Department of Medicine, University of Louisville, Louisville, KY, USA.
Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA.
Inhal Toxicol. 2020 Nov-Dec;32(13-14):468-476. doi: 10.1080/08958378.2020.1845257. Epub 2020 Nov 12.
The inhalation of air-borne toxicants is associated with adverse health outcomes which can be somewhat mitigated by enhancing endogenous anti-oxidant capacity. Carnosine is a naturally occurring dipeptide (β-alanine-L-histidine), present in high abundance in skeletal and cardiac muscle. This multi-functional dipeptide has anti-oxidant properties, can buffer intracellular pH, chelate metals, and sequester aldehydes such as acrolein. Due to these chemical properties, carnosine may be protective against inhaled pollutants which can contain metals and aldehydes and can stimulate the generation of electrophiles in exposed tissues. Thus, assessment of carnosine levels, or levels of its acrolein conjugates (carnosine-propanal and carnosine-propanol) may inform on level of exposure and risk assessment.
We used established mass spectroscopy methods to measure levels of urinary carnosine ( = 605) and its conjugates with acrolein ( = 561) in a subset of participants in the Louisville Healthy Heart Study (mean age = 51 ± 10; 52% male). We then determined associations between these measures and air pollution exposure and smoking behavior using statistical modeling approaches.
We found that higher levels of non-conjugated carnosine, carnosine-propanal, and carnosine-propanol were significantly associated with males ( < 0.02) and those of Caucasian ethnicity ( < 0.02). Levels of carnosine-propanol were significantly higher in never-smokers ( = 0.001) but lower in current smokers ( = 0.037). This conjugate also demonstrated a negative association with mean-daily particulate air pollution (PM) levels ( = 0.01).
These findings suggest that urinary levels of carnosine-propanol may inform as to risk from inhaled pollutants.
空气中有毒物质的吸入与不良健康结果有关，而增强内源性抗氧化能力可以在一定程度上减轻这种影响。肌肽是一种天然存在的二肽（β-丙氨酸-L-组氨酸），在骨骼肌和心肌中含量丰富。这种多功能二肽具有抗氧化特性，可缓冲细胞内 pH 值，螯合金属，并隔离丙烯醛等醛类物质。由于这些化学特性，肌肽可能对吸入的污染物具有保护作用，这些污染物可能含有金属和醛类物质，并能刺激暴露组织中亲电物质的产生。因此，评估肌肽水平或其丙烯醛缀合物（肌肽丙醛和肌肽丙醇）的水平可以为暴露水平和风险评估提供信息。
我们使用已建立的质谱方法，测量了路易斯维尔健康心脏研究（平均年龄 = 51±10；52%为男性）参与者的尿液中肌肽（ = 605）及其与丙烯醛的缀合物（ = 561）的水平。然后，我们使用统计建模方法确定这些指标与空气污染暴露和吸烟行为之间的关联。
我们发现，未缀合的肌肽、肌肽丙醛和肌肽丙醇水平与男性（ < 0.02）和白种人（ < 0.02）显著相关。从不吸烟者的肌肽丙醇水平明显更高（ = 0.001），而当前吸烟者的水平则更低（ = 0.037）。该缀合物还与平均每日颗粒物空气污染（PM）水平呈负相关（ = 0.01）。
这些发现表明，尿液中肌肽丙醇的水平可能反映了吸入污染物的风险。
