Estimation of mean nuclear volume of neocortical neurons in sudden infant death syndrome cases using the nucleator estimator technique

Altered placental development in pregnancies resulting in sudden infant death syndrome (SIDS)

BACKGROUND

Sudden infant death syndrome (SIDS) is postulated to be a developmental disorder originating during fetal life in utero. Knowledge regarding the intrauterine environment in which SIDS infants develop is, however, inadequate and how the placenta develops prior to a SIDS event has not been studied.

AIM

To investigate the morphological development of the placenta obtained from full-term infants who subsequently succumbed to SIDS.

STUDY DESIGN

To estimate the percentage and total volumes of the chorionic villi and villous trophoblast membrane using stereological techniques.

SUBJECTS

Placentas were obtained retrospectively from normal birthweight (SIDS-NBW n=18) and small-for-gestational age (SIDS-SGA, n=14) infants who had succumbed to SIDS, and compared to either control (n=8) or SGA placentas (n=7), respectively.

RESULTS

SIDS-NBW placentas displayed evidence of augmented villous growth shown by significantly greater volumes of placental chorionic villi (gas-exchanging (GE) villi) in comparison to controls; this was not observed for SIDS-SGA placentas. However, both SIDS-NBW and SIDS-SGA placentas displayed significantly greater volumes of the cytotrophoblast (CT) (SIDS-NBW only), syncytiotrophoblast (SIDS-SGA only) and syncytial knots (SCT-K) and those displaying apoptotic syncytial nuclei (AP SCT-K). In contrast, SGA placentas displayed significantly reduced volumes of chorionic villi, GE villi and the villous trophoblast indicating a SIDS-specific effect associated with augmented placental growth.

CONCLUSIONS

Our findings provide initial evidence that placental abnormality, although not necessarily causative, may precede a subset of SIDS cases supporting the hypothesis that the origins of SIDS begin during fetal life in utero.

Analyses of the potential oxygen transfer capability in placentae from infants succumbing to sudden infant death syndrome

BACKGROUND

Morphometric oxygen diffusive conductance (Dp) was estimated to assess the potential efficiency of oxygen transfer across the materno-fetal interface in placentae obtained from victims of sudden infant death syndrome (SIDS).

STUDY DESIGN

SIDS placentae were retrieved from archived storage and classified into normal birth weight (NBW, n=16), or small for gestational age (SGA, n=9) and compared against control placentae (n=40) or SGA (n=24) placentae. A combination of stereological techniques and physiological constants were used to estimate total Dp.

RESULTS

SIDS NBW cases showed a crucial reduction in fetal capillary surface area when compared with control placentae. SIDS SGA showed a number of deficiencies in basic volumetric and surface area parameters. Values for total and specific Dp in placentae in both SIDS groups were maintained at levels comparable with control and SGA cases, respectively.

CONCLUSION

Since more reductions were observed in SIDS SGA group, this suggests that factors responsible for these reductions maybe associated with SGA rather than being SIDS-specific factors.