DICOMOSA Group, Department of Psychology, Area of Psychobiology, Universidade da Coruña, A Coruña, Spain; Department of Cell and Molecular Biology, Universidade da Coruña, A Coruña, Spain.
Gerontology Research Group, Universidade da Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), SERGAS, A Coruña, Spain.
J Am Med Dir Assoc. 2017 Dec 1;18(12):1049-1057. doi: 10.1016/j.jamda.2017.06.021. Epub 2017 Aug 8.
Frailty is a multidimensional syndrome correlated to the loss of homeostasis and increased vulnerability to stressors, which is associated with increase in the risk of disability, comorbidity, hospitalization, and death in the elderly. It is based on the interplay of physiological, psychological, social, and environmental factors.
Because aging involves a detrimental immune response, this work aimed to assess the possible role of chronic low-grade immune stimulation on frailty status in the elderly.
Biomarkers involved in indoleamine 2,3-dioxygenase 1 and guanosine triphosphate cyclohydrolase I enzymatic pathways (namely neopterin, tryptophan, kynurenine, phenylalanine, tyrosine, and nitrite) were analyzed in a population of Spanish older adults aged 65 years and above, and their relationships with frailty status were evaluated.
Significant increases in neopterin levels, kynurenine/tryptophan ratio, and phenylalanine/tyrosine ratio, and significant decreases in tryptophan, nitrite and tyrosine concentrations in frail individuals compared with nonfrail persons were obtained. Significant correlations were also observed between immune biomarkers, indicating they change in parallel, thus, pointing to interrelated causes. Besides, reference ranges for a number of immune biomarkers in the population of robust older adults were established for the first time.
Results obtained in the present study are consistent with the idea that frailty status in the elderly is associated with an additional degree of immune stimulation, manifested in a more intense disturbance of indoleamine 2,3-dioxygenase 1 and guanosine triphosphate cyclohydrolase I pathways than in nonfrail or prefrail older adults.
衰弱是一种与内稳态丧失和对压力源的易感性增加相关的多维综合征，与老年人残疾、合并症、住院和死亡风险增加有关。它基于生理、心理、社会和环境因素的相互作用。
由于衰老涉及到有害的免疫反应，这项工作旨在评估慢性低度免疫刺激对老年人衰弱状态的可能作用。
分析了西班牙 65 岁及以上老年人中涉及吲哚胺 2,3-双加氧酶 1 和鸟苷三磷酸环化水解酶 I 酶途径的生物标志物（即新蝶呤、色氨酸、犬尿氨酸、苯丙氨酸、酪氨酸和亚硝酸盐），并评估了它们与衰弱状态的关系。
与非衰弱个体相比，衰弱个体的新蝶呤水平、犬尿氨酸/色氨酸比值和苯丙氨酸/酪氨酸比值显著升高，而色氨酸、亚硝酸盐和酪氨酸浓度显著降低。免疫生物标志物之间也存在显著相关性，表明它们平行变化，因此指向相互关联的原因。此外，还首次为健康老年人的许多免疫生物标志物建立了参考范围。
本研究的结果与以下观点一致，即老年人的衰弱状态与额外程度的免疫刺激有关，表现在吲哚胺 2,3-双加氧酶 1 和鸟苷三磷酸环化水解酶 I 途径的紊乱程度比非衰弱或衰弱前老年人更严重。
