Introduction: The Mystery of Life vs. Medical Progress
Therapeutic cloning - a technology that promises to cure everything from Parkinson's to heart disease using the patient's own cells - has divided scientists, ethicists and politicians since its inception. While some see a medical miracle, others warn of an ethical slippery slope where human life is reduced to biological "spare parts."
The breakthrough came in 1996 with the cloning of Dolly the sheep, which proved that adult cells could be "reprogrammed" into an embryo-like state 2 . Since then, the debate has swung between hopes of healing and fears of erosion of human dignity. In 2001, the first human cloned embryo was created in the US, and the world's reactions revealed a global moral schism 6 7 .
1. What is Therapeutic Cloning?
From science fiction to laboratory reality
Therapeutic cloning (somatic cell nuclear transfer) differs radically from reproductive cloning. The goal is not to create a whole human being, but to utilize embryonic stem cells as "universal cells" for tissue repair.
How the technology works, step by step:
- An egg cell is taken from a donor, and its nucleus - containing the genetic material - is removed
- A skin or blood cell from the patient is isolated, and the cell's nucleus is extracted
- The patient's cell nucleus is implanted into the empty egg cell
- An electric shock triggers cell division, and a blastocyst stage (5-6 day old embryo) forms
- Inner cell mass (with stem cells) is extracted from the blastocyst, and the embryo is destroyed
- The stem cells are stimulated to develop into specific cells: Neurons for Parkinson's, insulin-producing cells for diabetes, or heart muscle cells 2 6
2. Landmark Experiment: The First Human Cloned Embryo
Advanced Cell Technology (2001) - a step toward medical revolution
In 2001, the American company Advanced Cell Technology (ACT) announced that they had created the first human cloned embryo. This marked a technological breakthrough with enormous ethical implications 6 7 .
Method:
- Egg donors were hormonally stimulated to produce mature eggs
- 22 egg cells were enucleated (nucleus removed)
- Cumulus cells (support cells from the ovaries) from the same donors were used as nucleus donors
- Nuclear transfer performed using a thin glass needle
- Electrical activation and chemical stimulation with ionomycin and 6-DMAP to initiate cell division
Results and Challenges:
- Only 6 of 22 eggs developed to early embryo stages
- None reached the blastocyst stage (necessary for stem cell extraction)
- Main challenge: Lack of control over the reprogramming process 7
| Stage | Number of Embryos | Success Rate |
|---|---|---|
| 2-cell | 3 | 13.6% |
| 4-cell | 2 | 9.1% |
| 6-cell | 1 | 4.5% |
| Blastocyst (goal) | 0 | 0% |
"Even though the experiment failed to produce stem cells, it proved that human cloning was technically possible. The reactions were intense: President George W. Bush condemned it as 'creating life to destroy it', while the Parkinson's Association feared Norwegian restrictions would force patients abroad 6 7 ."
3. Medical Potential: Why Scientists Believe in the Technology
A personalized medical revolution without rejection risk
Therapeutic cloning promises treatments tailored to the individual patient. Since the cells come from the patient's own DNA, the risk of rejection that plagues organ transplants is eliminated 5 .
Potential Applications:
- Nervous diseases: Restoration of dopamine-producing cells in Parkinson's
- Diabetes: Production of insulin-secreting beta cells
- Heart disease: Repair of heart muscle damaged by infarction
- Burn wounds: Formation of new skin from keratinocytes 3
Expert Opinions:
"ES cells (from blastocysts) can be stimulated to develop in planned directions - theoretically the possibilities are unlimited."
- Professor Hans Prydz, University of Oslo 3
"10% of the population with chronic diseases could benefit from such cell therapy."
- Harry Griffin, Roslin Institute (where Dolly was created) 5
| Disease | Cell Type That Can Be Formed | Research Status |
|---|---|---|
| Parkinson's disease | Dopaminergic neurons | Animal trials (rats) |
| Type 1 diabetes | Beta cells | In vitro studies |
| Spinal cord injuries | Oligodendrocytes | Preclinical phase |
| Heart attack | Cardiomyocytes | Animal trials (pigs) |
4. The Ethical Minefield: Where is the Limit?
"Ethics is about what we should do, not what we can do" - Erling Tiedemann, The Ethics Council 5
Main Arguments Against Therapeutic Cloning:
- Human dignity undermined: "Producing spare parts from embryos is a violation of human dignity," argues theologian Kurt Christensen 5
- Slippery slope toward reproductive cloning: The technology for therapeutic cloning could be misused to clone whole humans 6 8
- Instrumentalization: Embryos are created only to be destroyed - "life as means, not ends" 1
Psychological Dimensions:
Reproductive cloning of humans would lead to identity crises: "Cloned persons would be compared to the originals and suffer under existential questions," warns psychologist Valeria Sabater 8 .
5. The Researcher's Toolkit: Key Reagents and Their Functions
What is needed to perform therapeutic cloning?
| Reagent/Equipment | Function |
|---|---|
| Hyaluronidase | Breaks down the egg cell's protective layer for easier manipulation |
| Piezo-electric micropipette | Precise injection/removal of cell nuclei without damaging the cell |
| Ionomycin & 6-DMAP | Chemical activation agents that mimic sperm fertilization |
| Growth medium (e.g. DMEM) | Nutrient solution to maintain cell growth and division |
| Anti-apoptosis agents | Prevents cell death under stressful laboratory conditions |
6. Global Politics: A Patchwork of Laws
From prohibition to cautious acceptance - national differences
Country Policies:
- USA: Private research allowed since 1995; publicly funded research limited. President Bush: "We shall not create life to destroy it" 1 7
- UK: Allows therapeutic cloning since 2000 under strict rules (max 14 days development) 1
- Germany: Total ban due to constitutional protection of "all human life" 1
- Norway and Denmark: Ban on research on fertilized eggs; only stem cells from surplus IVF embryos allowed 3
International Context:
The EU Parliament encourages member states to ban the technology, while the UK goes its own way 1 .
7. The Future: Is Therapeutic Cloning Already Obsolete?
Induced pluripotent stem cells (iPSCs) - an ethical compromise?
In 2008, Japanese researchers introduced a revolutionary alternative: iPSCs. Here, skin cells are reprogrammed directly into stem cells without the use of egg cells or embryos 9 .
Advantages:
- Avoids ethical battles: No embryos are destroyed
- Simpler technology: Does not require egg donors
Challenges:
iPSCs may be genetically less stable than embryonic stem cells.
Pioneers Shift Focus:
2008
Ian Wilmut ("Father of Dolly") abandoned cloning in favor of iPSCs
Poul Maddox-Hyttel (University of Copenhagen) confirms: "Therapeutic cloning is technically complicated and ethically burdensome - iPSCs have greater potential" 9
Conclusion: Medicine's New Horizons or Ethical Dead End?
Therapeutic cloning presents a paradox: It combines groundbreaking medical potential with deep ethical dilemmas. The technology has already driven forward knowledge about cell reprogramming, but its practical use is rapidly declining due to the emergence of iPSCs. As Outi Hovatta from Karolinska Institutet concludes: "Our cloning research was completely worthless - we've packed it up" 9 .
Yet it served as a springboard: Without it, the stem cell revolution would have been impossible. The question is no longer whether we can use human embryos, but whether we should when alternatives exist. As the Danish Ethics Council formulates it: "Sometimes we must say no, even though it's difficult. We don't buy organs from India, even though we can" 5 . Therapeutic cloning may become an ethical dead end, but its legacy - personalized regenerative medicine - is here to stay.