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Placental Malaria: Hypertension, VEGF, and Prolactin?

Posted by plosmedicine on 31 Mar 2009 at 00:05 GMT

Author: Roy Douglas Pearson
Position: -
Institution: Gerstein Science Information Center
E-mail: r.pearson@utoronto.ca
Additional Authors: n/a
Submitted Date: February 05, 2007
Published Date: February 6, 2007
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

Placental Malaria: Hypertension, VEGF, and Prolactin?

The findings byMuehlenbachs [1] et al. that placental malaria (PM) is associated with hypertension in the primigravidae (18-20y) is significant, and not to be explained at this time of writing. The authors also provide data suggesting that the maternal-fetal conflict, during chronic PM and hypertension in first-time mothers involves the VEGF pathway.

Previously [2-5], I have posited that prolactin might have a role in PM and these new findings might provide further indirect evidence for such a role. It should be remembered that there is an extensive and decades-old literature [see Horrobin’s chpt. 23, in (6)] on the role of prolactin in hypertension; and moreover specifically, the relationship between prolactin and pregnancy-related hypertension [7, 8].

Regarding the VEGF pathway, Malaguarnera et al. [9] have recently shown that prolactin induces VEGF production in human macrophages. It is conceivable that hyperprolactinemia (pituitary and or placental) could up-regulate placental macrophage production of VEGF.

Space does not permit a discussion of the well known fact of increased pregnancy related prolactin in the primigravidae, but this has been noted elsewhere [2] concerning maternal malaria.

Although there has been controversy of late [2, 10], regarding my “prolactin hypothesis” in maternal malaria, it is time definitive experiments be conducted to ascertain if prolactin is playing a role in PM, and in other infectious diseases as well.

References
1. Muehlenbachs A, Mutabinwa TK, Edmonds S, Fried M, Duffy PE (2006) Hypertension and maternal-fetal conflict during pregnancy. PLoS Med 3:e446.
2. Pearson RD (2004) Malaria in pregnancy: the “cortisol” and “prolactin” hypotheses. Clin Infect Dis 39: 146-147.
3. Pearson RD (2003) HIV (AIDS), maternal malaria and prolactin. AIDS 17: 2002-2003.
4. Pearson RD (2002) Is prolactin responsible for avian, saurian, and mammalian relapse and periodicity of fever in malarial infections? Can J Zool 80:1313-1315.
5. Pearson RD (2001) Prolactin, pregnancy and anaemia in severe malaria. Trends Parasitol 17: 362.
6. Horrobin DF (1973) Prolactin: Physiology and Clinical Significance. Lancaster: MTP Pub. 240 p.
7. Marlettini MG, Cassani A, Morselli-Labate AM, Crippa S, Contarini A, et al. (1990) Maternal and fetal prolactin in pregnancy-induced hypertension. Arch Gynecol Obstet 247: 73-81.
8. Bellmann O, Praetorius D, Sonntag M, Hansmann M, Fimmers R (1987) Relationship between prolactin in amniotic-fluid during early 2nd trimester and pregnancy-induced hypertension. Clin Exp Hypert – Part B- Hypert Preg 6:34-34.
9. Malaguarnera L, Imbesi RM, Scuto F, D’Amico F, Licata A, et al. (2004) Prolactin increases HO-1 expression and induces VEGF production in human macrophages. J Cell Biochem 93: 197-206.
10. Mavoungou E (2006) Interactions between natural killer cells, cortisol and prolactin in malaria during pregnancy. Clin Med Res 4:33-41.

Roy Douglas Pearson
Gerstein Science Information Centre
9 Kings College Circle,
Toronto, Ontario
CANADA M5S 1A5

No competing interests declared.