Hematopoesis Flashcards
TPO does what
stimulates BFU(EMeg)–> CFU-MEG for platelet production
EPO does what
Stimulates BFU-E->CFU-E for RBC production
G-CSF does what
stimulates CFU-GM–>CFU-G for neutrophil production
GM-CSF does what?
acts on all blast cell lines
Cells involved in myeloposiesis (aka granulopoiesis)
Monocytes, Neutrophils, Eosinophils, basophils
Cells involved in ertyhropoiesis
red blood cells
cells involved in thrombopoiesis
platelets
cells involved in lymphopoiesis
T cells, B cells, NK cells
Which cells are defined as blasts (<4%)
*not identifyable microscopically but by their responsiveness to growth factors
PSC–>CFEGEMM and common myeloid progenitor
then BFUE-CFUGM-CFUbaso
all of these are acted on by GMCSF
List normal maturation of granulocyte
Blast--> Promyelocyte--> myelocyte--> Metamyelocyte--> bands--> neutrophil
mature species outnumber younger species why?
because maturation is a process of DIFFERENTIATION alongside a process of DIVISION
(age=increase in rounds of division)
key regulator of granulopoiesis/ myelopoiesis
GM-CSF
eosinophils branch of when during myelopoiesis–>
between morphological bast stage and promyelocytes (in response to GM-CSF
G-CSF role in myelopoeisis
acts more specifically on neutrophil precursors
list the maturation of RBC’s
blast--> pronormoblast--> basophillic erythroblast--> polychromatophillic erythroblast--> normochromic erythroblast
erythropiesis is under the control of which growth factor
Erythropoietin
EPO production is regulated by?
Hypoxia–> causes HIF-1 to be up-regulated which goes to nucleus and up-regulates EPO to be made and released by renal peritubular capillaries
renal failure can cause
ANEMIA: loss of EPO production and timely release
describe nascent RBC’s
–> anucleate, polychromatic reticulocytes
larger than usual, filled with RNA, so will stain with methylene blue
Do blasts have nuclei
YES
Pletelet maturation
blast–> immature megakaryocyte–> mature megakaryocyte–>platelets
platelet production is under control of –>
TPO
describe megakaryocytes
poly ploid (16-32 haploid nuclei)–> extend snake-like protoplatelets into bone marrow blood vessels
TPO is made in the
liver
How does TPO work
binds megakaryocytes–>stimulates production from immature precursors and platelet production from immature megakaryocytes
low platelet count…
–> allows more TPO to bind megakaryocytes, stimulating more thrombopoiesis.
hematopoetic GFR’s work via
JAK2 signal transduction
*acquired mutations here will give you cancer!
red cell production requirements
heme synthesis
globin synthesis
DNA synthesis
regulation
heme synthesis
iron
B6
succinyl Coa
glycine
hemoglobin=
heme + globin
heme=
iron + protoporphyrin
heme synthesis also requires…
B12 and folate
DNA synthesis requires
- dNTP’s–>thymidine (THYMINE)–>which requires B12 and folate
- deoxynucleotide reductase
proper regulation of EPO requires
healthy kidneys
normal bone marrow micro-environment
Iron deficieny results in–>
red cells without enough hemoglobin
most common cause of microcytic hypochromatic anemia
iron Deficiency anemia
RDW correlates with
anisocytosis
Characteristic but not diagnostic of Iron def. anemia
poikilocytosis and anisocytosis
why is free plasma iron bad
causes free radicals
>would augment bacterial growth
(ergo iron is low during inflammatory state and hepcidin is up)
gastric environment that favors iron uptake
acidic (low pH)–>therefore co-admin of Vitamin C will increase the amount of iron one takes up
iron is absorbed in the…
deodenum
b12 is absorbed in the
illuem
iron travels in the blood
with ternsferrin–> in the ferrous state Fe3++
dietary iron–>
usually Fe+++
iron is transported into the enterocyte via
DMT1–> in the fe++ state
how does fe+++/transferrin get into the bone marrow to make heme
binds to transferrin receptor in erythroid precursors in the bone marrow
storage form of iron
ferritin
where is iron stored
macrophages in the liver, spleen bone marrow
how does iron get from gastric lumen into enterocyte
dmt-1
how is heme iron absorbed
heme carrier protein 1
how does iron get from enterocyte to plasma
ferroportin
inhibitor of feroportin
hepcidin
how is DMT1 regulated
iron dependent regulation of its mRNA
hepcidin transcription is increased by
IL-6 9we dont want the bacteria to have iron
TIBC goes up or down in infection
down–>bind up iron making it unavailable to bacteria
transporter responsible for moving iron from macrophages in storage pool–>making it available in plasma for erythroid precursors
ferroportin
Most useful measure of iron metabolism in anemias of unknown etiology
serum ferritin
measures storage iron
simplest measure of transferrin-bound iron
serum iron
*but does not directly address iron stores
Serum ferritin is propoertional to
amount of storage pool iron in the body
TIBC=
total amount of transferrin in ciruclation
transferrin saturation
serum iron (transferrin bound fe)// total transferrin *tells us how active transport system is
UIBC=
TIBC-serum ferritin
WHen would you see an increase in Soluble Transferrin receptor?
when iron storage pool is depleted following loss of serum iron
*macrophages increase the amount of transferrin receptors–> manifests as increase in sTFR–>
reliable indicator between anemia or chronic disease and iron deficiency anemia
sTFR will be increased in iron deficiency anemia and NOT in anemia of chronic disease
ferritin is an
accute phase protein and will be elevated in inflamatory states
markers of Iron defieincy anemia
- increased soluble transferrin receptor
- decreased serum ferritin
- decreased serum iron
- increased TIBC
- increased ferroportin
normal iron/transferrin levels increase or decrease hepdicin production
increase–>which decreases ferroportin and iron uptake
below average iron/transferrin levels increases or decreases hepcidin production
decreases –.ferroportin is increased and more iron is absorbed
reduced globin production=
thalassemia
characters of beta thalassema
microcytic, hypochromic, with target cells (nonspecific)
differentiates beta thal from IDA
MCV < 70 and a NORMAL or increased NUMBER OF BLOOD CELLS
IDA HAS NORMAL OR REDUCED # OF RBC’S
reduced
confirmation of beta thal–>
hg electrophoresis
normal heomoglobin : HgbA
alpha2beta2
HgA2
alpha2delta2
fetal Hgb
Alpha2gamma2
beta thalassemia will result in which types of Hgb in the adult
over production of Hgb delta–> so increased Hgb A2
beta thalassemias are more susceptible to…
point mutations
alpha thals are more susceptible to
deletions
Hgb H
three deletions of alpha globin gene–> result is beta tetramers–>increased afinity for O2–>poor deivery
Hgb Bart;s–>
deletion of four ALPHA alleles–>result is gamma tetramer, and fetus dies
which alpha thal can be confused for IDA
alpha thalassemia type 3
Type 2 alpha thal in adulthood
> normal hgb electrophoresis as adults
>mild microcytic anemia
Type 2 alpha thal prenatal
excess Hgb Barts at birth
Dx of Thalassemia 2 trait
Pcr based (electrophresis and/or sequencing)
overall cause of megaloblastic anemia
inhibition of DNA synthesis
causes leading to megaloblastic anemia
- pernicious anemia–>b12 def.
- impaired folate uptake
- drug effect (HAART and hydroxyurea)
- Myelodysplastic syndrome
Most megaloblastic anemias can be dx with…
bone marrow biopsy
the urge to breath is regulated by Co2
co2 concentration–> not o2
2 overall causes of reduced circulating red cell mass
- decreased produciton of RBC’s
2. increased loss of RBCs
discuss anemia of chronic inflammation
IL6 induces liver to produce–> increased hepcidin (acute phase reactant)–> decreased uptake and release from macorphages storage pool (via destrcution of ferroportin) –> erythroppiesis comes to a screeching HALT
normocytic anemias
- anemia of chronic disease
- thalassemias (sickle cell)
- pregnancy
- hemolysis
- b2 or b6 defiency
Anemia of chronic disease will present as what?
everybody is ordered off the street
- increased hepcidin–>ferroportin inhibited
- therefore decreased serum iron
- decreased transferrin
- decreased TIBC
- increased ferritin
* iron shunted from plasma–>into storage macrophages!***
confirmation of anemia of CD
bone marrow biopsy
chronic disease that can cause anemia
cancer of any type RA
TB
AIDS
reticulocyte count with ACD and IDA
will be low–> unable to compensate
also could be an EPO problem