Quantitative profiling and baseline intervals of trace elements in healthy lung tissues

Background

Human lung tissue, as an interface with the environment, is susceptible to various environmental pollutants, including trace metals. However, quantitative data on trace metals in human lung tissues remain poorly described.

Methods

This study aimed to characterize the elemental composition of histologically healthy, unaffected parts of human lung tissues, associated with non-infective, non-infiltrative, and non-malignant diseases (n = 60) for essential (Cr, Mn, Fe, Co, Cu, Zn, and Se) and toxic trace elements (Sr, Ni, As, Cd, and Pb). Additionally, we investigated the influence of personal factors (sex, age, and smoking habits) on the examined trace element profiles, as well as between the trace elements correlations in the healthy human lungs.

Results

Among the analyzed trace elements, Fe was the most prevalent, while As was the least prevalent in healthy lung tissues. Stratifying by age revealed significantly higher Cr and Co (less Sr, Ni, and Pb) and lower Se levels in older individuals (above 65 years) compared to their younger counterparts. Sex-based differences were also notable, with Cu and Co 1.2- and 2.3-fold higher levels in females than in males. Exploring the impact of smoking habits revealed a striking 10-fold increase in Cd levels in the lung tissues of smokers compared to non-smokers. Correlation analyses showed significant positive associations between concentrations of certain toxic and essential trace elements in healthy lung tissues.

Conclusions

This study could contribute to the establishment of baseline intervals for essential and toxic trace elements, valuable for toxicological and clinical assessment, in healthy, unaffected human lungs, and indicates the influence of sex, age, and smoking. However, further larger-scale studies are needed to make more stable conclusions.