outcome.

In vivo optical imaging of matrix metalloproteinase activity detects acute and chronic contact hypersensitivity reactions and enables monitoring of the antiinflammatory effects of N-acetylcysteine

The aim of this study was to determine whether the severity of contact hypersensitivity reactions (CHSRs) can be observed by noninvasive in vivo optical imaging of matrix metalloproteinase (MMP) activity and whether this is an appropriate tool for monitoring an antiinflammatory effect. Acute and chronic CHSRs were elicited by application of a 1% trinitrochlorobenzene (TNCB) solution for up to five times on the right ear of TNCB-sensitized mice. N-Acetylcysteine (NAC)-treated and sham-treated mice were monitored by measuring ear swelling and optical imaging of MMP activity. In addition, we performed hematoxylin-eosin staining and CD31 immunohistochemistry for histopathologic analysis of the antiinflammatory effects of NAC. The ear thickness and the MMP activity increased in line with the increasing severity of the CHSR. MMP activity was enhanced 2.5- to 2.7-fold during acute CHSR and 3.1- to 4.1-fold during chronic CHSR. NAC suppressed ear swelling and MMP signal intensity in mice with acute and chronic CHSR. During chronic CHSR, the vessel density was significantly reduced in ear sections derived from NAC-treated compared to sham-treated mice. In vivo optical imaging of MMP activity measures acute and chronic CHSR and is useful to monitor antiinflammatory effects.

Dipeptidyl peptidase-4 inhibitors and their potential role in the management of atherosclerosis--A review

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a relatively new class of anti-diabetic drugs that have therapeutic potential in the management of atherosclerosis. Of the numerous DPP-4 inhibitors in clinical practice no studies have been conducted to compare their anti-atherosclerotic effects despite growing evidence of their usefulness in the high risk population.

OBJECTIVE

The aim of the study was to review the anti-athero-thrombotic effects of DPP-4 inhibitors in atherosclerotic diseases.

METHOD

A literature search was conducted on MEDLINE and the COCHRANE Library using the terms "DPP-4 Inhibitors", "atherosclerosis", "GLP", "inflammation", "cytokines", "stroke", "ischaemic heart disease", "hypertension" and "peripheral vascular disease". A mathematical model devised by us was used to derive and compare the anti-inflammatory effects of the DPP-4 inhibitors using protective score [PS]. Data was analysed for alogliptin, linagliptin, saxagliptin, sitagliptin, and vildagliptin.

RESULTS

Sixty two published studies collected in the search were assessed for relevance to this study. Sitagliptin had the highest PS [n=5] while linagliptin and saxagliptin yielded the lowest PS [n=1]. This comparison and scoring system was limited to the data collected; which did not investigate for all athero-thrombotic factors selected in this study.

CONCLUSION

The findings suggest potential usefulness of DPP-4 in atherosclerotic diseases. It also reflected a possible superiority of sitagliptin over the other DPP-4 inhibitors in the management of atherosclerosis. Further investigations are required to establish specific inflammatory cytokines influenced by the DPP-4 inhibitors and to elucidate their clinical application in athero-thrombotic disease.

Mechanical stretch: physiological and pathological implications for human vascular endothelial cells

Vascular endothelial cells are subjected to hemodynamic forces such as mechanical stretch due to the pulsatile nature of blood flow. Mechanical stretch of different intensities is detected by mechanoreceptors on the cell surface which enables the conversion of external mechanical stimuli to biochemical signals in the cell, activating downstream signaling pathways. This activation may vary depending on whether the cell is exposed to physiological or pathological stretch intensities. Substantial stretch associated with normal physiological functioning is important in maintaining vascular homeostasis as it is involved in the regulation of cell structure, vascular angiogenesis, proliferation and control of vascular tone. However, the elevated pressure that occurs with hypertension exposes cells to excessive mechanical load, and this may lead to pathological consequences through the formation of reactive oxygen species, inflammation and/or apoptosis. These processes are activated by downstream signaling through various pathways that determine the fate of cells. Identification of the proteins involved in these processes may help elucidate novel mechanisms involved in vascular disease associated with pathological mechanical stretch and could provide new insight into therapeutic strategies aimed at countering the mechanisms’ negative effects.

EFFECT OF GLYCATED SERUM ALBUMIN ON FUNCTIONAL MARKERS IN HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS IN THE PRESENCE OF SHEAR STRESS

Regions of the vasculature subjected to low wall shear stress and disturbed flow patterns are prone to atherosclerotic plaque formation. Pro-inflammatory conditions induced by products of protein glycation in diabetes substantially enhance this risk. One of the contributory factors is the enhanced production of ROS by advanced glycation end products (AGE) of proteins and lipids formed in chronic diabetes. In this study, we examine the interaction of oscillatory wall shear stress and glycated serum albumin (AGE-HSA) in modulating NOsynthase activity and expression of pro-inflammatory molecules such as RAGE, s-ICAM-1 and matrix metalloproteinase (MMP-9) in cultured HUVEC. Our findings indicate that orbital shear stress (OSS) up-regulates RAGE expression at low (LSS 4.5 dyn/cm2) more than at high shear stress (HSS 12 dyn/cm2) at 4 h. This effect is promoted in the AGE-HSA (2 mg/mL) in a dose-dependent manner. Augmentation of NOsynthase activity was lower at LSS and further inhibited in the presence of AGE-HSA. Expression of s-ICAM-1 was found to be shear stress modulated with additive up-regulation in combination with AGE-HSA while MMP-9 was not affected by shear stress or AGE-HSA individually but in combination caused significant up-regulation. These changes in endothelial function correlate with mechanisms that initiate atherogenic process in diabetic macrovascular pathology.

The important role of catestatin in cardiac remodeling

Catestatin (CST) was first discovered as a potent non-competitive and reversible inhibitor of catecholamine secretion. Recent reports on plasma CST level in heart diseases suggested a cardioprotective role for this peptide. Given that cardiac remodeling is the dominant pathologic process in cardiac dysfunction, we propose that CST participates in the regulation of concern pathways and contributes to the inhibition of cardiac remodeling. In this minireview, the potential mechanism of cardiac remodeling involving CST will be discussed from three aspects: hypertrophy, fibrosis, and apoptosis.

Matrix metalloproteinases in coronary artery disease

Matrix metalloproteinases (MMP) are a family of zinc-containing endoproteinases that degrade extracellular matrix (ECM) components. MMP have important roles in the development, physiology and pathology of cardiovascular system. Metalloproteases also play key roles in adverse cardiovascular remodeling, atherosclerotic plaque formation and plaque instability, vascular smooth muscle cell (SMC) migration and restenosis that lead to coronary artery disease (CAD), and progressive heart failure. The study of MMP in developing animal model cardiovascular systems has been helpful in deciphering numerous pathologic conditions in humans. Increased peripheral blood MMP-2 and MMP-9 in acute coronary syndrome (ACS) may be useful as noninvasive tests for detection of plaque vulnerability. MMP function can be modulated by certain pharmacological drugs that can be exploited for treatment of ACS. CAD is a polygenic disease and hundreds of genes contribute toward its predisposition. A large number of sequence variations in MMP genes have been identified. Case-control association studies have highlighted their potential association with CAD and its clinical manifestations. Although results thus far are inconsistent, meta-analysis has demonstrated that MMP-3 Glu45Lys and MMP-9 1562C/T gene polymorphisms were associated with CAD risk.

C-reactive protein induces expression of matrix metalloproteinase-9: a possible link between inflammation and plaque rupture

BACKGROUND

Matrix metalloproteases (MMPs) have been implicated in the pathogenesis of acute coronary syndromes (ACS). However, little is known about the mechanisms responsible for MMP expression in ACS. C-reactive protein (CRP) not only is an independent risk factor for cardiovascular events, but also may exert direct pro-atherosclerotic effects. Therefore, we aimed at determining whether CRP might induce MMP-9 in two different experimental conditions: 1) smooth muscle cells (SMCs) in vitro, and 2) patients with ACS.

METHODS AND RESULTS

Effects of increasing concentrations of CRP on MMP-9 expression were evaluated in vitro in human SMCs. TIMP-1 protein expression, the selective inhibitor of MMP-9, was also evaluated. CRP dose-dependently induced MMP-9 expression in SMCs by promoting MMP-mRNA transcription, as well as MMP-9 secretion. In contrast, no differences were found for TIMP-1 protein expression. In vivo, MMP-9 and CRP levels were measured in blood samples obtained from the aorta (Ao) and the coronary sinus (Cs) of patients with normal coronary arteries (controls, n=21), stable angina (n=24), and ACS (n=30). Both MMP-9 and CRP plasma levels were significantly increased across the coronary circulation only in patients with ACS. Interestingly, a significant correlation between MMP-9 and CRP plasma levels was found.

CONCLUSIONS

CRP induced MMP-9 expression and activity in human SMCs in culture; patients presenting with ACS have increased transcoronary plasma levels of MMP-9 and CRP with a significant correlation between these two markers. This may explain the heightened risk of coronary events in subjects with elevated levels of CRP.

Long-term safety and tolerability of the oral direct renin inhibitor aliskiren with optional add-on hydrochlorothiazide in patients with hypertension: a randomized, open-label, parallel-group, multicentre, dose-escalation study with an extension phase

BACKGROUND

Most patients with hypertension will require combination therapy with at least two agents from different antihypertensive classes to achieve blood pressure (BP) control. Thiazide diuretics, such as hydrochlorothiazide (HCTZ), are widely used in combination therapy. The volume reduction with these agents stimulates the renin-angiotensin system (RAS), making RAS inhibitors such as the direct renin inhibitor aliskiren a logical choice for combination therapy with HCTZ.

OBJECTIVE

The aim of this study was to investigate the long-term safety, tolerability and efficacy of the direct renin inhibitor aliskiren, with or without addition of the diuretic HCTZ.

METHODS

In the 12-month core study, patients with hypertension (mean sitting diastolic BP ≥90 mmHg and <110 mmHg) were randomized in a 3 : 2 ratio to once-daily aliskiren 150 mg or 300 mg. At months 2, 3, 4, 6 and 9, treatment was adjusted in patients not achieving a BP goal of <140/90 mmHg. Patients not at goal on aliskiren 150 mg once daily were up-titrated to aliskiren 300 mg once daily. Patients not at goal with aliskiren 300 mg once daily received add-on HCTZ 12.5 mg once daily, which was up-titrated to 25 mg once daily if BP remained inadequately controlled. At month 12, patients who received aliskiren/HCTZ 300 mg/25 mg once daily for at least 8 months in the core study were eligible to enter a 4-month extension study.

RESULTS

Overall, 1625/1955 patients completed the core study, and 870/1955 patients received add-on HCTZ; 189/198 patients completed the 4-month extension. Aliskiren, with or without add-on HCTZ, was generally well tolerated; the incidence of adverse events (AEs) during the core study was similar among the four final treatment groups. The most frequently reported AEs in the core and extension studies were mild and transient cases of nasopharyngitis, headache and dizziness. Few patients exhibited laboratory abnormalities. Overall, aliskiren, with or without add-on HCTZ, reduced mean BP by 18.0/12.7 mmHg at core study endpoint, and 61.2% of patients achieved BP control. BP reductions with aliskiren/HCTZ 300 mg/25 mg combination therapy at the core study endpoint were maintained during the extension study.

CONCLUSION

In patients with hypertension, long-term treatment with aliskiren, with or without add-on HCTZ, is well tolerated and provides effective BP lowering that is sustained over 12 months.

Matrix metalloproteinases and membrane damage markers in sera of patients with acute myocardial infarction

Coronary artery disease is a multifunctional disease and represents one of the leading causes of death worldwide. Oxidative stress appears as an etiological factor for myocardial damage during acute myocardial infarction. Some data suggest that acute coronary syndromes may also be influenced by matrix metalloproteinases through degradation of the fibrous cap of vulnerable atherosclerotic lesions. It has been indicated that gelatinases A and B play a key role in acute myocardial infarction and deoxyribonuclease I has been postulated to be a novel early phase marker of disease. The aim was to study activity of gelatinases A and B in acute myocardial infarction and its association with some membrane damage markers. Seventy-five patients with disease and seventy-five healthy controls were enrolled. Activities of lactate dehydrogenase, malate dehydrogenase, and deoxyribonuclease I were estimated using standard spectrophotometric assay and isoforms of lactate and malate dehydrogenases were determined using direct zymography. Activity of dehydrogenases was significantly higher in patients, while deoxyribonuclease I was lower. Isoform 2 of lactate dehydrogenase was significantly higher in the patient group. Gelatinases A and B were detected only in patients group. The results suggest determination of serum malate dehydrogenase activity to be used as an additional parameter for acute myocardial infarction diagnosis. Those findings suggest important role of gelatinases A and B as biomarkers of early stage of acute myocardial infarction together with membrane damage parameters.

[Gelatinases A and B activities in the serum of patients with various coronary artery disease stages]

BACKGROUND/AIM

The main characteristic of matrix metalloproteinases (MMPs) is the degradation of extracellular matrix. Synthesis of MMPs has been reported in coronary atherosclerotic lesions in patients with coronary disease (CD) suggesting a pathogenic role of MMPs in its development. Recently there is increasing evidence that gelatinase A (pro MMP-2) and gelatinase B (proMMP-9) play a pathogenic role in the development of the atherosclerotic plaques. The aim of the study was to determine, by the use of a gel image system, a possible presence of active gelatinases in the serum of the patients with CD, as well as if their activity is higher in these patients than in healthy people.

METHODS

By gelatin zymography we analyzed the activity of proMMP-2 and proMMP-9 in the serum of 50 patients with various coronary artery disease stages and in the serum of 15 healthy controls. The activity was measured by using a gel image system (Kodak Image 1D 3.6.).

RESULTS

ProMMP-2 and proMMP-9 activity was significantly higher in the serum of patients with CD compared to controls. There was higher activity of MMP-2 and MMP-9 in the serum of patients with acute myocardial infarction (AMI) compared to patients with stable angina pectoris, as well as higher proMMP-9 activity in patients with unstable angina pectoris compared to patients with stable angina pectoris.

CONCLUSION

ProMMP-2 and proMMP-9 participate in processes associated with destabilizing plaques and understanding the processes of MMPs activation and regulation may have significant benefits in clinical interpretation. The reported higher proMMP-2 and proMMP-9 activity in the serum of patients with CD suggests a role of proMMP-2 and proMMP-9 in prognostic stratification of these patients and in designing new drugs.

Antihypertensive efficacy and tolerability of aliskiren/hydrochlorothiazide (HCT) single-pill combinations in patients who are non-responsive to HCT 25 mg alone

OBJECTIVE

Thiazide diuretics such as hydrochlorothiazide (HCT) are a widely used first-line treatment for hypertension, but most patients will not achieve blood pressure (BP) control with HCT alone and so will require combination therapy. In this study the efficacy, safety and tolerability of a single-pill combination (SPC) of the direct renin inhibitor aliskiren with HCT were investigated in patients non-responsive to HCT 25 mg therapy.

METHODS

In this study, 722 patients with hypertension and an inadequate response to 4 weeks of HCT 25 mg (mean sitting diastolic BP > or =90 and <110 mmHg) were randomized to once-daily, double-blind treatment for 8 weeks with an SPC of aliskiren/HCT 300/25 mg or 150/25 mg, or continued HCT 25 mg monotherapy. Least-squares mean changes in mean sitting systolic/diastolic BP (msSBP/DBP) from double-blind baseline were analyzed for the ITT population at week 8 endpoint.

RESULTS

Aliskiren/HCT 300/25 mg and 150/25 mg SPCs lowered msSBP/DBP from baseline by 16.7/10.7 and 12.9/8.5 mmHg, respectively, both significantly greater reductions than HCT 25 mg alone (7.1/4.8 mmHg; both p < 0.001). Rates of BP control (<140/90 mmHg) were also significantly higher with aliskiren/HCT 300/25 mg (58%) and 150/25 mg (49%) than with HCT (26%; both p < 0.001). Aliskiren/HCT 300/25 mg provided significantly greater msSBP/DBP reductions and rates of BP control than the 150/25 mg SPC dose (all p < 0.05). Aliskiren/HCT SPC treatment showed similar tolerability to HCT alone and a numerically lower incidence of hypokalemia (serum potassium <3.5 mmol/L; aliskiren/HCT, 1.3-2.2%: HCT alone, 3.4%).

CONCLUSION

Aliskiren/HCT SPCs provide clinically significant BP reductions and improved BP control rates in patients who are non-responsive to HCT 25 mg monotherapy. Limitations of the study were the mainly Caucasian patient population and the non-responder design.

Renin inhibitors: optimal strategy for renal protection

Diabetic nephropathy and hypertension are the major causes of chronic kidney disease. The renin system plays a key role in the control of blood pressure (BP), as well as in the regulation of renal and adrenal function. Chronic activation of the renin system can lead to organ damage, particularly renal damage; increasing evidence indicates that suppression of the renin system can provide renal protection. Despite the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), the renin system is not completely suppressed. The direct renin inhibitors (DRIs) provide suppression of the entire renin system at the rate-limiting step. Studies in humans with early DRIs indicated potential renoprotective effects, but these agents failed in clinical development due to poor oral bioavailability. Aliskiren is a new orally active DRI with proven BP-lowering effects. Animal studies indicate that aliskiren may provide renal protection, and data from human studies are anticipated.

Increased levels of interleukin-6 and matrix metalloproteinase-9 are of cardiac origin in acute coronary syndrome

OBJECTIVES

To investigate the association between inflammatory mediators, matrix degrading enzymes and acute coronary syndrome (ACS) and the impact of early reperfusion therapy on circulating biomarkers.

DESIGN

Peripheral serum levels of interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and matrix metalloproteinase-9 (MMP-9) were determined in 134 patients with ACS. These biomarkers were serially monitored in ten patients with intravenous thrombolytic therapy (IVT).

RESULTS

Serum levels of IL-6, hs-CRP and MMP-9 were higher in unstable angina (UA) and myocardial infarction (MI) groups than in control or SA group (p<0.05). Peripheral IL-6 level in patients with MI was greater after percutaneous coronary intervention (PCI) (p<0.01) or IVT (p<0.05). Serial concentration determination revealed marked elevation of serum IL-6 and MMP-9 levels, both reaching peak values (like creatine kinase-MB).

CONCLUSIONS

Elevated levels of IL-6, hs-CRP and MMP-9 provide a link between inflammation, matrix degradation and the development and progression of ACS. IL-6 and MMP-9 appear to be released mainly from vulnerable plaque or necrotic myocardium during the acute phase of MI.