Relationship between adenosine and T-helper 1/T-helper 2 balance in hyperemesis gravidarum.

BACKGROUND: Adenosine modulates the T-helper (Th) 1/T-helper (Th) 2 balance. We evaluated the relationship between changes in plasma adenosine and the T-helper (Th) 1/T-helper (Th) 2 balance in hyperemesis gravidarum. METHODS: Plasma adenosine concentrations and the Th1/Th2 ratio were examined in the peripheral blood of 24 women with hyperemesis gravidarum and normal pregnancies. The proportion of CD4-positive cells that expressed intracellular cytokines (interferon gamma and interleukin 4) was analyzed by flow cytometry. The ratio of interferon-gamma-secreting cells to interleukin-4-secreting cells was taken as the Th1/Th2 ratio in vivo. The change induced by adenosine-receptor blocker 8-sulfophenyltheophylline was also measured in vitro to evaluate the possible role of adenosine in modifying the Th1/Th2 balance. RESULTS: In hyperemesis gravidarum, plasma adenosine and the proportion of interleukin-4-secreting cells were increased significantly, and the Th1/Th2 ratio was significantly lower than in normal pregnancy (p<0.05). The decrease in the proportion of IL-4-secreting cells after adenosine receptor blockade in hyperemesis gravidarum significantly exceeded that of normal pregnancy (p<0.05). CONCLUSIONS: Increased plasma adenosine may be involved in regulating the Th1/Th2 balance in hyperemesis gravidarum.

Regulation of plasma adenosine levels in normal pregnancy.

The aim of this study was to investigate the possible mechanism of the regulation of plasma adenosine concentration [ADO] in normal pregnancy. We measured the activities of circulating enzymes that are involved in the production and metabolism of adenosine, and plasma [ADO] in nonpregnant (n = 14) and normal pregnant women (n = 14) in the third trimester. In pregnant women, the activity of plasma 5'-nucleotidase and plasma [ADO] were significantly elevated and plasma adenosine deaminase activity was significantly reduced. Enzymatic activities of both plasma enzymes appear to be changed in a way that would favor increased adenosine concentrations.

Serum adenosine deaminase activity in women with pre-eclampsia.

The present study investigated serum adenosine deaminase (ADA) activity and the patterns of two ADA isoenzymes, ADA1 and ADA2, and to evaluate the possible role of cell-mediated immunity as causes of the changes in ADA activity in pre-eclampsia. We measured serum activities of total ADA, ADA1 and ADA2 in pre-eclampsia (n = 22) and normal pregnancy (n = 22). Peripheral blood monocyte counts and neopterin levels, reflecting the activation of the monocyte-macrophage cell system, were also measured. In pre-eclampsia, serum total ADA and ADA2 activities were significantly increased compared with normal pregnancy (p < 0.05), which were accompanied by increases in serum neopterin levels. These results suggest that increased total ADA activity reflects increases in ADA2 activity, which may be in part related to enhanced cell-mediated immunity during pre-eclampsia.

Plasma 5'-nucleotidase activities and uric acid levels in women with pre-eclampsia.

The present study investigated plasma activity of 5'-nucleotidase, a key enzyme in the production of adenosine, in pre-eclampsia, and evaluated the relationship between changes in 5'-nucleotidase activity, and levels of uric acid, endproduct of the purine metabolism, and the severity of pre-eclampsia. We measured plasma 5'-nucleotidase activities and uric acid levels in women with 18 normal pregnancies, mild and severe pre-eclampsia. In mild and severe pre-eclampsia, plasma 5'-nucleotidase activities and uric acid levels were significantly increased compared with those in normal pregnancy (p < 0.05). Plasma 5'-nucleotidase activity increased according to increases in uric acid levels and the severity of pre-eclampsia. These results suggest that increased plasma 5'-nucleotidase activity may, at least in part, be related to changes in purine metabolism in pre-eclampsia.