., Role of breast milk in a mouse model of maternal transmission of asthma risk.

LEME A.S., HUBEAU C., GOLDMAN A., AND KOBZIK L

San Diego, Estados Unidos

Congreso; American Thoracic Society Meeting; 2005

American Thoracic Society

RATIONALE: Breast milk has beneficial effects on neonatal health and immunity. One exception is suggested by epidemiologic data linking nursing by asthmatic mothers to increased risk of allergy. We sought to test the contribution of breast milk mediator(s) in our mouse model of maternal transmission of asthma risk (J. Immunol 170:1683, 2003). METHODS: asthmatic mother BALB/c mice were sensitized by 2 i.p. injections of ovalbumin (OVA) in alum and repeatedly challenged with OVA aerosols prior to mating with normal males. On day 1 after birth, litters from asthmatic mothers were adoptively transferred for nursing to normal mother mice which had just given birth (NM/AB), and the normal babies were transferred for nursing to asthmatic mother mice (AM/NB). The baby mice were subjected to a suboptimal sensitization protocol (single i.p. injection of antigen, day 3) prior to aerosol challenge (days 12-14) and evaluation for airway hyperresponsiveness (AHR) and allergic airway inflammation (AI). We tested susceptibility to both OVA and an unrelated allergen, casein (Cs). RESULTS: Offspring of asthmatic, but not normal, mother mice, showed AHR and AI, indicating a maternal transfer of asthma risk. After adoptive nursing, both groups (NM/AB, AM/NB) showed AHR (Penh after methacholine aerosol, 50 mg/ml, 3.7+0.7, 4.2+0.5, respectively vs 1.1+0.1 normal controls, n=25, p<0.01) and AI, seen as eosinophilia on histology and bronchoalveolar lavage (40.7+4.5% , 28.7+3.7%, vs. 1.0+0.5% normals, n=25, p<0.01). Increased AHR and AI were observed with both OVA and Cs. CONCLUSIONS: Breast milk is sufficient, but not necessary, for maternal transmission of asthma risk to offspring in this model. Since the effect is allergen-independent, the data suggest that cytokines or other mediator(s) can be transferred across the placenta or through breast milk.