Comparative in vitro study of the effectiveness of Green tea extract and common storage media on periodontal ligament fibroblast viability

Exposure of fexofenadine, but not pseudoephedrine, is markedly decreased by green tea extract in healthy volunteers

Green tea (GT) alters the disposition of a number of drugs such as nadolol and lisinopril. However, it is unknown whether GT affects disposition of hydrophilic anti-allergic drugs. The purpose of this study was to investigate whether pharmacokinetics of fexofenadine and pseudoephedrine are affected by catechins, major GT components. A randomized, open, 2-phase crossover study was conducted in 10 healthy Japanese volunteers. After overnight fasting, subjects were simultaneously administered fexofenadine (60 mg) and pseudoephedrine (120 mg) with an aqueous solution of green tea extract (GTE) containing (-)-epigallocatechin gallate (EGCG) of approximately 300 mg or water (control). In vitro transport assays were performed using human embryonic kidney (HEK) 293 cells stably expressing organic anion transporting polypeptide (OATP)1A2 to evaluate the inhibitory effect of EGCG on OATP1A2-mediated fexofenadine transport. In the GTE phase, the area under the plasma concentration-time curve and the amount excreted unchanged into urine for 24h of fexofenadine were significantly decreased by 70% (P < 0.001) and 67% (P < 0.001), respectively, compared with control. There were no differences in T_max and the elimination half-life of fexofenadine between phases. Fexofenadine was confirmed to be a substrate of OATP1A2, and EGCG (100 and 1000 μM) and GTE (0.1 and 1 mg/mL) inhibited OATP1A2-mediated uptake of fexofenadine. On the contrary, the concomitant administration of GTE did not influence the pharmacokinetics of pseudoephedrine. These results suggest that intake of GT may result in a markedly reduced exposure of fexofenadine, but not of pseudoephedrine, putatively by inhibiting OATP1A2-mediated intestinal absorption.

Periodontal Ligament Fibroblast Cell Viability Following Treatment with Different Concentrations of Green Tea, Aloe Vera and a Mixture of their Extracts

Objectives: Various studies have identified green tea and Aloe vera as a suitable medium for avulsed teeth. The aim of this study was to evaluate and compare the viability of periodontal ligament (PDL) fibroblasts following treatment with the extracts of these two plants and their mixture. Materials and Methods: Human PDL fibroblasts were purchased and treated with different concentrations of Aloe vera, green tea, and a combination of these two extracts. Hank's balanced salt solution and culture medium were employed as positive and negative controls, respectively. Viability was assessed using the MTT assay. Two-way ANOVA and post-hoc tests were used for statistical analysis (P<0.05). Results: There was a significant difference in PDL fibroblast viability between different concentrations of the extracts. Higher concentrations of green tea and the combination of the two extracts significantly increased cell viability. Higher concentrations of Aloe vera had the least positive effect on maintaining the viability of these cells. Conclusion: If confirmed by further studies, the combination of Aloe vera and green tea extracts might be considered as a suitable media for different purposes like storing avulsed teeth.

Efficacy of Hank's balanced salt solution compared to other solutions in the preservation of the periodontal ligament. A systematic review and meta-analysis

This systematic review and meta-analysis (MA) aimed to verify the capacity of different storage media to preserve viability of periodontal ligament cells in comparison to Hank’s Balanced Salt Solution. The searches, selection process, data extraction and Risk of Bias control were conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Five MA were conducted to compare the cell viability between milk versus Hank's balanced salt solution (HBSS) in a dichotomous (1) or continuous (2) data model; tap water versus HBSS (3); medicinal herbals versus HBSS (4); and saline solution versus HBSS (5). 693 potentially studies were identified, with 18 studies included in the qualitative and 8 studies included in the quantitative analysis. Most of the articles presented a low risk of bias. HBSS medium showed a superior ratio of cell viability compared to tap water (RR 0.26; 95% CI [0.21, 0.32]; p < 0.00001; I2 = 96%) and saline solution (RR 0.76; 95% CI [0.69, 0.84]; p < 0.0001; I2 = 99%). Herbal medicines showed a similar ratio of cell viability when compared to HBSS (RR 0.97; 95% CI [0.94, 1.00]; p = 0.08; I² = 50%). Mixed results were observed between milk and HBSS: a superior ratio of HBSS was observed in an overall evaluation (RR 0.26; 95% CI [0.21, 0.32]; p < 0.00001; I² = 96%), and a similar ratio was achieved when periodontal ligament (PDL) cells were removed prior to immersion in the solution (RR 0.94; 95% CI [0.87, 1.01]; p = 0.10; I2 = 0%) or rinsed in tap water or maintained in open air prior to immersion (RR 0.63; 95% CI [0.35, 1.12]; p = 0.11; I2 = not applicable). This systematic review and MA suggests that milk and herbal medicines could represent an alternative to HBSS. However, more studies are necessary to obtain a reliable conclusion.

Which is the most recommended medium for the storage and transport of avulsed teeth? A systematic review

BACKGROUND/AIMS

A wide variety of materials has been researched for their use as potential storage media for avulsed teeth, but it is essential to recognize the medium most recommended for improvement of the prognosis of avulsed teeth. The aim of this systematic review was to identify the most recommended medium to store and transport avulsed teeth based on the survival of periodontal ligament (PDL) cells as determined by in vitro studies.

METHODS

Only laboratory-based experimental studies on PDL cells found on adult permanent teeth were included. Data were collected using PubMed, CINAHL plus (EBSCO host), and the Cochrane Library, along with Google Scholar and a hand search. The key terms employed were permutations of [avulsed permanent teeth* OR dental avulsion* OR knocked out teeth*] AND [storage media* OR transport media* OR biological transport* OR PDL cell viability* OR PDL cell survival*]. A customized data extraction pro forma was used to extract the data and to evaluate the quality and risk of bias.

RESULTS

The initial search yielded 978 articles, but only 67 were selected. Milk was the most recommended individual medium followed by Hank's balanced salt solution. Among natural products other than milk, propolis and coconut water were most frequently recommended. Recommendations were based on maintenance of PDL cell viability followed by ease of availability, low cost, and long shelf life.

CONCLUSIONS

Natural products are more effective in maintaining the PDL cell viability compared to synthetic products. Some storage media recommendations were also based upon practical aspects. Although natural products other than milk have more recommendations as a group, milk is the most recommended storage medium individually, based not only on PDL cell viability, but also practical considerations.