Their methodology has been spelled out in exquisite detail in the journal Cell in the hope that other laboratories will be able to replicate their success.
This achievement has been accomplished in other animals, the most famous example being Dolly the sheep who was closed 17 years ago. Despite ultimately proven false reports from Korea a few years back, no scientist has yet cloned a human.
In this experiment, the researchers took human donor eggs and embryonic skin cells, and through a process called somatic nuclear transfer swapped out the egg DNA for the DNA from the skin cells.
These eggs cells could then be coaxed to replicate into a ball of about 200 cells called a blastocyst which is the earliest form of an embryo. All the cells fo the embryo contained the skin cell’s DNA. The goal of the research was not to allow these cells to grow into a full human, but rather to produce a reservoir of embryonic stem cells.
Embryonic stem cells can of course differentiate into all type of cells found in all types of tissues in all the organs of the body. In fact, the researchers did demonstrate that their cloned embryonic stem cells could evolve into several different cell types in the lab.
Though the researchers hope to use this method to treat mitochondrial diseases by creating new cells with healthy donor mitochondria and patient DNA, its potential for regenerative medicine is spectacular.
It remains to be proven if the method will work with skin cells from an adult, but if so, the ability to produce healthy new cells to be used in adulthood is tremendous, despite ethical issues.
The authors conclude:
We demonstrate here for the ﬁrst time the successful reprogramming of human somatic cells into ESCs following SCNT. By systematic analysis of SCNT procedures, in some cases informed by studies in the rhesus monkey, we identiﬁed several steps, including spindle removal, donor cell fusion, and cytoplast activation, that are critical for cellular reprogramming and SCNT blastocyst development.
One of the fundamental differences of SCNT-based reprogramming is that NT-ESCs contain mtDNA almost exclusively originating from the oocyte. This fact is generally underappreciated but may represent an advantage over iPSC derivation because it ensures that NT-ESCs acquire the potential to produce metabolically functional cells and tissues for cell therapies, irrespective of the nuclear donor cell mtDNA. Thus, SCNT offers a strategy for correcting of mtDNA mutations and rescuing the metabolic function of pluripotent cells from patients with inherited or acquired mtDNA diseases.