Bacteria associated with periodontal disease are also increased in health.

BACKGROUND: The objective of this cross-sectional clinical study was to analyze the differences in the microbiome in gingival sulci of adult patients in the presence or absence of chronic periodontitis. MATERIAL AND METHODS: Patients with or without periodontal disease were included in this cross-sectional study. Subgingival biofilm samples were collected and analyzed by 16S massive pyrosequencing. Functional analyses were also performed. RESULTS: A total of 15 phyla, 154 genera and 351 species were detected globally. Differences between disease and non-disease samples were observed in all taxonomical levels which suggest functional profile changes in the community. It was found that the main species associated with non-disease samples were reduced in disease but not completely suppressed. Analysis of the functional potential of the biofilms revealed a significantly higher activity related to endocytosis and phosphatidylinositol signaling in the disease group but lower cell adhesion molecules. CONCLUSIONS: Specific differences between health and disease suggest functional profile changes in the community, although bacteria associated with periodontal disease are also increased in health. Transcriptome studies should be conducted to confirm and deepen metabolic dysfunctions.

Simvastatin exerts antiproliferative and differentiating effects on MG63 osteoblast-like cells: Morphological and immunocytochemical study.

BACKGROUND AND OBJECTIVE: Current evidence suggests that statins exert an anabolic effect on bone and may therefore impact on osteogenic differentiation and proliferation. These effects can be useful for their use in guided bone regeneration. The objective of this study was to determine the in vitro effects of simvastatin on the differentiation and proliferation of MG63 human osteoblast tumor cells. MATERIAL AND METHODS: MG63 human osteosarcoma cells were cultured in the presence of simvastatin or solvent alone for 72 hours, and their proliferation was assessed by MTT assay. Cells from the culture were prepared for light, transmission and scanning electron microscopy studies. immunocytochemical was used to analyze the differentiation and proliferation markers Musashi-1, Ki-67, CD56 and CD44. RESULTS: Cultured MG63 control cells showed spheroid morphology with numerous secretion vesicles accumulated on the surface, observing no cytoplasmic projections with intercellular connections. However, cells cultured with simvastatin had a polygonal and spindle-shaped morphology, with cytoplasmic projections that interconnected cells. There were numerous microvilli-like filamentous projections on the surface with no defined pattern. At 72 hours of culture, CD56, Ki-67 and Musashi-1 expression was significantly reduced (P < .001) in simvastatin-treated cells. CD44 expression was intense in both groups and was not affected by simvastatin treatment. CONCLUSION: MG63 cells cultured with simvastatin for 72 hours undergo morphological and surface changes. Simvastatin treatment exerts antiproliferative and differentiating effects on these cells as well as promoting recovery of cellular homeostasis.

Oral bacteria in placental tissues: increased molecular detection in pregnant periodontitis patients.

OBJECTIVES: The objective of this study was to identify the DNA of oral bacteria in placental samples from women with and without periodontitis who had or had not had preterm births and/or low birthweight (PB/LBW) neonates. METHODS: Data were gathered from 57 puerperal women in relation to socio-demographic, gynaecological, and periodontal variables and to placental histomorphology. Fifty-seven biopsies, 28 from mothers with periodontitis, were taken aseptically from preterm placentas (n = 36) and from full-term placentas (n = 21). Total DNA was extracted, and the presence of 15 oral bacteria was assessed using Nested-PCR. RESULTS: The placentas from women with periodontitis showed a higher prevalence of periodontopathogens compared to those from women without periodontitis (P = 0.009). Samples showed low prevalences of Actinomyces israelii, Parvimonas micra and Tannerella forsythia. An association was found between Eikenella corrodens in placenta and periodontitis (P = 0.002). The most ubiquitous bacterium, Fusobacterium nucleatum, was more prevalent in mothers with periodontitis and PB/LBW (P = 0.033). Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia and Aggregatibacter actinomycetemcomitans were not detected. CONCLUSIONS: These results, along with previous findings, show that oral bacteria may be normally present in the placenta, however, the levels of certain oral pathogens in the placenta would highly depend on the mother's periodontal state.

Human adipose-derived mesenchymal stem cells reduce inflammatory and T cell responses and induce regulatory T cells in vitro in rheumatoid arthritis.

OBJECTIVES: Adult mesenchymal stem cells were recently found to suppress effector T cell and inflammatory responses and have emerged as attractive therapeutic candidates for immune disorders. In rheumatoid arthritis (RA), a loss in the immunological self-tolerance causes the activation of autoreactive T cells against joint components and subsequent chronic inflammation. The aim of this study is to characterise the immunosuppressive activity of human adipose-derived mesenchymal stem cells (hASCs) on collagen-reactive T cells from patients with RA. METHODS: The effects of hASCs on collagen-reactive RA human T cell proliferation and cytokine production were investigated, as well as effects on the production of inflammatory mediators by monocytes and fibroblast-like synoviocytes from patients with RA. RESULTS: hASCs suppressed the antigen-specific response of T cells from patients with RA. hASCs inhibited the proliferative response and the production of inflammatory cytokines by collagen-activated CD4 and CD8 T cells. In contrast, the numbers of IL10-producing T cells and monocytes were significantly augmented upon hASC treatment. The suppressive activity of hASCs was cell-to-cell contact dependent and independent. hASCs also stimulated the generation of FoxP3 protein-expressing CD4(+)CD25(+) regulatory T cells, with the capacity to suppress collagen-specific T cell responses. Finally, hASCs downregulated the inflammatory response and the production of matrix-degrading enzymes by synovial cells isolated from patients with RA. CONCLUSIONS: The present work identifies hASCs as key regulators of immune tolerance, with the capacity to suppress T cell and inflammatory responses and to induce the generation/activation of antigen-specific regulatory T cells.

Poly(ADP-ribose) polymerase expression in kidney transplantation: from alfa (alpha) to Omega (Omega).

INTRODUCTION: Overactivation of the enzyme poly(ADP-ribose) polymerase (PARP-1) can be induced by ischemia-reperfusion and involved in the renal injury subsequent to kidney transplant. The poly(ADP-ribosy)lation mechanism alters free radical-induced DNA damage, which is repair by PARP-1 polymer. However, PARP-1 overexpression induces cellular necrosis. Our aim was to study the immunohistochemical PARP-1 expression in kidney transplant biopsies associated with various events. MATERIALS AND METHODS: We studied the nuclear expression of PARP-1 in kidney tubule cells by immunohistochemistry using the monoclonal antibody PAR01 in donor biopsies without acute tubular necrosis (ATN) (n = 60; controls), allografts that suffer ATN (n = 90) or an episode of acute humoral rejection (n = 12) or acute tubulointerstitial rejection (n = 25), or chronic allograft nephropathy (n = 25). Furthermore, we also studied protocol biopsies with subclinical rejection (n = 60). Renal lesions in transplant biopsies were graded blindly using 1997 Banff criteria without any clinical information. RESULTS: Biopsies without morphological features of ATN, namely acute tubulointerstitial rejection, borderline or subclinical rejection, showed lesser PARP-1 expression compared with biopsies with ATN or with ischemic mechanism of acute humoral rejection or chronic allograft nephropathys. We observed an inverse relation between PARP-1 expression and renal function (P < .001). Overall, renal biopsies showing ATN revealed greater expression of PARP-1 (r = 0.785, Pearson test). A significant relationship with PARP-1 expression was demonstrated with renal function (effective diuresis, serum creatinine levels) and pretransplant cold ischemia time (P < .001). CONCLUSION: Kidney transplant events including ischemia were associated with the highest PARP-1 expression and worse allograft renal function.

Role of poly (ADP-ribose) polymerase in kidney transplant and its relationship with delayed renal function: multivariate analysis.

UNLABELLED: Kidney allografts undergo pretransplant cold ischemia and consequent ischemia-reperfusion injury (IR). Poly (ADP-Ribose) polymerase (PARP-1) overactivation leads to massive NAD+ consumption and ATP depletion with induction of cellular necrosis under ischemic conditions, which may lead to an increase in acute tubular necrosis (ATN) and a delay in total recovery of renal function (RFR) of the transplanted organ. MATERIALS AND METHODS: Nuclear PARP-1 immunohistochemical expression (clone: PARP01) was studied in 155 paraffin-embedded renal biopsies from suboptimal donors and 95 kidney allograft biopsies with histopathological diagnosis of ATN. RESULTS: In 50% of ATN biopsies, more than 50% of tubular nuclei were immunostained for PARP-1. PARP-1 expression was higher in ATN biopsies than in those from suboptimal donors (2.40 +/- 0.74 vs 0.92 +/- 1.13, P = 0.0001 Mann-Whitney). PARP-1 showed a statistically significant relationship with the time required to achieve effective diuresis (Rho:0.779), with serum creatinine, and with duration of cold ischemia (Rho:0.803). These relationships were stronger in the biopsies with ATN. In conclusion, multivariate analysis demonstrated that PARP-1 expression and cold ischemia duration in kidney biopsies with ATN predicted the short-term delay in total recovery of renal function and serum creatinine in the first month.

Role of poly-(ADP-ribose) polymerase in transplant acute tubular necrosis and its relationship with delayed renal function.

The enzyme poly(ADP-ribose) polymerase (PARP-1) participates in the repair of DNA damaged by genotoxic agents such as oxygen-derived free radicals. If the allograft suffers pretransplant cold ischemia and subsequent ischemia-reperfusion injury (IR), overactivation of PARP-1 can be induced, which may lead to an increase in acute tubular necrosis (ATN) and a delay in total recovery of renal function (RRF) of the transplanted organ. We studied the nuclear expression of PARP-1 in tubular cells by immunohistochemistry with the monoclonal antibody PAR01 in 104 kidney transplant biopsies from allografts with ATN. In 50% of biopsies with ATN, >50% of tubular nuclei were PARP-1+; only 9.6% of biopsies were negative. The increase in the immunohistochemical expression of PARP-1 showed a statistically significant relationship with the duration of cold ischemia, with serum creatinine levels, and with the time required to achieve effective diuresis (P < .0001, Spearman test). Cold ischemia of >24 hours and serum creatinine levels >1.7 mg/dL showed a statistically significant relationship with the highest PARP-1 expression levels (2.83 +/- 0.4 vs 1.36 +/- 0.8, P < .0001, Mann-Whitney U test). We conclude that PARP-1 plays an important role in ATN and RRF and is related to the extent and severity of ATN and to the renal allograft function.

Altered drug membrane permeability in a multidrug-resistant Leishmania tropica line.

We selected a Leishmania tropica cell line resistant to daunomycin (DNM) that presents a multidrug-resistant (MDR) phenotype characterized by overexpression of a P-glycoprotein of 150 kDa. The resistant line overexpressed an MDR-like gene, called ltrmdr1, located in an extrachromosomal circular DNA. DNM uptake experiments using laser flow cytometry showed a significant reduction in drug accumulation in the resistant parasites. The initial stages of the interaction of DNM with membranes from wild-type and DNM-resistant parasites were defined by a rapid kinetic stopped-flow procedure which can be described by two kinetic components. On the basis of a previous similar kinetic study with tumor cells, we ascribed the fast component to rapid interaction of DNM with membrane surface components and the slow component to passive diffusion of the drug across the membranes. The results reported here indicate that entrance of DNM into wild-type parasites was facilitated in respect to the resistant ones. We propose that resistance to DNM in L. tropica is a multifactorial event involving at least two complementary mechanisms. an altered drug membrane permeability and the overexpression of a protein related to P-glycoprotein that regulates drug efflux.

Detection of hepatitis B virus in the liver by in situ hybridization (ISH) in HBsAg seropositive and seronegative patients.

The presence of hepatitis B virus (HBV) DNA in the liver of 119 patients was studied to assess the diagnostic value of in situ hybridization (ISH) and its relationship with viral replication and histological liver damage. Liver biopsies of 119 patients (55 hepatitis B surface antigen -HBsAg- seropositive and 64 HBsAg seronegative) were studied retrospectively. Among the HBsAg seropositive patients, the ISH was positive in 26 cases (47%) and negative in 29 (53%) and the former group had higher levels of serum transaminases. The hepatocyte number with positivity for HBsAg and hepatitis B core antigen (HBcAg) in the liver were similar in both ISH-positive and -negative patients. The histological activity index (Knodell) was higher in ISH-positive patients (11 vs 7, p < 0.001). Six patients out of 12 were positive by PCR. In the HBsAg seronegative patients, the ISH was negative in 57 cases and positive in 7. These 7 were positive for anti-HBs (5 cases) and/or anti-HBc (6 cases); 4 were confirmed by PCR. Thus, our data suggest that the ISH technique is useful for detecting viral nucleic acid in the liver, but that the HBV-DNA cannot always be considered as a replication marker, because we also show that some HBsAg seronegative patients with chronic liver disease do have HBV-DNA in their liver cells.

Antiproliferative effect of topic hyaluronic acid gel. Study in gingival biopsies of patients with periodontal disease.

Hyaluronic acid (HA) is the most abundant glycosaminoglycan of high molecular weight in the extracellular matrix of soft periodontal tissues. Our group recently demonstrated an HA-induced reduction in lymphoplasmocyte inflammatory infiltrate in periodontal disease. The objective of this study was to determine the effect of an HA gel of high molecular weight on cell proliferation, inflammation, and different periodontal lesion parameters. A double-blind clinical trial was conducted on the effect of an HA gel on cell proliferation in gingival biopsies from 28 patients with periodontal disease. A split-mouth design was used, randomly applying the gel to one quadrant and a placebo to the contralateral one. A gingival biopsy was taken for histopathological and immunohistochemical study, in order to determine the expression of cell proliferation antigen Ki-67 and to evaluate the inflammatory infiltrate. HA gel treatment induced a significant reduction in the proliferation index of the gingival epithelium, with 276 (range 234-317) Ki-67-positive cells per mm2 in treated samples versus 514 (range 158-876) per mm2 in controls (Mann-Whitney U test, p<0.003). In 13 patients, the number of Ki-67-positive fibroblastic cells was reduced by the treatment, whereas in 6 patients no differences were found (global difference, p=0.12). In 10 patients, Ki-67-positive cells were decreased in chronic inflammatory infiltrate present in the lamina propria, whereas in 6 patients no differences were found (global difference, p=0.054). We conclude that high molecular-weight HA gel reduces cell proliferation in epithelial cells such as fibroblasts and lymphocytes, abates the inflammatory process, and improves the periodontal lesion in patients with chronic periodontitis.

Captopril inhibits pp60(c-src) tyrosine phosphorylation in cultured human mesangial cells.

The present experiments were devoted to analyzing the mechanisms involved in the captopril-dependent inhibition of human mesangial cell proliferation. Studies were performed in cultured human mesangial cells incubated with captopril, an angiotensin II-converting enzyme inhibitor with antioxidant properties, lisinopril, a non-antioxidant angiotensin II-converting enzyme inhibitor, and tocopherol, a pure antioxidant. Both angiotensin II-converting enzyme inhibitors significantly inhibited fetal calf serum-induced [3H]thymidine uptake by human mesangial cells, in a dose- and time-dependent manner, an effect which was not observed with tocopherol. The antiproliferative effect of captopril and its ability to block tyrosine phosphorylation of human mesangial cells proteins were significantly greater than those of lisinopril. Moreover, captopril significantly prevented the fetal calf serum-induced tyrosine phosphorylation of pp60(c-src). The present results suggest that the antiproliferative ability of captopril does not completely depend on its angiotensin II-converting enzyme inhibitor properties, pointing to a possible interaction of the drug with the intracellular mechanisms responsible for the transmission of the proliferative signals.

Immunohistochemical study of 30 cases of cyclosporin A-induced gingival overgrowth.

Immunohistochemical techniques were used to study the presence of cyclosporin A (CsA) and leukocyte subsets in 30 gingival biopsies of renal transplant subjects with gingival overgrowth (GO). Statistical analysis revealed significant differences in the total number of inflammatory cells determined by monoclonal antibody CD45, the monocyte/macrophage (CD68) subset, the plasmatic cells (EMA), and the total of T-lymphocytes (CD3) (P < 0.001, Student t test) between the treated subjects and the healthy control group. Differences were found in the helper/inducer T lymphocytes CD4 (P < 0.001 Student t test) and cytotoxic/suppressor T lymphocyte (CD8) (P < 0.01, Student t test) subsets between both groups. The CD4/CD8 ratio was greater in the transplant subjects than in the control group (1.82 +/- 0.16 versus 1.35 +/- 0.05 respectively) (P < 0.05 Student t test). There was no significant difference in the populations CD16+, CD57+, and CD20+. The CD45+ CD4+, and CD68+ cells increased in number along with the degree of GO. The number of epithelial cells/mm2 which displayed a deposit of CsA increased in accordance with the degree of GO (P < 0.05, Kruskal-Wallis's test). Likewise, the intraepithelial deposit of CsA in the GO region was found to be related to the inflammatory infiltrate CD4+, CD8+, and CD68+ (r = 0.7432; r = 0.7346; r = 0.77005, respectively). Our findings suggest that the intraepithelial deposit of CsA and the inflammatory infiltrate play a predominantly pathogenic role and are both related to the degree of GO.

Presence of cytomegalovirus genome and leucocyte subsets in renal transplant biopsies. Relationship with prognosis.

The influence of immunosuppressant therapy and of the presence of CMV genome on the distribution of lymphoid subpopulations of the inflammatory infiltrate in renal graft rejection was analyzed, as was the role of both factors in the evolution and survival of the graft. The study included 22 patients treated with Cyclosporin A (CsA) and 22 patients treated with Azathioprine (AZA). Inflammatory infiltrate was studied by immunostaining with a panel of monoclonal antibodies, and CMV DNA was detected by in situ hybridization on tissue sections. In patients treated with CsA, increased cellularity was found at both glomerular and interstitial levels, consisting mainly of macrophages and T-cells, which was consistent with the higher rate of glomerulointerstitial rejection found in this group. In contrast, the vascular type of rejection predominated in AZA treated patients. However, the presence of CMV DNA did not influence the phenotype of the inflammatory infiltrate, and was not associated with any specific lesion. Furthermore, the final outcome of the renal graft was independent of the detection of CMV. Therefore, this study provides no evidence of any active role of the CMV genome in renal graft rejection, and suggests that therapy should be adapted to the type of rejection as defined on morphologic and immunophenotypic grounds.

Small-cell epidermoid carcinoma with melanocyte colonization arising in a mature ovarian cystic teratoma.

A case of small-cell epidermoid carcinoma, a rare tumor of the aerodigestive tract, is presented arising in a mature cystic teratoma of the ovary in a 69-year-old woman. Microscopically the small-cell epidermoid carcinoma had a uniform cell population with focal differentiation into keratinous cells. Both the small and keratinized cells were positive for epithelial membrane antigen and CAM 5.2 but negative for vimentin and neuroendocrine markers. This tumor is different from other recently described primary and metastatic small-cell tumors of the ovary. Furthermore, this small-cell epidermoid carcinoma behaved in a nonaggressive fashion. Melanocyte colonization seen in the small-cell epidermoid carcinoma areas of the tumor was a result of its invasion of preexistent areas of a teratoid blue nevus. The staining pattern of HMB-45 demonstrated that pigment was transferred to, but not produced by, the neoplastic small cells.

Correlation of morphological findings with functional reserve in the aging donor: role of the poly (ADP-ribose) polymerase.

INTRODUCTION: The enzyme poly (ADP-ribose) polymerase (PARP-1) participates in the first events of DNA repair in higher organisms. Under conditions of tissue ischemia, this action can lead to significant decreases in NAD(+), massive adenosine triphosphate (ATP) depletion, and cell death. In renal grafts with pretransplantation cold ischemia and subsequent ischemia-reperfusion injury, overactivation of PARP-1 may lead to a higher index of acute tubular necrosis, a delay in total recovery of the function of the transplanted organ, and an early progression to chronic graft nephropathy. The present study examined whether increased tubular expression of PARP-1 in kidneys from aged donors contributed to recipient renal function. MATERIAL AND METHOD: We studied the nuclear expression of PARP-1 using immunohistochemistry with monoclonal antibody PAR01 in 75 kidney biopsy specimens from 40 aged donors. RESULTS: Immunohistochemical expression of PARP-1 showed a statistically significant relationship with donor age (r =.408, P =.006, Spearman test), with time required to achieve effective diuresis (r =.386, P =.01, Spearman test) and with creatinine levels in the first 3 months. We also highlighted a greater intensity of PARP-1 expression in suboptimal donor kidneys that failed to reduce the serum creatinine levels to <1.7 mg/dL (creatinine <1.7 PARP: 1.29 +/- 1.49 vs creatinine >1.7 PARP: 2.29 +/- 1.33, P =.047, Mann-Whitney U test). CONCLUSION: We conclude that the determination of PARP-1 in biopsy specimens from aged donors may be a useful predictive factor for renal graft function.

Low serum mannose-binding lectin levels are associated with inflammation and apoptosis in early surveillance allograft biopsies.

INTRODUCTION: Mannose-binding lectin (MBL) is a protein of the innate immune system that participates in host defense and the tissue injury/repair process, enhancing the clearance of apoptotic cells by macrophages. The aim is to characterize the relationship between pre-transplant MBL levels, histological lesions and number of apoptotic cells in early surveillance renal allograft biopsies. PATIENTS AND METHODS: Consecutive renal transplant recipients were recruited and MBL levels were classified into tertiles. The first tertile was considered the low MBL group. Surveillance biopsies were done during the first 6 months and were evaluated according to Banff criteria. Renal inflammatory infiltrates were studied by immunohistochemical techniques. Apoptosis was studied using morphological methods in renal tubular cells and was expressed as the number of apoptotic cells/mm(2). RESULTS: MBL was determined in 126 patients and a surveillance biopsy with sufficient tissue was obtained in 41 of them. Patients with low pre-transplant MBL levels showed a higher acute Banff index (3.14 ± 1.96 vs. 1.88 ± 1.56, p = 0.044) and an increased proportion of biopsies with tubular cell apoptosis The proportion of biopsies with tubular cell apoptosis was higher in patients with low pre-transplant MBL levels in comparison with patients with high MBL levels (4.3 ± 3.6 versus 0.2 ± 0.9 p = 0.012) and increased interstitial number of inflammatory cells and significantly the macrophages/mm(2) (109 ± 118 vs. 32 ± 46; p = 0.04). CONCLUSION: Low pre-transplant serum MBL levels are associated with more severe inflammation and increased apoptosis in early surveillance renal allograft biopsies suggesting that MBL modulates renal inflammation after transplantation.

Peripheral nerve reconstruction with epsilon-caprolactone conduits seeded with vasoactive intestinal peptide gene-transfected mesenchymal stem cells in a rat model.

OBJECTIVE: Attempts have been made to improve nerve conduits in peripheral nerve reconstruction. We investigated the potential therapeutic effect of a vasoactive intestinal peptide (VIP), a neuropeptide with neuroprotective, trophic and developmental regulatory actions, in peripheral nerve regeneration in a severe model of nerve injury that was repaired with nerve conduits. APPROACH: The sciatic nerve of each male Wistar rat was transected unilaterally at 10 mm and then repaired with Dl-lactic-ε-caprolactone conduits. The rats were treated locally with saline, with the VIP, with adipose-derived mesenchymal stem cells (ASCs) or with ASCs that were transduced with the VIP-expressing lentivirus. The rats with the transected nerve, with no repairs, were used as untreated controls. At 12 weeks post-surgery, we assessed their limb function by measuring the ankle stance angle and the percentage of their muscle mass reduction, and we evaluated the histopathology, immunohistochemistry and morphometry of the myelinated fibers. MAIN RESULTS: The rats that received a single injection of VIP-expressing ASCs showed a significant functional recovery in the ankle stance angle (p = 0.049) and a higher number of myelinated fibers in the middle and distal segments of the operated nerve versus the other groups (p = 0.046). SIGNIFICANCE: These results suggest that utilization of a cellular substrate, plus a VIP source, is a promising method for enhancing nerve regeneration using Dl-lactic-ε-caprolactone conduits and that this method represents a potential useful clinical approach to repairing peripheral nerve damage.

Acute myocardial infarct size is related to periodontitis extent and severity.

Cardiovascular disease has been associated with 40% of deaths in high-income countries and 28% in lower-income countries. The relationship between periodontitis and acute myocardial infarction is well documented, but it has not been established whether the extent and severity of periodontitis influence the infarct size. This cross-sectional and analytic study was designed to investigate the association of chronic periodontitis extent and severity with acute myocardial infarct size as indicated by serum cardiac troponin I and myoglobin levels. Sociodemographic, periodontal, cardiologic, and hematologic variables were gathered in 112 consecutive patients with myocardial infarction. The extent (Arbes Index) and severity (Periodontal Inflammatory Severity Index) of the chronic periodontitis were significantly associated with troponin I levels after controlling for sociodemographic and clinical confounders (change in R (2) = .041, p < .02, and R (2) = .031, p = .04). However, only the extent index accounted for levels of myoglobin (change in R (2) = .030, p < .05), total leukocytes (change in R (2) = .041 p < .02), and neutrophils (change in R (2) = .059, p < .01). Mediated regression analysis showed that leukocytes and neutrophils may underlie these observed relationships of chronic periodontitis with troponin I and myoglobin. To our knowledge, this study contributes the first research data demonstrating that the extent and severity of periodontitis is positively associated with acute myocardial infarct size as measured by serum troponin I and myoglobin levels.