We are apt to scoff at stories of virgin birth, and the term itself is something of an oxymoron, since the virgin usually has had some ‘knowledge’ of a male progenitor. Many of the classical Greco-Roman heroes, like Hercules, who were the product of a virgin birth, were fathered by gods, as was the Christ, according to Christian dogma. But virgin birth or, at least, reproduction that takes place in the absence of fertilization, called parthenogenesis, occurs in nature all the time, both in plants (e.g. roses and orange trees) and animals (some kinds of ants, bees and wasps). Now, researchers have discovered ways of engendering parthenogenesis in mammals.
Early work on stem cells involved human embryos and, consequently, gave rise to ethical debate and controversy that threatened further research efforts. But in a ground-breaking paper titled ‘Nonhuman Primate Parthenogenetic Stem Cells’ (http://dtn.fm/3aP4i), published in 2003, Kent Vrana et al, wrote about their stem cell work using monkeys and reported that ‘stem cells were created via parthenogenetic activation of eggs’. This use of non-human cells provided a route out of the moral dilemma. Then, building on the insights of Vrana and his colleagues, a team at the privately-held Stemron Corporation of Rockville, Maryland, led by David Wininger reported in ‘Human Embryonic Stem Cell Lines Derived from Discarded Embryos’ (http://dtn.fm/o8ZcS) that it had ‘grown parthenogenetic human embryos to the blastocyst stage at which stem cells can be obtained’ and that ‘cells taken from one of the embryos survived for a few days’.
An April 2003 story in New Scientist titled ‘Virgin birth method promises ethical stem cells’ (http://dtn.fm/e2eWb), commenting on the Wininger breakthroughs, discusses how this is possible. Unfertilized eggs have two complete sets of chromosomes and during fertilization one set is discarded. ‘But an electric or chemical shock can make the egg develop as if fertilized and retain the extra set’. In parthenogenesis, an unfertilized egg keeps two sets of chromosomes and begins developing as if it had been fertilized and thus ‘produces embryos that could never become human beings’. The destruction of ‘these embryos to obtain stem cells would avoid the ethical concerns that have led to restrictions or bans on embryonic stem cell research in many countries.’
One area involving stem cells that shows remarkable promise is in the treatment of Parkinson’s disease. According to the Harvard Stem Cell Institute HSCI), Parkinson’s is ‘associated with the death of cells in a part of the brain… which produces the neurotransmitter dopamine’. Researchers at the HSCI have ‘orchestrated the transformation by biologically reprogramming the mature skin cells into induced pluripotent stem cells, and then encouraging the stem cells to become dopaminergic neurons. Neurons were also made from skin cells collected from individuals with genetic mutations associated with high risk for Parkinson’s disease’.
International Stem Cell Corporation’s (OTCQB: ISCO) UniStemCell for Parkinson’s has completed the Food & Drug Administration’s (FDA) Investigational New Drug (IND) phase, and the company announced recently that it had received authorization to initiate a phase I/IIa clinical trial of human parthenogenetic stem cells-derived neural stem cells (ISC-hpNSC) for the treatment of Parkinson’s Disease.
The phase I/IIa clinical study, which will be performed at the Royal Melbourne Hospital in Melbourne, Australia, is a dose escalation safety and preliminary efficacy study of ISC-hpNSC intracranially transplanted into patients with moderate to severe Parkinson’s disease. The open-label, single center, uncontrolled clinical trial will evaluate three different dose regimens of 30,000,000 to 70,000,000 neural cells. A total of 12 participants with moderate to severe Parkinson’s disease will be treated. Following transplantation, the patients will be monitored for 12 months at specified intervals to evaluate the safety and biologic activity of ISC-hpNSC. PET scans will be performed at baseline, as part of the screening assessment, and at 6 and 12 months after surgical intervention. Clinical responses compared to baseline after the administration of ISC-hpNSC will be evaluated using various neurological assessments.
In announcing the study, Russell Kern, PhD, ISCO’s executive vice president and chief scientific officer commented, “We are the first company in the world to conduct clinical trials of human pluripotent stem cells based product for the treatment of Parkinson’s disease. We believe the outcome of the study will produce findings in-line with our preclinical studies, where we demonstrated not only safety of our proprietary neural stem cells, but also their functional efficacy. The cells were able to successfully integrate into the brain and provide a significant increase of dopamine levels in the nigrostriatal system”
This is welcome news. As the Harvard Stem Cell Institute reminds us: ‘Approximately one to two percent of the population over the age of sixty receives a diagnosis of Parkinson’s disease, although scientists believe that may be a very conservative estimate (and) at least one million Americans are currently known to be living with the condition.’
For more information, visit www.internationalstemcell.com
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