Did you mean the opposite with regards to fusion and fission? because it is the fission that increases during a fasting state ..
Is fission really increased during a fasting state? Would appreciate any references on that for further researching this issue (fasting/mitophagy). What do you mean with fasting, as there might be differences concerning mitochondrial dynamics for short term (<48h) and prolonged (>48h) fasting. I believe that prolonged fasting (>48h) increases fusion.
During starvation, Sirt5 deletion blunted mitochondrial elongation, resulting in increased mitophagy. Our results indicate that starvation induced mitochondrial elongation and evasion from autophagic degradation requires the energy sensor Sirt5.
https://www.ncbi.nlm...pubmed/28340937
In this report, we provide evidence that glucose deprivation in cultured cells and fasting in mice induces mitochondrial fusion. We show that in response to glucose starvation, HDAC6 binds and deacetylates MFN1, leading to MFN1 activation and mitochondrial fusion.
https://www.ncbi.nlm...les/PMC4231308/
During autophagy mitochondria elongate, are spared from degradation and sustain cell viability.
During starvation, cellular cyclic AMP levels increase and protein kinase A (PKA) is activated. PKA in turn phosphorylates the pro-fission dynamin-related protein 1 (DRP1), which is therefore retained in the cytoplasm, leading to unopposed mitochondrial fusion. Elongated mitochondria are spared from autophagic degradation, possess more cristae, increased levels of dimerization and activity of ATP synthase, and maintain ATP production. Conversely, when elongation is genetically or pharmacologically blocked, mitochondria consume ATP, precipitating starvation-induced death. Thus, regulated changes in mitochondrial morphology determine the fate of the cell during autophagy.
https://www.ncbi.nlm...pubmed/28340937
Inhibition of fusion would yield smaller fragmented or “bite sized” mitochondria that would be physically ideal for degradation in autophagosomes. Additional evidence of the importance of fragmented mitochondria for mitophagy is the fact that Drp1 (a fission mediator) knockout MEFs are impaired in fasting and uncoupling induced mitophagy [109-111]. A fundamental role for mitochondrial dynamics during mitophagy is also supported by the fact that acute fasting promotes hyper-fusion of mitochondria via protein kinase A mediated inhibition of Drp1. This hyperfused state of mitochondria is thought to prevent mitochondrial degradation by mitophagy during short periods of nutrient limitations although mitochondria are eliminated following chronic starvation conditions.
https://www.ncbi.nlm...les/PMC3969632/
But on ther other hand the last paper seems to indicate that mitochondria are eliminated following chronic starvation while acute fasting promotes hyper-fusion. (?)
On the basis of the following abstract (fulltext not available) I would expect effective mitophagy to happen between 24h and 40h fasting, then probably fusion takes over and mitophagy declines. Please correct me, if my assumption is wrong.
A 24-hour fasting increased mitophagy flux as demonstrated by a 44.2% increase in the number of mitophagy events in heart sections. The average size of mitophagy events within studied myocytes increased by 13.4%. Western blot analysis showed an increase in LC3-II protein levels in both total cardiac tissue lysates and the mitochondrial fractions, suggesting that autophagy and mitophagy were enhanced in parallel. However, after 48 hours of starvation, mitophagy events decreased by 50.1% compared to events at 24 hours of fasting and decreased by 28% compared to the control fed animals. The average area of each mitophagy event after 48 hours of fasting decreased by 39.9% compared to that at 24 hours and decreased by 31.9% compared to control. Interestingly, Western Blot analysis showed that LC3-II protein levels were increased in the total cardiac tissue lysates but reduced in the mitochondrial fractions, suggesting that the 48-hour fasting enhanced general autophagy but inhibited mitophagy.
https://www.fasebj.o...pplement.1015.1
Where did you read that less stearic acid intake causes fission?
It makes perfectly sense to me that zero stearic acid intake = less fusion (= more fission).
Turnbuckl can you please share with us what diet you followed when you were using the protocol? If 10g food-grade stearic acid (= 5g pure stearic acid) is all what it needs to inhibit fission, then just 50g cashew nuts (1,7g stearic acid) and 50g fat/oil like olive or coconut oil (1,2g) (so 3g stearic acid altogether) could completely neutralize the hyper-fission state and so the protocol. Were you very strict and controlled your stearic acid intake through foods when doing the protocol or are saturated fats usually not on your daily menu?
This is particularly a great question for the FQAD folks as most of them follow a low-carb/keto diet and ingest lots of saturated fats. So my idea is to combine the protocol with a 24h fast prior to N+R. In this case the problem of lysosomal overload may also be reduced due to autophagy events that have already taken place and emptied glycogen storage.
Edited by Biotochandron, 05 April 2020 - 09:56 AM.