IL-22-expressing CD4+ AhR+ T lymphocytes are associated with RANKL-mediated alveolar bone resorption during experimental periodontitis.

BACKGROUND AND OBJECTIVE: Over the past few years, the importance of interleukin-22 (IL-22) and T-helper (Th)22 lymphocytes in the pathogenesis of periodontitis has become apparent; however, there are still aspects that are not addressed yet. Cells expressing IL-22 and aryl hydrocarbon receptor (AhR), transcription factor master switch gene implicated in the differentiation and function of Th22 lymphocytes, have been detected in periodontal tissues of periodontitis-affected patients. In addition, IL-22 has been associated with osteoclast differentiation and their bone resorptive activity in vitro. However, the destructive potential of IL-22-expressing AhR+ Th22 lymphocytes over periodontal tissues during periodontitis has not been demonstrated in vivo yet. Therefore, this study aimed to analyze whether IL-22-expressing CD4+ AhR+ T lymphocytes detected in periodontal lesions are associated with alveolar bone resorption during experimental periodontitis. MATERIAL AND METHODS: Using a murine model of periodontitis, the expression levels of IL-22 and AhR, as well as the Th1-, Th2-, Th17- and T regulatory-associated cytokines, were analyzed in periodontal lesions using qPCR. The detection of CD4+ IL-22+ AhR+ T lymphocytes was analyzed in periodontal lesions and cervical lymph nodes that drain these periodontal lesions using flow cytometry. In addition, the expression of the osteoclastogenic mediator called receptor activator of nuclear factor-κB ligand (RANKL) was analyzed by qPCR, western blot, and immunohistochemistry. Finally, alveolar bone resorption was analyzed using micro-computed tomography and scanning electron microscopy, and the bone resorption levels were correlated with IL-22 and RANKL expression. RESULTS: Higher levels of IL-22, AhR, and RANKL, as well as IL-1ß, IL-6, IL-12, IL-17, IL-23, and TNF-α, were expressed in periodontal lesions of infected mice compared with periodontal tissues of sham-infected and non-infected controls. Similarly, high RANKL immunoreaction was observed in periodontal tissues of infected mice; however, few or absent RANKL immunoreaction was observed in controls. This association between RANKL and periodontal infection was ratified by western blot. Furthermore, a higher detection of CD4+ IL-22+ AhR+ T lymphocytes was found in periodontal lesions and cervical lymph nodes that drain these periodontal lesions in infected mice compared with non-infected controls. Finally, the increased IL-22 and RANKL expression showed positive correlation between them and with the augmented alveolar bone resorption observed in experimental periodontal lesions. CONCLUSION: This study demonstrates the increase of IL-22-expressing CD4+ AhR+ T lymphocytes in periodontitis-affected tissues and shows a positive correlation between IL-22, RANKL expression, and alveolar bone resorption.

Capsular-defective Porphyromonas gingivalis mutant strains induce less alveolar bone resorption than W50 wild-type strain due to a decreased Th1/Th17 immune response and less osteoclast activity.

BACKGROUND: Encapsulation of Porphyromonas gingivalis has been demonstrated as responsible of several host immunological changes, which have been associated with the pathogenesis of periodontitis. Using a murine model of periodontitis and two isogenic non-capsulated mutants of P. gingivalis, this study aimed to analyze whether P. gingivalis encapsulation induces more severe alveolar bone resorption, and whether this bone loss is associated with a T-helper (Th)1 and Th17-pattern of immune response. METHODS: Experimental periodontal infections were generated by oral inoculation with the encapsulated W50 wild-type strain or isogenic non-encapsulated ΔPG0116-PG0120 (GPA) and ΔPG0109-PG0118 (GPC) mutants of P. gingivalis. Periodontal infections induced with the encapsulated HG184 or non-encapsulated ATCC 33277 strains of P. gingivalis were used as controls. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. The expression levels of Th1, Th2, Th17, or T regulatory-associated cytokines and RANKL, as well as the periodontal bacterial load, were quantified by quantitative polymerase chain reaction. The detection of Th1 and Th17 lymphocytes was analyzed by flow cytometry. RESULTS: In the periodontal lesions, both capsular-defective knockout mutant strains of P. gingivalis induced less alveolar bone resorption than the encapsulated W50 wild-type strain. This decreased bone loss was associated with a dismissed RANKL expression, decreased Th1- and Th17-type of cytokine expression, reduced Th1 and Th17 lymphocyte detection, and low osteoclast finding. CONCLUSION: These data demonstrate that encapsulation of P. gingivalis plays a key role in the alveolar bone resorption induced during periodontitis, and this bone loss is associated with a Th1- and Th17-pattern of immune response triggered in the periodontal lesions.

Alveolar bone resorption and Th1/Th17-associated immune response triggered during Aggregatibacter actinomycetemcomitans-induced experimental periodontitis are serotype-dependent.

BACKGROUND: Aggregatibacter actinomycetemcomitans expresses several virulence factors that may contribute to the pathogenesis of periodontitis. Based on the antigenicity of the O-polysaccharide component of the lipopolysaccharide (LPS), different A. actinomycetemcomitans serotypes have been described. Among them, serotype b has demonstrated a stronger capacity to trigger Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor production on immune cells in vitro. With a murine model of experimental periodontitis, this investigation aimed to analyze the alveolar bone resorption and the pattern of immune response triggered by the different A. actinomycetemcomitans serotypes within periodontal lesions. METHODS: For periodontal lesion induction, mice were orally infected with the different A. actinomycetemcomitans serotypes or their purified LPS. Alveolar bone resorption was analyzed using microcomputed tomography and scanning electron microscopy. Bacterial infection, receptor activator of nuclear factor-kappa B ligand (RANKL) and Th1 and Th17-associated cytokine, CC-chemokine, and CC-chemokine receptor levels were quantified by quantitative polymerase chain reaction (qPCR). T lymphocytes isolated from periodontal lesions were analyzed by flow cytometry. RESULTS: In periodontal lesions, serotype b of A. actinomycetemcomitans induced higher alveolar bone resorption and expression of RANKL compared with the other serotypes. In addition, serotype b induced greater levels of Th1- and Th17-related cytokines, CC-chemokines, and CC-chemokine receptors than the others. Similarly, higher numbers of infiltrating Th1 and Th17 lymphocytes were detected in serotype b-induced periodontal lesions. CONCLUSIONS: These results demonstrate that periodontal lesions induced with different A. actinomycetemcomitans serotypes elicited distinct alveolar bone resorption and immune response. In particular, serotype b was more pathogenic than the others and induced stronger Th1 and Th17 patterns of immune responses during experimental periodontitis.

Efficacy of a multidisciplinary treatment program in patients with severe fibromyalgia.

The purpose of this study was to evaluate the efficacy of a multidisciplinary treatment program in patients severely affected by fibromyalgia. Thirty-four fibromyalgia patients were randomly divided into two groups. The control group: 17 women who continued their medical treatment and participated in four educational sessions and the experimental group that included 17 patients who besides the former medical treatment also underwent a weekly 1-h session program for 8 weeks including massage therapy, ischemic pressure on the 18 tender points, aerobic exercise and thermal therapy. At the beginning of the program, there were no significant differences between the two groups in any of the parameters. At the end of treatment, there was a significant improvement in the experimental group in the following items: vitality, social functioning, grip strength and the 6-min walk test. At 1 month after the end of treatment, the experimental group showed significant differences in overall health perception, social functioning, grip strength and the 6-min walk test. At that time, considering the threshold for clinical efficacy set at an improvement of 30% or above for the analyzed variables, 25% of the patients met the requirement for improvement of the following: number of symptoms: Visual Analogic Scale for fatigue, Fibromyalgia Impact Questionnaire and Beck Anxiety Inventory. In conclusion, patients with severe manifestations of fibromyalgia can obtain improvement with a short-term, low-cost and simple-delivery multidisciplinary program. However, additional studies including higher numbers of patients are needed to confirm the beneficial effect of this treatment program.