John Hemming's Web Log

In Parkinson’s disease, dopaminergic neurons (primarily those in the substantia nigra pars compacta) undergo progressive dysfunction and death. In amyotrophic lateral sclerosis (ALS aka MND in the UK), both upper and lower motor neurons progressively degenerate. The cells deteriorate in different ways. However, the nub of both of theses diseases is the deterioration of a particular type of neuron. An interesting question is what it is about these neurons that makes them vulnerable to rapid deterioration. Neurons are high energy cells. Dopaminergic neurons have to maintain a massive network of axons linking them to other cells. Similarly motor neurons need to maintain long axons of possibly 1 metre in length. All of this takes energy. However, what distinguishes these two types of cells is that they rely to a greater extent on Oxidative Phosphorylation (that is using the Krebs cycle to produce energy) than other neurons. OxPhos, has the effect of generating more free radical...

ALS (Amyotrophic Lateral Sclerosis) tends to be called MND (Motor Neuron Disease) in the UK. It is also known as Lou Gehrig's disease because he was a famous baseball player whose career was ended when he died of ALS in his 30s. There are perhaps two main versions of ALS Familial (or inherited) and Sporadic which does not appear to be inherited. MND is perhaps a broader category which includes Progressive Muscular Atrophy (PMA), Primary Lateral Sclerosis (PLS) and Progressive Bulbar Palsy (PBP) as well as ALS. In this post I am going to concentrate on ALS. That is not to say that things I say in this post do not necessarily also apply to the other types of MND, but I have not looked at that question as yet. I wrote a post a few weeks ago What causes Parkinson's Disease - is it actually an accelerated form of brain aging? and since then have been doing some experimentation with a small number of biohackers who have Parkinsons Disease. The hypothesis is basically that th...

An interesting paper was published recently. Intracellular metabolic gradients dictate dependence on exogenous pyruvate This was from the same lab as the excellent paper A non-canonical tricarboxylic acid cycle underlies cellular identity . An interesting question that the paper answers is what drives the need for external pyruvate. The paper concludes "The requirement for pyruvate over lactate can be partially rescued by NAD+, suggesting that at least part of the role of pyruvate in development is regulation of cellular redox62. ". What I find particularly interesting about the link to NAD+ is that Complex 1 (which is reduced in stem cells) has a major role in maintaining NAD+ levels. Hence if it is to be inhibited in some form then something else needs to be done to maintain NAD+ levels. Although Complex 1 maintains mitochondrial NAD+ rather than cytosolic NAD+, depletion in the Mitochondria will block the Malate-Aspartate shuttle affecting the cytosol Pyruvate in th...

Recently another paper was produced which hinted at a link between mitochondrial DNA damage and aging. In fact I have been of the view for some time that the damage to mitochondrial DNA is what drives both aging and development at the lowest level. I have said this before, but thought a summary would be useful. It is worth, however, explaining a few terms first before going into the details of how this happens. It is well known that animals (including people) are made of large number of cells. Within those cells there are little "organelles" called mitochondria that are used to convert nutrients into ATP (Adenosine Tri Phosphate) which is used by cells as a form of energy. There is a hypothesis that is generally believed to be true that this structure of cells arose from some bacteria going into old cells called archea as it created a form of symbiosis where the larger cells provided nutrients to the bacteria for the bacteria to process those. This is called Endosymbio...

The idea that Parkinson's Disease (PD) is an accelerated form of brain aging has been around for quite a long time. However, as with aging more generally any hypothesis as to the mechanisms behind Parkinson's needs to explain all the known research data. I have been discussing PD with a number of people over the past few months. The results from research indicate that Parkinsons is not primarily caused by genetic factors. That is because there are studies where individual twins get Parkinsons, whilst their twin does not. I was wondering, therefore, what might be an alternative cause. This paper is one that substantiates the argument that normally the brain does not age as fast as the rest of the body. What we need to look at is what might cause this to happen. If we start with the assumption from my previous posts that aging results from the mutation of mitochondrial DNA (mtDNA) then we need to find something that prevents the mutation of mtDNA in the brain that does n...

Software Developer and Artifical Intelligence Expert Samuel Collingwood Smith has been working with me on a number of projects for a last few years, mostly in the Artificial Intelligence / AI / bio-hacking space. We entered a number of competitions, some of which were against billion dollar organisations and in one case came in the top-ten with software that runs on a desktop PC, on an nVidia card, against thirty other competitors. As well as using open source AI models hosted in Python, Smith has used his C# and C++ tools to develop his own scratch-written neural network engine, LearnSilver. This is a C# native neural network library that can also execute on CUDA enabled nVidia cards with C/C++, including many gaming graphics cards. It enable significant processing on consumer hardware. It supports training, serialisation of entire models with a single method call and recurrent networks. TALIS is a side, personal project Smith worked on prior to joining me in setting up our new AI c...