ischemic   stroke ( is ) and   myocardial infarction ( mi ) are 
 atherosclerosis - associated complications that are the leading 
 causes of mortality and disability all over the world . 

is and mi share common features , but at the same time there are 
 differences in many risk factors , at least quantitative , if not 
 qualitative . compared with myocardial infarction ,
stroke patients 
 are at least 10 years older , the incidence in middle - aged men 
 compared with women is smaller , and increasing blood pressure is 
 more strongly associated with stroke , whereas increasing plasma 
 cholesterol is less strongly associated with stroke .
recent studies showed that aberrant immune response evolves during 
 both is and mi that is deleterious and contributes to cell death 
 after the insults [ 3 , 4 , 
 5 ] .
both pathologies are characterized 
 by expression of proinflammatory cytokines , adhesion molecules , 
 and importantly , chemokines that orchestrate the infiltration of 
 leukocytes into infarct area , expression of damaging agents and 
 activation of complement system ( for review see [ 6 , 
 7 ] ) .
chemokines are low molecular weight polypeptides that , besides 
 other functions , exert potent chemotactic and activating effects 
 on specific leukocyte populations .
recently , there has 
 been growing interest in applications of chemokine biology into 
 clinic , including atherosclerosis .
cc chemokine ligand 
 ( ccl)2 , more widely known as monocyte chemoattractant protein-1 
 ( mcp-1 ) , is a potent mononuclear cell attractant .
it has 
 been previously implicated in the development of both is and mi . 
 for example , in animal experiments , high levels of mcp-1 mrna have 
 been found in the brain 6 hours after cerebral ischemia . 
 the maximal expression of this chemokine was observed between 12 
 hours and 2 days [ 11 , 12 ] . 

mcp-1 mrna expression was 
 upregulated in infarcted area after mi in the same manner like in 
 is [ 13 , 14 ] .
most of the data about cytokine and chemokine involvement in 
 pathogenesis of is and mi has been derived from animal studies . 
 nowadays , more attention is being paid to studies utilising human 
 subjects . in this context , blood becomes an invaluable target for 
 such studies , due to its relative availability .
recently , it has 
 been shown that the levels of several cytokines are elevated in 
 the blood of patients with is and mi [ 15 , 
 16 , 17 , 
 18 ]
we , therefore , 
 performed the present study to provide additional data on 
 involvement of mcp-1 in mi , and namely in is .
doing so , we wished 
 to complement existing studies targeted at evaluation of chemokine 
 inflammatory response in pathogenesis of these two 
 atherosclerosis - associated complications .
forty patients with is ( 17 female , age [ years , mean  sd ] : 67.5  10.5 ) and 64 patients with mi ( 8 female , age 55  8.8 ) 
 were entered in the study .
patients with concurrent diseases or 
 conditions interfering with the aim of the study , such as 
 infections , malignancies and those on immunosuppressive drugs were 
 excluded from study .
diagnosis of is was based on clinical history and neurological 
 examination and was confirmed by brain ct .
on ct examination , all 
 stroke patients presented anatomically relevant hypodense areas in 
 subcortical parts of cerebral hemispheres .
diagnosis of mi was determined from the presence of > 30 minutes 
 of continuous chest pain , st - segment elevation > 2.0  mm on at 
 least 2 contiguous ecg leads , and more than a 3-fold increase in 
 serum creatine kinase levels .
regarding risk factors , 44% of mi and 50% of is patients had 
 hypertension , 18% of mi and 9% of is patients had diabetes 
 mellitus , 54% of mi and 18% of is patients reported 
 themselves   as current smokers , and 8% of mi and 5% of is 
 patients reported themselves as alcohol consumers . in 
 addition 7% of is patients previously had ischemic heart 
 disease .
forty healthy subjects ( 7 female , age 52  3 ) free of clinical 
 signs of infection , other systemic diseases , and negative family 
 history of is or mi served as control population .
venous blood samples were obtained from is and mi patients within 
 24 hours after disease onset and once from controls .
is patients were recruited at erebouni medical center , yerevan , 
 armenia ; mi patients were diagnosed at the faculty hospital 
 olomouc , czech republic .
protein levels in serum obtained from study participants 
 were measured using a solid - phase sandwich enzyme - linked 
 immunosorbent assay ( mcp-1 quantikine elisa kit , r&d systems , 
 abingdon , uk ) .
briefly , 100  l of duplicated samples or 
 standards ( reeombinant human mcp-1 ) were incubated ( 2 hours at 
 room temperature ) in the wells precoated with primary antihuman 
 mcp-1 antibody .
after incubation , wells were washed three times 
 and horseradish peroxidase - conjugated polyclonal antibodies 
 against mcp-1 were added ( for 2 hours at room temperature ) . 

finally , tetramethylbenzidine substrate solution was applied for 
 30  minutes and , after stopping the reactions by 2  m 
 sulfuric acid , the absorbance was measured at 450  nm ( with 
 correction at 540  nm ) .
the data were evaluated with kim - e 
 software ( usol , prague , czech republic ) ; the detection limit of 
 the mcp-1 assay was 5.0  pg / ml .
spss 11 ( spss inc , chicago , ill ) software was used to calculate 
 basic statistical parameters and to perform the mann - whitney 
 u - test to test for differences in chemokine protein levels 
 between the mi , is , and control groups as well as for further 
 subanalysis .
fisher 's exact test was used to compare differences 
 in qualitative parameters between is and mi groups .
spearman 's 
 rank correlation was used to evaluate relationship between age and 
 mcp-1 levels .
data on mcp-1 levels was presented as median 
 [ interquartile range ( iqr ) ] .
forty patients with is ( 17 female , age [ years , mean  sd ] : 67.5  10.5 ) and 64 patients with mi ( 8 female , age 55  8.8 ) 
 were entered in the study .
patients with concurrent diseases or 
 conditions interfering with the aim of the study , such as 
 infections , malignancies and those on immunosuppressive drugs were 
 excluded from study .
diagnosis of is was based on clinical history and neurological 
 examination and was confirmed by brain ct .
on ct examination , all 
 stroke patients presented anatomically relevant hypodense areas in 
 subcortical parts of cerebral hemispheres .
diagnosis of mi was determined from the presence of > 30 minutes 
 of continuous chest pain , st - segment elevation > 2.0  mm on at 
 least 2 contiguous ecg leads , and more than a 3-fold increase in 
 serum creatine kinase levels .
regarding risk factors , 44% of mi and 50% of is patients had 
 hypertension , 18% of mi and 9% of is patients had diabetes 
 mellitus , 54% of mi and 18% of is patients reported 
 themselves   as current smokers , and 8% of mi and 5% of is 
 patients reported themselves as alcohol consumers . in 
 addition 7% of is patients previously had ischemic heart 
 disease .
forty healthy subjects ( 7 female , age 52  3 ) free of clinical 
 signs of infection , other systemic diseases , and negative family 
 history of is or mi served as control population .
venous blood samples were obtained from is and mi patients within 
 24 hours after disease onset and once from controls .
is patients were recruited at erebouni medical center , yerevan , 
 armenia ; mi patients were diagnosed at the faculty hospital 
 olomouc , czech republic .
mcp-1 protein levels in serum obtained from study participants 
 were measured using a solid - phase sandwich enzyme - linked 
 immunosorbent assay ( mcp-1 quantikine elisa kit , r&d systems , 
 abingdon , uk ) .
briefly , 100  l of duplicated samples or 
 standards ( reeombinant human mcp-1 ) were incubated ( 2 hours at 
 room temperature ) in the wells precoated with primary antihuman 
 mcp-1 antibody .
after incubation , wells were washed three times 
 and horseradish peroxidase - conjugated polyclonal antibodies 
 against mcp-1 were added ( for 2 hours at room temperature ) . 

finally , tetramethylbenzidine substrate solution was applied for 
 30  minutes and , after stopping the reactions by 2  m 
 sulfuric acid , the absorbance was measured at 450  nm ( with 
 correction at 540  nm ) .
the data were evaluated with kim - e 
 software ( usol , prague , czech republic ) ; the detection limit of 
 the mcp-1 assay was 5.0  pg / ml .
spss 11 ( spss inc , chicago , ill ) software was used to calculate 
 basic statistical parameters and to perform the mann - whitney 
 u - test to test for differences in chemokine protein levels 
 between the mi , is , and control groups as well as for further 
 subanalysis .
fisher 's exact test was used to compare differences 
 in qualitative parameters between is and mi groups .
spearman 's 
 rank correlation was used to evaluate relationship between age and 
 mcp-1 levels .
data on mcp-1 levels was presented as median 
 [ interquartile range ( iqr ) ] .
in this study , mcp-1 immunoreactive protein was determined in 
 peripheral blood of patients with mi and is . prior to chemokine analysis , the differences in risk factors among 
 our study groups were estimated .
also , there were differences in 
 male / female ratio ( is , 42% versus mi , 12% , p <
.0001 ) 
 and in number of smokers ( mi , 54% versus is , 18% , p < .0001 ) .
number of sufferers from diabetes was 2-fold higher in 
 mi group compared with is , but this difference did not reach 
 significance ( mi , 18% versus   is , 9% , p > .05 ) .
the study 
 groups did not differ with regard to hypertension and alcohol 
 consumption . in comparison to control subjects ( median [ iqr ] : 239    pg / ml ) , 

the levels of mcp-1 protein were elevated in patients from both 
 study groups ( figure 1 ) .
this increase was more apparent 
 in the is group ( 384    pg / ml ) , for which also a greater degree 
 of interindividual variability was observed than among patients 
 with mi ( 360    pg / ml ) . while only 10/40 ( 25% ) of control 
 subjects had mcp-1 level higher than 314 pg / ml ( 75th percentile of 
 the control group ) , in patients with is this proportion reached 
 68% ( 27 /40 ) and in mi group it was 61% ( 39/64 ) .
the 
 differences between both investigated patient groups and controls , 
 therefore , reached high significance ( is versus   c , p < .001 ; mi 
 versus   c , p < .002 ) , while there was no difference between 
 patients ' groups themselves ( is versus   mi , p > .05 ) .
further , we investigated whether mcp-1 protein is influenced by 
 risk factors of mi and is .
serum chemokine levels were compared 
 between patients with and without diabetes , hypertension ; smokers 
 and nonsmokers ; and also groups divided based on alcohol 
 consumption .
data analysis showed that none of the above risk 
 factors had an influence at circulating mcp-1 levels in patients 
 with mi and/or is ( table 1 ) .
furthermore no gender 
 effect mcp-1 levels was apparent in both studied groups as well 
 as in control group ( is 
 males versus   females : 417   versus   253 , p > .05 ; mi males versus   females : 343   versus   397 , 
 p > .05 ; c males versus   females : 244   versus   234 
 , p > .05 ) , and there was no correlation between age and the 
 chemokine levels ( is : rs = 0.009 , p > .05 , 
 mi : rs = 0.06 , p > .05 , 
 c : rs = 0.168 , p > .05 ) .
this study aimed at the evaluation of the mcp-1 chemokine in the 
 circulation of patients with myocardial infarction and ischemic 
 stroke .
these two atherosclerosis - associated complications share 
 many similarities , but at the same time they have at least 
 quantitative if not qualitative differences in their risk factors 
 .
this trend is preserved in our patients ' characteristics : 
 our is patients were older and the different incidence in males 
 and females is less pronounced in is compared to mi . also , is 
 patients were more prone to hypertension than mi patients . 

presence of these features , therefore , confirms that our patients ' 
 groups were properly created and reflect the actual situation with 
 is and mi phenotypes .
our data showed almost 2-fold increase of serum mcp-1 levels in 
 patients with mi and is compared with control group of healthy 
 subjects .
we also found that serum mcp-1 levels did not differ 
 between is and mi patients .
finally , the levels of this chemokine 
 were not influenced by known risk factors for these diseases such 
 as hypertension , diabetes , smoking , or alcohol consumption . in myocardial infarction , elevation of circulating mcp-1 has been 
 already reported [ 19 , 
 20 , 21 ] and , 
 therefore , our findings of 
 increased mcp-1 in our patients with mi are of a confirmatory 
 nature
. however , infrequent reports regarding this chemokine in 
 ischemic stroke are contradictory [ 22 , 
 23 ] .
losy and zaremba 
  reported that blood mcp-1 levels were not increased in 
 his group of 23 patients with is .
by contrast and in line with our 
 results , reynolds et al   demonstrated elevation of the 
 mcp-1 chemokine in the blood from a big group of more than 200 
 stroke patients .
this discrepancy may occur due to low number of 
 subjects included in the study by losy and zaremba   and 
 possibly also by marked variability of circulating mcp-1 levels .
there are at least two mechanisms by which the observed 
 upregulation of mcp-1 protein levels in circulation of patients 
 with is and mi can be achieved .
the main sources of 
 mcp-1 are endothelia and macrophage like cells , which 
 are known to play a significant role in atherosclerosis 
 development and plaque formation . in vitro studies
have revealed 
 that endothelial cells are able to produce mcp-1 in response to 
 ldl an important atherosclerosis triggering factor [ 25 , 
 26 ] .
second , increased mcp-1 levels can mirror the development of 
 inflammatory response in heart and brain .
numerous studies on 
 animal models of stroke showed that mcp-1 and mip-1beta are two 
 main chemokines that orchestrate infiltration of blood - derived 
 monocytes and lymphocytes into ischemic area .
the upregulation of 
 mcp-1 mrna levels is detected in both permanent and transient 
 models of focal ischemia [ 11 , 
 12 ] .
moreover study by hughes et 
 al   demonstrated that mcp-1 deficiency is protective in a 
 murine stroke model .
the same processes are taking place in heart 
 during mi [ 13 , 14 ] . 

furthermore , it has been demonstrated 
 that mice lacking ccr2 , the primary receptor for mcp-1 , showed 
 significant impairment of monocyte infiltration , reduction of 
 tnf - alpha , and matrix metalloproteinases expression in infarcted 
 area in experimental mi .
our data showed that elevation of mcp-1 in the blood is a common 
 feature for mi and is .
this may suggest that in 
 atherosclerosis - associated complications , inflammatory response , 
 share some similarities and are not organ - specific .
this 
 interpretation fits in with other current reports [ 29 , 
 30 , 31 ] , 
 including our recent observation of approximately 2-fold increase 
 of mcp-1 in the blood of patients with peripheral arterial disease 
 .
unexpectedly , in our study none of four investigated common risk 
 factors for mi and is did not influence serum mcp-1 levels . in 
 number of previous studies in patients with myocardial infarction , 

the association of mcp-1 levels with several risk factors such as 
 hypertension   and 
 diabetes   has been reported . 
 however , these were large - population - based studies where even 
 slight differences may be identified .
for example , in the study by 
 de lemos et al   more than 2000 subjects were enrolled and 
 thus the authors were able to identify a rather minor difference 
 of 6% as significant .
it is , therefore , possible that in our 
 relatively small patient population of 64 mi patients , differences 
 of similar magnitude may not be visible . regarding patients with 
 ischemic stroke
, there have been no studies on influence of risk 
 factors on mcp-1 levels .
we , therefore , plan to further explore 
 this phenomenon so that it can be assessed if monitoring mcp-1 
 serum levels can be included into the algorithm of management 
 of is patients as an independent marker .
in conclusion , our data expand previous observations showing that 
 mcp-1 plays an important role in inflammatory response developing 
 during myocardial infarction and ischemic stroke .
further work is , 
 however , necessary to define more precisely the relationship 
 between mcp-1 and clinical course of investigated diseases . 

emphasis should be given to patients ' stratification in order to 
 ascertain clinical utilisation of mcp-1 measurements , namely in 
 ischemic stroke .
 chemokine - driven migration of inflammatory cells has been 
 implicated in pathogenesis of atherosclerosis - associated 
 conditions such as ischemic stroke and myocardial infarction . in 
 this study 
 , a candidate chemokine , monocyte chemoattractant 
 protein ( mcp)-1 , was investigated in patients with both 
 aforementioned manifestations of atheroslerotic inflammation . 
 
 mcp-1 levels in serum were determined by elisa in 40 healthy , 
 control subjects ( c ) , 40 patients with ischemic stroke ( is ) , and 
 in 64 patients with myocardial infarction ( mi ) . 
 statistical 
 analysis utilised mann - whitney test , fisher 's exact test , and 
 spearman 's rank correlation ( p < .05 ) . in comparison to control 
 subjects ( c ; median / interquartile range : 239/126  pg / ml ) , mcp-1 
 serum levels were increased in both investigated patient cohorts 
 ( is : 384/370 , p < 
 .001 ; mi : 360/200 , p < .002 ) . 
 there was a 
 substantial variability of mcp-1 serum levels , especially in the 
 is group . 
 no relationship was observed between chemokine levels 
 and atherosclerosis risk factors ( hypertension , diabetes , smoking , 
 and alcohol consumption ) , and mcp-1 was also not related to age or 
 gender . 
 elevation of mcp-1 in circulation of patients with 
 atherosclerosis - associated complications implicates this cc 
 chemokine ligand ( ccl)2 in inflammatory processes , which 
 contribute to pathogenesis of myocardial infarction and ischemic 
 stroke . 
 further investigations , including patient stratification , 
 are however necessary to evaluate if mcp-1 can be utilised for 
 clinical management of patients with these diseases . 