کشف باکتری دهان که ، عامل چاقی میشود
Is Obesity An Oral Bacterial Disease?
کشف نوعی باکتری دهانی توسط محققان و دانشمندان در دانشگاه بوستون که موجب عامل بروز بیماری چاقی است به اعتقاد این محققان این باکتری عامل بروز بیماری چاقی در افراد است که بنظر میرسد با شناخت این باکتری میتوان راحتتر با بیماری اپیدمی و شایع چاقی مبارزه کرد..جی.مکس گودسون به همراه همکارانش نتایج تحقیقات خود را در مجله «دنتال ریسرچ» چاپ و آنان اعلام خواهندنمود که این باکتری به چاق شدن افراد کمک زیادی میکند و این باکتری در بزاق افراد زندگی میکند. این محققان در این مطالعات بزاق دهان 313 فرد مبتلا به چاقی و 232 فرد سالم را مورد مطالعه و آزمایش قرار دادهاند و همچنین دیانای این افراد را نیز بررسی کردهاند. تفاوت عمده ای در هفت نفر از 40 نمونه ها در باکتری بزاق افراد چاق مشاهده گردید
علاوه بر این, بیش از 98 درصد از زنان در این وزن مشخص شده است که نمونه های موجودیت یک نوع باکتری, به نام selenomanas noxia, در سطوح مختلف بزرگتر از 1.05 درصد از کل بزاقی باکتری است.این اطلاعات بیانگر آنست که ترکیب بزاق باکتری تغییرات وزن (چاقی) زنان است. به نظر می رسد احتمال دارد که این نوع باکتری می تواند بعنوان ارتباط یک شاخص وضعیت وزن در حال توسعه(چاقی) و احتمالا علیت بنیادی بکارگرفت .دکتر goodson یادآور شد که دلایل برای یک ارتباط میان باکتری دهانی وچاقی یک امر پیچیده میباشد. شاید این رابطه را مربوط به رژیم غذایی یا به دلیل تغییر نظیر متابولیک باشد.
دکتر goodson در مرحله بعدی این تحقیق, برای پیشبرد برنامه ها بررسی این رابطه خواهد بود . علاوه بر این , وی امیدوار است که ارتباط افزایش وزن در کودکان را بررسی و ارتباط آن را با بیماری دهانی بیابد.وتا در نهایت ببینید ارتباط چاقی مربوط به.,این باکتری دهانی مشخص گردد که قطعااین شواهد باکتری دهانی ممکن است مسبب چاقی باشد.
Science News :Is Obesity An Oral Bacterial Disease?
ScienceDaily (July 9, 2009) — A scientific team from The Forsyth Institute has discovered new links between certain oral bacteria and obesity. In a recent study, the researchers demonstrated that the salivary bacterial composition of overweight women differs from non-overweight women. This preliminary work may provide clues to interactions between oral bacteria and the pathology of obesity. This research may help investigators learn new avenues for fighting the obesity epidemic.
This work will be published in the Journal of Dental Research."There has been a world-wide explosion of obesity, with many contributing factors," said Dr. J. Max Goodson, senior author of the study. "However, the inflammatory nature of the disease is also recognized. This led me to question potential unknown contributing causes of obesity. Could it be an epidemic involving an infectious agent?" "It is exciting to image the possibilities if oral bacteria are contributing to some types of obesity," added Goodson.
Summary of Study
In order to measure the salivary bacterial populations of overweight women, samples were collected from 313 women with a body mass index between 27 and 32 (classifying them as overweight). Using DNA analysis, the researchers measured the bacterial populations of this group and compared it with historical data from 232 individuals that were not overweight. Significant differences in seven of the 40 species studied occurred in the salivary bacteria of subjects in the overweight group.
In addition, more than 98 percent of the overweight women could be identified by the presence of a single bacterial species, called Selenomanas noxia, at levels greater than 1.05 percent of the total salivary bacteria. These data suggest that the composition of salivary bacteria changes in overweight women. It seems likely that these bacterial species could serve as indicators of a developing overweight condition and possibly be related to the underlying causation.
Dr. Goodson noted that the reasons for a relationship between obesity and oral bacteria are likely complex. The observed relationship may be circumstantial as being related to diet or opportunistic due to metabolic changes. In the next phase of this research, Dr. Goodson plans to further examine this relationship by initially conducting a controlled cohort study to see if this initial observation can be reproduced. In addition, he hopes to conduct longitudinal studies in children to see if oral infection relates to weight gain. Ultimately, the development of strategies to eliminate specific oral bacteria would be required to provide definitive evidence that certain oral bacteria may be responsible for weight gain.
J. Max Goodson, DDS, PhD, is a Senior Member of the Staff at The Forsyth Institute and heads up The Forsyth Clinical Research Collaborative (CRC). . Principal research personnel associated with the CRC include scientists that conduct clinical and health care delivery research.
This work was supported in part by Interleukin Genetics of Waltham, MA and by a grant from the National Institute of Dental and Craniofacial Research.
The Forsyth Institute is the world's leading independent organization dedicated to scientific research and education in oral health and related biomedical sciences
Is Obesity an Oral Bacterial Disease?
J.M. Goodson1,*, D. Groppo2, S. Halem1 and E. Carpino1
1 The Forsyth Institute, 140 The Fenway, Boston, MA 002115; and
2 Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
The world-wide explosion of overweight people has been called an epidemic. The inflammatory nature of obesity is widely recognized. Could it really be an epidemic involving an infectious agent? In this climate of concern over the increasing prevalence of overweight conditions in our society, we focus on the possible role of oral bacteria as a potential direct contributor to obesity. To investigate this possibility, we measured salivary bacterial populations of overweight women. Saliva was collected from 313 women with a body mass index between 27 and 32, and bacterial populations were measured by DNA probe analysis. Levels in this group were compared with data from a population of 232 healthy individuals from periodontal disease studies. The median percentage difference of 7 of the 40 bacterial species measured was greater than 2% in the saliva of overweight women. Classification tree analysis of salivary microbiological composition revealed that 98.4% of the overweight women could be identified by the presence of a single bacterial species (Selenomonas noxia) at levels greater than 1.05% of the total salivary bacteria. Analysis of these data suggests that the composition of salivary bacteria changes in overweight women. It seems likely that these bacterial species could serve as biological indicators of a developing overweight condition. Of even greater interest, and the subject of future research, is the possibility that oral bacteria may participate in the pathology that leads to obesity.
Key Words: bacterial physiology • obesity • overweight • infectobesity saliva • body mass index • oral health
The bacteria of the oral cavity can be altered in disease conditions such as oral cancer and dental caries. The meanings of these associations can be useful diagnostics and potentially reflect an underlying etiology. With the recognition that there are likely as many as 700 bacterial species that can inhabit the oral cavity of man (Paster et al., 2001), and the development of molecular microbiological assays based on DNA probe arrays (Paster et al., 2001; Socransky et al., 2004), the screening of individuals in various disease categories for changes in oral bacterial populations becomes a practical procedure that can provide insight into the pathological manifestations and potential etiologic consequences of the underlying disease process.
Overweight individuals were recruited from a Boston population by subway advertisement. After obtaining informed consent, we screened 410 persons, and 313 Caucasian females in good general health, between the ages of 20 and 45 yrs, with a body mass index (BMI) between 27 and 32, were recruited for this study. Women who smoked were not excluded. Individuals accepted into the study were not on long-term medication (e.g., hypertensives, psychiatric therapies) and did not have chronic or acute illnesses requiring chronic medical treatment and/or systemic therapy.
The control population consisted of 232 healthy individuals (58% female), also from Boston, greater than 18 yrs of age (40 ± 16 yrs), with at least 20 teeth (average missing, 2.0 ± 2.3) and no known systemic diseases (e.g., diabetes or AIDS). These individuals had not received systemic antibiotic therapy within the preceding 3 mos and did not require antibiotic prophylaxis. They were healthy controls for periodontal disease studies and had no pocket depth or attachment level measurements > 3 mm.
Salivary bacterial species were identified and enumerated by DNA probe analysis with whole genomic probes (Socransky et al., 2004). Each person provided a 1 to 3 mL sample of whole unstimulated saliva by expectorating into a sterile graduated cylinder. A 0.2-mL sample of whole saliva was mixed by vortex with 1.5 mL filter-sterilized Tris EDTA buffer. A 0.2-mL sample of this diluted saliva was transferred to a new tube, and 0.1 mL of 0.5 M NaOH was added. This sample was heated in a boiling water bath for 10 min, neutralized by the addition of 0.8 mL 5 M ammonium acetate, applied to the surface of a nylon membrane, and evaluated individually for the levels of 40 species of oral bacteria, by means of the "checkerboard" DNA probe set. Numbers of bacteria in each sample were determined by analysis of scanned images of samples compared with standards and computed as 100 x log10 N, with N being the number of bacteria in each of the 40 bacterial species monitored for each of the saliva samples. The DNA probe method was adjusted to detect approximately 104 bacteria (sensitivity), with 93.5% of cross-reactions exhibiting less than 5% of the homologous probe signal (specificity).
For each saliva sample, numbers of each of the 40 bacteria were divided by the sum of the numbers of all 40 bacterial species from that sample and multiplied by 100 to obtain an estimate of the percentage of that species in each sample (DNA percent). This procedure is justified for estimating percentages, since the total counts of these 40 bacteria have been found to represent 55%–60% of the bacteria in subgingival biofilms. Medians were computed as descriptive variables for bacteria in saliva samples. Differences between healthy and overweight individuals were tested by the Mann-Whitney U-test adjusted for the reduction in power due to multiple comparisons. Categorization analysis was accomplished with commercial software (CART, Salford Systems, Sunnyvale, CA, USA), with percentages of bacteria as the predictor and class (healthy or overweight) as the target variable, with the Gini algorithm.
As part of a larger study, we measured salivary bacterial populations of 313 overweight women, targeting 40 bacterial species from 6 bacterial phyla (Euzeby, 2008). The median percentage difference of 7 of the 40 species measured was greater than 2% in the saliva of overweight individuals (Fig. 1A , Table ). This included one species of Selenomonas in the phylum Firmicutes (S. noxia), two species of Actinomyces in the phylum Actinobacterium (A. gerencseriae and A. naeslundii 2), one species of Neisseria in the phylum Proteobacteria (N. mucosa), two species of Fusobacterium in the phylum Fusobacteria (F. periodonticum and F. nucleatum ss vincentii), and one species of Prevotella in the phylum Bacteroidetes (P. melaninogenica). All Firmicutes, except Eubacterium sp. and G. morbillorum, had a significantly greater median percent in overweight individuals. Significantly greater median percentages were seen in species of the other 5 phyla as well
Source: Forsyth Institute.