Fighting bacterial resistance is one of the concerns in modern days, as antibiotics remain the main resource of bacterial control. Data shows that for every antibiotic developed, there is a microorganism that becomes resistant to it. Natural polymers, as the source of antibacterial agents, offer a new way to fight bacterial infection. The advantage over conventional synthetic antibiotics is that natural antimicrobial agents are biocompatible, non-toxic, and inexpensive. Chitosan is one of the natural polymers that represent a very promising source for the development of antimicrobial agents. In addition, chitosan is biodegradable, non-toxic, and most importantly, promotes wound healing, features that makes it suitable as a starting material for wound dressings. This paper reviews the antimicrobial properties of chitosan and describes the mechanisms of action toward microbial cells as well as the interactions with mammalian cells in terms of wound healing process. Finally, the applications of chitosan as a wound-dressing material are discussed along with the current status of chitosan-based wound dressings existing on the market.

Chitosan as a Wound Dressing Starting Material: Antimicrobial Properties and Mode of Action

The microbiome is represented by microorganisms which live in a symbiotic way with the mammalian. Microorganisms have the ability to influence different physiological aspects such as the immune system, metabolism and behaviour. In recent years, several studies have highlighted the role of the microbiome in the pathogenesis of autoimmune diseases. Notably, in systemic lupus erythematosus an alteration of the intestinal flora (lower Firmicutes/Bacteroidetes ratio) has been described. Conversely, changes to the gut commensal and periodontal disease have been proposed as important factors in the pathogenesis of rheumatoid arthritis. At the same time, other autoimmune diseases (i.e. systemic sclerosis, Sjogren's syndrome and anti-phospholipid syndrome) also share modifications of the microbiome in the intestinal tract and oral flora. Herein, we describe the role of the microbiome in the maintenance homeostasis of the immune system and then the alterations of the microorganisms that occur in systemic autoimmune diseases. Finally, we will consider the use of probiotics and faecal transplantation as novel therapeutic targets.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/cei.13158

The microbiome in autoimmune diseases.

Modern seafood processing practices result in amassment of a large volume of waste products, i.e., skin, head, tails, shells, scales, backbones, etc. These waste products may often encompass several high-value products which are still untapped due to the dearth of appropriate management. Moreover, inadequate disposal of waste also has negative implications on both environment and human health. This seafood waste often contains a huge amount of chitin, a polysaccharide that exhibits exceptional inherent characteristics including biocompatibility, biodegradability, antimicrobial, antitumor and antioxidant activities. The present review summarizes the existing methods for recovery of chitin and its derivatives from marine waste. The preparation of chitin nanoparticles was discussed along with blending of chitin and chitosan with other biopolymers. The recent trends of the application of chitin and chitosan nanostructures in various sectors were explored. This review is an attempt to highlight the extraction methods of chitin and chitosan from marine waste resources and its transformation into valuable commercial products as a solution to waste management.

/pdf/seafood-waste-a-source-for-preparation-of-commercially-zj5mv8vwkv.pdf

Seafood waste: a source for preparation of commercially employable chitin/chitosan materials

Background: Rheumatoid arthritis (RA) and periodontitis are both chronic inflammatory disease which demonstrate similarities in terms of mechanism, histopathology and demography. An association between these conditions has been demonstrated previously but has been called into question more recently. Methods: The published databases MEDLINE, EMBASE and PsycINFO were searched using search terms related to RA and periodontitis. Articles were selected if they included data on the number of people with RA diagnosed with periodontitis (or periodontal disease parameters) compared to a control comparison group. Review articles, case reports, animal model studies, non-English language and articles with unavailable abstracts were excluded. Data was extracted, critically appraised using the Downs and Black tool and a random effect Mantel-Haenszel meta-analysis was performed. Results: 21 papers met the eligibility criteria and provided data for the meta-analysis; 17 studies (including a total of 153,492 participants) comparing RA to healthy controls and 4 (including a total of 1378 participants) comparing RA to osteoarthritis (OA). There was a significantly increased risk of periodontitis in people with RA compared to healthy controls (RR: 1.13; 95% CI: 1.04, 1.23; p=0.006; N: 153,277) with a significantly raised mean probing depth, risk of bleeding on probing (BOP) and absolute value of clinical attachment loss in those with rheumatoid arthritis. When comparing RA and OA, there was no significant difference in the prevalence of periodontitis, however the risk of BOP was greater in OA than RA. Conclusion: The significant association between RA and periodontitis is supported by the results of our systematic review and meta-analysis of studies comparing RA to healthy controls. In our meta-analysis, however, this is not replicated when comparing RA to OA controls.

/pdf/hand-to-mouth-a-systematic-review-and-meta-analysis-of-the-3bhj04z7lj.pdf

Hand to Mouth: A Systematic Review and Meta-Analysis of the Association between Rheumatoid Arthritis and Periodontitis.

Inhibition of MMPs and ADAM/ADAMTS.

Periodontitis (PD) and rheumatoid arthritis (RA) are immunoinflammatory diseases where leukocyte infiltration and inflammatory mediators induce alveolar bone loss, synovitis, and joint destruction, respectively. Thus, we reviewed the relationship between both diseases considering epidemiological aspects, mechanical periodontal treatment, inflammatory mediators, oral microbiota, and antibodies, using the keywords "periodontitis" and "rheumatoid arthritis" in PubMed database between January 2012 and March 2015, resulting in 162 articles. After critical reading based on titles and abstracts and following the inclusion and exclusion criteria, 26 articles were included. In the articles, women over 40 years old, smokers and nonsmokers, mainly constituted the analyzed groups. Eight studies broached the epidemiological relationship with PD and RA. Four trials demonstrated that the periodontal treatment influenced the severity of RA and periodontal clinical parameters. Nine studies were related with bacteria influence in the pathogenesis of RA and the presence of citrullinated proteins, autoantibodies, or rheumatoid factor in patients with PD and RA. Five studies investigated the presence of mediators of inflammation in PD and RA. In summary, the majority of the articles have confirmed that there is a correlation between PD and RA, since both disorders have characteristics in common and result from an imbalance in the immunoinflammatory response.

/pdf/relationship-between-periodontitis-and-rheumatoid-arthritis-2mfb61chzr.pdf

Relationship between Periodontitis and Rheumatoid Arthritis: Review of the Literature.

The purpose of this study was to evaluate the effect of Atorvastatin (ATV) on alveolar bone loss induced in rats. Periodontitis was induced by ligature placement around the upper second left molar in a total of 24 male Wistar rats (± 200 g). Groups of 6 animals received via oral gavage either saline or ATV (1, 3 and 9 mg/kg) during 11 days. After this time, the animals were sacrificed and their maxillae were removed, defleshed, radiographed by Digora System®, and latter stained to be photographed using a digital camera. Data were analyzed statistically by ANOVA and Bonferroni test at 5% significance level and presented as mean ± SEM. ATV (9 mg/kg) caused a significant increase on gray tone variation of over 48% (118.3 ± 12.0 gray tones) when compared to saline (79.8 ± 6.2 gray tones), indicating greater radiographic density. These data were corroborated by macroscopic findings, where ATV (9 mg/kg) reduced alveolar bone loss by over 47% (p<0.05), when compared to the group of untreated animals (saline). In summary, ATV was able to prevent alveolar bone loss seen on a ligature-induced periodontitis model.

/pdf/effect-of-atorvastatin-in-radiographic-density-on-alveolar-51ze5zzfll.pdf

Effect of Atorvastatin in radiographic density on alveolar bone loss in wistar rats

Chitosan is a naturally occurring polysaccharide obtained from chitin, present in abundance in the exoskeletons of crustaceans and insects. It has aroused great interest as a biomaterial for tissue engineering on account of its biocompatibility and biodegradation and its affinity for biomolecules. A significant number of research groups have investigated the application of chitosan as scaffolds for tissue regeneration. However, there is a wide variability in terms of physicochemical characteristics of chitosan used in some studies and its combinations with other biomaterials, making it difficult to compare results and standardize its properties. The current systematic review of literature on the use of chitosan for tissue regeneration consisted of a study of 478 articles in the PubMed database, which resulted, after applying inclusion criteria, in the selection of 61 catalogued, critically analysed works. The results demonstrated the effectiveness of chitosan-based biomaterials in 93.4% of the studies reviewed, whether or not combined with cells and growth factors, in the regeneration of various types of tissues in animals. However, the absence of clinical studies in humans, the inadequate experimental designs, and the lack of information concerning chitosan's characteristics limit the reproducibility and relevance of studies and the clinical applicability of chitosan.

/pdf/versatility-of-chitosan-based-biomaterials-and-their-use-as-487hw16gay.pdf

Versatility of Chitosan-Based Biomaterials and Their Use as Scaffolds for Tissue Regeneration.

Effect of alendronate on bone-specific alkaline phosphatase on periodontal bone loss in rats.

Background and Objective

Atorvastatin (ATV) has bone anabolic properties, and alendronate (ALD) is an important antiresorptive drug. This study aimed to evaluate the effects of the combination of ALD and ATV on ligature-induced alveolar bone loss in rats.



Material and Methods

Periodontitis was induced by ligature in 78 Wistar rats. Groups of six rats prophylactically received 0.9% saline (SAL), ALD (0.01 or 0.25 mg/kg subcutaneously) or ATV (0.3 or 27 mg/kg by gavage). Then, groups of six rats received the combination of ALD+ATV (0.25 mg/kg + 27 mg/kg, 0.01 mg/kg + 0.3 mg/kg, 0.25 mg/kg + 0.3 mg/kg or 0.01 mg/kg + 27 mg/kg) prophylactically. An extra group of six rats received therapeutic SAL or a lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) therapeutically. Three extra groups of six rats each received SAL or a lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) prophylactically or therapeutically for histometric and immunohistochemical analyses. The rats were killed on day 11 after ligature placement, and the maxillae were removed and processed for macroscopic, histomorphometric and TRAP immunohistochemical analyses. Gingival samples were collected to evaluate myeloperoxidase (MPO) activity. Blood samples were collected to measure serum bone-specific alkaline phosphatase (BALP) and transaminase levels and for hematological studies. Rats were weighed daily.



Results

All combined therapies prevented alveolar bone loss when compared with SAL or low doses of monotherapy (ALD or ATV) (p < 0.05). The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively), administered either prophylactically (39.0%) or therapeutically (53.5%), prevented alveolar bone loss. Decreases in bone and cementum resorption, in leukocyte infiltration and in immunostaining for TRAP and MPO activity corroborated the morphometric findings. The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) prevented BALP reduction (p < 0.05) and did not alter the level of serum transaminases. Moreover, the lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) also reduced neutrophilia and lymphomonocytosis and did not cause weight loss when compared with administration of SAL.



Conclusion

The lower-dose combination of ALD+ATV (0.01 mg/kg + 0.3 mg/kg, respectively) demonstrated a protective effect on alveolar bone loss.

/pdf/low-dose-combination-of-alendronate-and-atorvastatin-reduces-ynitha0vvn.pdf

Iracema Matos Melo

Papers

Relationship between Periodontitis and Rheumatoid Arthritis: Review of the Literature.

Effect of Atorvastatin in radiographic density on alveolar bone loss in wistar rats

Versatility of Chitosan-Based Biomaterials and Their Use as Scaffolds for Tissue Regeneration.

Effect of alendronate on bone-specific alkaline phosphatase on periodontal bone loss in rats.

Low-dose combination of alendronate and atorvastatin reduces ligature-induced alveolar bone loss in rats.