Metabolic syndrome: pathogenesis, medical care and dental implications

BACKGROUND: The dental literature contains little information about metabolic syndrome (MetS) and its dental implications. TYPES OF STUDIES REVIEWED: The authors conducted a MEDLINE search for the period 2000 through 2005, using the term "metabolic syndrome" to define its pathophysiology, medical treatment and dental implications. RESULTS: MetS is the co-occurrence of abdominal obesity, hyper-triglyceridemia, reduced high-density lipoprotein cholesterol levels, hypertension and impaired fasting glucose, which results from consumption of a high-calorie diet and decreased levels of physical activity superimposed on the appropriate genetic setting. Components of MetS synergistically promote the development of atherosclerosis, resulting in myocardial infarction and stroke. CLINICAL IMPLICATIONS: Deteriorating oral health status is associated with worsening of the atherogenic profile. Tooth loss often results in chewing difficulties because of inadequate occlusive surfaces and may lead to alterations in food selection and dietary quality. This, in turn, adversely affects body composition and nutritional status, both of which are related to vascular health. Dentists should develop treatment plans that preserve and restore the dentition, thus ensuring maximum masticatory efficiency and affording patients the optimum opportunity to consume food that will not foster atherogenesis.     

Saliva electrophoretic protein profiles in infants: changes with age and impact of teeth eruption and diet transition

Objective

The objective of this study was to describe the changes in salivary protein profiles in infants between the ages of 3 and 6 months, and to evaluate the impact of teeth eruption and introduction of solid foods on such profiles.

Design

73 infants were followed longitudinally at 3 and 6 months of age. Their whole saliva proteins were separated by SDS–PAGE electrophoresis and semi-quantified by image analysis. Amylase activity was also measured on a sub-sample of the population (n = 42 infants). Bands which abundance was significantly different between the two ages according to paired comparisons were identified by mass spectrometry techniques.

Results

Out of 21 bands, 13 were significantly different between 3 and 6 months of age. Two short variants of amylase increased in abundance with age, as did amylase activity. Other changes possibly translated developmental physiological events, for example maturation of the adaptive immune system. The balance between S-type cystatins and cystatins A and B was modified, in favour of S-type cystatins at 6 months of age. Teeth eruption resulted in an increase in albumin abundance, whilst introduction of solid foods was associated with higher levels of β-2 microglobulin and S-type cystatins.

Conclusions

Salivary profiles were modified substantially between the ages of 3 and 6 months. Both teeth eruption and diet had an impact on abundance changes for some proteins, revealing dynamic interactions between saliva proteome, oral physiology and diet.     

高容血液稀释对正颌外科病人血液动力学和凝血功能的影响

目的 探讨术前急性高容量血液稀释对正颌外科病人血液动力学和凝血功能的影响，评估该方法临床应用的价值。方法 选择择期行正颌外科双颔手术的病人40例，随机分为ABCD四组，每组10例。A为贺斯实验组。术前输注6％羟乙基淀粉和乳酸林格液各占总量1／2，行急性高容血液稀释；B为贺斯对照组，用6％羟乙基淀粉和乳酸林格液补充术中丢失血液和体液；C为佳乐施实验组，术前输注4％琥珀酰明胶和乳酸林格液各占总量1／2，行急性高容血液稀释；D为佳乐施对照组，用4％琥珀酰明胶和乳酸林格液补充术中丢失血液和体液。四组病例术中均采用硝普钠控制性降压，平均动脉压（MAP）控制在50～60mmHg。实验组在插管后稀释前即刘（T0），稀释后手术开始前即刻（T1），手术结束即刻（T2），术后第一日8AM（T3）时；对照组在手术开始前即刻（T1），手术结束即刘（T2），术后第一日8AM（T3）时，记录RBC、HBG、HCT及凝血指标的变化，以及血液动力学的变化。结果 MAP：A、C组T1低于T0（P〈0．01）；T2高于T1（P〈0．01）。HR：A、C组T2高于T0、T1（P〈0．01）。RBC、HGB、HCT和PLT：A、C组T1低于T0（P〈0．01），T3升高超过T1且接近T0。结论 术前急性高容量血液稀释对正颌外科病人血液动力学的稳定影响小，能减少血液的丢失。贺斯与佳乐施两种胶体液均可引起部分凝血指标的改变，但二者均不影响凝血功能。可以作为正颌外科手术选择性应用的一种有效的辅助方法。     

Cellular immunity and hypersensitivity as components of periodontal destruction

BACKGROUND: Cellular immunity has been implicated in periodontal destruction for over 25 years. Studies in the 1970s used lymphocyte transformation and lympho-kine assays to establish a role for cell-mediated mechanisms in periodontal disease. lmmunohistological studies subsequently showed that the formation of gingivitis followed a similar pattern to the formation of a delayed type hypersensitivity reaction. Further functional studies suggested that a T cell/macrophage immunoregulatory imbalance may exist locally in the periodontitis lesion and that this imbalance may be antigen specific. RECENT EVIDENCE: More recently, T cell subsets have been dichotomised on the basis of their cytokine profiles. In general, Thl cells produce IL-2 and IFN-gamma while Th2 cells produce IL-4, IL-5 and IL-6. The major function of Th l cells is to mediate delayed type hypersensitivity. In contrast the major function of Th2 cells is to provide B cell help.
HYPOTHESIS: A model for periodontal disease has now been developed based on this functional dichotomy which provides a framework for the study of cytokine profiles in periodontal disease. Early studies in this context have demonstrated a higher proportion of IL-4 producing cells in periodontitis tissues suggesting a role for Th2 cells in the progressive lesion. Clonal studies have shown that the selection of a particular cytokine profile is not antigen dependent and that differences may be due to the host susceptibility although this remains to be determined.
CONCLUSION: These emerging data clearly establish a role for cell-mediated mechanisms in the control of periodontal destruction and raise the possibility that in the future cytokine therapy for the treatment of periodontal disease in susceptible subjects may become a viable option.     

Gamma-interferon enhances expression of CD14/MyD88 and subsequent responsiveness to lipopolysaccharide from Actinobacillus actinomycetemcomitans in human gingival fibroblasts

OBJECTIVES: CD14, toll-like receptor 4 (TLR4) and MyD88 have been shown to mediate responsiveness in host cells to lipopolysaccharide. We investigated here the regulatory effects of inflammatory cytokines on the expression of membrane CD14 (mCD14), TLR4 and MyD88, and on subsequent responsiveness to lipopolysaccharide from Actinobacillus actinomycetemcomitans in human gingival fibroblasts. MATERIALS AND METHODS: Following treatment with either interleukin-1beta, tumor necrosis factor-alpha (TNF-alpha) or gamma-interferon (IFN-gamma), expression of mCD14/TLR4 and MyD88 was determined by flow cytometry and western blotting, respectively. After pretreatment with IFN-gamma, cells were pre-incubated with either anti-CD14 antibody MY4 or anti-TLR4 antibody HTA125 and subsequently treated with A. actinomycetemcomitans lipopolysaccharide. Then, phosphorylation of mitogen-activated protein (MAP) kinases and IkappaBalpha was examined by western blotting, and production of interleukin-6 and interleukin-8 was measured by their respective enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: IFN-gamma stimulated expression of mCD14, whereas -1beta and TNF-alpha did not. Expression of MyD88 but not TLR4 was also enhanced by IFN-gamma. The lipopolysaccharide activated MAP kinases, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38, and IkappaBalpha and stimulated production of interleukin-6 and interleukin-8. The lipopolysaccharide-stimulated interleukin-6 and interleukin-8 production was markedly inhibited by MY4 or HTA125. Pretreatment with IFN-gamma augmented the following activation of MAP kinases and IkappaBalpha and production of interleukin-6 and interleukin-8 in response to the lipopolysaccharide. CONCLUSIONS: These results suggest that the augmentation by IFN-gamma of the responsiveness to A. actinomycetemcomitans lipopolysaccharide, such as activation of MAP kinases and IkappaBalpha and terminal cytokine production in human gingival fibroblasts, may be partially mediated by up-regulation of CD14 and MyD88 expression.     

Immune responses to trichloroethylene and skin gene expression profiles in Sprague Dawley rats

Objective To characterize the immune reaction in SD rats exposed to trichloroethylene （TCE） and to identify the gene expression profiles involved in skin after TCE exposure. Methods Fifteen percent of TCE was injected intradermally into the rat back （100 μL/120 g） at intervals of 7 days. Whole blood was collected 24 h after the fifth or seventh intradermic administration of TCE. The percentages of CD4＋ and CD8＋ of T lymphocytes were measured by a flow cytometer. The concentrations of IFN-gamma and 1L-4 in the serum were semi-quantified by ELISA. Total RNAs of skin samples at 3 h or 24 h after the seventh dose of TCE in SD rats were extracted, and gene expression proftles of these tissues were analyszed by rat toxicology U34 array of Affymetrix. Results Obvious decline of CD4＋ in T lymphocytes was observed in the TCE-administer group. No significant concentration differences in IFN-gamma and IL-4 were found between TCE-treated and control rats. Gadd45a and Mel were significantly up regulated in skin tissue 24 h after TCE exposure. The expression regulation of immune response factors was as active as proteins associated with lipid metabolism and synthesis process in these skin samples of SD rats exposed to TCE. Conclusion T-helper type 1 cells mediate immune response can not be elicited in TCE-treated SD rats, but certain immune disorder can be induced.     

Investigation of IL4 gene polymorphism in individuals with different levels of chronic periodontitis in a Brazilian population

BACKGROUND: Cytokines are key factors that mediate the inflammatory process during periodontal disease. Recent works have shown that the levels of cytokine expression are regulated by genetic polymorphisms, and that these variations can interfere with the progression of disease. The-590 (C-->T) polymorphism of the IL4 gene is associated with high levels of IgE in asthmatic families, and the frequency of the T allele was increased in asthmatic children. The concentration of IgE in gingival tissue was found to be elevated in patients with periodontitis. OBJECTIVE: In this study the relationship between the-590 (C-->T) polymorphism in the IL4 gene and different levels of chronic periodontal disease was investigated. MATERIAL AND METHODS: DNA was extracted from buccal epithelial cells of 113 unrelated adult individuals with different levels of periodontitis. The PCR-RFLP technique was used to investigate the polymorphism in the promoter of IL4 gene. RESULTS: No significant differences in the allele and genotype frequencies of the polymorphism were found between control and groups with periodontal disease. CONCLUSION: : We conclude that the-590 (C-->T) polymorphism in the IL4 gene is not associated with the susceptibility to chronic periodontal disease.     

创伤性凝血病患者血清hs-CRP及TNF-α水平与预后的关系

目的：探讨创伤性凝血病患者血清hs-CRP及TNF-α水平及与预后的关系。方法回顾性分析50例创伤性凝血病患者的临床资料,根据患者不同预后分为存活组与死亡组,比较2组凝血功能指标及血清 TNF-α及hs-CRP水平。结果治疗28 d时,存活31例,死亡19例,病死率38％;存活组患者入院时PLT显著高于死亡组,且PT、APTT、D-dimer显著低于死亡组,差异均有统计学意义（P＜0.05）;存活组患者入院时血清hs-CRP及TNF-α水平均显著低于死亡组,差异有统计学意义（P＜0.05）。结论创伤性凝血病患者血清hs-CRP及TNF-α水平显著升高,并可作为判断患者预后的指标。