# MOLECULAR BASIS OF PLACENTAL WATER AND SOLUTE TRANSPORT

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 1993 · $141,655

## Abstract

Transplacental transport of water and solutes is central to fetal growth
and well-being. Despite this, the pathways and molecular mechanisms of
transport and the forces driving maternal-fetal exchange are still largely
unexplored. There is evidence that paracellular pathways connect the
maternal intervillous space and the fetal extracellular space, but osmotic
and diffusional forces acting via these pathways cannot account for the
observed rates of water and solute transfer. Thus it is probable that a
large fraction of w and small solute transport takes place across the
cellular syncytiotrophoblast, via solubility-diffusion, channel, or
carrier-mediated mechanisms. No information exists on the osmotic or
diffusional permeabilities of either apical or basal syncytiotrophoblast
membranes nor on the transmembrane pathways for water and solute movement.
'ne goals of this project are to define the molecular mechanisms and
pathways of water and solute =sport across the syncytiotrophoblast apical
and basal membranes and t identify the factors which regulate membrane
permeability to water and solutes. This approach is necessary as the two
syncytial surfaces are very different in both structure and function. The
key elements in the proposed analyses are the use of new optical techniques
for measurement of membrane transport and o recently developed
syncytiotrophoblast membrane preparation. "Paired" apical and basal
membrane vesicle fractions will be prepared from the same placental tissue
and used to measure the osmotic and diffusional permeabilities of water and
the permeability coefficients for a range of solutes. The effects of solute
lipophilicity and molecular volume on transport will be investigated to
determine whether solute crosses apical and basal membranes by lipid,
protein channel or carrier-mediated pathways. The gestational development
of apical and basal permeability will be determined as a framework for
exploring the relationship between membrane structure and function. Strong
evidence exists to suggest significant differences in permeability between
pre-term and full-term membranes. These differences will be exploited to
identify the molecular factors which regulate membrane permeability; the
composition and structure of pre-term apical and basal membranes will be
analyzed in parallel with the measurements of water and so permeability.
The analyses will include measurements of phospholipid and protein
composition, membrane fluidity, lipid phase separation and lateral
mobility. Ibis research will provide for the first time, quantitative
information on these basic placental transport processes in the human, and
their gestational development. In the longer term, this research will
provide the basis for an integrated placental transport model, will aid in
the analysis of transport disorders such as pre-term labor and intrauterine
growth retardation and in understanding how changes in membrane composition
and structure in vivo can affect trans...

## Key facts

- **NIH application ID:** 2199921
- **Project number:** 5R01HD026392-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **SAM.gov UEI:** KMH5K9V7S518
- **Principal Investigator:** Nicholas Illsley
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $141,655
- **Award type:** 5
- **Project period:** 1990-08-01 → 1994-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2199921

## Citation

> US National Institutes of Health, RePORTER application 2199921, MOLECULAR BASIS OF PLACENTAL WATER AND SOLUTE TRANSPORT (5R01HD026392-04). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2199921. Licensed CC0.

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