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today's instructor is Dr Steve Emerson from Michigan, is 
chief of hematology at -er, HUP? not sure. anyway, he's going to talk 
about stem cells. 

Dr Giger is saying the paper we write should refer to 
at least one original article, of something you read and you understand, 
and backed up with other original papers or reviews. you can also use 
notes, like lecture notes. or books. this is not a torturous type of 
experience.
should be 3-5 pp long - double spaced (?)

Ok, when you were 
little, did you see Hemo the Magnificent,the old Frank Capra film? no - 
no one did. well, it's good. but no one here has seen it.

Blood and 
hematopoiesis. it's a cool thing. it's simple, and relatively easy to 
understand, and ties in really well with other diseases and drugs and 
stuff.  

From ground zero - working to the top

starts like this- 80 
million years ago when we were fish in the primordial ooze, life was 
grand, b/c all the cells of our bodies were bathed by the ocean around us 
and we could absorb by passive transport. as we grew, it was hard to get 
bathed appropriately so fish developed circulatory systems for ocean 
water. but then fish wanted to leave ocean. how to keep bathing tissues? 
well, take ocean with you. this is why blood is salty. ionic composition 
of blood is about the same as ocean, but a bit more hypertonic- like the 
hypertonic primordial sea. blood is the ocean with modifications. first 
you have proteins in there for various reasons. biggie is albumin- that's 
what keeps things in the vessels. the other biggie is the globulins. now, 
there are also cells. with specialized functions. think of it simplly.


red cells- about 45% of blood in people - there for O2 transport. Even 
with the ocean with us, that's not enough O2 to get to tissues. we'd 
still be anaerobic if we didn't have RBCs. 

platelets are there to plug 
up holes in blood vessels right away. there are way more than you need. 
you only need about 40,000/cc to clot but you have way more. 

white 
cells- lots of nucleated cells floating around for defense purposes; 
we're surrounded by pathogens and have to fight them off. TH1, TH2, all 
that stuff. But what's really important is this: a military analogy, if 
you will. 

platelets - cell fragments
red cells carry O2 - no nucleus

white cells - have nucleus. 

monocytes are scouts - float to tissue, 
pick up first signs of infection, lie in wait, act as spies and do some 
killing. very mobile, sneaking around, good at picking up info, 
processing it (APC, dendritic cells)

neutrophil/PMN: these are the 
infantry. there are tons of them, they are stupid, they do whatever they 
are told, will kill whatever they are told to kill and they are 
expendable and don't live that long. medically, you need a lot of these 
b/c they do not last that long. you need to have them to stay free from 
bacterial infections b/c w/o them, bacteria get into you through the gut 
really quickly. this happens when kids are born w/o neutrophils - they 
die in hours. and neutropenic patients get infections from their own guts 
all the time. 

eosinophil: granules are pink. loving dawn == greek eos 
phil. big pink granules contain powerful toxins. lipases, proteasess, 
etc. these are the SWAT team. high powered rifles, which are around in 
small numbers to kill toxic invaders like parasites, who have thick 
walls, so you need big guns to get through. when these degranulate they 
chew up whatever is there. but if you have too many, they can go nuts 
like the guy who goes crazy and shoots up the campus. so you just have a 
few of them. so anyone who gets hypereosinophilic gets vasculitis. 
in 
people, they can get endocarditis from too many eosinophils. 

these 
cells are controlled by the officer guard - the lymphocytes. there aren't 
as many of those, they live longer, and they are intelligent - they tell 
the others what to do. 

carrying this one step further- B cells are 
lieutenants - they go to OCS and learn one task really well - either 
decoding, or maps, or whatever, then they mostly hang out in LNs and 
spleen and play cards. they are called up by Sr officers (T cells) during 
war, and are told to do what they were trained for. So then they expand 
and make their Ab product. then they go back to where they came from 
(well, memory cells do).

T cells are generals, live mos to years. they 
instruct the B cells. 

any questions?

that's all that's important; the 
rest is detail.
where do the cells come from? well, fetal liver. adult 
bone marrow. 

how does this work? all that is important to know is two 
things. they are all different from each other, and they are not mature. 
the key thing to understanding hematopoiesis is a thought experiment. 
consider where the cells were one division ago - before they were the way 
they are on the slide now?
if you have 500 cells now, you'd have had 250 
somewhat less mature cells then. two divisions back, there'd be 125, less 
mature. so go 9 divisions back, there was one cell. very primitive.

that 
cell looks like a big cell with some blue cytoplasm, and a big 
purple/pink nucleus. not much different about it. it's a blast. these are 
normal blasts on this slide, normally about 1 out of 1000 cells in BM are 
blasts. if you take one, and isolate it, and tell it to divide over and 
over, eventually daughter cells will differentiate, and you can tell the 
genetic program of the cell by what it makes. so if it makes red cells, 
it was a red cell precursor. now and then, you find a really primitive 
cell that makes more than one cell line.

stem cell hematopoiesis can be 
observed in a lab like this.
the idea here is that in the beginning, 
lining your BM, about 1 in 10 million cells was a pluripotent stem cell, 
right on the endosteum. every once in a while, this cell undergoes 
quantum mitosis, in which one daughter cell from first division returns 
as a stem cell, and the other moves out into the marrow cavity like going 
to kindergarten. first 9-10 divisions are like going to elementary school 
and college - cells grow and divide and choose a lineage to go into. The 
final divisions are grad school - already focused, already in one colony 
- so then it can only make red cells, or eos, or whatever. in the final 
stages it will be recognizable as a precursor to that. 

also, first 
divisions are slow - weeks/mos, and final ones are rapid - days.

so 
having said that, if you take one of these primitive cells away from the 
bone, it will die. it needs some polypeptide hormones called 
hematopoietic growth factors. there are lots of them. looking at the 
chart - to make RBCs, you need EPO, GM-CSF, IL-3, SCF(stem cell factor). 
there are tons of these, you don't have to remember them, but know they 
come in general flavors.

most important ones are the ones that have only 
one activity and no side effects. EPO only makes RBCs out of precursors. 
no other action. 
G-CSF - granulocyte colony stimulating factor -makes 
neutrophils (neupogen?)
those are unilineage hormones.

another type is 
more generalized - GM-CSF (granulocyte/monocyte CSF), IL-3 - these make 
many types of cells differentiate. they pump up hematopoiesis overall. 
also there are one that work on stem cells - SCF, stem cell factor.


finally, there are other hormones that suppress hematopoiesis. most 
important clinically is TNFa, cachectin. this is what you make when you 
are chronically ill. monocytes make it. so this is what causes anemia of 
chronic disease. 

comparison of myeloid growth factors:
four hormones 
will make white cells grow
GM-CSF, G-CSF, M-CSF (macrophage), IL-3
this 
is all you need to know about hematopoiesis!

Chronic Myelocytic Leukemia 
(CML): neutrophilic leukocytosis and transformation
in this disease, 
people make too many neutrophils. in the bone marrow there are huge 
numbers of cells instead of 50% fat. this disease is associated with the 
Philadelphia translocation. chromosome 9 is too long, and 22 is too short 
- due to transfer of a piece of DNA. this discovery lead to the whole 
cancer genetics disease. 

look at blodo of these patients- white count 
10-20 x normal; and also there are a lot of segs, too many immature 
cells, and too many eos and basos .red cells and platelets also abnormal. 
knowing this, what do you think is going on? there are too many 
precursors to all the granulocytes. other cells are also involved but not 
lymphocytes. where is this happening? 
CFU-GEMM is damaged - this cell is 
hwere the translocation occurs. cells prior to this in the lineage are 
clean. so, you could cure this by removing all this bone marrow, killing 
off all CFU-GEMM and later cells, and giving back stem cells. they'll 
probably try this soon. but this causes a big period of complete 
immunosuppression. because it takes a long time to grow new cells from 
the very primitive cells. 

now, who cares about this disease? so what if 
you have too many PMNs? well, over time, these patients tend to die. half 
within 5 yrs, almost all by 14 years. why? well, the cell become 
unstable. they become susceptible to acute leukemias, blasts crowd out 
marrow, no functioning cells occur.

rather than just taking over and 
making all mature cells of its clone, you make a lot of immature blasts 
and suppress other cell lines. so patients bleed, get bacterial 
infections. 

slide: blood smear - CML patient- the circulating blasts 
are huge - 5x normal - nuclei are dense, like rocks. these do not flow 
well through capillaries at all. leukemic blasts will plug up blood 
vessels. they will get infarcts. 

growth factors in clinical practice:

we want to use hormones with simple activities, few side effects.

now:

erythropoietin (Epogen) - increases RBC production. it's a glycoprotein 
hormone that makes erythroid precursors grow up. it's regulated via an 
oxygen sensor in the kidney (10% made in liver which is main source in 
fetus).  Article 13 yrs ago in NEJM - patients who had total renal 
failure - anephric - had PCVs 15. WHen they were given EPO, as 
subcutaneous injections 3x weekly, PCVs rose to normal. and that's all 
that happened to them. this is uniformly seen in patients in renal 
failure. they feel much better. the only problem with EPO is if you give 
too much you get too many RBCs, and strokes and stuff. also in sports 
medicine - some oxygen carrying benefit to this exists, and runners are 
usually anemic b/c they dehydrate when they run so this is natural 
defense to prevent stroke when running - but they can shoot up EPO and 
get around that, if they want to risk it. also patient can become iron 
deficient from making so many RBCs, too. you have to watch iron status.


G-CSF - increases granulocyte production - Neupogen. bone marrow cells 
make this. when you get an infection, they make more - monocytes make 
TNFa and IL1, which circulate to BM and turn on G-CSF production. no side 
effects to using Neupogen clinically. Useful for BMT patients for rapid 
regrowth.
also makes mature neutrophils work better.

GM-CSF - useful for 
BMT patients

the only problems with using these is you must be careful - 
leukemic cells can also divide in the presence of these growth factors. 
almost each leukemic sample tested in one study grew faster in the 
presence of GM-CSF. so if you give it to a leukemia patient you could 
make things worse. so theyare very careful with these drugs. 

soon:

thrombopoietin - in the past few years two hormones have been found - one 
is TPO and one is IL-11 (already approved). both make megakaryocytes 
develop, and make platelets form. 

maybe one day:
FLT-3 ligand - we 
thought thiss might be what made stem cells grow. TPO might be a stem 
cell growth factor. We don't really know anything about it yet though. 




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