Albumin Decrease Is Associated with Spontaneous Preterm Delivery within 48 h in Women with Threatened Preterm Labor

Threatened preterm labor (TPTL) accounts
for ∼30% of pregnancy-related
hospital admissions. Maternal peripheral leukocytes can be used to
monitor a variety of physiological processes occurring in the body.
Two high-throughput mass spectrometry methodologies, SWATH and iTRAQ,
were used to study differentially expressed peripheral blood leukocyte
lysate proteins in symptomatic women admitted for TPTL who had a preterm
birth within 48 h (n = 16) and those who did not
(n = 24). The SWATH spectral library consisted of
783 proteins. SWATH methodology quantified 258 proteins (using ≥2
peptides) and 5 proteins (ALBU, ANXA6, HNRPK, HSP90A, and PDIA1) were
differentially expressed (p < 0.05, Mann–Whitney U). iTRAQ workflow identified 765 proteins; 354 proteins
were quantified and 14 proteins (MIF, UBIQ, HXK3, ALBU, HNRPD, ST1A2,
RS15A, RAP1B, CAN1, IQGA2, ST1A1, COX5A, ADDA, and UBQL1) were significantly
different between the two groups of women (p <
0.05, Mann–Whitney U). Albumin was the only
common differentially expressed protein in both SWATH (28% decrease)
and iTRAQ studies (45% decrease). This decrease in albumin was validated
using ELISA (11% decrease, p < 0.05, Mann–Whitney U) in another 23 TPTL women. This work suggests that albumin
is a broad indicator of leukocyte activation with impending preterm
birth and provides new future work directions to understand the pathophysiology
of TPTL.