A reason for hope for long time sufferers
Modern studies have shown encouraging signs relating to Stem Cell research for Alzheimer’s Disease. This is extremely exciting news for those sufferers confronting the disease and struggling for effective results via more traditional methods.The future looks bright for those seeking Alzheimer's treatment using Stem Cells.
Alzheimer's disease (AD) is a progressive degenerative neurologic disorder that impairs memory and cognition or intellectual abilities of the affected individuals. Often called dementia, it is a fatal condition that progresses from amnesia, disorientation, behavioral problems, and loss of the ability to function on a daily basis. There is a genetic predisposition of 5% in most cases, and no single cause has been identified. The risk factors for AD are advanced age, cardiovascular disease, low education, depression, and the apolipoprotein-E4 (ApoE4) gene and diet.
Memory loss can be episodic as well as failure to recall past facts and events, known as semantic memory. The lower forebrain nerves are most affected by the neurodegenerative process. Deposition of beta-amyloid or Abeta proteins, called plaques, occurs both inside and outside of the nerve cells (neurons). Ironically, targeting the removal of the amyloid with drugs does not improve the disease or its progression. Intracellular formation of neurofibrillary tangles (tangled nerve strands) and loss of nerves are the two other primary anatomic features of AD. The brain starts to shrink, starting in the hippocampus.
In the last few years, animal studies raised hope that stem cell replacement therapy would provide a cure by providing new nerves for those lost to the disease.
Stem cells obtained from embryos and adult tissue were injected into the intact brain of mice or rats showed that these cells were incorporated into the animal’s brain tissue and differentiated into functional nerve tissue. In the damaged brain, stem cells migrated towards the damaged regions of the brain, where they implanted, grew new cells and matured into functional neurons. They also helped gather up amyloid plaques by stimulating microglial growth (inflammatory cells of the immune system).
One study out of the University of Michigan under the direction of Dr. Eva Feldman, mice had their memory tested after the new cells were placed in their brains and compared them to untreated mice. The mice that received the nerve stem cells had improved short and long-term memory. Another parameter measure was spatial awareness, and those that received the stem cells improved that ability.
Precursor cells to nerves can be given intravenously, and the cells migrate into brain-damaged areas and help them to recover and function. Animal models of AD show that transplanted stem cells or neural precursor cells (NPCs) survive, migrate, and differentiate into all types of nerves that help with memory and learning. Besides replacing lost or damaged cells, stem cells lower inflammation and reduce cell death.
Due to the progressive nature of AD, the only way for stem cell therapy to be successful is that it must address a well-defined clinical subset of patients such as those with early disease of the hippocampal nerves.
The stem cells most commonly utilized in recent AD research studies are embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), brain-derived neural stem cells (NSCs), and induced pluripotent stem cells (iPSCs). ESCs come from the inner cell mass of the developing embryo on day 5 to 6. They are pluripotent because they can generate cell types from all three cell layers needed for a complete human; ectoderm, mesoderm, and endoderm. MSCs are multipotent and come from umbilical cord blood (UCB-MSCs) or Wharton’s jelly and also can be found in a few adult stem cell areas, including bone marrow and fat. They can make multiple cell types of the mesodermal type.
NSCs are also multipotent and are responsible for producing all neural cell types during development. NSCs are limited to certain regions in the brain in adults. And because the rate of new nerve cell growth decreases with age from 800 new ones in early adulthood to 100 new ones in later adulthood if the person is relatively disease-free. Thus, using existing bodily cells has limited potential with AD.
As far as the wider medical world is concerned, there is still research required to test the effectiveness of Alzheimer’s in the treatment of this debilitating disease. However, the positives of stem cells far outweigh ineffective traditional methods and are great cause for optimism.