#1

Does anyone know whether rapa affects the RCDW?

I have had a score of 15.2 this week. Usually Im around 13. I have low inflamnation (on CRP), am fit and well and take 8mg a week of Rapamycin. The only health issue I have is a chronically low ferritin (about 20) which leads to mild anaemia and for which I take iron periodically. Have been investigated and no-one knows the cause.

My question is whether Rapa’s inhibition of mTOR is altering erythropoiesis (the production of red blood cells) or maybe it is my iron-deficiency after all.

Anyone noticed RCDW effects on Rapa?

Iron Absorption and Vitamin C
#2

Yes, but since mine have been all over the place since starting rapamycin, and I can’t find any significant correlation, the effect is probably not too big. Of course, it would probably be dose-dependent

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#3

I think Rapamycin reduces MCV. Hence as it cycles in and out MCV will vary to a greater extent which will cause an increase in RDW.

The low iron (possibly also caused by rapamycin) will also cause problems creating RBCs. I would not be surprised if that hit RDW as well as cells may not get enough haemoglobin because a shortage of iron.

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#4

Thanks. Useful to know although my iron malabsorption (more likely than bleeding) predates Rapamycin use by several years, and my MCV is always normal.

Boy did the RDW result dent my ‘biological’ age on the Morgan-Levine clock. Such a heavy weighting on that particular item :thinking:

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#5

MCV is an average with the distribution indicated by RDW.

#6

To properly assess this I would need 3 additional items:
#1 Reticulocyte count
#2 Ferritin
#3 HsCRP

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#7

Thanks John. Useful to know

#8

Ferritin is 53,
CRP 0.2
By retic count do you mean the RBC count? In the UK the CBC (full blood count as we call it) doesnt routinely record reticulocyte percentage, just the red blood cell numbers. Mine was 4.58.

Tracking my RDW, while always on Rapamycin, it does seem somwhat correlated with my ferritin ie when at 100+ug/l my RDW was 13.2.

Iron/ferritin is interesting. I never suffer with fatigue etc even when my ferritin has been as low as 10. Some studies note high ferritin/iron as pre-aging. I know PD Mangan often refers to studies on ‘iron dumping’ that is associated with healthspan through blood donation.

Sounds as if others dont see significant RDW increases with Rapa.

#9

The reticulocyte count relates to how many new cells are being put out into circulation. Generally these should be about 1% of your RBC’s as it generally takes 100 days for an RBC to be destroyed and degraded. The MCV of Reticulocytes is ~140, compared to mature RBCs that are typically in the 80-100 range, but typically in a very tight range, which is what the RDW is looking at. So if you have a lot of reticulocytes coming out, e.g. a reticulocyte count of 2% or 4% that will substantially increase the RDW.

An increased reticulocyte count, if you have this leads to a workup for why … which I’m very familiar with, but won’t go through. But, this is a specific test you’ll need that is cheap.

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#10

Thanks and useful to know. Will look into it.

#11

I have done a number of 8 week on/8 week off cycles of taking rapamycin (either 4 mg or 6 mg s week). I get a complete blood test at the end of each half cycle. Rapamycin consistently lowers my RDW by about 1 point, from about 12.5 to 11.5. I don’t see such strong and consistent effects on any other blood parameter.

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#12

Same here. I know lower RDW is correlated to longer lifespan but mine fluctuates all over the place

#13

I’ve been on Rapa for almost 15 years, have bloodwork done once a month. My RCDW is always within norm and fluctuates from 13.4 to 14.1. Most of my results are around 13.7.

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#14

Clearly low iron causes problems with the red blood cell labs, including RDW, but I haven’t seen any evidence rapamycin causes red blood cell problems. There are lots of possible reasons for low iron, many from causes due to aging, like atrophic gastritis and celiac disease. Also, regardless of iron, RDW tends to go up with age.

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#15

AIUI Rapamycin reduces the size of RBCs. As it is cycled, therefore, RBCs will vary in size. Hence RDW will go up without indicating any health harm.

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#16

My low iron is very longstanding. Usually a red flag for a man (GI bleeding, malignancy for example) but no clear cause found so probably a (mal)absorption issue. All other blood/biomarkers normal.

Given the responses I agree the changes in RDW are unlikely to be Rapamycin related either.

I tolerated 16,000ft altitude in Peru last year too without any hypoxia so no concerns. I’ll just supplement with iron periodically when my ferritin/Hb gets too low.

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#17

After reading this research, I think you are right: low iron and smaller RBC might well be caused by rapamycin.

The research describes how everolimus decreases RBC size, decreases serum iron, and decreases MCV. This would also increase RDW with cyclic use of rapamycin.

The levels of everolimus used to treat the disease studied, Tuberous sclerosis complex (TSC), was not stated, but from what I could find, the target micromolar level (continuous over the treatment) would be similar to the peak of taking a 20 mg dose of everolimus: roughly 7 micromolar. So I find it plausible that long-term cyclic use of rapamycin could cause low iron and smaller and more varied-size RBC.

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#18

MCV is an interesting biomarker. Larger MCV associates with greater mortality. It can be symptomatic of damage from alcohol consumption and be linked with myeloma. It is a biomarker I have had issue with because I am a binge drinker. However, I have managed to bring it down by reducing the harm from alcohol consumption whilst not reducing alcohol consumption in any material way (in fact I may be drinking more, I do keep track, but don’t analyse the figures).

mTOR inhibition is separately associated with a reduction in iron levels. I had a week of iron supplementation because my iron levels were getting low and I did a blood draw on Thursday that I have not yet had the results from which will give an initial idea as to where I am now.

Ferritin floats around quite a bit anyway.

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#19

Might be time to discount the Morgan-Levine clock when on Rapamycin, given the heavy weighting towards RDW.

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#20

The Morgan Levine formula is helpful, but really should not be anyones test of what is working.

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