Huanxin Meng

Elevation of C-reactive protein and interleukin-6 in plasma of patients with aggressive periodontitis.

BACKGROUND AND OBJECTIVE Systemic levels of C-reactive protein and interleukin-6 have been reported to be elevated in patients with periodontitis compared with periodontally healthy individuals. Most studies included patients with chronic periodontitis and comprised predominantly Caucasians. The aim of this study was to determine the relative levels of C-reactive protein and interleukin-6 in plasma of patients with aggressive periodontitis in China and to examine the relationships between these two inflammatory mediators and clinical parameters, peripheral blood cells and protein variables. MATERIAL AND METHODS Plasma samples were collected from 84 patients with aggressive periodontitis and from 65 control subjects. Periodontal examination consisted of taking probing depth and attachment loss measurements. The levels of plasma C-reactive protein and interleukin-6 were determined using enzyme-linked immunosorbent assays. RESULTS The levels of plasma C-reactive protein in patients with aggressive periodontitis were significantly higher than those in control subjects (1.87 vs. 0.52 mg/L). The level of plasma interleukin-6 in patients with aggressive periodontitis was 1.20 pg/mL, higher than that in control subjects (0.08 pg/mL). Multiple linear regression analysis showed that log C-reactive protein was significantly related to severe sites percentage and albumin following correction for age, gender, body mass index and smoking (p = 0.000, p = 0.008, respectively). Log interleukin-6 was found to be significantly correlated with periodontal diagnosis, leukocyte count and level of fasting blood glucose after adjusting for the confounders (p = 0.000, p = 0.009 and p = 0.013, respectively). CONCLUSION Patients with aggressive periodontitis have significantly elevated levels of plasma C-reactive protein and interleukin-6. These elevated inflammatory factors might potentially increase the risk for cardiovascular events and glucose dysregulation in relatively young individuals.

Elevated Plasma Calcifediol Is Associated With Aggressive Periodontitis

BACKGROUND Vitamin D is associated with a number of inflammatory diseases and plays a significant role in regulating bone metabolism. Serum calcifediol was demonstrated to be potentially associated with periodontal disease. The purpose of this study was to evaluate whether an association exists between plasma calcifediol concentrations and aggressive periodontitis (AgP) and whether plasma levels of bone-related biomarkers (osteocalcin, alkaline phosphatase, calcium, and phosphorus) regulated by vitamin D are related to AgP. METHODS Sixty-six patients with generalized AgP, 52 patients with chronic periodontitis, and 60 healthy controls were included in this study. Periodontal examination consisted of probing depth, attachment loss, and bleeding index measurements. Hematic calcifediol and bone-related biomarker levels were detected using radioimmunity assay kits or a biochemical analyzer. RESULTS Plasma calcifediol levels in patients with AgP were higher than those of healthy controls (29.28 versus 21.60 nmol/l; P <0.05) and were statistically significantly correlated with bleeding index (r = 0.321; P <0.05). Plasma osteocalcin concentrations in patients with AgP were higher than those of healthy controls (0.90 versus 0.70 ng/ml; P <0.05). Serum inorganic phosphorus values of both periodontitis groups were lower than those of healthy controls (1.06 +/- 0.18 mmol/l and 1.10 +/- 0.15 mmol/l versus 1.26 +/- 0.17 mmol/l; P <0.05). CONCLUSION Plasma calcifediol levels might be associated with periodontal inflammation.

Influence of Placement Depth on Bone Remodeling Around Tapered Internal Connection Implant: A Clinical and Radiographic Study in Dogs

BACKGROUND The aim of this study is to evaluate the influence of placement depth on bone remodeling around implants with two different types of tapered internal implant-abutment interface (IAI): tapped-in (TI) tapered internal IAI and screwed-in (SI) tapered internal IAI in dogs. METHODS The second, third, and fourth premolars and the first molar in mandibles of six beagle dogs were extracted. After 8 weeks, two SI implants and two TI implants were placed in one side of the mandible. There were four experimental groups: 1) SI placed crestally (SIC); 2) TI placed crestally (TIC); 3) SI placed 1.5 mm subcrestally (SIS); and 4) TI placed 1.5 mm subcrestally (TIS). Healing abutments were connected 12 weeks after implant surgery. Implants and teeth were brushed every second day during the healing period. Clinical and radiographic parameters were recorded at 4, 10, and 16 weeks after second-stage surgery. RESULTS Differences between SI and TI implants inserted in the same vertical position were not significant for peri-implant probing depth (PD), clinical attachment level (CAL), or bone resorption (P >0.05). Subcrestal placement of both implants had greater PD and CAL compared to crestal groups. However, distance from IAI to the first bone-implant contact was lower in subcrestal groups compared to crestal groups (1.27 ± 0.42 mm for SIC versus 0.46 ± 0.26 mm for SIS, P <0.05; 1.36 ± 0.31 mm for TIC versus 0.78 ± 0.42 mm for TIS, P <0.05). CONCLUSIONS Tapered internal IAI configuration had no significant effect on crestal bone resorption. Moreover, subcrestal placement of tapered internal IAI had a positive impact on crestal bone preservation around the cervix of the implant.

Correlation between single nucleotide polymorphisms in a calprotectin subunit gene and risk of periodontitis in a Chinese population

S100A8, the light subunit of calprotectin, has been known to be associated with periodontal inflammation. The present study looked to detect whether three polymorphisms in the upstream region of the S100A8 gene are correlated with periodontitis. Three hundred and twenty one subjects, including chronic periodontitis (CP) patients, aggressive periodontitis (AgP) patients and periodontally healthy controls, were recruited. The SNPs rs3795391, rs3806232 and rs3885688 were analyzed by PCR‐RFLP analysis. No person carried the rs3885688 polymorphism in this cohort. For the other two polymorphisms, the combined effects of genotype/allele and gender were shown to be associated with the risk of periodontitis using multivariate logistic regression analysis. The G+ genotype/G allele may be considered to exert a significant protective effect in males against AgP (Genotype: rs3795391: P= 0.032, rs3806232: P= 0.017; Allele: rs3795391: P= 0.024, rs3806232: P= 0.013). Although the combined effects of genotype and gender on CP susceptibility were not observed for these two polymorphisms, there does seem to be increased risk of CP in males with allele A compared to females with allele A (rs3795391: P= 0.008; rs3806232: P= 0.009). Hence we found an important association between polymorphisms in the S100A8 gene and periodontitis in a Chinese population.

Initial Periodontal Therapy Reduced Systemic and Local 25-Hydroxy Vitamin D3 and Interleukin-1β in Patients With Aggressive Periodontitis

BACKGROUND 25-hydroxy vitamin D(3) is the major circulating metabolite of vitamin D. Elevated plasma 25-hydroxy vitamin D(3) levels were verified to be associated with generalized aggressive periodontitis (GAgP). In the present study, the influence of initial periodontal therapy on systemic and local levels of 25-hydroxy vitamin D(3) and three related elements (osteocalcin and interleukin-1beta and -6) in patients with GAgP was investigated. METHODS Nineteen patients with GAgP were enrolled. All patients received initial periodontal therapy. Gingival crevicular fluid at two sites of each subject were obtained before therapy and 2 and 6 months after therapy. Plasma was obtained before and 2 months after therapy from 12 of 19 subjects. Systemic and local levels of 25-hydroxy vitamin D(3), osteocalcin, and interleukin-1beta and -6 before and after therapy were measured using radioimmunoassay or enzyme-linked immunosorbent assay kits and compared. RESULTS The respective systemic 25-hydroxy vitamin D(3) and interleukin-1beta levels significantly dropped from baseline to 2 months after therapy (29.28 nmol/l versus 22.50 nmol/l, P = 0.001, and 6.71 ng/l versus 3.23 ng/l, P <0.001, respectively). The respective local 25-hydroxy vitamin D(3) and interleukin-1beta levels significantly decreased from baseline to 2 and 6 months after therapy (8,950 nmol/l versus 5,650 nmol/l versus 3,438 nmol/l, P <0.001, and 10,595 ng/l versus 5,495 ng/l versus 3,960 ng/l, P <0.001, respectively). Systemic and local 25-hydroxy vitamin D(3) concentrations were positively correlated at baseline (r = 0.877; P = 0.022), as was osteocalcin (r = 0.939; P = 0.005). CONCLUSIONS 25-hydroxy vitamin D(3) and interleukin-1beta levels were systemically and locally reduced in patients with GAgP by initial periodontal therapy. 25-hydroxy vitamin D(3) might be involved in periodontal inflammation.

Genetic study of families affected with aggressive periodontitis

Periodontitis is a multifactorial disease associated with several risk and susceptibility factors (66). Risk factors are part of the causal chain, or expose the host to the causal chain. The presence of a risk factor directly increases the probability of a disease occurring, and the absence of a risk factor reduces this possibility. Risk factors are modifiable. Contrary to modifiable risk factors, susceptibility factors often refer to nonmodifiable determinants or background factors, such as age, gender and genetic make-up. It is now evident that genetics form an important aspect in most diseases, including periodontitis. Elucidation of the genetic basis of periodontitis should permit a better understanding of disease etiology, allowing improved classification, diagnosis and treatment of periodontal diseases. Aggressive periodontitis (formerly termed earlyonset periodontitis, subdivided into prepubertal periodontitis, juvenile periodontitis and rapidly progressive periodontitis) is a group of infrequent types of periodontitis, characterized by early age of onset and rapid destruction of the tooth-supporting tissues in otherwise healthy individuals (5, 51). In patients with aggressive periodontitis, exposure to local irritants usually cannot account for the marked alveolar destruction, suggesting that host factors are involved in determining susceptibility to the disease. Although a variety of factors, such as microbial, environmental and behavioral factors, and systemic disease, are suggested to influence the risk of aggressive periodontitis, an individual s genetic make-up is a crucial factor influencing their systemic or host responserelated risk (42, 55). It is commonly believed that family studies remain the best approach for studying possible genetic causes of aggressive periodontitis. Therefore, this review focuses on family studies of aggressive periodontitis and the utility of genetic analytical methods in periodontology.

Detection of Eight Periodontal Microorganisms and Distribution of Porphyromonas gingivalis fimA Genotypes in Chinese Patients With Aggressive Periodontitis

BACKGROUND The microbiologic feature of aggressive periodontitis (AgP) in Chinese patients has not yet been determined. This study aims to investigate the prevalence of eight periodontal microorganisms and the distribution of the Porphyromonas gingivalis fimA genotype in a cohort of Chinese patients with AgP. METHODS Saliva and pooled subgingival plaque samples were collected from 81 patients with AgP (25 with incisor-first molar type and 56 with generalized type [GAgP]) and 34 periodontally healthy controls. Eight periodontal microorganisms, including Aggregatibacter actinomycetemcomitans, P. gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter rectus, Prevotella intermedia, Prevotella nigrescens, and Fusobacterium nucleatum were detected in these samples by the polymerase chain reaction (PCR). In addition, the distribution of fimA genotypes was assessed in P. gingivalis-positive individuals by PCR. RESULTS The prevalence of P. gingivalis, T. forsythia, T. denticola, C. rectus, P. intermedia, F. nucleatum, and A. actinomycetemcomitans in patients with AgP was significantly higher than that in healthy controls. The prevalence of A. actinomycetemcomitans in patients with GAgP was relatively low (30.4%) compared with other pathogens. Results of logistic regression analysis showed that younger patients were more likely to harbor A. actinomycetemcomitans (odds ratio = 2.85). Type II was the most prevalent fimA genotype of P. gingivalis in patients with AgP. CONCLUSIONS P. gingivalis, T. forsythia, T. denticola, C. rectus, P. intermedia, and F. nucleatum were the predominant periodontal pathogens of patients with GAgP in China. Type II of fimA was the most prevalent genotype of P. gingivalis in patients with AgP. The prevalence of A. actinomycetemcomitans in patients with GAgP was relatively low.

Family‐based association analysis of S100A8 genetic polymorphisms with aggressive periodontitis

BACKGROUND AND OBJECTIVE It is known that S100A8, a member of the S100 calcium-binding protein family, is associated with inflammatory diseases, including periodontitis. Our previous population-based study found an association between two polymorphisms, rs3795391 (A > G) and rs3806232 (A > G), in the upstream region of the S100A8 gene and aggressive periodontitis (AgP) in Chinese people. Based on those results, this investigation set out to analyze and corroborate whether the association also exists within families. MATERIAL AND METHODS Two hundred and four subjects from 73 nuclear families were recruited. All probands and their relatives were diagnosed according to the 1999 classification of periodontal diseases. Anticoagulated peripheral blood samples were collected from all the subjects, and DNA was extracted. The two single nucleotide polymorphisms (SNPs; rs3795391 and rs3806232) were detected and analyzed by standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Analysis of genotype/allele was performed by Family-Based Association Test (FBAT) software ( http://www.biostat.harvard.edu/~fbat/default.html). RESULTS There was a statistically significant association of the SNP rs3795391 with AgP in the additive genetic model (chi(2) = 3.9836, d.f. = 1, p = 0.0459). Allele A showed significantly preferential transmission to the AgP affected individuals (Z = 1.996, p = 0.0459). The other SNP, rs3806232, showed no significant results in all models. CONCLUSIONS This family-based association study supports the previous findings that SNP rs3795391 (A > G) of the S100A8 gene might contribute to AgP susceptibility. This is, to our knowledge, the first investigation about AgP using FBAT in genetic analysis.

Elevation of vitamin D-binding protein levels in the plasma of patients with generalized aggressive periodontitis

BACKGROUND AND OBJECTIVE Vitamin D-binding protein (DBP) is a multifunctional and highly expressed plasma protein. Among its diverse roles, including those in the immune and inflammatory responses, it is the primary carrier of vitamin D, which has been implicated in periodontitis. We hypothesized that there is a correlation between systemic DBP levels and generalized aggressive periodontitis (GAgP). MATERIAL AND METHODS Forty-four patients with GAgP and 32 healthy controls were recruited. Clinical parameters were examined, including the mean bleeding index, probing depth, attachment loss and percentage of severely affected sites. Blood chemistry analyses were performed for each subject. Plasma levels of DBP, interleukin-6 (IL-6) and procalcitonin (PCT) were measured using ELISAs, and plasma levels of 25-hydroxy-vitamin D(3) (25(OH)D(3)) were detected using a radioimmunoassay. RESULTS Significantly higher levels of plasma DBP, IL-6, PCT and 25(OH)D(3), as well as leukocyte counts, neutrophil counts and neutrophil percentages were found in patients with GAgP compared with healthy controls (p < 0.05 for all). Multiple linear regression analysis showed that the plasma DBP levels were significantly correlated with GAgP, plasma PCT levels and smoking status (p < 0.05 for all). In the GAgP group, the plasma DBP levels in smokers were significantly higher than those in nonsmokers (p < 0.001). CONCLUSION Elevated plasma vitamin DBP levels are associated with GAgP.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear. MATERIAL AND METHODS The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8. RESULTS The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15). CONCLUSION These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.