Legislators in the US have kicked off the 110th Congress with a second determined attempt to push through legislation easing the current tight restrictions on federal funding of embryonic stem-cell research.

The Stem Cell Research Enhancement Act of 2007 (H.R. 3), which is expected to be taken up by the House of Representatives this Thursday (11 January), is part of the ‘100-hour’ agenda pledged by House Democrats before last November’s mid-term election. Having assumed control of both congressional chambers, the Democrats aim to pass six major pieces of legislation addressing party priorities within the first 100 hours of floor time in the 110th session.

A parallel bill, S.5, is being introduced in the Senate. Both have cross-party support and both revive to the letter the Stem Cell Research and Enhancement Act of 2005 (H.R. 810), passed by the Senate and House last year with bipartisan majorities of 63-37 and 238-194 respectively. That was not enough votes, though, to override a presidential veto. In July, President George W. Bush exercised the first – and, to date, only – veto of his administration to quash the legislation.

Second veto seen as 'inevitable'

Given President Bush’s implacable opposition to embryonic stem cell research on the moral grounds that it involves destroying embryos – not to mention his core support from the religious right and pro-life groups – a second veto is seen as almost inevitable. The question, then, is whether its backers can muster enough votes to force the revived legislation through.

Some legislators believe this is possible with Congress now in the hands of the Democrats, although a number of the Republicans ousted in last November’s election also supported H.R. 810. Alternatively, the Stem Cell Research and Enhancement Act could be watered down – for example, by including an oversight body – to placate its opponents.

The proposed legislation would amend the Public Health Service Act so that the federal government could conduct and support research using human embryonic stem cells, subject to certain conditions. For example, the cells would have to come from embryos donated by in vitro fertilisation clinics and these embryos would have to be surplus to clinical need.

Federal backing severely restricted

At the moment, federal backing for embryonic stem cell research in the US is severely restricted under an executive order passed by President Bush in August 2001. This limited government funding to research using the 22 or so embryonic stem cell lines then available for study. Researchers say this restricted pool has now been superseded by new stem cell lines with better potential for therapeutic intervention.

Critics of embryonic stem-cell research have seized on the publication earlier this week of new research indicating that stem cells with potential to replace damaged tissue can be harvested from amniotic fluid in the womb. However, other researchers and the US Biotechnology Industry Organization (BIO) stress that the breakthrough is no reason to back off on embryonic stem cell research.

In fact, the lead author of the study published in Nature Biotechnology has already balked at amniotic fluid-derived stem cells being used as a political football. In a letter to the sponsors of H.R.3, Dr Anthony Atala from Wake Forest University School of Medicine stated: “It is very possible that research involving embryonic stem cells will have critical implications for advancing research into amniotic fluid stem cells. It is essential that National Institute of Health-funded researchers are able to fully pursue embryonic stem-cell research as a complement to research into other forms of stem cells.” By Peter Mansell