Neurotrophins and neurotransmitters in human palatine tonsils: An immunohistochemical and RT-PCR analysis

NGF and Its Receptors in the Regulation of Inflammatory Response

There is growing interest in the complex relationship between the nervous and immune systems and how its alteration can affect homeostasis and result in the development of inflammatory diseases. A key mediator in cross-talk between the two systems is nerve growth factor (NGF), which can influence both neuronal cell function and immune cell activity. The up-regulation of NGF described in inflamed tissues of many diseases can regulate innervation and neuronal activity of peripheral neurons, inducing the release of immune-active neuropeptides and neurotransmitters, but can also directly influence innate and adaptive immune responses. Expression of the NGF receptors tropomyosin receptor kinase A (TrkA) and p75 neurotrophin receptor (p75NTR) is dynamically regulated in immune cells, suggesting a varying requirement for NGF depending on their state of differentiation and functional activity. NGF has a variety of effects that can be either pro-inflammatory or anti-inflammatory. This apparent contradiction can be explained by considering NGF as part of an endogenous mechanism that, while activating immune responses, also activates pathways necessary to dampen the inflammatory response and limit tissue damage. Decreases in TrkA expression, such as that recently demonstrated in immune cells of arthritis patients, might prevent the activation by NGF of regulatory feed-back mechanisms, thus contributing to the development and maintenance of chronic inflammation.

Infant-feeding methods and childhood sleep-disordered breathing

OBJECTIVE

Childhood sleep-disordered breathing has an adverse impact on cognitive development, behavior, quality of life, and use of health care resources. Early viral infections and other immune-mediated responses may contribute to development of the chronic inflammation of the upper airway and hypertrophic upper airway lymphadenoid tissues underlying childhood sleep-disordered breathing. Breastfeeding provides immunologic protection against such early exposures. Therefore, we sought to explore whether sleep-disordered breathing severity would differ for children who were breastfed as infants.

METHODS

The parents or guardians of 196 habitually snoring children (mean +/- SD: 6.7 +/- 2.9 years old) who were undergoing overnight polysomnography at Kosair Children's Hospital Sleep Medicine and Apnea Center completed a retrospective survey on the method(s) used to feed the child as an infant.

RESULTS

Among habitually snoring children, those who were fed breast milk for at least 2 months had significantly reduced sleep-disordered breathing severity on every measure assessed, including apnea-hypopnea index, oxyhemoglobin desaturation nadir, and respiratory arousal index. Breastfeeding for longer than 5 months did not contribute additional benefits.

CONCLUSIONS

Our findings support the notion that breastfeeding may provide long-term protection against the severity of childhood sleep-disordered breathing. Future research should explore mechanism(s) whereby infant-feeding methods may affect the pathophysiology of development of childhood sleep-disordered breathing.