Research Progress on Relationship Between Iron Overload and Lower Limb Arterial Disease in Type 2 Diabetes Mellitus

Acute hyperglycemia impedes spinal cord injury recovery via triggering excessive ferroptosis of endothelial cells

Spinal cord injury (SCI) is a serious central nervous system injury that often causes sensory and motor dysfunction in patients. Diabetes seriously destroys the blood spinal cord barrier (BSCB) and aggravates SCI. Ferroptosis is a new type of programmed cell death. The role of ferroptosis in diabetes-medicated BSCB destruction has not been clearly elucidated. Here, we built a type 1 diabetes (T1D) combined with SCI rat model and confirmed that hyperglycemia exacerbates SCI-mediated BSCB destruction. Pathological mechanism demonstrated that except for apoptosis, the excessive ferroptosis is another caused factor for endothelial cells (ECs) loss under hyperglycemic condition. More importantly, ferrostatin-1(a ferroptosis inhibitor) treatment significantly inhibited the ferroptosis of ECs, and promoted the BSCB repair in T1D combined with SCI rat. The mechanism study further revealed that hyperglycemia not only induces the elevated reactive oxygen species (ROS) via activating RAGE, but also suppresses the xCT expression in system Xc- in ECs, which decreases GPX4 expression and induces ferroptosis. Additionally, hyperglycemia also accelerated the transfer of iron ions from serum to spinal cord after SCI. In summary, our results suggest that the excessive ferroptosis of ECs is essential for the severe BSCB destruction in T1D combined with spinal cord injury rat.

The relationship between whole blood iron and fasting blood glucose in community-dwelling elderly people: a cross-sectional study

Iron overload increases fasting blood glucose level in mice, leading to insulin insensitivity. However, no such relationship has been shown in the population. The relationship between whole blood iron levels and fasting blood glucose levels remained unclear. This study aimed to determine whether whole blood iron levels were associated with fasting blood glucose levels in community-dwelling older adults. This cross-sectional study was based on a community population and analyzed the distribution of whole blood iron and fasting blood glucose in a community population. A sample of 1560 community residents had their fasting blood glucose, gender, and age measured during the study. Covariates were assessed using correlation analysis, partial correlation analysis, and Student's t-test. To further investigate the impact of confounding factors in this study, we compared variations in whole blood iron levels between genders. Pearson correlation analysis showed no correlation between whole blood iron and fasting blood glucose. After adjusting for age and gender, no correlation was found between whole blood iron and fasting blood glucose as well. However, Pearson correlation analysis showed a correlation between whole blood iron and age(P<0.05, r=-0.181). whole blood iron concentrations gradually decreased with age. At the same time, mean whole blood iron concentrations were lower 420 mg/l among women and men in the community. And the mean levels of whole blood iron were higher in men(504.08 mg/l ± 45.98 mg/l) than in women(453.80 mg/l ± 38.13 mg/l). Our study indicated no association between whole blood iron. Age was a covariate, but fasting blood glucose was not, and fasting blood glucose was independently associated with whole blood iron concentrations, suggesting that older women in this community need adequate iron supplementation.

Iron homeostasis in older adults: balancing nutritional requirements and health risks

Iron plays a crucial role in many physiological processes, including oxygen transport, bioenergetics, and immune function. Iron is assimilated from food and also recycled from senescent red blood cells. Iron exists in two dietary forms: heme (animal based) and non-heme (mostly plant based). The body uses iron for metabolic purposes, and stores the excess mainly in splenic and hepatic macrophages. Physiologically, iron excretion in humans is inefficient and not highly regulated, so regulation of intestinal absorption maintains iron homeostasis. Iron losses occur at a steady rate via turnover of the intestinal epithelium, blood loss, and exfoliation of dead skin cells, but overall iron homeostasis is tightly controlled at cellular and systemic levels. Aging can have a profound impact on iron homeostasis and induce a dyshomeostasis where iron deficiency or overload (sometimes both simultaneously) can occur, potentially leading to several disorders and pathologies. To maintain physiologically balanced iron levels, reduce risk of disease, and promote healthy aging, it is advisable for older adults to follow recommended daily intake guidelines and periodically assess iron levels. Clinicians can evaluate body iron status using different techniques but selecting an assessment method primarily depends on the condition being examined. This review provides a comprehensive overview of the forms, sources, and metabolism of dietary iron, associated disorders of iron dyshomeostasis, assessment of iron levels in older adults, and nutritional guidelines and strategies to maintain iron balance in older adults.

Iron Metabolism Markers and Lower Extremity Arterial Disease in People with Type 2 Diabetes

OBJECTIVE

To determine the levels of serum iron, ferritin, total iron-binding capacity, and hepcidin in patients with type 2 diabetes mellitus (T2DM), and to elucidate the relationship of these biomarkers with lower extremity arterial disease (LEAD).

METHODS

Three hundred fifteen patients with T2DM were selected for the study and divided into non-LEAD (n = 119) and LEAD groups (n=196) based on the ankle-brachial index (ABI) results. Demographic data and clinical test results were collected from all patients. Serum iron, ferritin, total iron-binding capacity, and hepcidin levels were measured, and the transferrin saturation was calculated.

RESULTS

Hepcidin levels were substantially higher in the LEAD group (19.17 ± 8.66 ng/mL) than the non-LEAD group (15.44±7.55 ng/mL, P < 0.001), and there was a negative correlation between the ABI and serum lecithin level (r = -0.349, P < 0.001). There were no other correlations with the other iron metabolism indicators. The results of dichotomous logistic regression with LEAD as the dependent variable revealed that smoking history (OR = 4.442, P = 0.008), hypertension history (OR = 3.721, P = 0.006), cardiovascular disease history (OR = 11.126, P < 0.001), diabetes duration (OR = 1.305, P < 0.001), age (OR = 1.056, P = 0.021), hs-CRP level (OR = 1.376, P = 0.002), HbA1c concentration (OR = 1.394, P = 0.001), and hepcidin level (OR = 1.097, P = 0.003) were independent risk factors for LEAD in T2DM patients.

CONCLUSION

Serum hepcidin levels were elevated in the LEAD group compared with the non-LEAD group, and elevated hepcidin levels were associated with the development of LEAD in T2DM patients, suggesting that hepcidin may be involved in the occurrence and development of LEAD in T2DM patients.