Hyperbaric Oxygen Therapy and its role in the treatment of Alzheimer’s
Alzheimer’s disease is a progressively impairing disease of the brain and the most common cause of dementia. It is a general brain condition encompassing memory loss, decreased thinking & decision-making capacity, and a general difficulty in performing routine activities. It generally occurs in elderly people aged over 60. Multiple medications are being used for Alzheimer’s disease but almost all of them delay its progression and none reverse its debilitating effects. A new modality of treatment that is showing promising results in research to reverse the effects of Alzheimer’s disease is Hyperbaric Oxygen Therapy.
What is Hyperbaric Oxygen Therapy?
Breaking down the constituent words: Hyper means “increased” and baric means “pressure”, Hyperbaric Oxygen Therapy simply means treatment that involves providing 100% pure Oxygen at high pressure (about twice or thrice that of normal pressure in air).
It is a new and promising method of treating many conditions in which conventional methods of treatment have failed to adequately treat the condition & in those where lack of oxygen might be one of the causative factors. Hyperbaric Oxygen Therapy can overcome the shortage of Oxygen abruptly thus proving efficient in the treatment of such conditions.
One such condition for which Hyperbaric Oxygen Therapy is an emergent option is Alzheimer’s disease. Let’s talk more about it
What is Alzheimer’s disease?
Alzheimer’s disease is a progressive neurologic condition that causes the death of nerves and loss of tissue throughout the brain, gradually reducing it in size and significantly affecting all of its functions. Its primary target in the brain is an area called the hippocampus which controls memory, thought, and language. This causes early symptoms of Alzheimer’s disease as described below.
What are the symptoms of Alzheimer’s disease?
Alzheimer’s disease begins as mild memory loss, leading to the inability to carry out normal conversations or respond to environmental stimuli. It progresses to impair the ability to think, make decisions, or judge situations accurately.
Alzheimer’s disease is usually a disease of the elderly, but it gives early warning signs which help in diagnosing it early. These signs include getting lost in a known place, repeating questions, misplacing things, or developing mood & personality changes.
If you are having these symptoms and you’re under the age of 60, you should know that these are not signs of a normal aging process, and it’s best to get evaluated by a neurologist, especially if you have a family history of Alzheimer’s disease.
What are the causes of Alzheimer’s disease?
Alzheimer’s disease is attributed to factors related to Age, its associated comorbidities (Infections, Diabetes Mellitus), and the Familial tendency to get the disease.
As we age, blood flow to the brain decreases, which leads to less nutrition for the brain cells, decreasing their activity and eventually causing their death. The main culprit in causing Alzheimer’s is perhaps the buildup of amyloid (a protein) plaques, which are sticky and decrease the flow of nerve signals across junctions.
Other causes include dysfunction of mitochondria (the powerhouse of cells), and uncontrolled free radicals which cause the death of nerve cells.
According to research, Diabetes is also found to be a risk factor in the pathogenesis of Alzheimer’s due to its effects on vessels, reducing blood flow to brain cells.
Age is the most common risk factor for developing Alzheimer’s disease. Patients aged over 65 are at higher risk, with it doubling every 5 years i.e. patients aged 70 will be at twice the risk than patients at 65 to develop Alzheimer’s disease.
Alzheimer’s disease is also known to run in families. According to research, a person having a variant of Apolipoprotein E (APOE) gene on 19th chromosome renders him/her more susceptible to developing Alzheimer’s disease. Another research suggests having a close relative like a parent or sibling also leaves you more likely to develop Alzheimer’s disease than those without a first-degree relative having this disease. In fact, people who develop Alzheimer’s disease before the age of 60 (3% of total cases) are more likely to have it due to genetic cause (passing of faulty gene APOE).
How is Alzheimer’s disease diagnosed?
Alzheimer’s disease is initially a diagnosis of exclusion. A series of tests are run to rule out other causes of impairment, such as blood tests or imaging tests. Blood tests are run to rule out Vitamin B12 deficiency or thyroid disease. Doctors may also evaluate you for a history of stroke, depression, or Parkinson’s disease to evaluate their role in presenting symptoms.
Clinically, the doctor will evaluate your memory, thinking skills, and behavioural changes by Mental status and Neuropsychological tests. The doctor can also interview patient’s friends and family as they are a better judge of symptoms over time than the patient himself.
Sometimes the doctor may evaluate the patient’s Cerebrospinal fluid to look for Alzheimer’s disease-related Amyloid and tau proteins. The ratio of these proteins helps determine if Alzheimer’s disease is present or not.
Imaging scans such as Magnetic resonance imaging (MRI), Computerized tomography (CT) scans are used to evaluate the brain. The most useful scan for the diagnosis of Alzheimer’s disease is the Positron emission tomography (PET) scan, which identifies brain areas with decreased glucose metabolism or detects Amyloid or tau proteins.
What are the different treatment options available for Alzheimer’s disease?
Alzheimer’s disease is primarily treated by Acetylcholine Esterase Inhibitor drugs i.e Rivastigmine, Donepezil which decreases the destruction of Acetylcholine, a molecule that mediates signal transmission across nerves by its enzyme. This improves nerve conduction in brain.
Another class of drugs is NMDA (N-methyl-D-aspartate) receptor antagonists i.e. Memantine which prevent release of nerve-damaging calcium ions into nerve cells. These drugs although currently the primary line of treatment work only to slow down progress of Alzheimer’s and none to actually reverse its debilitating effects.
Search for treatment that actually reverses the cognitive impairment caused by Alzheimer’s has led to research on the effects of Hyperbaric Oxygen Therapy, and the results are both surprising and promising leading to a new era in treatment of Alzheimer’s disease.
Role of Hyperbaric Oxygen Therapy in the treatment of Alzheimer’s disease
Research suggests that Hypoxia (reduced supply of oxygen to tissues) plays a role in development of Alzheimer’s disease. This means that reversing hypoxia by providing oxygen to body can reverse its effects, and this is exactly what hyperbaric oxygen therapy does; it supplies pure oxygen to body at twice the atmospheric pressure overcoming hypoxia and reversing its effects on brain.
This increase in blood flow is aided by stimulatning an increase in cerebral vascular diameter which caused an increase in brain perfusion per unit time.
Initial research by Tel-Aviv University consisted of special 5XFAD mouse models treated with Hyperbaric Oxygen Therapy in sixty-minute sessions. The results were amazing; scans showed up to 40% reduction in amyloid plaque formation. Growth of small plaques stopped completely whereas growth of medium and large plaques was slowed down.
Apart from that, formation of new plaques was completely stopped; this was associated with changes in amyloid precursor protein processing.
Mice’s exploratory behavior also improved and they showed better nest construction, both an indicator of improved cognitive function.
This success in mice models led to researchers shifting to research in Human subjects. A study was conducted that consisted of 6 subjects, aged above 64 years and with significant memory loss. Study was carried out for 3 months having total of 60 sessions, each of 90 minutes. Each patient was exposed to about 2ATA with air breaks every 20 minutes.
Results after 3 months were promising. Magnetic Resonance Imaging (MRI) scans showed improved blood flow (up to 23%) to many areas of the brain. Researchers carried out cognitive tests which showed an improvement from an average score of 102 to 109. Memory tests also showed improvement from previous score of 86.6 to 100.9.
Another human study consisted of 42 Alzheimer’s disease patients ,out of which 12 were treated with Hyperbaric Oxygen Therapy and 30 were control individuals. Patients were treated with a daily oxygen therapy session for 20 days at 2 ATA pressure and 99.9% Oxygen.
Patient was kept on follow-ups for 1, 3 and 6 month periods. Follow up at 1 month supported previous study that Hyperbaric Oxygen Therapy does improve cognitive function. However follow-ups at 3 or 6 months didn’t showed this improvement which might suggest that this improvement was not permanent by a single hyperbaric oxygen therapy regime. But ADL score (Activities of Daily Living score) seemed to improve at all 1, 3 & 6 months periods meaning that Hyperbaric Oxygen therapy did improve patients’ ability to perform routine tasks i.e eating, going to toilet, mobility thus improving the quality of their lives.
PET Scans at 6 month follow up showed increased usage of glucose by many areas in thr brain too. All these effects are more positive than the effects of conventional drugs like donepezil which makes Hyperbaric Oxygen Therapy a promising alternative treatment.
Another research that focused primarily on PET scans of patients treated with Hyperbaric Oxygen Therapy consisted of subjects being treated for 50 minute sessions 5 days per week for 66 days at 1.15 ATA. At the end PET scans were taken which showed improved global brain metabolism of up to 38% in some areas.
After 40 sessions patients also reported increase memory and concentration span. Physical tests indicated better motor speed and knee bending.
These disease-reversing effects of Hyperbaric Oxygen Therapy on Alzheimer’s disease are attributed to the following features:
- Improved blood flow to the brain tissues by overcoming the vessel diameter reduction due to Alzheimer’s
- Reduction of Amyloid plaques by targeting its precursor proteins
- Reducing Inflammation of brain tissues
- Improving mitochondrial dysfunction by supplying ample oxygen.
How Prevalent is Alzheimer’s disease in India?
Over 3.7 million Indians suffer from Alzheimer’s disease. Alarmingly this number is predicted to double in the next decade to 7.6 million, according to the Dementia India Report 2010 by the Alzheimer’s and Related Disorders Society of India (ARDSI). Indians are mostly treated by conventional methods which can’t adequately and efficiently handle this patient load.
As previously mentioned, Hyperbaric Oxygen Therapy is a promising modality in Alzheimer’s treatment. One facility that provides this treatment option is HCAH Transition Care Centre (AOHC Centre) in Gurgaon, Haryana. This facility is certified by HBOT India for Hyperbaric Chamber Operations. They can be contacted through their website https://hbot-india.com
References:
- Shapira R, Gdalyahu A, Gottfried I, Sasson E, Hadanny A, Efrati S, Blinder P, Ashery U. Hyperbaric oxygen therapy alleviates vascular dysfunction and amyloid burden in an Alzheimer’s disease mouse model and in elderly patients. Aging (Albany NY). 2021 Sep 9;13(17):20935-20961. doi: 10.18632/aging.203485. Epub 2021 Sep 9. PMID: 34499614; PMCID: PMC8457592
- Chen, J., Zhang, F., Zhao, L., Cheng, C., Zhong, R., Dong, C., & Le, W. (2020). Hyperbaric oxygen ameliorates cognitive impairment in patients with Alzheimer’s disease and amnestic mild cognitive impairment. Alzheimer’s & Dementia : Translational Research & Clinical Interventions, 6(1).
