Physiological effects of oral glucosamine on joint health: current status and consensus on future research priorities

The aim of this paper was to provide an overview of the current knowledge and understanding of the potential beneficial physiological effects of glucosamine (GlcN) on joint health. The objective was to reach a consensus on four critical questions and to provide recommendations for future research priorities. To this end, nine scientists from Europe and the United States were selected according to their expertise in this particular field and were invited to participate in the Hohenheim conference held in August 2011. Each expert was asked to address a question that had previously been posed by the chairman of the conference. Based on a systematic review of the literature and the collection of recent data, the experts documented the effects of GlcN on cartilage ageing, metabolic/kinetic and maintenance of joint health as well as reduction of risk of OA development. After extensive debate and discussion the expert panel addressed each question and a general consensus statement was developed, agreeing on the current state-of-the-art and future areas for basic and clinical studies. This paper summarizes the available evidence for beneficial effects of GlcN on joint health and proposes new insight into the design of future clinical trials aimed at identifying beneficial physiological effect of GlcN on joint tissues.

Repeated allergen challenge in rats increases vitamin A consumption

BACKGROUND

Vitamin A plays an important role in airways epithelial repair and differentiation. Allergen challenge induces epithelial damage and shedding, which cause an increase in repair activity.

OBJECTIVE

To examine whether repeated allergen challenges could increase vitamin A consumption in a rat model.

DESIGN

Allergic bronchitis was induced in 12 animals, and 12 rats remained naive. After 14 days, repeated allergen inhalation challenges were performed in the sensitized rats for 2 weeks. On day 16, allergen challenge was performed and bronchoconstriction was measured in all 24 rats. On day 30, all rats were killed. BAL was performed and ex vivo tumor necrosis factor (TNF)-alpha and nitric oxide (NO) production was measured in the lavage cells. Liver, lung tissue, and serum were collected for measurement of vitamin A concentration.

RESULTS

The study rats showed severe bronchoconstriction after allergen challenge compared to the naive rats, and ex vivo TNF-alpha and NO production was significantly higher in the sensitized rats. Serum and lung concentrations of vitamin A were not different among the two groups. However, the vitamin A liver concentration in the study rats was significantly lower compared to the naive rats.

CONCLUSIONS

We conclude that vitamin A utilization is increased during repeated allergen challenge and allergic bronchitis, most probably due to increased demand for epithelial repair.

Concentration of interleukin-1beta and neutrophil elastase activity in gingival crevicular fluid during experimental gingivitis

BACKGROUND/AIM

The aim of the present study was to measure interleukin-1beta concentrations and neutrophil elastase activity in gingival crevicular fluid (GCF) during experimental gingivitis in humans.

MATERIAL AND METHODS

12 healthy young men participated. After prophylaxis, they performed optimal hygiene to reach plaque and gingivitis indices of or approaching zero. All oral hygiene measures were then ceased for a period of 18 days. The Quigley-Hein plaque index (PLI) and Saxer & Mühlemann papillary bleeding index (PBI) were assessed. GCF samples were taken from the mesiobuccal site of two contralateral teeth in the upper jaw by means of periopapers at baseline and on days 3, 7, 14 and 18. After measuring the gingival crevicular fluid volume (GCFV) with the Periotron 8000, the samples were analyzed in our laboratory for the detection of IL-1beta concentration by ELISA.

RESULTS

PLI and PBI showed a reduction prior to baseline reaching almost zero, both increasing from day 0 to day 18 (PLI=from 0.1 to 2.9, PBI=from 0 to 2.0). IL-1beta concentration increased from 229.25 ng/ml (day 0) to 526.13 ng/ml (day 18). Clinical data and IL-1beta concentrations were correlated with elastase activity (EA). No significant correlation could be demonstrated between the clinical parameters assessed and IL-1beta or EA (Spearman rank correlation coefficient). A correlation between GCFV and PBI from day 0 to day 18 could be demonstrated.

CONCLUSION

Overall, both IL-1beta and EA showed an increase from baseline throughout the whole study.

Retinyl palmitate supplementation by inhalation of an aerosol improves vitamin A status of preschool children in Gondar (Ethiopia)

We report successful vitamin A supplementation by inhalation of retinyl palmitate in a placebo-controlled pilot study in twenty-five preschool children (2-5 years of age) in the rural district of Gondar, Ethiopia. Preschool children (n 161) were randomly selected from 220 households. Out of this cohort, twenty-five children were randomly assigned to each of two treatment groups: one receiving retinyl palmitate by inhalation of two puffs of an aerosol containing 1 mg (3000 IU) per delivery to give a total of 2 mg (6000 IU); and the other receiving an aerosol without retinyl palmitate. Both treatments were administered every 2 weeks for 3 months. Serum retinol and retinol-binding protein concentrations in the vitamin A-treated group were 0.68 (SD 0.31) mumol/l and 59.4 (SD 24.2) mg/l before and 1.43 (SD 0.46) mumol/l (P < 0.01) and 97.3 (SD 31.2) mg/l (P < 0.05) 3 months after supplementation with retinyl palmitate, suggesting that this novel method of delivery of retinyl palmitate by inhalation is effective in improving vitamin A status.

Impaired responses to sweet taste in vitamin A-deficient rats

In brief-exposure, two-choice preference tests (sucrose solution v water), vitamin A-deficient (VAD) rats exhibited a decreased preference for sucrose relative to control rats. There was no difference in total fluid intake from both choices between the two groups, nor was any significant difference found in circumvallate taste papilla keratin size. It is concluded that the impaired preference for sucrose in VAD rats is due to a specific impairment in taste sensation rather than general malaise.

Improving medical approaches to primary CNS malignancies--retinoid therapy and more

Successfully inducing differentiation in ectodermal diseases, retinoids harbour considerable therapeutic potential in the treatment of neuroectodermal-neuroepithelial malignancies. The principal tissue retinoid, retinoic acid, can be potently upregulated in vivo by a relatively specific catabolic inhibitor, R75251 (liarozole). Both substances have been given orally over 2 years in addition to standard treatment, and have been well tolerated. Corresponding closely to plasma retinoid levels, cutaneous side effects facilitate individual dosing. We evaluate this adjuvant retinoid approach and additional efforts to improve therapy of primary CNS malignancies, including the topical administration of retinoids in gamma linolenic acid.