Georgios Belibasakis

It is estimated that over 1 million Swedes have asthma. Approximately 1/3 has uncontrolled, whereas around 5% has severe diagnosis. The treatment of severe asthma requires the use of a high dose of inhaled medications. The side effects of such medications have frequently oral manifestation. The most notable is gingivitis, a clinical sign of compromised oral health. Gingivitis is caused by disturbance of the host-microbe balance of the oral ecosystem (‘dysbiosis’). Since the nasal and oral cavities form a common beginning of the respiratory track, a plausible hypothesis is that oral dysbiosis may trigger respiratory track dysbiosis, consequently exacerbating asthma. While gingivitis is common in asthmatic patients, the dysbiotic interplay between the mouth and the lungs is unknown. Understanding this reciprocal pathogenic process, will optimize asthma assessment, phenotyping and prevention. The Department of Dental Medicine and the Eastman Dental Institute (Folktandvården) are joint collaborators in the project which capitalizes on the SCAPIS-2 national cohort in Stockholm. The originality lies in the clinical aim to concomitantly assess oral and respiratory clinical health, focusing on adult asthmatic patients. Surprisingly, oral and respiratory health assessments are never performed together in healthcare protocols, despite that oral cavity and lungs are in a continuum. By overarching these two assessments, the project will shed light into the interconnection of the clinical status of oral and respiratory conditions. The innovation lies in the biological aim to evaluate the full profile of oral dysbiosis in asthmatic patients. Saliva is optimal for applying combined proteomics and metagenomics to decipher the host protein and microbial profile of the patients. Clinical translation will help physicians identify prognostic factors, optimize asthma phenotyping, and intensify oral healthebased prevention, advocating for wholistic evaluation of respiratory and oral health. Short-term goal is to intensify preventive oral health measures for reducing dysbiosis queues that lead to asthma exacerbation. Monitoring the salivary proteome and microbiome profiles will give added value to the prognostic accuracy of asthma. Mid-term goal is to prevent asthma exacerbations, thus avoiding the need for additional inhaled medications. Long-term goal is to reduce morbidity and mortality of asthmatic patients, contributing to their well-being throughout life.

1) Project file. Modulation of dental plaque interactions with host cells by the periodontal pathogen Tannerella forsythia 2) Content of research project. The oral cavity, similarly to other human organs, is colonized by various microorganisms. Bacterial colonization is controlled by the host immune system and most oral bacteria are beneficial for humans. However, overgrow of some microorganisms might lead to the development of periodontitis, one of the most frequent infectious diseases of adults world-wide, which results in tooth loss, if untreated. In most cases, periodontitis is associated with increased numbers of the "red complex" bacteria - Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia - in the oral biofilm (dental plaque). These bacteria possess specific virulence factors, which facilitate invasion into the human body and cause tissue destruction. Studies in the last years provided evidence that the periodontal pathogen P. gingivalis is able to manipulate distinct components of the host immune system and, consequently, changes the interaction between the oral microbial community as a whole and the immune system. This ability of P. gingivalis is now considered as a key for the progression of periodontitis. 3) Hypothesis. It is currently unclear if other members of the red complex group possess a comparable ability to manipulate the host immune system. Based on own recent data we hypothesize that the periodontal pathogen T. forsythia is an emerging candidate for research into that direction. Thus, this project is designed to investigate T. forsythia for its host-manipulative ability. 4) Methods. To test our hypothesis, we have chosen a combined cell biology / microbiology approach. We will use a biofilm model consisting of five commensal oral microorganisms into which T. forsythia will be incorporated. To delineate effects caused by this pathogen, we will compare the reactions of different human cells involved in the immune response to the biofilm, once with and once without T. forsythia. We will set-up different biofilm-cell co-culture models and we will specifically investigate the biofilm-induced response in epithelial cells, neutrophils, macrophages, and gingival cells, which form the body`s first line of defense against bacterial infection. We will measure several functional parameters involved in the host response against infection and in the control of microbial growth. 5) Explanation indicating what is new/special about the project. The data obtained in this interdisciplinary project will unravel if and how T. forsythia is involved in manipulating the host immune response and disturbing the balance between the immune system and the oral microbial community. The results of this project might pinpoint novel therapeutic and prophylaxis approaches against periodontitis. Above that, learning about new facets of microbial-host interactions will contribute to increasing our general understanding of how bacteria thrive in our body.