The male excess in sudden infant deaths
Sophia M Moscovis1, Sharron T Hall, Christine J Burns
11School of Biomedical Sciences, Faculty of Health, University of Newcastle, Australia.
Insights
Sudden infant death syndrome (SIDS) risk may involve inflammatory responses. This study found sex differences in cytokine production, with males showing lower inflammation, potentially linked to testosterone, impacting SIDS risk factors.
Area of Science:
- Immunology
- Developmental Biology
- Toxicology
Background:
- Sudden Infant Death Syndrome (SIDS) peaks during a vulnerable developmental stage where infants rely on innate immune responses.
- Dysregulated inflammatory responses are increasingly implicated in the pathophysiology of SIDS.
- Key SIDS risk factors include exposure to cigarette smoke, viral infections, and male sex, all potentially influencing immune function.
Purpose of the Study:
- To investigate the impact of SIDS risk factors (cigarette smoke, viral infection surrogates, and sex) on inflammatory cytokine responses.
- To compare cytokine production between male and female peripheral blood cells.
- To explore the relationship between sex hormones, specifically testosterone, and inflammatory responses in the context of SIDS.
Main Methods:
- Peripheral monocytic blood cells from healthy, non-smoking males and females were stimulated with endotoxin.
- Interferon-gamma (IFN-γ) was used as a surrogate for viral infection, and water-soluble cigarette smoke extract (CSE) for smoke exposure.
- Cytokine levels (pro-inflammatory and IL-10) were measured, and correlations with testosterone levels were analyzed.
Main Results:
- Male cells generally exhibited lower pro-inflammatory cytokine responses compared to female cells, with an inverse trend for IL-10.
- Exposure to CSE significantly reduced certain cytokine levels in male cells.
- Females showed significant correlations between testosterone levels and pro-inflammatory cytokines, unlike males.
Conclusions:
- Sex-based differences in inflammatory responses, particularly concerning testosterone levels, may play a role in SIDS susceptibility.
- The findings suggest that the interplay between testosterone, cortisol, and immune responses during a critical infant developmental period warrants further investigation.
- Understanding these immune dysregulations could inform strategies for SIDS prevention.
Abstract:
The peak age at which sudden infant death syndrome (SIDS) occurs corresponds to the developmental period in which infants are dependent on their innate responses to infection. There is a growing body of evidence indicating that dysregulation of inflammatory responses might contribute to the physiological changes leading to these sudden deaths. This study examined the effects of three important risk factors for SIDS on inflammatory responses: cigarette smoke, virus infection and male sex. Cytokine responses of peripheral monocytic blood cells of healthy, non-smoking males and females to endotoxin were measured. Surrogates for virus infection or cigarette smoke were assessed using IFN-γ or water-soluble cigarette smoke extract (CSE). For most conditions, cells from males had lower pro-inflammatory cytokine responses than those of females. An opposite trend was observed for IL-10. Significantly lower levels of some cytokines were noted for cells from male donors exposed to CSE. In females, there were significant correlations between testosterone levels and levels of pro-inflammatory cytokines, but none for males. Testosterone levels in females correspond to those among male infants in the age range at greatest risk of SIDS. The effects of the testosterone surge in male infants need to be examined in relation to changes in cortisol levels that occur during the same period of infant development.
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