Article type: Research Article
Authors: Zhu, Aiqina; 1 | Wu, Zhoub; 1; * | Zhong, Xina | Ni, Junjunb | Li, Yinglana | Meng, Jieb | Du, Cana | Zhao, Xuea | Nakanishi, Hiroshib | Wu, Shizhenga
Affiliations: [a] Institution of Geriatric Qinghai Provincial Hospital, Xining, China | [b] Department of Aging Science and Pharmacology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
Correspondence: [*] Correspondence to: Zhou Wu, MD, PhD, Department of Aging Science and Pharmacology, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan. Tel.: +81 92 642 6412; Fax: +81 92 642 6415; E-mail: email@example.com.
Note:  These authors contributed equally to this work.
Background: Systemic inflammation is known as a risk factor of cognitive decline. Objective: To investigate the effects of propolis on cognitive decline and systemic inflammation in elderly people living at high altitude.
Methods: Sixty participants (average 72.8 years) living at altitude (2,260 meters) were randomized to receive propolis (0.83 g, n = 30) or placebo (n = 30) for 24 months. Cognitive outcomes were assessed using MMSE and serum cytokine levels were measured for 24 months in a double-blind study.
Results: MMSE scores were 26.17 at baseline and 23.87 at 24 months in placebo group. Compared to placebo group, improvements of MMSE scores were significant in propolis-treated subjects (p = 0.007) with a response emerging over time (time points×group interaction, p = 0.016). In addition, the serum IL-1β and IL-6 levels were significantly different across treatments (p < 0.0001) showing upward and downward trends in placebo- and propolis-treated subjects, respectively (p < 0.0001). Serum levels of TNF-α were not significantly different across treatment (p = 0.0528) but with a response emerging over time (time points×group interaction, p = 0.016). In contrast, serum levels of TGFβ1 were significantly different across treatments (p < 0.0001) showing downward and upward trends in placebo- and propolis-treated subjects, respectively. Serum levels of IL-10 were significant for the effect of groups (p = 0.0411). Furthermore, MMSE scores correlated with the decrease in IL-1β and the increase in TGFβ1 in serum.
Conclusion: Elderly people living at high altitude developed to MCI in 24 months with exacerbation of systemic inflammation. Ingestion of propolis (>12 months) protected against cognitive decline after systemic inflammation was reduced.
Journal: Journal of Alzheimer’s Disease, vol. Preprint, no. Preprint, pp. 1-10, 2018
Accepted 9 February 2018 | Published: 4 April 2018
* THESE STATEMENTS HAVE NOT BEEN EVALUATED BY THE FOOD AND DRUG ADMINISTRATION. THIS IS NOT INTENDED TO DIAGNOSE, TREAT CURE OR PREVENT ANY DISEASE.