Since a long time there are competing hypotheses about ALS, does it start in the brain as a majority of scientists think, or does it start in a distal way as some talented scientists suggest?

Magnetic resonance imaging of the brain and cervical spinal cord is often performed in diagnostic evaluation of suspected motor neuron disease/amyotrophic lateral sclerosis. Anatomist90 via Wikipedia

Analysis of MRI-derived tissue damage metrics in a common domain facilitates group-level inferences on pathophysiology.

This approach was applied to address competing hypotheses of directionality of neurodegeneration, whether anterograde, cranio-caudal dying-forward from precentral gyrus (posterior frontal lobe of the brain) toward the cervical spinal cord, or dying-back with the disease progressing in the other direction.

In this cross-sectional study, MRI was performed on 75 Motor neuron disease patients and 13 healthy controls. MRI scans were reviewed by a consultant neuroradiologist to exclude significant confounding pathology.

Precentral gyral thickness was estimated from volumetric T1-weighted images using FreeSurfer, corticospinal tract fractional anisotropy from diffusion tensor imaging using FSL, and cross-sectional cervical cord area between C1-C8 levels using Spinal Cord Toolbox.

To analyse these multimodal data within a common domain, individual parameter estimates representing tissue damage at each corticospinal tract level were first converted to z-scores, referenced to healthy control norms.

Mixed-effects linear regression models were then fitted to these z-scores, with gradients hypothesized to represent directionality of neurodegeneration.

The results are a bit confusing, it seems that from C5, there is a forward propagation toward lower cervical vertebras, while above C1 there is a backward propagation toward precentral gyrus!

A major limitation of this study is that they only studied the brain and the upper part of the spinal cord. Upper motor neurons have their body in the motor area and extend to the junction with lower motor neurons (with eventually inter-neurons in between). The lowest corticospinal nerve they studied C8, contributes to the motor innervation of many of the muscles in the trunk and upper limb. Its primary function is the flexion of the fingers. So this study would be conclusive only if all patients had a bulbar pathology, yet only 17 patients on 75 had a bulbar onset.

Read the original article on Pubmed

I dislike publishing about CRISPR technology or about ALS mice models yet the results in this article, if replicated, are amazing. It means that for 5% of ALS patients, there is an hope that a future drug might extend their survival by more than 12 years!

Although CRISPR-based gene-editing technology has received unreasonable hype, it represents a promising approach to providing genetic therapies for inherited disorders, including amyotrophic lateral sclerosis.

Toxic gain-of-function superoxide dismutase 1 (SOD1) mutations are responsible for approximatively 20% of familial Amyotrophic Lateral Sclerosis cases. This means 5% of all ALS cases.

Current clinical strategies to treat SOD1-Amyotrophic Lateral Sclerosis are designed to lower SOD1 levels, notably throught the use of ASOs. On October 17, 2021, a presentation of the phase 3 VALOR study indicating that Biogen's Tofersen did not demonstrate statistical significance in the primary measure of disease progression.

On June 3, 2022, additional 12-month open label extension data was presented, demonstrating a some positive effect for participants who received Tofersen early in their disease.

In this new publication, authors from Biogen used an AAV-gene therapy to deliver CRISPR guide RNAs designed to disrupt the human SOD1 transgene in SOD1 mice (huSOD1). Those transgenic mice express the human SOD1 gene, not the murine gene, so their disease is closer to the human disease than in other SOD1 mice models.

This intrathecal injection into neonatal huSOD1 mice caused robust and sustained mutant huSOD1 protein reduction in the cortex and spinal cord, and restored motor function.

Neonatal treatment also reduced spinal motor neuron loss, denervation at neuromuscular junction and muscle atrophy, diminished axonal damage and preserved compound muscle action potential throughout the lifespan of treated mice. SOD1 treated mice achieved significant disease-free survival, extending lifespan by more than 110 days. 110 days for a mice that can live 2 years is equivalent to 12 years for humans!

Yet this is not realistic for human patients, as even if we can detect patients at risk at neonatal stage, most of them will not develop ALS, and furthermore reducing their SOD1 level means they will be susceptible to the very diseases that this therapy tries to attenuate.

Importantly, a one-time intrathecal or intravenous injection of this therapy, immediately before symptom onset, also extended lifespan by at least 170 days.

The authors' approach also uncovered key parameters that resulted in improved efficacy compared to similar approaches and can also serve to accelerate drug target validation.

One question I have is why these technologies are not used to convert the mutated SOD1 gene into the normal wild-type SOD1 gene. This is important because living with reduced levels of SOD1 puts the patient at risk for neurodegeneration!

Let's hope this will lead to a full drug development program at Biogen. Yet there will be internal competition with the team in charge of Torfersen.

Read the original article on Pubmed

On the 14th November Alsnewstoday published a bizarre story about a person who supposedly healed from ALS with an unspecified regimen at Lifestyle Healing Institute.

There is no scientific publication about this case even if the post tells a scientific publication may be written in the future with Florida Gulf Coast University. Yet a quick search on Pubmed shows no publication on ALS in this small university, so FGCU may not have someone working on this disease.

Lifestyle Healing Institute is not a medical institute, it is unclear what is the scientific basis behind this "institute". They claim to have a "patended" method, yet a search in patent database does not return anything with Lifestyle Healing Institute as assignee.

It is possible there are some revert cases of ALS. I once discuss with someone who told they were able to revert the "pre-ALS" case of their father mostly by changing his diet. Another person told on a forum they reverted their case simply by becoming obese and when later they decided to thin a bit, symptoms reappeared. And many studies tell that the less dangerous BMI for ALS patients is 27, which is being overweight.

However it is a bit surprising that a patient is diagnosed with ALS if the symptoms are simply "difficulty using his hands" and change of gait. ALS is not something mild, it kills most of patients in a few years. So one can wonder if this person does not have ALS, but something closer to Parkinsonism. Despite the textbooks describing very different diseases, in real life at the beginning of the disease they might look similar. Parkinsonism has been reverted in mice through an adapted diet.

Finally it is interesting to note that ALsnewstoday is published by BioNews, Inc. As their website tells, BioNews business model is to funnel "hard to reach" patients to clinical trials or commercial organizations.

A recent study proposes that age-related dysregulation of TDP-43 exacerbates post-stroke inflammation and ischemic damage and may contribute to neurodegenerative processes. Stroke is a leading cause of death and the leading cause of long-term disability. Patients who survive a stroke are at greater risk of later developing vascular and/or Alzheimer-type dementia. This risk is particularly high in the elderly because various cellular processes are altered during aging.

In addition to processes associated with chronic neurodegeneration, a growing body of research suggests that dysregulation of TDP-43 neurons can occur as a result of brain injury, including single and repetitive traumatic brain injury. Researchers have recently shown that aging-associated processes significantly affect microglia activation patterns and innate immune signaling after stroke in aged female and male mice. However, how aging affects immune signaling in neurons and/or microglia/neuron crosstalk in response to ischemic injury remains unclear.

In a new paper, researchers have focused their study on transactive response (TAR) DNA-binding protein 43 (TDP-43). TDP-43 has been identified as a major constituent of ubiquitinated nuclear and cytoplasmic inclusions in fronto temporal degeneration (FTD), ALS, and Alzheimer's disease. While normally localized to the nucleus, in these diseases TDP-43 forms insoluble ubiquitinated inclusions in which it is abnormally phosphorylated and cleaved into C-terminal 35 and 25 kDa fragments lacking the N-terminal nuclear localization signal.

As previous work, notably of famous researchers like Jean-Pierre Julien, suggested that TDP-43 could serve as a modulator of inflammation, by acting as a co-activator of p65 NF-κB, these researchers hypothesized that the age-related progressive accumulation of cytoplasmic TDP-43 could trigger the activation of pathogenic NF-κB pathways, leading to dysregulation of the innate immune response and thus increasing the susceptibility of neurons to ischemic injury.

They therefore designed a study to identify and characterize age-related expression patterns of TDP-43 in neurons and microglia and to assess its role as a modulator of inflammation following ischemic injury.

The observed that accumulation of cytoplasmic TDP-43 was associated with increased microglial activation and innate immune signaling observed by in vivo bioluminescence imaging and immunofluorescence analysis. The presence of ubiquitinated TDP-43 aggregates and its cleaved TDP-35 and TDP-25 fragments was markedly increased in 12-month-old mice, which showed larger infarcts as well as increased neuronal death.

The researchers then showed that the increase and/or overexpression of cytoplasmic TDP-43 drives the NF-κB response and further increases the levels of pro-inflammatory markers and ischemic damage after stroke. Taken together, their results suggest that TDP-43 may act as a modulator of age-related inflammation after stroke.

The researchers then analyzed post-mortem brains autopsied at different times after a human stroke, hypothesizing that they would find TDP-43 immunoreactive structures located in the cytoplasm of neurons in the periphery and in the central region of the lesion. ischemic. To investigate this issue, they performed immunohistochemical analyzes of post-mortem post-stroke brain tissue autopsied 1 to 5 days after the stroke. The analysis was performed focusing on two distinct regions of the ischemic lesion, the peri-infarction and central region (cortical sections) and compared to the corresponding controls. The analysis was carried out using an anti-human TDP-43 antibody. In healthy areas, the antibody was found present in well circumscribed and positively stained nuclei, while the cytoplasmic compartment was almost completely devoid of TDP-43 immunoreactivity. In contrast, areas with TDP-43 after acute ischemic stroke revealed increased immunoreactivity in the cytoplasm and, in some cases, extending to cell processes.

The increase in cytoplasmic TDP-43 immunoreactivity was greatest at day 5 after stroke. Stroke in humans is therefore associated with increased TDP-43 immunoreactivity in the the cytoplasmic compartment.

One should note that the conclusions are not exactly the same in experiments in mice and post-mortem observation of brains. In the first case, the poorly localized aggregates of TDP-43 are an element favoring the arrival of the stroke, in the other case, it is on the contrary the arrival of the stroke which seems to create the presence of these poorly localized aggregates.

I watched the first day of NINDS ALS Strategic Plan Workshop, and unfortunately I can't attend the second day.

Here is my take on what I watched:

• The introduction was interesting because it offered a large overview of the research effort. I noted than East Carolina university works on restoring homeostatsis as opposed to inhibiting or activating pathways. I will try to find a link to publications.

• I do not know if it's a cultural bias (I am French) but everyone looked happy and were congratulating each other.

• There were a lot of discussion, but few information provided.

• I think that overall the purpose of this meeting was that NINDS needed to connect with organisations that could use some money.

The first day there were three main themes:

• Accelerating Research on the Biology Behind ALS

1 Unlock sporadic ALS to identify new therapeutic targets across ancestries.

Basically what scientists said is that there is only one subject of discussion: Genetics behind ALS. For them even sporadic ALS is from genetic origin. No other subject was discussed even if scientists agree they do not understand what is causing ALS.

As usual for them ALS is indeed a disease of motor neurons even if one component of Relyvrio, the recent FDA approved drug is a bile acid synthesized in the liver.

2 Understand the molecular mechanisms underlying clinical heterogeneity in ALS.

Clearly there is no room for other domain than molecular biology, even if molecular biology was unable to provide any success in neurodegenerative and chronic diseases and limited ones in other diseases such as cancer.

3 Harness emerging technologies to uncover new disease mechanisms of ALS

There are new tools in molecular biology (things like two photon microscopy) and scientists want to play with them.

• Translating Fundamental Research into Potential ALS Therapies

1 Establish a network of ALS Centers of Excellence to support ALS translational research

This is a call to network research centers which is probably a good idea.

2 Enhance and expand ALS biosample and data infrastructure

A call for more public databases, even if they are numerous today. In my opinion, public databases are only a tool for academics to make quick and cheap studies but they are not used for more useful goals.

3 Increase the biotherapeutic pipeline by enabling clinical trials and fostering academic/industry collaboration

A lot of words, but little content. It's well known that there is little connection between academics and industry and a general contempt of the later towards the former.

Optimizing ALS Clinical Research

There were three sub-themes, but basically it was a long and unclear discussion on the premise that ALS starts 10 years before diagnostic.

It looked to me as medieval debates about "How many angels can dance on the head of a pin?" Some scientists told it in a very polite way, when they stated that it was totally impossible and even dangerous to treat preventively people at risk, and anyway most people at risk will not develop any disease.

You can contact me through the link in the header of this page

Numerous studies have suggested that the medical classification of many neurodegenerative diseases (Alzheimer's, ALS, Parkinson's, many dementias) is artificial because patients may have biomarkers involving up to four comorbidities.

The coexistence of amyotrophic lateral sclerosis (ALS) with clinical forms of Parkinson disease (PD), although uncommon, is found to a greater degree than one would expect by chance. The pathological mechanisms of ALS and Parkinson disease are still not understood, and the coexistence of these two diseases suggests that they could share mechanisms in common.

In this publication, authors from Colombia, Brazil, USA present a sample of patients with clinically definitive or probable ALS who were evaluated with single-photon emission computed tomography (SPECT/TRODAT) and compared with non-ALS controls. SPECT is a nuclear medicine tomographic imaging technique using gamma rays.

Dopamine is a neurotransmitter that modulates a variety of human functions such as motion, cognition, emotions, and the peristaltic reflexes in the gastrointestinal tract. The transport of this molecule at the neuron pre- and postsynaptic junctions is mediated by an axonal membrane dopamine transporter (DAT) that regulates dopamine levels within the synaptic cleft.

Development of various imaging ligands that specifically bind to DAT has been of interest to understand the functioning of these transporters and also to diagnose and monitor the treatment of Parkinson disease. TRODAT was shown to have a high sensitivity and specificity to measure the gradual loss of DAT in Parkinson disease patients.

Patients with clinically definite or probable ALS were assessed with the amyotrophic lateral sclerosis functional rating scale (ALSFRS) to define severity and had their demographic data collected. The TRODAT results of patients with ALS were compared with those of patients with a diagnosis of Parkinson disease with less than 10 years of duration, and with patients with a diagnosis of others movement disorders not associated with neurodegenerative diseases.

A total of 75% of patients with ALS had TRODAT results below the levels considered normal; that was also true for 25% of the patients in the control group without neurodegenerative disease, and for 100% of the patients in the Parkinson disease group. A statistically significant difference was found between patients with ALS and the control group without neurodegenerative disease in the TRODAT values < 0.05.

Conclusions: This study fits with the neuropathological and functional evidence that demonstrates the existence of nigrostriatal dysfunction in patients with ALS.

Sometimes ALS and Parkinson's are associated, for example in a unique neurodegenerative disease found on the island of Guam which is attributed to a toxin in cycad flour.

Progressive degeneration of functionally related groups of neurons occurs in certain infective, toxic, nutritional and genetically determined neurological diseases. It also takes place in normal aging, and several of the regions that undergo selective decay with the passage of time.

One (old) hypothesis that I like, is that features associated with Parkinson's disease, Alzheimer's disease, and ALS may be non-specific indicators of neuronal "disease", with certain morphological markers tending to appear more frequently in particular circumstances and particular regions associated with the pathology of particular diseases.

Tofersen is an investigational antisense oligonucleotide designed to reduce protein superoxide dismutase 1 (SOD1) synthesis through the degradation of SOD1 mRNA. This seems to me counterproductive for ALS patients, and facts seem to agree with me.

A phase 1 clinical trial (NCT01041222) tested four different doses of tofersen in 33 patients. The most common side effects were post-lumbar puncture syndrome, also known as spinal headache, injection-related back pain, and nausea. Subsequently, a second larger phase 3 trial (NCT02623699) named VALOR was initiated. Yet, in October 2021, it was announced that in this Phase 3 VALOR study, the primary endpoint measured by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) did not reach statistical significance.

Surprisingly (or maybe unsurprisingly), the principal investigator stated that "The results from the VALOR study are encouraging as they show reduction of SOD1 protein, reduction of neurofilament, a potential biomarker for neurodegenerative disease, and positive signals across multiple key endpoints including measures of important aspects of the daily lives of SOD1-ALS patients”.

In particular, finding encouragement in the reduction of the SOD1 protein is bizarre at best. The SOD1 protein is what protects the central nervous system against the toxicity of metabolic end products. Indeed, in this case, these patients have SOD1 mutations, but why wasn't Torfersen engineered to modulate the mutated SOD1 gene by alternative splicing, functionally converting it to a normal SOD1 gene?

Another study was planned for 2022, which, as usual for recent ALS studies, was supported by famous ALS scientists such as Merit E Cudkowicz, Albert C. Ludolph or Pamela J Shaw.

In this phase 3 trial, the scientists randomly assigned adults with amyotrophic lateral sclerosis SOD1 in a 2:1 ratio to receive eight doses of tofersen or a placebo over a 24-week period. Eight doses is a lot when it's given intrathecally. Intrathecal drug delivery is the introduction of a therapeutic substance into the cerebrospinal fluid by injection into the subarachnoid space of the spinal cord to bypass the blood-brain barrier. It's an odd choice to deliver an ALS drug because it punctures the barrier that protects the central nervous system. We know that in 3% of cases, intrathecal administration of chemotherapy leads to paralysis! In this case, this barrier was perforated eight times, which means that the risk of paralysis is much higher. Serious neurological adverse events occurred in 7% of Tofersen recipients.

The primary endpoint was the change from baseline to week 28 in total score on the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale among participants with more rapidly progressing disease predicted. Secondary endpoints included changes in total cerebrospinal fluid SOD1 protein concentration, plasma neurofilament light chain concentration, slow vital capacity and portable dynamometry in 16 muscles.

A combined analysis of the randomized component of the trial and its 52-week open-label extension compared outcomes in participants who started tofersen at entry into the trial with those in participants who switched from placebo to drug at week 28. A total of 72 participants received tofersen and 36 received placebo.

Morally and ethically, this means that 36 patients received eight intrathecal injections of placebo. Not only were they losing time, but they risked further health degradation by this procedure.

As in the first phase III clinical trial in the more rapidly progressing subgroup, the change at week 28 in the ALSFRS-R score (primary endpoint) was -6.98 with tofersen and -8.14 with the placebo. Administration of Tofersen also resulted in greater reductions in cerebrospinal fluid SOD1 and plasma neurofilament light chains than placebo, but overall results for secondary clinical endpoints did not differ significantly between the two groups.

At the end of the trial, 95 of the participants went on to open label extension which will last up to four and a half years. All expansion participants receive tofersen.

An analysis six months after the start of the extension found a significant difference in motor function between those who had been on tofersen from the start and those who had been on a placebo for six months before starting tofersen. After a year on the drug, the participants showed a stabilization of muscle strength and this is a remarkable finding, according to the researchers. Some scientists have even gone so far as to claim that "most of the course participants on our site regained and/or maintained a number of their activities of daily living". We see these kinds of marketing claims in all ALS clinical trials, but no one has ever encountered these lucky patients.

From a business perspective, it's hard to see Biogen's interest in Torfensen. The SOD1 gene is only mutated in about 2% of ALS patients, and there are hundreds of SOD1 mutations, so Torfensen, if effective, would be usable for less than 2% of patients.

And indeed Torfensen is not effective in ALS: If in 28 weeks the change is only 1.16 point, that means absolutely nothing in terms of improvement. Simply taking a new medication to make swallowing easier or wearing better-fitting clothing could improve the ALSFR by one or two points.

Biogen changed its strategy a few years ago in order to increase the chances of success of the clinical trials it funds. This was at a time when molecular biologists were promising wonders. Biogen could change strategy again. It would be a welcome change if human physiology were better considered in future studies.

A new publication by Jamie K Wong, and colleagues including two well known ALS scientists argues apolipoprotein B-100 in sporadic amyotrophic lateral sclerosis CSF is the putative agent responsible for inducing motor disability, motor neuron degeneration and pathological translocation of TDP-43.

While there are publications with similar claims about every week, this one sounds impressive, the scientists here have really worked hard to make sure they haven't left any stone unturned.

For a layperson like me, at first glance, this publication makes sense as there is a special relation between ALS and lipid metabolism. Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fats, cholesterol and fat soluble vitamins) to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph. There are multiple classes of apolipoproteins and several sub-classes

ApoD level increases in nervous system with a large number of neurologic disorders inclusive of Alzheimer's disease, schizophrenia, and stroke. ApoE has been implicated in dementia and Alzheimer's disease.

So why not ApoB and ALS? Moreover overproduction of apolipoprotein B can result in lipid-induced endoplasmic reticulum stress and insulin resistance in the liver. ER stress leads to mislocalized misfolded proteins in cytosol, and half of ALS patients exhibit insulin resistance. In addition patients with ALS have higher levels of LDL-C, ApoB, and ApoB/ApoAI ratio already 20 years before diagnosis.

Yet this is not a study on humans but on mice and motor neurons in-vitro, and as usual a lot could be said about mice animal models of ALS. So maybe their claim, that ApoB is the agent responsible for inducing sporadic ALS, needs more work.

In addition a recent publication claimed that ALS patients that have elevated levels of ApoB in blood are associated with a lower risk of death. ApoB is also correlated with LDL (the "bad" cholesterol). Another study claimed the contrary. Yet another study did not find any evidence of association between lipoprotein or apolipoprotein levels and clinical findings.

There is also a lack of associations of cholesterol-lowering drugs (which lowers ApoB), antihypertensive drugs, and antidiabetics with the risk of ALS.

So we must remain cautious again, anyway even if this finding about ApoB and ALS was true, a commercial drug would be available only in 10 or 20 years.