Blood Cadmium Levels and Oxygen Desaturation during the 6-Minute Walk Test in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Background and Objectives: chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and a history of exposure to noxious stimuli. Cigarette smoking is the most important causal factor for developing COPD. Cadmium, a minor metallic element, is one of the main inorganic components in tobacco smoke. Inhaled cadmium was associated with a decline in lung function, gas exchange impairment, and the development of obstructive lung disease. Patients with COPD who had oxygen desaturation during the 6-min walk test (6MWT) had a significantly worse prognosis than non-desaturation in COPD patients. Nonetheless, few studies have addressed the influence of blood cadmium levels on exercise-induced oxygen desaturation in COPD patients. Our objective was to assess the potential impact of blood cadmium levels on oxygen desaturation during the 6MWT among COPD patients. Materials and Methods: we performed a retrospective analysis of patients with COPD who were examined for blood cadmium levels in a tertiary care referral center in Taiwan, between March 2020 and May 2021. The 6-min walk test was performed. Normal control subjects who had no evidence of COPD were also enrolled. Results: a total of 73 COPD patients were analyzed and stratified into the high-blood cadmium group (13 patients) and low-blood cadmium group (60 patients). A total of 50 normal control subjects without a diagnosis of COPD were enrolled. The high-blood cadmium group had a significantly higher extent of desaturation than the low-blood cadmium group. The frequency of desaturation during 6MWT revealed a stepwise-increasing trend with an increase in blood cadmium levels. A multivariable logistic regression model revealed that blood cadmium levels were independently associated with desaturation during the 6MWT (odds ratio 12.849 [95% CI 1.168–141.329]; p = 0.037). Conclusions: our findings indicate that blood cadmium levels, within the normal range, were significantly associated with desaturation during 6MWT in patients with COPD.

Urinary cadmium concentration is associated with the severity and clinical outcomes of COVID-19: a bicenter observational cohort study

“…Cadmium exposure has been reported to alter reduction–oxidation (i.e., redox) balance and subsequently induce ROS overproduction, trigger oxidative stress and mitochondrial electron transport chain dysfunction, stimulate endoplasmic reticulum stress signaling pathways with ensuing apoptotic cell death, and thereby alter inflammatory responses and inhibit immune function [ 6 , 16 , 18 – 20 , 34 ]. Nickel can impair immune system function by causing oxidative stress, mitochondrial damage, and apoptosis.…”

“…Cadmium exposure inhibits innate and adaptive immunity by increasing inflammatory cytokines and chemokines, dysregulating gene expression, and increasing susceptibility to microbial invasion, including viral infection. Cadmium can upregulate the generation of reactive oxygen species (ROS) and activate oxidative stress leading to cell apoptosis, tissue damage and eventually organ dysfunction [ 6 , 16 , 18 – 20 ].…”

Urinary cadmium concentration is associated with the severity and clinical outcomes of COVID-19: a bicenter observational cohort study

“…Endothelial oxidative stress causes a reduction in vascular nitric oxide bioavailability, and this effect is proportional to the severity of COVID-19 and may participate in the pathogenesis of microvascular endothelial damage, cytokine storm, immunothrombosis, microangiopathy, and multi-organ injury during SARS-CoV-2 infection [16][17][18]. Cadmium exposure has been reported to alter reduction-oxidation (i.e., redox) balance and subsequently induce ROS overproduction, trigger oxidative stress and mitochondrial electron transport chain dysfunction, stimulate endoplasmic reticulum stress signaling pathways with ensuing apoptotic cell death, and thereby alter in ammatory responses and inhibit immune function [5,11,[13][14][15]22].…”

“…Cadmium exposure inhibits innate and adaptive immunity by increasing in ammatory cytokines and chemokines, dysregulating gene expression, and increasing susceptibility to microbial invasion, including viral infection. Cadmium can upregulate the generation of reactive oxygen species (ROS) and activate oxidative stress leading to cell apoptosis, tissue damage and eventually organ dysfunction [5,11,[13][14][15]. SARS-CoV-2 infection can also lead to the excessive production of ROS, thereby inducing oxidative stress, endothelial dysfunction, persistent in ammation, and dysfunction of antioxidant defense mechanisms [16][17][18].…”