| Infant intrauterine growth restriction (IUGR), a complication of pregnancy, results in the delivery of hypoglycemic growth-retarded infants. Pregnant women with untreated diabetes mellitus, on the other hand, are usually hyperglycemic and are likely to deliver babies that are heavier than normal. Both conditions can be detected and monitored by ultrasound during pregnancy; however, the chemical information necessary for absolute diagnosis of these and other placenta-related complications cannot be obtained until costly and time-consuming tests are performed after delivery. And the necessary histochemical tests destroy the tissue, making further study impossible.
Researchers at Oita Medical University in Japan used Fourier-transform infrared spectroscopy (FTIR) to measure the absorbance of placental samples from women with IUGR and diabetes mellitus, as compared to normal women (Biopolymers 2001, 62, 22–28). They learned that FTIR spectral analysis is a facile, inexpensive, and nondestructive method that correlates well with histochemical measurements of “glycomaterial” content (polysaccharides, glycoproteins, and glycolipids), an important indicator of these conditions.
The team divided each placenta into three sections—the upper one-third portion (P1) closest to the maternal blood supply, the middle third (P2), and the lower third (P3). They removed tiny samples from each portion for FTIR analysis and processed the remaining tissue for histochemical staining. The researchers monitored IR peaks around 1080 cm–1, which to corresponds to glycomaterials.
Team members compared changes in the relative glycomaterial shifts and staining intensities for the three portions. IUGR placentas showed a shift of the P2 glycomaterial peak to a lower wavenumber relative to P1 and P3, as well as less histochemical staining for P2 than the peripheral sections (normal placentas showed homogeneous staining). Conversely, the middle portions of placentas from mothers with diabetes mellitus showed a dramatic increase in wavenumber to match the more intense P2 staining.
This correlation indicates potential for FTIR spectral analysis as a clinical diagnostic tool for pregnancy complications. Further studies to understand the molecular basis of the observed spectral changes will follow.
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