erythropoietin, erythropoiesis and chronic mountain sickness (cms)

Erythropoietin, Erythropoiesis and Chronic Mountain Sickness

(CMS)

H.-C. Gunga1, G. Valverde2, H. Spielvogel3, and K. Kirsch1

1Institut für Physiologie, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin 2Universidad Mayor de San Andrés, La Paz, Bolivia

3Instituto Boliviano de Biologia de Altura (IBBA), La Paz, Bolivia

HAPPOM Symposium - LIMA 2007

2/35Erythropoietin, Erythropoiesis and CMS

! Introduction Evolutionary backgroundOxygen sensing mechanisms

! Methods

! Human studies on EPO, sTfRNormobaric-Normoxic EnvironmentCircadian, monthly, annual variations

Hypobaric-Hypoxic EnvironmentShort, intermittent, and long-term exposure

Chronic Mountain Sickness (CMS)

! Summary and Conclusions

Contents


Bed restBed rest

Humans in

Extreme Environments

Humans in

Extreme Environments

ComparativePhysiology

ComparativePhysiology

Tropics/Desert

Tropics/Desert

High Altitude

High Altitude

Micro-G(Space)Micro-G(Space)

PalaeophysiologyEvolutionaryAnthropology

PalaeophysiologyEvolutionaryAnthropology

History of Applied Science

History of Applied Science

Nathan Zuntz (1847 – 1920)Operation „Paperclip“

Nathan Zuntz (1847 – 1920)Operation „Paperclip“

ModerateAltitude

(<2,300 m)

ModerateAltitude

(<2,300 m)

HighAltitude

(>3,000 m)

HighAltitude

(>3,000 m)

Real Micro-g

Space (near Earth orbit)Space (near Earth orbit)

Exercise PhysiologyExercise

Physiology

Marathon-running

Marathon-running

SurvivaltrainingSurvivaltraining

HDTHDT IsolationIsolation ImmersionImmersion

GoldMiningGold

Mining

Simulated Micro-g

•Introduction


Rift Valley, Human Evolution, and Altitude


Hochachka PW, Gunga HC & Kirsch K.Our ancestral physiological phenotype: An adaptation for

hypoxia tolerance and for endurance performance?PNAS 95: 1915-1920 (1998)

Adaptation and Conservation of Physiological Systems

in Evolution Human Hypoxia Tolerance


Erythrocytes in different Species

Withers PC. Comparative animal physiology.Saunders 1992

Human red blood cells (7.5 μm; PCV 44% ~ 3.200 m2; Blood volume in mammals 6-8% - diving mammals > 8% of body mass)


Signal Transduction Pathway - Hypoxia Inducible Factor (HIF-1 alpha)

(Wenger 2002)


• Erythropoietin (EPO)is a glycoprotein hormone.

• EPO is produced by specialized cells in the kidneys (90 %) and the liver (10 %).

Erythropoietin


Erythropoietin and Erythropoiesis


Physiological variables in the

etiology of CMS

CMS/EE:

Severe HypoxemiaPulmonary hypertension

ErythrocytosisConsensus Symptoms....



! Methods





Contents


•EPO (IBL)

Median: 12 mIU/ml Range: 4 -36 mIU/ml

•sTfR (R&D)

Caucasians (living <300 m above sea-level)

Median: 18,4 nmol/l Range 8.7 – 28,1 nmol/l

ELISA Tests

•Methods


• Transferrin is a transport protein for iron (Fe).

• The diferric (2*Fe) transferrin is binding to TfR.

• During the phase of cellular proliferation iron is incorporatedinto the interior of the erythroblast.

• This is important for the synthesis of hemoglobin.

4-22

Transferrin and Transferrin-receptor


Transferrin Receptor

• Transferrin Receptor (TfR)is a transmembranal protein, expressed mainly on the surface of erythroid cells

Cell interior



! Methods





Contents


Circadian Variations of Serum Erythropoietin

Gunga HC, Kirsch K, Baartz F, Maillet A, Gharib C, Nalishiti W, Rich I & Röcker L.Erythropoietin under real and simulated microgravity conditions in humans.

Journal of Applied Physiology 81: 761-773 (1996)

•Epo-Studies




Erythropoietin during Isolation and Confinement


Gunga H.C. et al. Erythropoietin regulations in humans under different environmental and experimental conditions. Respiration and Neurobiology. Epub ahead, March 12, 2007

Annual variations of serum erythropoietin concentrations


Erythropoietin before, during and after moderate

hypobaric-hypoxic exposure (2,315 m)

Gunga HC, Kirsch K, Röcker L & Schobersberger W .Time course of erythropoietin, triiodothyronine, throxine,

and thyroid-stimulating hormone at 2,315 m.Journal of Applied Physiology 76: 1068-1072 (1994)


Erythropoietin and intermittent

hypobaric�hypoxic exposure(3,600 m)

Gunga HC, Röcker L, Behn C, Hildebrandt W, Koralewski E, Rich I, Schobersberger W & Kirsch K.

Shift working in the Chilean Andes (3,600 m) and its influence on erythropoietin and the low-pressure system.



The distribution of hematocrit values at sea level, Cerro de Pasco, and Morococha

Winslow and Monge, 1987


Gender differences in four common high altitude medical

conditions as reported in the literature by

Hultgren (1997)


N = 105

Females (N = 34)63.5 ± 9.4, min 37.0, max. 80 yrs

Males (N = 71)62.1 ± 11.0, min 35.0, max 89.0 yrs

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85-89

age_group

0

2

4

6

8

10

12

14

16

18

20

22

10

12

8

4

11

23

2

0

2

1

6

8

11

13

10

10 8

0

2

sexfemalemale

Age distribution

Inclusion criteria:

•Whole life at high altitude: (3,600 - 4,100

•Excessive erythrocytosis: [Hct > 60 %]


Differences between females and males for Hct (p=0.011) and Hb (p=0.011)

female male

55

60

65

70

75

80

Hct

(%)

80

female male

19,0

20,0

21,0

22,0

23,0

24,0

25,0

26,0

Hb

(g/d

l)

80


No differences between females and males for age, EPO and sTfR

p=0.50

female male

30

40

50

60

70

80

90

year

s

27

p=0.52

female male

0,00

50,00

100,00

150,00

200,00

250,00

[EPO

] (U

/l

2

54

51

67

53

10149

p=0.47

female male

25,00

50,00

75,00

100,00

125,00

150,00

sTf-R

(nm

ol/L

101


No correlation between the hematological parameters (Hct, Hb) and EPO

55 60 65 70 75 80Hct (%)

0.00

50.00

100.00

150.00

200.00

250.00

[EPO

] (U

/l)

femalesmales

19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0

Hb (g/dl)

0.00

50.00

100.00

150.00

200.00

250.00

[EPO

] (U

/l)

15-22


No correlation between the hematological parameters (Hct, Hb) and sTfR

55 60 65 70 75 80Hct (%)

25.00

50.00

75.00

100.00

125.00

150.00

sTf-R

(nm

ol/l

19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0Hb (g/dl)

25.00

50.00

75.00

100.00

125.00

150.00

sTf-R

(nm

ol/l)

femalesmales


No correlation between age, EPO, and sTfR

years30 40 50 60 70 80 90

0.00

50.00

100.00

150.00

200.00

250.00

[EPO

] (U

/l)

femalesmales

30 40 50 60 70 80 90years

25.00

50.00

75.00

100.00

125.00

150.00

sTf-R

(nm

ol/l)

17-22


No correlation between EPO and sTfR in the majority of the subjects with high sTfR

25.00 50.00 75.00 100.00 125.00 150.00sTf-R (nmol/l)

0.00

50.00

100.00

150.00

200.00

250.00

[EPO

] (U

/l)

femalesmales

28nmol/l

36 U/l



! Methods





Contents


• Males are more frequently affected by EE than females

• Males with EE show higher Hct and [Hb]

• High [sTfR] in the majority of the subjects with EE but no correlation to [EPO]

• Effects of blood letting on circulating [EPO] have to be clarified in patients with EE

• Effects of iron status/metabolism on hematopoiesis in patients with EE are unclear


Physiological variables in the

etiology of CMS


Winslow, Statham and Gibson, 1979

Changes induced by decreasing the hematocrit in eight patients with CMS


Arterial oxygen saturation (SaO2) in long-term high altitude residents while awake (A) and during stages of sleep (1-REM) at 3,100 m

During sleep hypoxemia occurs in polycythemics but not in normals. Ear oximeter data.

Kryger and Grover, 1983


Arterial PCO2 in normal high altitude residents (N=159) and patients with CMS (N=22)Differences in the height of the curves represent different numbers of subjects and patients studied

Cruz and Recavarren, 1982


Richalet et al, 2005

Mean nocturnal O2 saturation (A) and apnea-hypopnea index (B) in groups of patients before and after treatment with 250 (D250) or 500 (D500) mg of Acetazolamide

compared with a CMS placebo-treated group (Placebo) and normal control subjects (Nb = number of events)


Erythropoietin during long-term simulated micro-g conditions (Head-down tilt �6°)




Modulation of Erythropoietin Regulation in Dogs

Ehmke J, Just A, Eckhardt KU, Persson PB, Bauer C & Kirchheim HR.Modulation of erythropoietin formation by changes in blood volume in conscious dogs.

Journal of Physiology 488: 181-191 2 (1996)

•Conclusions


Vásquez R., and Villena M. (2001). Normal Hematological Valuesfor Healthy Persons Living at 400 Meters in Bolivia. High AltitudeMedicine & Biology 3:361-367


The morphology of red blood cells at high altitudes


Red-cell indexes in subjects at low and high altitudes


Two main Groups: �normal� [EPO] (< 36 U·l-1) and with very high [EPO] (> 100 U·l-1). What about the �intermediates� (36≤[EPO]≤100)

Hct (%)

Cut-off EPO � HA ?

55 60 65 70 75 80

0.00

50.00

100.00

150.00

200.00

250.00[E

PO] (

U/l)

femalesmales

36 Ul

100.0 Ul

????

B

A


At least two groups with excessive erythrocytosis (EE):

• “normal” [EPO] (< 36 U·l-1)• very high [EPO] (> 100 U·l- 1)

No studies before evaluated “normal” reference levels for [EPO] and [sTfR]in altitude residents

" can the published cut-off values be adopted ?

18-22


Effect of high altitude (4,300 m) on hematocrit levels of men and woman

Hannon et al. 1966


Normal hematocrit values at sea level as a function of age for 7,426 normal males and 7,704 normal females in the United States

(Fulwood 1982)


Vásquez R., and Villena M.Normal Hematological Values for Healthy Persons Living at 400 Meters in Bolivia.

High Altitude Medicine & Biology 3:361-367 (2001)

Histograms of showing frequency (counts) for

hematocrit values and the mean and 2 standard deviation (SD) values

observed in 1934, 15- to 29 healthy male and female residents in

Potosi, Bolivia (4,000 m)

erythropoietin, erythropoiesis and chronic mountain sickness (cms)

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