Lungs, growth and development

Abnormal nutrient delivery may also have an effect on lung growth and development. Subtle deficiencies of vitamin A can affect airway branching and lung epithelial cell differentiation [46]. There are additional effects of vitamin A depletion on surfactant protein production which in turn could affect airway host defence [47]. Collectively, these phenomena are viewed as key abnormalities in asthma. There is, therefore, a potential for aberrant nutrient delivery to have an impact not only on IgE sensitisation to allergen but also on airway development. Clearly further research is required in this area. 

Shannon JM, Deterding RR. Epithelial-mesenchymal interactions in lung development. In McDonald JA, ed. Lung Growth and Development. New York Marcel Dekker, 1997 81-118. 

Maximizing nutritional status through pancreatic enzyme replacement and vitamin and nutritional supplements is necessary for normal growth and development and for maintaining long-term lung function. 

Vitamin A is essential for growth and development of cells and tissues. In its active form, retinoic acid (RA), it controls the regular differentiation as a ligand for retinoic acid receptors (RAR, RXR) and is involved in the integration (gap junction formation) of cell formations (Biesalski, 1996 Biesalski et al, 1999). Vitamin A plays a substantial role, especially in the respiratory epithelium and the lung. During moderate vitamin A deficiency, the incidence for diseases of the respiratory tract is considerably increased and repeated respiratory infections can be influenced therapeutically by a moderate vitamin A supplementation (Biesalski et ah, 2001 Greenberg et ah, 1997 John et ah, 1997). 

Many of the studies on the effects of chemical exposures on the growth and development of the lungs have been performed in experimental animals however, patterns of lung development differ between animals and humans. Because of these differences, extreme care must be taken when extrapolating the results from animal studies to human situations. 

This topic is included because of its potential growth and development. Interest in this has exploded in the last several years. Absorbed drug can be addressed from several viewpoints (1) effect of systemically absorbed bronchodilator on bronchodilation (or other lung effect), ordinarily achieved by local deposition, and (2) utilization of the lung as a route for systemic delivery for treatment of nonpulmonary diseases. 

Vitamin D Vitamin D is produced when ultraviolet light (UV) shines on the skin and triggers the conversion of a steroid known as ergosterol to vitamin D. Its major role is to help the body use calcium, and a deficiency causes rickets in children, the same condition caused by calcium deficiency. Vitamin D supplements are rarely needed, except by those who are almost never exposed to the sun. Both vitamin A and vitamin D are essential to normal growth and development. Overdosage of vitamin D can have serious consequences, however. Calcium deposits can form in the kidney, lungs, or tympanic membrane of the ear (leading to deafness). Infants and small children are especially susceptible to vitamin D toxicity. 

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