Intravenous prostaglandin E1 reduces monocyte chemoattractant protein-1 levels in peripheral arterial obstructive disease

Role of monocyte chemoattractant protein-1 (MCP-1) as an immune-diagnostic biomarker in the pathogenesis of chronic periodontal disease

OBJECTIVE

Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine responsible for the initiation, regulation and mobilization of monocytes to the active sites of severe periodontal inflammation. The present study aims at evaluating the levels of MCP-1 in GCF, saliva and serum and to analyze the changes following phase I periodontal therapy. Assessment of possible correlations between levels of MCP-1 in the three biological fluids was also done.

METHODS

Fifteen healthy and 30 patients of severe chronic periodontitis (diseased) participated in the study. Patients of the diseased group underwent scaling/root planing. Evaluation of PI, GI, PD, CAL and collection of samples of GCF, serum and saliva was done at baseline and 6 weeks following periodontal therapy. MCP-1 levels were quantified in all samples using ELISA.

RESULTS

Compared to healthy controls, MCP-1 levels were statistically significantly higher in GCF (p<0.001), saliva (p=0.002) and serum (p<0.001) in subjects with chronic periodontitis. Levels of MCP-1 in all the three fluids decreased significantly in patients after periodontal therapy (p<0.001). There was a significant positive correlation between MCP-1 levels in GCF, saliva and serum in patients of chronic periodontitis both pre (r>0.9) and post-treatment (r>0.6).

CONCLUSIONS

The results suggest that levels of MCP-1 in GCF and saliva can be reliable indicators of severity of periodontal destruction and their serum levels reflect the systemic impact of this local inflammatory disease thereby strengthening the reciprocal oro-systemic association.

Preventive aspects in peripheral artery disease

The prevalence of peripheral artery disease is steadily increasing and is associated with significant morbidity, including a significant percentage of amputations. Peripheral artery disease often goes undiagnosed, making its prevention increasingly important. Patients with peripheral arterial disease are at increased risk of adverse cardiovascular outcomes which makes prevention even more important. Several risk factors have been identified in the pathophysiology of peripheral artery disease which should be modified to decrease risk. Smoking, hyperlipidemia, hypertension, and diabetes are among proven risk factors for the development of peripheral artery disease, thus smoking cessation, lipid control, blood pressure control, and glucose control have been tried and shown to be effective in preventing the morbidity associated with this disease. Pharmacologic agents such as aspirin and clopidogrel alone or in combination have been shown to be effective, though risk of bleeding might be increased with the combination. Anticoagulation use is recommended only for acute embolic cases. Other treatment modalities that have been tried or are under investigation are estrogen replacement, naftidrofuryl, pentoxifylline, hyperbaric oxygen, therapeutic angiogenesis, and advanced glycation inhibitors. The treatment for concomitant vascular diseases does not change in the presence of peripheral artery disease, but aggressive management of risk factors should be undertaken in such cases.

Prostaglandin E1 dose-dependently promotes stability of atherosclerotic plaque in a rabbit model

This study evaluated the effect of prostaglandin E1 (PGE1) on the stability of atherosclerotic plaque. A vulnerable plaque model was established in rabbits, using balloon injury combined with a high-cholesterol diet. The rabbits were distributed into a control group, a low-dose PGE1 treatment group, a moderate-dose PGE1 treatment group, a high-dose PGE1 treatment group, and a simvastatin treatment group, with treatments lasting for 4 weeks. At week 13 (at the end of the experiments), atherosclerotic plaque was triggered by injection of Russell's viper venom (Chinese) and histamine. Serological, pathological, immunohistochemical, and gene-expression studies were subsequently performed. PGE1 treatment did not alter serum lipid levels; however, PGE1 dose-dependently increased the thickness of the fibrous caps, and decreased the plaque vulnerability index. The plaque contents of macrophage- and the mRNA levels of monocyte-chemotactic protein-1, matrix metalloproteinase-1, and matrix metalloproteinase-9 were markedly reduced in all of the PGE1 treatment groups, with the high-dose of PGE1 being more effective than the simvastatin treatment. These findings suggest that PGE1 dose-dependently enhances the stability of atherosclerotic plaque. The high-dose of PGE1 presented more protection in terms of inhibiting macrophage accumulation and inflammatory expression in plaque. Our findings suggest a novel drug for the treatment of atherosclerosis.

Association between plasma monocyte chemoattractant protein-1 levels and the extent of atherosclerotic peripheral artery disease

Peripheral artery disease occurs at advanced ages and accounts for substantial cardiovascular morbidity and mortality. Monocyte chemoattractant protein-1 (MCP-1), a member of the cysteine-cysteine family of chemokines, is one of the cytokines involved in the pathogenesis of atherosclerosis and is also known as cysteine-cysteine chemokine ligand 2 (CCL2). The aim of the current study was to investigate the association between the extent of atherosclerotic peripheral artery disease (PAD) and the increase in MCP-1 level. Eighty consecutive patients who had undergone peripheral angiography for suspected PAD were included. Of these patients, 48 (60%) had hypertension, 23 (28.8%) had type 2 diabetes mellitus, 39 (48.8%) had a family history of coronary artery disease, 23 (28.8%) were cigarette smokers, and 42 (52.5%) had hypercholesterolemia. Angiography revealed that the peripheral arteries of the lower extremity were normal in 41 (51.3%) patients, whereas 39 (48.7%) patients had varying degrees of PAD. The patients were queried regarding age, gender, and atherosclerotic risk factors. The plasma MCP-1 levels were significantly lower in the patients without PAD than those in the patients with PAD (172.27 ± 38.05 pg/mL vs. 200.87 ± 39.31 pg/mL, p = 0.001). Moreover, as the severity of PAD increases, MCP-1 levels also increase. Thus, the plasma MCP-1 level can be used in the diagnosis of PAD and in determining the extent of atherosclerotic PAD of the lower extremities, as in determining the extent of coronary artery disease.

Patient-based outcomes using the Walking Impairment Questionnaire for patients with peripheral arterial occlusive disease treated with Lipo-PGE1

BACKGROUND

Patients with peripheral arterial occlusive disease (PAD) experience deteriorating ambulatory function and consequently impaired quality of life (QOL). QOL in patients receiving prostaglandin E(1) in lipid microspheres (lipo-PGE(1); Liple) for the treatment of PAD has not been evaluated using the Japanese version of the Walking Impairment Questionnaire (WIQ).

METHODS AND RESULTS

Data from 169 patients (98 men, 71 women; mean [median] age, 74+/-10 [74] years) with an ankle-brachial pressure index <0.9 were analyzed. WIQ scores and symptom scores significantly improved after lipo-PGE(1) treatment (P<0.01). Physicians' assessments of global improvement significantly correlated with all 4 WIQ subscales (R< or =0.31).

CONCLUSIONS

WIQ is a valid tool for evaluating therapeutic response in patients with PAD. Lipo-PGE(1) improves QOL as evaluated by patients themselves.

Pharmacological treatment of patients with chronic critical limb ischemia: L-propionyl-carnitine enhances the short-term effects of PGE-1

PURPOSE

To evaluate the therapeutic effects of L-propionyl-carnitine (LPC) in patients with critical limb ischemia (CLI), as defined by the TASC guidelines.

METHODS

The study, double-blinded, randomised, assessed intravenous infusion of LPC 1.2 g/day in combination with PGE-1, 60 mg/day (LPC group: 37 patients), or PGE-1 only (control group: 38 patients) in a total of 75 patients suffering from CLI. Treatment duration was 20 days. We evaluated rest pain, maximum walking distance (MWD) and skin ulcer size.

RESULTS

In both groups we observed a significant reduction in pain score and ulcer size and an increase in MWD. In the patients treated with the combination, the improvement was greater: median value for pain score decreased from 2.75 to 0.85 in the LPC group and from 2.51 to 1.71 in the control group; MWD increased from 55 M to 130 M in the LPC group, and from 55 M to 102 M in the control group; median decrease of ulcer size was significantly greater in patients treated with LPC + PGE1.

CONCLUSIONS

Our study shows that LPC, whose effectiveness on claudication is already known, has favourable effects in patients with CLI, since it reinforces the effects produced by PGE-1.

Selective inhibition of cytokine-activated extracellular signal-regulated kinase by cyclic AMP via Epac1-dependent induction of suppressor of cytokine signalling-3

Here we demonstrate that elevation of cyclic AMP (cAMP) levels in human umbilical vein endothelial cells (HUVECs) specifically attenuates ERK1,2 activation in response to either leptin or a soluble interleukin IL-6 receptor-alpha/IL-6 (sIL-6R alpha/IL-6) trans-signalling complex but not protein kinase C activator phorbol 12-myristate 13-acetate. The inhibitory effects of cAMP on sIL-6R alpha/IL-6-stimulated phosphorylation of ERK1,2 and STAT3 were abolished by either short interfering (si) RNA-mediated knockdown or genetic ablation of suppressor of cytokine signalling-3 (SOCS-3). The inhibitory effect of cAMP could not be reversed by inhibition of cAMP-dependent protein kinase (PKA) but was blocked by depletion of the alternative intracellular cAMP sensor exchange protein activated by cAMP 1 (Epac1), which is also required to observe SOCS-3 accumulation in response to cAMP. Interestingly, the ability of cAMP elevation to inhibit IL-6 signalling was blocked by ERK inhibition. Consistent with this observation, cAMP elevation in HUVECs produced a transient yet robust activation of ERK, and subsequent phosphorylation of transcription factor C/EBP beta, both of which were resistant to PKA inhibition. However, siRNA depletion and immunoblotting experiments revealed that neither Epac1 nor Epac2 contributed to the PKA-independent activation of ERK1,2 observed following cAMP elevation. Together, these observations suggest that while SOCS-3 induction and subsequent inhibition of cytokine-mediated phosphorylation of ERK1,2 and STAT3 in response to cAMP require Epac1 and a transient PKA-independent activation of the ERK pathway, these two events are controlled by distinct mechanisms. In addition, it reveals a novel Epac-dependent mechanism by which cAMP can specifically inhibit ERK in response to cytokine receptor activation.

Prostaglandin E1 inhibits IL-6-induced MCP-1 expression by interfering specifically in IL-6-dependent ERK1/2, but not STAT3, activation

IL (interleukin)-6 exerts pro- as well as anti-inflammatory activities. Beside many other activities, IL-6 is the major inducer of acute phase proteins in the liver, acts as a differentiation factor for blood cells, as migration factor for T-cells and is a potent inducer of the chemokine MCP-1 (monocyte chemoattractant protein-1). Recent studies have focused on the negative regulation of IL-6 signal transduction through the IL-6-induced feedback inhibitors SOCS (suppressor of cytokine signalling) 1 and SOCS3 or the protein tyrosine phosphatases SHP-2 (Src homology 2 domain-containing protein tyrosine phosphatase 2) and TcPTP (T-cell protein tyrosine phosphatase). Studies on the cross-talk between pro-inflammatory mediators (IL-1, tumour necrosis factor, lipopolysaccharide) and IL-6 elucidated further regulatory mechanisms. Less is known about the regulation of IL-6 signal transduction by hormone/cytokine signalling through G-protein-coupled receptors. This is particularly surprising since many of these hormones (such as prostaglandins and chemokines) play an important role in inflammatory processes. In the present study, we have investigated the inhibitory activity of PGE(1) (prostaglandin E(1)) on IL-6-induced MCP-1 expression and have elucidated the underlying molecular mechanism. Surprisingly, PGE(1) does not affect IL-6-induced STAT (signal transducer and activator of transcription) 3 activation, but does affect ERK (extracellular-signal-regulated kinase) 1/2 activation which is crucial for IL-6-dependent expression of MCP-1. In summary, we have discovered a specific cross-talk between the adenylate cyclase cascade and the IL-6-induced MAPK (mitogen-activated protein kinase) cascade and have investigated its impact on IL-6-dependent gene expression.

Elevated Monocyte Chemoattractant Protein-1 Serum Levels in Patients at Risk for Coronary Artery Disease

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1) is involved in the recruitment of monocytes into the arterial vessel wall as one of the major events leading to atherosclerotic vascular diseases, such as coronary artery disease (CAD).

METHODS AND RESULTS

The study group comprised 263 volunteers aged between 18 and 85 years who were admitted to hospital or clinic for scheduled invasive and non-invasive diagnostic procedures. MCP-1 serum levels were determined using a sandwich-enzyme-linked immunosorbent assay. In each patient, the coronary risk factors (CRF), such as hypertension, high cholesterol, diabetes mellitus, obesity, positive family history, and smoking were evaluated. Low-density lipoprotein-cholesterol, lipoprotein(a), and hemoglobinA1C levels were determined. Patients with CAD proven by angiography had significantly increased MCP-1 levels. In patients without CAD, the increase in MCP-1 depended on the number of CRF. As a marker for endothelial activation the soluble adhesion molecules, soluble intercellular adhesion molecule and soluble E-selectin were measured and both markers were significantly elevated in patients with CAD or multiple CRF when compared with patients without CRF. Although this is not a direct proof, endothelial activation could contribute to elevated MCP-1 levels in atherosclerosis.

CONCLUSION

Elevated MCP-1 serum levels could serve as a direct marker of the inflammatory activity in patients at risk for coronary artery and other atherosclerotic vascular diseases.

Monocyte chemoattractant protein-1 in patients with peripheral arterial disease

BACKGROUND: Chemokine-driven migration of inflammatory cells has been implicated in the pathogenesis of atherosclerotic conditions including peripheral arterial disease (PAD). Monocyte chemoattractant protein-1 (MCP-1) is elevated in patients with coronary artery disease and in hypertensive patients. This study therefore investigated MCP-1 in patients with PAD. METHODS: Serum MCP-1 was determined by enzyme-linked immunosorbent assay in 36 healthy, control subjects and in 19 patients with PAD. Statistical analysis utilised the Mann-Whitney test and Spearman correlation (p < 0.05). RESULTS: MCP-1 (pg/ml) was increased in patients compared with in controls (mean+/-standard error of the mean: PAD group, 748+/-60; control group, 459+/-27; p=0.0001). MCP-1 levels tended to decrease with progressing disease. From atherosclerosis risk factors, diabetes inclined to increase MCP-1 levels; hypertension had no effect. Serum MCP-1 correlated with cholesterol, triglycerides, low-density lipoprotein but not high-density lipoprotein. Conclusion: Elevation of MCP-1 in the circulation of PAD patients shown in the present pilot study implicates this CC chemokine ligand 2 in inflammatory processes contributing to PAD clinical symptomatology. Further investigations are necessary to evaluate whether MCP-1 can be used as a potential marker of peripheral arterial disease follow-up and/or prognosis.