Biology of Frailty Program, Division of Geriatric Medicine and Gerontology, Johns Hopkins University, Baltimore, Maryland, USA.
J Gerontol A Biol Sci Med Sci. 2010 Aug;65(8):858-65. doi: 10.1093/gerona/glq066. Epub 2010 May 17.
Neopterin, a GTP metabolite expressed by macrophages, is a marker of immune activation. We hypothesize that levels of this serum marker alter with donor age, reflecting increased chronic immune activation in normal aging. In addition to age, we assessed gender, race, body mass index (BMI), and percentage of body fat (%fat) as potential covariates.
Serum was obtained from 426 healthy participants whose age ranged from 18 to 87 years. Anthropometric measures included %fat and BMI. Neopterin concentrations were measured by competitive ELISA. The paired associations between neopterin and age, BMI, or %fat were analyzed by Spearman's correlation or by linear regression of log-transformed neopterin, whereas overall associations were modeled by multiple regression of log-transformed neopterin as a function of age, gender, race, BMI, %fat, and interaction terms.
Across all participants, neopterin exhibited a positive association with age, BMI, and %fat. Multiple regression modeling of neopterin in women and men as a function of age, BMI, and race revealed that each covariate contributed significantly to neopterin values and that optimal modeling required an interaction term between race and BMI. The covariate %fat was highly correlated with BMI and could be substituted for BMI to yield similar regression coefficients.
The association of age and gender with neopterin levels and their modification by race, BMI, or %fat reflect the biology underlying chronic immune activation and perhaps gender differences in disease incidence, morbidity, and mortality.
Neopterin 是一种由巨噬细胞表达的 GTP 代谢物，是免疫激活的标志物。我们假设这种血清标志物的水平随供体年龄的变化而改变，反映了正常衰老过程中慢性免疫激活的增加。除了年龄，我们还评估了性别、种族、体重指数（BMI）和体脂肪百分比（%fat）作为潜在的协变量。
从年龄在 18 至 87 岁之间的 426 名健康参与者中获得血清。人体测量学测量包括 %fat 和 BMI。通过竞争性 ELISA 测量 Neopterin 浓度。通过 Spearman 相关或通过对 Neopterin 的对数转换进行线性回归分析 Neopterin 与年龄、BMI 或 %fat 的配对关联，而通过对 Neopterin 的对数转换进行多元回归模型分析总体关联作为年龄、性别、种族、BMI、%fat 和交互项的函数。
在所有参与者中，Neopterin 与年龄、BMI 和 %fat 呈正相关。对女性和男性的 Neopterin 作为年龄、BMI 和种族的函数进行多元回归建模表明，每个协变量对 Neopterin 值有显著贡献，并且最佳建模需要种族和 BMI 之间的交互项。协变量 %fat 与 BMI 高度相关，可以替代 BMI 以产生相似的回归系数。
年龄和性别与 Neopterin 水平的关联以及种族、BMI 或 %fat 对其的修饰反映了慢性免疫激活的生物学基础，以及疾病发病率、发病率和死亡率方面的性别差异的潜在原因。
