Expression of cytokine genes during ontogenesis of the central nervous system

Activation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system during inflammation and altered programming of the neuroendocrine-immune axis during fetal and neonatal development: lessons learned from the model inflammagen, lipopolysaccharide

The hypothalamic-pituitary-adrenal axis (HPAA) and autonomic nervous system (ANS) are both activated during inflammation as an elaborate multi-directional communication pathway designed to restore homeostasis, in part, by regulating the inflammatory and subsequent immune response. During fetal and neonatal development programming of the HPAA, ANS and possibly the immune system is influenced by signals from the surrounding environment, as part of an adaptive mechanism to enhance the survival of the offspring. It is currently hypothesized that if this programming is either misguided, or the individual's environment is drastically altered such that neuroendocrine programming becomes maladaptive, it may contribute to the pathogenesis of certain diseases. Current research, suggests that exposure to inflammatory signals during critical windows of early life development may influence the programming of various genes within the neuroendocrine-immune axis. This review will provide, (1) an overview of the HPAA and ANS pathways that are activated during inflammation, highlighting studies that have used lipopolysaccharide as a model inflammagen and, (2) evidence to support the hypothesis that inflammatory stress during fetal and neonatal development can alter programming of the neuroendocrine-immune axis, influencing stress and immune responsiveness, and possibly disease resistance later in life.

Transplantation of embryonic spinal cord-derived neurospheres support growth of supraspinal projections and functional recovery after spinal cord injury in the neonatal rat

Great interest exists in using cell replacement strategies to repair the damaged central nervous system. Previous studies have shown that grafting rat fetal spinal cord into neonate or adult animals after spinal cord injury leads to improved anatomic growth/plasticity and functional recovery. It is clear that fetal tissue transplants serve as a scaffold for host axon growth. In addition, embryonic Day 14 (E14) spinal cord tissue transplants are also a rich source of neural-restricted and glial-restricted progenitors. To evaluate the potential of E14 spinal cord progenitor cells, we used in vitro-expanded neurospheres derived from embryonic rat spinal cord and showed that these cells grafted into lesioned neonatal rat spinal cord can survive, migrate, and differentiate into neurons and oligodendrocytes, but rarely into astrocytes. Synapses and partially myelinated axons were detected within the transplant lesion area. Transplanted progenitor cells resulted in increased plasticity or regeneration of corticospinal and brainstem-spinal fibers as determined by anterograde and retrograde labeling. Furthermore, transplantation of these cells promoted functional recovery of locomotion and reflex responses. These data demonstrate that progenitor cells when transplanted into neonates can function in a similar capacity as transplants of solid fetal spinal cord tissue.