Microglia as Regulators of Neural Transmission

This study, freely available here(4.61MB), has some striking implications. These are listed below. The Science Daily news release can read here. Microglia are typically perceived as the immune cells of the CNS but this study builds on former studies all pointing to the possibility that our current understanding about neural transmission and memory is too constrained. This present study indicates:

• Microglia regulate the fate the synapses
• Microglia are constantly on the move and at a rapid pace.
• Microglia may be regulating memory consolidation.
• Our conceptual separation of immune processes and neural transmission is a fundamental error.

Immune Driven Psychopathology in Mice?

It all began way back in the 19th century. "Sickness Behavior" was observed in humans and farm animals. As that Wiki article goes on to explain, there are some interesting similarities between sickness behavior and depression. This has been an active area of research for many years now. One key article is this one from 2003. This strange and puzzling linkage between the nervous systems and immune systems has been evidenced by the following:

• Shizophrenia is associated with differing rates of cancer and autoimmune disease from others.
• Epileptics also have altered immunological responses, this possibly driven by hippocampal - fornix - PVN networks(guess).
• Traumatic brain injury can induce a variety of physiological changes, from altered melatonin production to variations in circadian cortisol secretion. 

This is going to be difficult ...

Another worrying study concerning mobile phones

There are now a number of studies pointing to the dangers of mobile phones. Of particular concern is the widespread and frequent use of mobile phones amongst teenagers. This study reveals a disturbing quality about the microwave radiation emitted from mobile phones: the markers of oxidative stress, MDA(malondialdehyde) and XO(xanthine oxidase) remain up to 40 days after exposure to the microwave radiation in a rat model. One factor causing this sustained expression of inflammatory markers was the persistent reduction in catalase, a key antioxidant pathway in our cells.

Previous research has found increased risk of brain tumours in the young. While the telecommunications industry strenously denies any danger from using mobile phones increasing research is painting a very different picture. Some authorities have even claimed that the widespread use of mobile phones is paving the way for an epidemic of brain tumours.

Thanks to Dr. Lefever for forwarding this study to me.

The full study can be downloaded here.

Cannabinoids and Multiple Sclerosis

Previous studies have indicated that cannabinoids can act as potent neuroprotectants in a variety of contexts. Hampson et al found that the two major cannabinoids in cannabis sativa, THC and cannabidiol, demonstrated antioxidant capacity greater than vitamins C and E and comparable to the most powerful laboratory antioxidant available to them. This finding may explain why, independent of cannabinoid receptor CB1 or CB2 activation, these cannabinoids demonstrate neuroprotective and anti-inflammatory properties.

This recent study highlights how CB2 receptor activation demonstrates powerful neuroprotective capacity in the animal model(EAE) of Multiple Sclerosis. (Click here for the news release.) In this study the administration of a CB2 agonist reduced neuron cell death by 50%, a remarkable result but one that is consistent with many other studies. They focused on activation of the CB2 receptor. This receptor plays an important regulatory role in the immune response and is also found in the broad equivalent of immune cells in the CNS: microglia.

The great promise of CB2 agonists is that these are non-psychoactive, thereby allowing a potent therapeutic effect without the patient having to deal with the psychoactive effects of THC, which activates the CB1 receptor. Some may retort that this is not a good thing and there may even be some merit in that because CB1 activation has been found to induce neurogenesis and also demonstrates some neuroprotective properties. However in relation to MS, because CB1 tends to inhibit neuronal activation(retrograde inhibitory transmitter), excessive activation of this receptor may make their symptoms worse. There have now been a number of studies where Multiple Sclerosis patients have been allowed to smoke cannabis. The results have been equivocal but there has been enough evidence that some governments have allowed the smoking of cannabis for those suffering MS. There are now so many studies pointing to the therapeutic of cannabinoids that even a study group in conservative Australia has called for the introduction of medicinal cannabis. Unfortunately there is also strong evidence that smoking marijuana can damage the lungs though there is no evidence of it increasing the risk of lung cancer.

A very important word of warning: women who are pregnant or planning to become pregnant must not smoke marijuana. While the evidence is slight it is sufficient to raise very serious concerns about smoking marijuana during pregnancy.

An important finding in this study is that CB2 agonists inhibited the recruitment of immune cells into the CNS. It may even be the case that this is a critical pre-condition for MS attacks to occur. Further research is required to clarify this issue.

With many studies now demonstrating considerable therapeutic potential for cannabinoids it is time for governments and the medical community to adopt a scientific attitude towards the use of cannabinoids in the treatment of a variety of inflammation related conditions. By way of example, consider this study of THC and cannabidiol in relation to Alzheimers. The results indicated that these cannabinoids not only inhibited production of ACHe, an enzyme targeted by many Alzheimers related drugs, but also played an important role in inhibiting the production of amyloid protein, considered by many to be very important in preventing Alzheimers Disease. In fact this study found that both THC and cannabidiol demonstrated greater efficacy than all the current Alzheimer drug interventions they tested.

Apart from their neuroprotective qualities, various studies have indicated that cannabinoid based therapies may be useful in the following pathologies:

Preventing the complications of diabetes
Allergies
Autoimmune conditions
Cancer treatment, particularly brain tumours.
Neuropathic pain.
Atherosclerosis