Background: Preterm infants experience increased oxidative stress and possess limited endogenous antioxidant reserves. Breastmilk provides critical protection, but its composition under maternal nutritional stress remains poorly characterized. Objectives: To evaluate the nutritional and antioxidant profile of colostrum and mature milk from mothers with preterm births and under nutritional stress. Methods: Breastfeeding mothers from Veracruz, México, who delivered preterm infants were recruited. Dietary intake was evaluated using a food frequency questionnaire. From the total cohort ( n = 42), a subset of mothers ( n = 32) provided colostrum and mature milk samples which were analyzed for total proteins, total polyphenols, and antioxidant capacity using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Associations with maternal body mass index, dietary intake, gestational age, and socioeconomic status were examined. Results: Mothers experienced nutritional stress, with low diversity, energy dense, and nutrient-poor dietary pattern dominated by consumption of ultra-processed foods. Despite this, breastmilk retained adequate levels of protein, polyphenols, and antioxidant capacity in both colostrum and mature milk. Conclusion: Even under maternal nutritional stress, breastmilk composition remained functionally resilient, delivering adequate levels of nutritional and antioxidant components, sufficient to meet the elevated demands of preterm infants.

The suprachiasmatic nucleus (SCN) is the master regulator of the circadian system, modulating the daily timing of physiological and behavioral processes in mammals. While SCN synchronization is primarily driven by environmental light signals, sex hormones, particularly androgens, have a crucial role in regulating behavioral and reproductive processes to align with daily or seasonal cycles. SCN cell populations express receptors for sex steroid hormones, contributing to circadian synchronization mechanisms. Specifically, the activation of androgen receptors in the SCN has been shown to modulate clock gene expression and influence circadian rhythms. Rabbits, widely used in experimental research, exhibit unique behavioral patterns, including plasticity in circadian typology and seasonal variations in testosterone secretion. In this study, we explored, in male rabbits, the effect of castration on the daily pattern of locomotor activity and the expression of the clock protein PERIOD 1 (PER1) in the SCN. Our results show that castration significantly reduces daily locomotor activity and PER1 expression in the SCN. Moreover, a 4 h delay in the acrophase of PER1 expression was observed. We conclude that androgens have an important role in SCN synchronization mechanisms, contributing to the organization of physiological and behavioral events in this species.

Background/Objectives: Human milk contains hormonal and immune bioactives that may vary with maternal, infant and perinatal characteristics including maternal body mass index (BMI), infant sex and birth mode. However, evidence linking these factors remains inconsistent. This exploratory study evaluated if maternal, infant and perinatal characteristics were associated with milk composition. Secondarily, hypothesis-generating analyses examined if milk hormones and cytokines were associated with infant anthropometric Z-scores. Methods: This cross-sectional study included 47 healthy term, exclusively breastfed mother–infant dyads with ages ranging from 0.39 to 6.01 months. Milk hormones (ghrelin, leptin, insulin and glucagon) and cytokines (IL-1β, IL-2, IL-4, IL-6, IL-7, MCP-1, IFN-γ and TNF-α) were quantified using multiplex assays and infant anthropometry was evaluated using WHO Z-scores. Adjusted models included infant age, postpartum maternal BMI, infant sex, and birth mode. Analyte-specific complete-case samples ranged from 37 to 44. All p values were nominal, and false-discovery-rate-adjusted q values assessed multiplicity. Results: Postpartum maternal BMI was positively associated with milk leptin (β = 0.152; p < 0.001; n = 39) and cesarean delivery, relative to vaginal delivery, was associated with lower milk glucagon (β = −0.579; p < 0.001; n = 37). Milk IFN-γ showed nominal exploratory positive associations with weight-for-length Z-score (β = 0.188; p = 0.017; n = 39) and BMI-for-age Z-score (β = 0.211; p = 0.032; n = 39). Conclusions: Postpartum maternal BMI and birth mode showed robust adjusted associations with leptin and glucagon, respectively. The cross-sectional design does not establish temporal direction or clinical relevance. The IFN-γ findings require longitudinal evaluation.

Uno de los problemas más comúnmente asociados a la obesidad son las alteraciones metabólicas. Sin embargo, estas, son el resultado de una exposición constante y prolongada a la inflamación de bajo grado provocada por la obesidad ¿Esta inflamación solo causa problemas a nivel metabólico? ¿Cómo afecta la inflamación de un individuo obeso su cerebro? El presente artículo pretende abordar estas preguntas y reflexionar con el lector, sobre la complejidad del entorno moderno y la obesidad, además de aportar sugerencias para su prevención y control.