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Faculty of Science, Mahidol University's Awards

      

 
Professor Dr. Nateetip Krishnamra
TRF Senior Research Scholar Year 2007

 

Biography and Research Summary


 

Professor Dr. Nateetip Krishnamra was born on June 1, 1951 in Bangkok. She received her primary and the first phase of her secondary education at Wattana Withayalai School in Bangkok before going for further education at Ashford School, Kent, England where she completed the G.C.E. O’ and A’levels. She received her B.Sc. in Biological Sciences with first class honours from Westfield-Queen Mary College, London University in 1974. After returning to Bangkok, Professor Dr. Nateetip Krishnamra joined the Department of Physiology, Faculty of Science, Mahidol University as a staff member in the same year. This was where she received her graduate training under the supervision of Professor Dr. Liangchai Limlomwongse, and received her M.Sc. and Ph.D. degrees in physiology in 1977 and 1980, respectively. She received a Ph.D. Student Award from the Professor Tab Nilanithi Foundation. Professor Dr. Nateetip Krishnamra was appointed Assistant Professor, Associate Professor, and Professor in 1981, 1987 and 1996, respectively. She has published 51 international papers and 11 local papers from her work on calcium and bone metabolism. As for administrative experience, she served as Deputy Dean for Policy and Planning for 2 years (1999-2000) during Professor Dr. Amaret Bhumiratana’s term as Dean of the Faculty of Science, Chair of the Faculty of Science Committee for Academic Ranking and Positions (2000-2006), and Chair of The Knowledge Management Committee (2006-2007). She served as Vice-President of the Mahidol University Senate (2004-2006), and is a member of the Mahidol University Sub-committee for Academic Ranking and Positions (2000-present). She also received the Faculty of Science’s Best Teacher Award in 2002, and a Senior Research Scholar Award from the Thailand Research Fund in 2004 and 2007. Professor Dr. Nateetip Krishnamra is married to Professor Somroek Krishnamra; they have one son, Somkrit Krishnamra.


 

The main part of her research is on prolactin (the milk-producing hormone from the anterior pituitary) and calcium metabolism, which covers new target organs of prolactin such as the intestine and bone. With her background as a physiologist, Professor Dr. Nateetip Krishnamra strongly believes that a complete understanding of the function of a hormone or any biomolecule requires experimentation at all levels of organization, i.e., the systemic or whole body, organ, tissue, cellular, and molecular levels. Thus her research publications reflect a systematic multidisciplinary approach to problem solving using in vivo, in situ, and in vitro techniques. Discipline-based investigations such as physiology, biochemistry, or molecular biology alone cannot provide conclusive answers to biomedical questions. This realization, together with the need to be able to translate the basic research findings into clinical relevancy, helped motivate her to form the Consortium for Calcium and Bone Research (COCAB), a unit in the Center of Excellence in Research at the Faculty of Science in 2003. Consortium members include basic science and clinical science researchers with shared interests in calcium/bone metabolism from Mahidol University, Srinakharinwirot Universtiy, Chulalongkorn University, Kasetsart Universtiy, and Thammasat University. The aims of COCAB are to acquire basic knowledge on the mechanism of calcium absorption, the regulation of bone remodeling and pathophysiological processes of metabolic bone diseases such as osteoporosis and bone disorders associated with distal renal tubular acidosis (dRTA).


 

Her current research is divided into 3 areas as follows:


(1) Mechanism of the intestinal calcium absorption

In vivo and in vitro animal experiments in her laboratory have led to a new classification of the active intestinal calcium transport into transcellular, voltage-dependent, and paracellular solvent drag-induced transport, with the last contributing as much as 75% of the total active transport. The current work focuses on finding out how certain tight junction-associated proteins, especially claudins, may be involved in the regulation of the charge selectivity property of the paracellular transport.


 

(2) Prolactin as a calcium regulating hormone

Her laboratory has investigated the role of prolactin as a calcium regulating hormone for the past 15 years and has produced 24 international publications, which show that prolactin can stimulate both passive and active calcium absorption through the Pl3Kinase, MAPK and possibly PKC signaling pathways. The current work focuses on how prolactin affects the expression of claudins. Prolactin also stimulates bone remodeling; however, the ultimate result is age dependent. Its stimulatory effect on bone resorption is mediated by an indirect action through inhibition of estrogen secretion, and a direct action via prolactin receptor binding on the bone forming cells, osteoblasts. Further in vitro studies in cell lines and primary osteoblasts indicate that prolactin exerts its action by altering the RANKL/osteoprotegerin ratio, resulting in osteoclast activation. The consortium members also investigate the mechanism by which prolactin stimulates the transport of calcium into milk during lactation, and sodium and chloride transport in the endometrium.


 

(3) Calcium and bone disorders in metabolic bone diseases

This part constitutes the translation between basic and clinical research. Current study focuses on finding out how proliferation and differentiation of progenitor cells and the activities of mature osteoblasts and osteoclasts are altered in chronic metabolic acidosis.


Future research


 

Future research will cover the same three areas, but to a greater depth with the use of some new technology:

(1) Study of the intestinal calcium absorption will focus on the paracellular transport mechanism, which appears to be different for passive and active transport. The roles of various combinations of claudins in the regulation of the charge selective property of the tight junction will be examined.

(2) The physiological significance of prolactin as a calcium regulating hormone and its signaling pathways will be evaluated in young growing animals, pregnant, lactating and aged animals. The interaction between prolactin and other hormones will also be examined at the cellular and molecular levels.

(3) New technology such as atomic force microscopy (AFM) and nanoindentation techniques will used to characterize the surface properties, stress and strain properties and microstructure of bone under different conditions. The development of a model of “bone membrane” for studying the control of calcium transport between blood and bone is crucial for understanding bone disorders such as osteoporosis.