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RESEARCH Open Access
Gingival crevicular fluid MMP-8-concentrations
in patients after acute myocardial infarction
Vicky Ehlers1*†, Ines Willershausen2†, Joachim Kraft2, Thomas Münzel3, Brita Willershausen1
Abstract
Background: The aim of this study was to determine the presence of matrix metalloproteinase-8 in the gingival
crevicular fluid (GCF) of patients after acute myocardial infarction (AMI).
Methods: A total of 48 GCF samples from 20 AMI patients, hospitalized at the Department of Cardiology and
Angiology of the Johannes Gutenberg University Mainz, were investigated. Besides the myocardial infarction all
patients suffered from chronic periodontal disease. Fifty-one GCF samples from 20 healthy age matched individuals
with similar periodontal conditions served as controls. The dental examination included the assessment of oral
hygiene, gingival inflammation, probing pocket depth, clinical attachment level and X-ray examination. The study
was only carried out after the positive consent of the regional ethic commission. A quantitative assessment of
aMMP-8 levels in the gingival crevicular fluid was performed with the help of the DentoAnalyzer (Dentognostics
GmbH, Jena, Germany), utilising an immunological procedure.
Results: The aMMP-8 concentrations found in the gingival crevicular fluid of the AMI patients significantly differed
(p = 0.001; mean value 30.33 ± 41.99 ng/ml aMMP-8) from the control group (mean value 10.0 ± 10.7 ng/ml
aMMP-8). These findings suggest that periodontal inflammation in AMI patients might be associated with higher
MMP-8-values compared to the healthy controls.
Conclusions: The acute myocardial infarction seems to influence the degree of periodontal inflammation, thus the
measurement of the gingival crevicular fluid MMP8 levels seems to be a helpful biochemical test to obtain
information about the severity of the periodontal disease.
Background
Clinical and radiological diagnoses as well as microbial
tests are the basis for an effective periodontal therapy.
The severity of periodontitis can be further quantified
by the presence of inflammatory parameters i.e MMPs
in the gingival crevicular fluid. This knowledge is helpful
for clinicians in finding the most effective treatment
modality [1].
Matrix metalloproteinases (MMPs) are a family of
enzymes that degrade various components of the extra-
cellular matrix [2,3]. Increased expression and activity of
MMPs has been linked with rheumatoid arthritis, tissue
degradation, bone resorption [4,5], tumor metastasis
and ischemic injury [6]; MMP-9 for instance is
physiologically found in the heart and its up regulation
is associated with heart failure, indicating a possible role
of MMP-9 in cardiomyopathy [7]. In the gingival crevi-
cular fluid (GCF) MMP-8 is regarded as the most pro-
minent collagenase (collagenase-2) associated with the
breakdown of connective tissue and periodontal progres-
sion [8-11]. It is therefore regarded as a helpful variable
in diagnostic research [12]. Periodontal treatment con-
cepts such as scaling and root planning are capable of
decreasing the MMP8 levels in the gingival crevicular
fluid [11]. However, when permanently exposed to high
MMP8 concentrations, inflamed periodontal pockets are
a risk of irreversible tissue destruction.
According to the World Health Organization Statistics
coronary heart disease (CHD) is the principal cause for
death and responsible for 50% of all death in the wes-
tern industrialised countries [13]. It has also been
reported that patients with CHD have poorer dental
health than controls without CHD [14,15] with
* Correspondence: vicky.ehlers@unimedizin-mainz.de
† Contributed equally
1Department of Operative Dentistry, University Medical Centre of the
Johannes Gutenberg University Mainz, Germany
Full list of author information is available at the end of the article
Ehlers et al. Head & Face Medicine 2011, 7:1
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HEAD & FACE MEDICINE
© 2011 Ehlers et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
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periodontitis associated with the development of
artherosclerosis.
Beck et al. [16] postulated that periodontal disease and
artherosclerosis seemed to share a similar pathway and
that certain individuals might be more likely than others
to respond to higher levels of inflammatory stimuli.
These factors lead to excessive production of cytokines
and other inflammatory mediators, enhancing the devel-
opment periodontal and arterial cell wall lesions. The
matrix metalloproteinases are among such inflammatory
mediators. Up regulation of MMP-8 for weeks or even
months is correlated with inflammation and bone
resorption [8,9,11]. In healthy individuals exists a bal-
ance between matrixmetalloproteinases (MMPs) and
tissue inhibitors of matrixmetalloproteinases (TIMPs).
The inflammation triggers an immunological response,
which immediately leads to the activation of matrixme-
talloproteinase-8 and to the reduction of collagen [17].
Thus, the disturbed balance of MMPs and TIMPs
through excessively unregulated MMP-8 has to be diag-
nosed at an early stage, even before the clinical signs are
evident, in order to prevent severe periodontitis.
The present study was performed to evaluate the level
of active matrix metalloproteinase-8 (aMMP-8) in the
GCF from patients after acute myocardial infarction and
from healthy controls and to compare the concentration
of aMMP-8 between these groups. Moreover, their clini-
cal periodontal status - including gingival inflammation,
probing pocket depth, clinical attachment level, reces-
sion and dental hygiene - was assessed.
The aim of this study was to determine a possible ele-
vation of aMMP-8 concentrations in AMI patients, indi-
cating that therapies to decrease MMP-8 activity may be
beneficial to prevent further or severe periodontal
breakdown and bone resorption particularly in risk
patients.
Methods
Study Population
In the study a total of 48 gingival crevicular fluid (GCF)
samples from 20 patients (42 to 84 years) with acute
myocardial infarction were collected and analyzed. The
samples were collected within one week after the
patients had experienced the myocardial infarction.
These samples were compared to 51 GCF samples from
20 healthy age matched controls from outpatients of the
Dental University of Mainz. Both AMI patients and con-
trol patients showed clinical and radiological signs of
moderate chronic periodontal diseases (PD ≤ 5 mm).
All subjects included in this examination gave
informed consent to participate and the study was
approved by the institutional review board of the Uni-
versity of Mainz, the ethics committee and the National
Board for Radiation Protection.
Inclusion criteria were the presence of an acute
myocardial infarction verified by characteristic electro-
cardiogram changes and evaluation of serum enzymes
(serum glutamic oxaloacetic transaminase, creatinine
phosphokinase). All patients had suffered a recent history
of acute myocardial infarction as verified by hospitaliza-
tion at the Department of Cardiology and Angiology of
the University of Mainz. The majority of the hospitalized
AMI collective either suffered from chronic periodontitis
or were edentulous. Only those patients with moderate
chronic periodontis were included in the present study.
The dental examination and assessment of sulcular fluid
samples aMMP-8 was carried out directly bed-side at the
Department of Cardiology and Angiology and only
patients deemed clinically stable to undergo a thorough
dental examination and measurement of aMMP-8 were
included in the study.
All control patients also suffered from moderate
chronic periodontitis but were in good general health
with exclusion criteria being a history of cardiovascular
disease, hypercholesterolemia or any other severe illness.
The control patients were not in systemic periodontal
therapy within the last 6 months.
Oral examination
For this investigation only AMI patients and volunteers
with more than five teeth could be included.
The selection of a total of 5 teeth per mouth as mini-
mum inclusion criteria resulted in the observation that a
great number of AMI patients were edentulous or
showed a low number of teeth. Therefore a third of the
recruited patients had to be excluded from the study.
The control patients were examined during a clinic
visit. All subjects underwent a questionnaire, a radiologi-
cal investigation and a thorough oral examination. The
dental examinations included standard periodontal para-
meters probing pocket depths (PD), clinical attachment
level (CAL), recession. Moreover, oral hygiene (PI, Quig-
ley-Hein-Plaque-Index) [18] and bleeding index (PBI,
Saxer/Mühlemann) [19] were recorded by the attending
dentist. All measurements were recorded at six sites on
each tooth and a total of 2-4 teeth per patient were ana-
lysed, using a standard periodontal probe (PCP 15,
Hu-Friedy, Chicago, IL, USA).
Measurement of aMMP-8
GCF was collected from up to four teeth before any
treatment measures from AMI patients and the control
group using a standardized MMP-8 collection strips
[12]. All patients showed a moderate chronic periodon-
tal disease (PD ≤ 5 mm) but no symptoms of acute
aggressive periodontal disease. The evaluated teeth
included anterior and posterior teeth. The aMMP-8
collection (aMMP-8 levels: healthy conditions: 0-7 ng/ml;
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severe periodontitis > 65 ng/ml) [8,17,20,21] was carried
out with the help of paper strips, which were placed in
the periodontal pockets for 30 seconds [1]. The
aMMP-8 was immediately eluted from the strips for 30
seconds and quantitatively assessed with the DentoA-
nalyzer (Dentognostics GmbH, Jena, Germany) [20,21].
The DentoAnalyzer automatically conducted the entire
assay process and the result of the test was revealed
within 12 minutes chair-side. With the help of this
assay the concentration of aMMP-8 can be measured
in a range from 2 ng/ml aMMP-8 eluate up to 200 ng/ml
aMMP-8 eluate [22-25].
Medical history
At the time of enrollment age and gender were assessed
for all patients. All subjects were also asked for classical
cardiovascular risk factors including family history of
coronary artery disease, smoking and diabetes mellitus.
The patients diagnosed with an acute myocardial
infarction had a medical history of an ST-elevated myo-
cardial infarction (STEMI) or Non-Stemi cardiac events
(NSTEMI). All of the AMI patients were hospitalized
and blood samples were taken as a means of clinical
diagnosis.
The blood pressure (hypertension was defined accord-
ing to WHO guidelines), the serum values for glucose,
hemoglobin, glycosylated hemoglobin (HbA1c), total
cholesterol, triglyceride (TG), leukocytes, fibrinogen, the
albumin excretion rate (AER), creatinine phosphatase
and CRP serum levels were obtained from the patients
during hospitalization.
Statistical analysis
All statistical analyses were performed using statistical
software (SPSS, 15.0 for Windows, Chicago, IL, USA).
Mean and standard deviation (SD) were calculated for
compare the data gained from the acute myocardial
patients and the control subjects. For the statistical eva-
luation of the differences between the two patient
groups, the Chi-Quadrat test and the Mann-Whitney-
test were used. In all test procedures a significance level
of p < 0.05 was considered statistically significant.
Results
All patients who were hospitalized on account of an
acute myocardial infarction (AMI) also suffered from
moderate chronic periodontitis. They had a mean age of
64.5 years (SD: 12.7 years), and the majority were of
male gender (85.4% male, 14.6% female). The age (63
years; SD: 6.1 years) and gender (male (60.8%) and
female (39.2%)) matched controls also suffered from
moderate chronic periodontitis, but showed no sign of
cardiovascular disease. Statistically there were no odd
differences between both age and gender of the patients
and controls.
The concentrations of aMMP-8 were significantly ele-
vated in gingival crevicular fluid (GCF) samples from
patients after acute myocardial infarction (p = 0.001;
median 13.5, mean value 30.33 ± 41.99 ng/ml aMMP-8
eluate) when compared to the GCF samples from the
control group (median 6, mean value 10.02 ± 10.7 ng/ml
aMMP-8 eluate) (Table 1).
Concerning the periodontal parameters such as
pocket depths, recessions and clinical attachment levels
there were no statistically odd differences regarding the
periodontal sites from AMI patients and from controls.
However the AMI patients demonstrated poorer dental
hygiene than the control patients and the Plaque-Index
(PI) was significantly higher (p = 0.002). In the AMI
patient group, periodontal sites grade 2 (35.4%) and
grade 3 (27.1%) dominated, 18.8% had grade 1, 16.7%
grade 0 and 2.1% grade 4. Grade 5 was recorded
neither among the AMI patients nor among the con-
trols. As expected grade 1 (39.2%) and grade 0 (33.3%)
were predominant in the control group, followed by
grade 3 (13.7%), grade 2 (9.8%) and grade 4 (3.9%)
(Table 1).
The degree of gingival inflammation represented by
PBI showed no odd differences between periodontal
sites of AMI patients and healthy patients (p = 0.775).
There were also no correlations between aMMP-8
concentration and gingival recession or clinical attach-
ment level. A significant association was found
between aMMP-8 concentration and pocket depth
both among the AMI patients and among the controls
(p = 0.002).
MMP-8 concentrations and Plaque-Index revealed a
statistically significant correlation considering both
groups together (patients and controls) (p = 0.027)
(Figure 1). There was also a week connection between
MMP-8 concentrations and gingival inflammation in
both groups (p = 0.883), but this was not statistically
significant.
Moreover, within the AMI patient group there were
no statistically differences between MMP-8 values and
stemi/non stemi or between MMP-8 concentrations and
smoking habits. No statistically odd correlations were
Table 1 Clinical data of the AMI patients and the controls
Patients Plaque-Index (%) MMP8 (ng/ml)
± SD
grade
0
grade
1
grade
2
grade
3
grade
4
AMI 16.7 18.8 35.4 27.1 2.1 30.3 ± 41.9
Control 33.3 39.2 9.8 13.7 3.9 10.0 ± 10.7
Ehlers et al. Head & Face Medicine 2011, 7:1
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found between medical data like blood glucose concen-
trations, number of leukocytes or LDL-values and
MMP-8 concentrations.
Discussion
In this study changes in gingival crevicular fluid MMP-8
levels in patients after myocardial infarction were inves-
tigated. We found significantly higher MMP-8 concen-
trations in myocardial infarct patients compared to
patients without cardiovascular disease but with a simi-
lar periodontal condition. The importance of the
collagenase activity in GCF, represented mainly through
MMP-8, as an indicator for periodontal collagen break-
down and alveolar bone resorption could be demon-
strated in a group of postmenopausal women during a
2-year follow up study [26].
Numerous studies have demonstrated a correlation
between CHD and periodontal disease [16,27,28]. In a
systematic review Humhrey et al. [29] showed that peri-
odontal disease including gingivitis, bone loss and miss-
ing teeth is an independent but relatively weak risk
factor for CHD. Individuals suffering from periodontal
disease have approximately a 24-35% increased risk of
developing CHD. In our study the AMI patients showed
higher MMP-8 levels, which might represent, together
with the present periodontal disease, a further negative
influence on the progression or severity of the myocar-
dial infarction.
It has been demonstrated that both cardiovascular
disease (CVD) and periodontal disease are more likely
to occur in male, older, smoking patients, suffering from
diabetes. Furthermore a low socio-economic status,
stress and social isolation are made responsible for the
occurrence of CVD [27,30]. In the study of Furuholm et
al. [31] the salivary MMP-8 levels in patients with CHD
were measured and compared with healthy control per-
sons. The authors found that the CHD patients showed
significantly higher levels of MMP-8. This suggests that
periodontal disease and CHD might have similar causa-
tive pathways.
In the Consensus Report of the Sixth European Work-
shop on Periodontology Kinane et al. [32] found evi-
dence a periodontal disease contributes to the total
infectious and inflammation burden and may contribute
to cardiovascular events and stroke in susceptible sub-
jects. They report that the impact of periodontal therapy
should investigated further.
Different studies evaluated to what extent chronic
infections are involved in the pathogenesis of CHD and
how chronic infections of dental origin are cumulative
in patients with CHD or acute myocardial infarction
[33-35]. In the study of Slade et al. [36] the relationship
Figure 1 Significant correlation between MMP-8-concentration and Plaque Index (PI) in the present study population.
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between periodontal disease, C-reactive protein and the
risk of artherosclerosis was examined among adults. A
moderately elevated serum C-reactive protein (CRP)
concentration is regarded as a marker of inflammation
and a risk factor for CVD.
Unrecognized infections such as periodontal disease
may induce acute-phase response, elevating CRP levels.
Mean CRP level among people with extensive periodon-
tal pockets was one-third greater than that for people
with less extensive periodontal pockets. They concluded
that extensive periodontal disease and body mass index
(BMI) are associated with increased CRP levels in other-
wise healthy, middle-aged adults. Therefore the authors
suggested the need for medical and dental diagnoses
when evaluating sources of acute-phase response in
some patients [36]. Grau et al. [37] investigated whether
periodontal disease, including periodontitis and gingivi-
tis, is a risk factor for cerebral ischemia. They found
that periodontal disease is an independent risk factor for
cerebral ischemia in men and younger subjects.
In the present study except for the Plaque-Index (PI)
all other periodontal parameters like probing depth,
recession, clinical attachment level and gingival inflam-
mation were not statistically different from the controls.
The statistically significant elevation of plaque accumu-
lation could be explained by the poorer dental hygiene
of the hospitalized AMI patients. Other studies have
shown that patients after AMI had a more insufficient
dental index than control persons [38]. Moreover the
positive correlation between PI and MMP-8 levels might
be caused by the potential inflammatory effect through
the dental plaque. In a large epidemiological survey
Mattila [39] showed that chronic periodontal diseases
are associated with an increased risk of CHD and that
the number of missing teeth has been linked with ele-
vated risk levels for CHD. In the Kuopio Ischemic Heart
Disease Risk Factor (KIHD) study of Tuomainen et al.
[40] baseline serum levels of MMP-8 in a great number
of Finnish men were measured and re-examined 4 years
later. They found that serum MMP-8 concentrations
were significantly higher in men with CVD than in men
without signs of CVD. These data imply that MMP-8
levels are elevated in prevalent or subclinical
atherosclerosis.
Therefore it is important that patients with CVD,
CHD or hospitalized AMI patients have an early dental
appointment to control and treat the periodontal
disease. The aim of this early treatment is to eliminate
or reduce high aMMP-8 activity with the help of period-
ontal therapy and to prevent further inflammation and
periodontal destruction. Several studies postulated that
patients who have periodontitis have a higher risk of
future CVD [33,41]. De Stefano et al. [41] found that
people with periodontitis had a 25 percent increased
risk of suffering from CVD. Moreover they found that
men with periodontitis had a 1.72 relative risk compared
with men without periodontitis.
In this study statistically significant correlations were
found between gingival crevicular MMP-8 concentra-
tions and periodontal parameters.
To the best of our knowledge, there are currently no
further studies with MMP-8 and patients after AMI.
Another study related to MMPs was found, where
Romanic et al. [42] investigated the role of MMP-9 in
myocardial infarction utilising an MMP-9 knockout
mouse model. Their results suggested that MMP-9 plays
an important role in ischemia-reperfusion-induced myo-
cardial infarction and that MMP-9 could be a target for
prevention or treatment of acute ischemic myocardial
injury.
Conclusions
It has been reported that chronic periodontal disease is
a weak risk factor for coronary heart disease. The early
diagnostic and information about the severity of this
inflammatory disease with the help of special biochem-
ical tests is very helpful particularly for patients after
myocardial infarction.
Thus, our results concerning the measurement of the
MMP-8 levels in gingival crevicular fluid give informa-
tion about a possible risk of the progression of period-
ontal disease. Consequently this marker plays an
important role in the diagnosis of the severity of period-
ontal disease which is might be beneficial for patients
after myocardial infarction. On the one hand it may be
useful to treat patients with periodontitis in order to
minimize one of the possible cardiovascular risk factors
and, on the other hand, to improve dental hygiene
among AMI patients. This can be considered helpful to
prevent the progression of the periodontal disease and
to minimize a possible interaction between the period-
ontal and the cardiovascular disease.
Author details
1Department of Operative Dentistry, University Medical Centre of the
Johannes Gutenberg University Mainz, Germany. 2Institute for Dental
Material Sciences and Technology, University Medical Centre of the
Johannes Gutenberg University Mainz, Germany. 3Department of Cardiology
and Angiology, University Medical Centre of the Johannes Gutenberg
University Mainz, Germany.
Authors’ contributions
VE and IW carried out the study and examined all patients. VE and IW
performed the statistical analysis. TM and JK participated in the design of
the study. BW conceived of the study, and participated in its design and
coordination. All authors read and approved the final manuscript.
Competing interests
The authors declare that they have no competing interests.
Received: 12 April 2010 Accepted: 10 January 2011
Published: 10 January 2011
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