INSTRUMENTOS DE LA POLÍTICA COMERCIAL

Conclusions

In vitro data suggest that oestradiol and progesterone associate loosely with

erythrocytes from women with SCD and can be removed by sequential “washes”. The association is non-specific and there are no saturable steroid receptors demonstrated on sickle erythrocytes. This association is significantly diminished in erythrocytes from women with homozygous Hb SS compared with Hb SC and Hb AA genotypes, possible due to differences in the lipid composition of the plasma membrane. No genomic effects are likely to occur as a result of this association and the biological characteristics of SCD red cells (as represented by osmotic fragility and red cell deformability tests), do not appear to be affected by ovarian steroid hormones. It is acknowledged, however, that these are gross tests of cell fimction and may not be able to detect the more subtle changes which may occur at the intracellular level.

Although SCD is itself a condition involving a “hypercoagulable” state, markers of coagulation are not fiirther increased in women with SCD exposed to contraceptive steroid hormones. About 37% of SCD women with natural menstrual cycles have crises, of moderate severity, associated with menstruation. Painfiil crises appear to be improved by the onset of the menopause. A larger than expected proportion of post­ menopausal women with SCD have reduced BMD (Z scores) compared to sex and ethnically matched controls, although this finding cannot necessarily be attributable directly to the haematological condition itself The Z scores of the lumbosacral spine are significantly lower than those of the hip and this may reflect the fact that the sites of sickling pain most frequently reported are the lumbar spine (49%) and femoral (30%) regions (Serjeant et al 1994).

With respect to the hypothesis which this work set out to test:

a) oestradiol and progesterone have direct effects on erythrocytes from women with SCD, which may, in turn, influence the clinical manifestations of the condition

Oestradiol and progesterone associate loosely with sickle red cells and evidence of specific receptors is not found with sickle red cells. The association is significantly lower in women with Hb SS compared to Hb SC or AA. These hormones do not appear to affect the biological characteristics of sickle red cells.

Clinical manifestations of sickle cell disease associated with the physiological hormonal variation of natural menstrual cycles and of the menopause, seem on first analysis, to be conflicting. A third o f women appear to have increased crises with menstruation when oestrogen and progesterone levels are at their nadir, whilst the postmenopausal women with even lower prevailing hormone levels, report fewer crises.

b) there is a specific interaction between the effects of oestradiol and

progesterone on sickle red cells and their concurrent effects on blood coagulation factors

Individuals with SCD have higher baseline levels of coagulation markers but ovarian steroid hormones do not further elevate the baseline levels.

c) by characterising these interactions, there is a potential for using them therapeutically to ameliorate the clinical course in women with the condition

As contraceptive steroid hormones do not appear to adversely affect the biological characteristics of red cell nor the coagulation markers in women with SCD, the use of COCP and HRT, both of which be of considerable practical relevance in this group of women, should be investigated further. Whether or not they confer specific additional

haematological benefits to women with SCD remains unproven by the features explored by the author. At the very least, the laboratory observations do not suggest any overwhelming evidence of actual or potential harm from pharmacological concentrations of oestradiol and progesterone in women with SCD.

Thus the sequence of observations and conclusions described above achieve the aims of this thesis which were to e?q)lore the potential for interactions between ovarian steroid hormones and erythrocytes in women with SCD and thereby, to establish an ethical basis for devising a patient level interventional study using therapeutic preparations of oestradiol and progesterone relevant to effective contraception and hormone replacement for these women.

Further Research Proposals

Having demonstrated that the use of COCP does not significantly increase the levels of haemostatic markers in women with SCO, interventional studies with therapeutic preparations of contraceptive steroids can be commenced. In order to recmit sufficient numbers and to include SCO women of different ethnic origins, with a fiill spectrum of disease manifestations, the author is of the opinion that these studies need to be

collaborative and multi-centred.

BMD is reduced in post-menopausal SCO women. Case-control trials on the use of HRT and SERMS in the prevention of bone mineral density changes in these women would be of considerable interest. This is an emerging area of study which is only recently of practical relevance given the increasing life expectancy of adults with SCD in developed countries. The author has also completed a pilot study in premenopausal SCD women with back pain not associated with sickling crises, which shows that the BMD in this group o f women is also lower than in ethnically matched controls. This brings up the possibility that there is a potential problem of osteoporosis in women with SCD which may only be partially explained by hormonal fectors. Furthermore, it suggests that the very prevalent symptoms of disabling bone pain in people with SCD may be contributed to by pathological mechanisms other than the characteristic one of ischaemic infarction during acute sickling crises.

REFERENCES

Abbasi AA, Prasad AS, Ortega J, Congco E and Oberleas D. Gonadal function

abnormalities in sickle cell anaemia. Studies in adult male patients. Ann Int Med 1976; 85:601-605

Adams R, McKie V, Nichols F et al. The use of transcranial ultrasonography to predict stroke in sickle cell disease. N Eng J Med 1992; 326: 605-610

Adadevoh BK and Isaacs WA. The effect of megestrol acetate on sickling. Am J Med Sc 1973; 265: 367-370

Adewuyi JO and Awarun JA. Deformabihty of stored normal and sickle haemoglobin erythrocytes. Afr J Med Sc 1990; 19(2): 115-119

Ahn YS, Temple JD Jnr, Fernandez LF et al. Danazol therapy renders red cells resistance to osmotic lysis. FASEB Journal 1989; 3(2): 157-162

Allan D, Limbrick AR, Thomas P and Westerman MP. The release of spectrin free spicules on reoxygenation of sickled cells. Nature 1982; 295: 612-613

Alleyne SI, D’Hereux Rauseo R and Serjeant OR. Sexual development and fertility of Jamaican female patients with homozygous sickle cell disease. Arch Int Med 1981;

141: 1295-1297

Aloia JF, Vaswami A, Yeh JK and Flaster E. Risk of osteoporosis in black women. Calc Tissue Int 1996; 59(6): 415-423

Allon M. Renal abnormalites in sickle cell disease. Arch Int Med 1990; 150: 501-504

Balias SK, Lewis CN, Noone AM, Krasnow SH, Kamalrulzaman E and Burka ER. Clinical haematological and biochemical features of Hb SC disease. Am J Hematol

1982;13: 37-51

Baum KF, Dunn DT, Maude GH and Seijeant OR. The painful crises of homozygous sickle cell disease. A study of risk factors. Arch Int Med 1987; 147: 1231-1234

Berlin E, Bhathena SJ, Judd JT, Nair PP, Jones DY and Taylor PR. Dietary fat and hormonal eflfects on erythrocyte membrane fluidity and lipid composition in adult women. Metabolism 1989; 38(8): 790-796

Bertles J and Dobler J. Reversible and irreversible sickling: a distinction by electron microscopy. Blood 1969; 33(6): 884-898

Bilto YY, Player M and Stuart J. Rheological action of oxypentifylline and structurally related xanthine derivatives on human erythrocytes. Clin Hemorheol 1988; 8: 213-221 BischofFF and Bryson G. Estradiol transport by human red cells. J Appl Physiol 1960;

15:515-90

Blackmore PF, Beebe SJ, Danforth DR and Alexander N. Progesterone and 17 a hydroxyprogesterone. J Biol Chem 1990; 265: 1376-1380

Blankenstien MA and Mulder E. Characterisation, assay and purification of steroid receptors. In: Cooke BA, King RJB and van der Mole HJ, editors. Hormones and their actions. Part I. Elsevier Science Publishers BV, Amsterdam 1988: 47-59

Bookchin RM, Balazs T and Landau LC. Determinants of red cell sickling. Effects of varying pH and of increasing intracellular hemoglobin concentration by osmotic shrinkage. J Lab Clin Med 1976; 87: 597-616

Booker AC, Orwoll ES, Johnston CC Jr, Lindsay RL, Wahner HW, Dunn WL, Calvo MS, Harris TB and Heyse SP. Prevalance of low femoral bone mineral density in older US adults fromNHANES III. J Bone Miner Res 1997; 12(11): 1761-1768

Bradford Hill A. A Short Textbook of Medical Statistics. Hodder and Stoughton, London 1978

Braiman MS and Rothschild KJ. Fourier transform infrared techniques for probing membrane protein structures. Ann Rev Biophys Biophys Chem 1988; 17: 541-570

Brann DW, Hendry LB and Mahesh VB. Emerging diversities in the mechanism of action of steroid hormones. J Steroid Biochem Mol Biol 1995; 52: 113-133

Brewer GJ and Oeshlegel FJ Jr. The antisickling effects of zinc. Biochem Biophys Res Comm 1974; 58(3): 854-861

Brewer GJ, Brewer LF and Prasad AS. Suppression of irreversibly sickled erythrocytes by zinc therapy in sickle cell anaemia. J Lab Clin Med 1977; 90: 549-554

Brinker MR, Thomas KA, Meyes SJ, Texada T, Humbert JR, Cook SD and Gitter R. Bone mineral density of the lumbar spine and proximal femur is decreased in children with sickle cell anaemia. Am J Orthoped 1998; 27(1): 43-49

Brinkmann AO, Mulder E and Van der Molen HJ. Model studies with erythrocytes on the initial steps of cellular uptake and binding of steroids. J Steroid Biochem Mol Biol 1972;3: 601-615

Brittain HA, Eckman JR, Swerlick RA, Howard RJ and Wick TM. Thrombospondin from activated platelets promotes sickle erythrocyte adherence to human micro vascular endothelium under physiologic flow: a potential role for platelet activation in sickle cell vaso occlusion. Blood 1993; 81(8): 2137-2143

Bromberg PA. Pulmonary aspects of sickle cell disease. Arch Intern Med 1974; 133: 652-656

Bromberger JT, Matthews KA, Kuller LH, Wing RR, Meilahn EN and Platinga P. Prospective study of the determinants of age of menopause. Am J Epid 1997; 145(2):

124-133

Brozovic M and Davies SC. Management of Sickle Cell Disease. Postgrad Med J 1987; 63 (742): 605-609

Campbell SJ, Mackie IJ, Robinson GE and Machin SJ. Contact factor mediated fibrinolysis is increased by the combined oral contraceptive pill. Br J Obstet Gynaecol

1993; 100: 79-84

Carol W, Klinger G, Jager R, Kasc R and Brandstadt A. Pharmcokinetics of ethinylestradiol and levonorgestrel after adminstration of two oral contraceptive preparations. Experimental & Clinical Endocrinology 1992; 99: 7-12

Carr BR. Disorders of the ovaries and female reproductive tract. In: Wilson JD, Foster DW, Kronenberg HM and Larsen PR, editors. Williams’ Textbook of Endocrinology. 9^ edition. WB Saunders, Philadephia 1998: 751-819

Chabbert Buffet N, Djakoure C, Maitre SC and Bouchard P. Regulation of the human menstrual cycle. Front Neuroendocrinol 1998; 19(3): 151-186

Chapman D, Jackson Ml and Haris PI. Investigations of membrane protein structures using Fourier transform irrfrared spectroscopy. Biochem Soc Trans 1989; 17(4): 617- 619

Charache S and Conley CL. Rate of sickling of red cells during deoxygenation of blood from persons with varying sickling disorders. Blood 1964; 24: 25-31

Charache S and Niebyl JR. Pregnancy in sickle cell disease. Clinics in Haematology 1985; 14(3): 729-746

Chien S. Rheology of sickle cell and erythrocyte content. Blood Cells 1977; 3: 283-303

Clark MR, Mohandas N and Shonet SB. Deformability of oxygenated irreversibly sickled cells. J Clin Invest 1980; 65: 189-196

Connor WE, Lin DS, Thomas G, By F, DeLoughery T and Zhu N. Abnormal phospholipid molecular species of erythrocytes in sickle cell anaemia. Journal of Lipid Research 1997; 38: 2516-2528

Cooper RA. Lipids of human red cell membrane: normal composition and variability in disease. Seminars in Haematology 1970; 7: 296

Cormack DH. The cell membrane. Ham’s Histology. 9^ edition. J.B. Lippincott Co., Philadelphia, USA 1987: 75-82

Cummings SR, Black DM, Nevitt MC, Cauley J, Ensrud K, Genant HK, Palermo L, Scott J and Vogt TM. Bone density at various sites for prediction of hip fractures. Lancet 1996; 341: 72-75

Dacie JV and Lewis SM (revised by Luzzatto L and Roper P). Investigations of the hereditary haemolytic anaemias: membrane and enzyme abnormalities. In: Dacie JV and Lewis SM, editors. Practical Haematology. 8* edition. Churchill Livingstone, Edinburgh 1995: 215-249

Dada OA, Lapido OA, Osinusi BO, Osotimehin BO and Nduka EU. Circulating blood levels of gonadotrophins and prolactin in the normal menstrual cycle. Int J Gynecol Obstet 1981; 19: 291-294

Damber MG, Sandstrom B, von Schoultz B and Stigbrand T. A new and sensitive method for quantifying and comparing the biological potency of various estrogens in man. Acta Obstet Gynecol Scand 1979; 58: 527-530

Dare FO, Makinde 0 0 and Faasuba OB. The obstetric performance of sickle cell disease patients and homozygous hemoglobin C patients in Ile-Ife, Nigeria. Int J Gynecol Obstet 1992; 37: 163-168

Davey DA. Dysfunctional uterine bleeding. In: Whitfield CR, editor. Dewhurst’s Textbook of Obstetrics and Gynaecology for Postgraduates. 5^^ edition. Blackwell Science, Oxford 1995: 590-609

de Abood M, de Castillo Z, Guerrero F, Espino M and Austin KL. Effect of Depo- Provera or Microgynon on the painful crises of sickle cell anaemia patients.

Contraception 1997; 56(5): 313-316

De Ceulaer K, Gruber C, Hayes RJ and Sergeant GR. Medroxyprogesterone Acetate and homozygous sickle cell disease. Lancet 1982; 2 (8292): 229-231

Denevuto F, Ligon DF, Friedrichsen, DH and Wilson HE. Human erythrocyte membrane uptake of progesterone and chemical alterations. Biochim Biophys Acta 1969; 193: 36-47

Diggs LW, Pulliam HW and King JC. The bone changes in sickle cell anaemia. South Med J 1937; 30: 249-259

Dormandy JA. Measurement of whole blood viscosity. In: Lowe GDO, Barbenel JC and Forbes CD, editors. Clinical aspects of blood viscosity and cell deformability. Springer Verlag, Berlin 1981: 67-78

Dormandy J, Flute P, Matrai A, Bogar L, Mikita J, Lowe GDO, Andersen J, Chien S, Shmalzer E and Herschenfeld A. The new St George’s Filtrometer. Clin Hemorheol 1985;5:975-983

Dunn JM and Haynes RL. Sickle cell thalassaemia in pregnancy. Am J Obstet Gynecol 1967; 9: 574

Durocher JR, Weir MS, Lundbland EG, Patow WE and Condrad ME . Effects of oral contraceptive and pregnancy on erythrocyte and surface charge. Proceedings of the Society for Experimental Biology and Medicine 1975; 150: 368-370

Eaton WA and Hoftrichter J. Hemoglobin S gelation and sickle cell disease. Blood 1987; 70:1245

Edlund M, Blomback M, von Schoultz B and Andersson O. On the value of

menorrhagia as a predictor of for coagulation disorders. Am J Haematol 1996; 53: 234- 238

Emond AM, Holman R, Hayes RJ and Serjeant GR. Priapism and impotence in homozygous sickle cell disease. Arch Intern Med 1980; 140 (11): 1434-1437

England JM, Walford DM and Waters DAW. Reassessment of the reliability of the haematocrit. Br J Haematol 1972; 23: 247-256

El Hazmi MAF, Bahakim HM and A1 Fawaz I. Endocrine function in sickle cell anaemia patients. J Tropical Paed 1992; 38: 307-313

El Hazmi MAF, Warsy AS and Bahakim H. Blood Proteins C and S in sickle cell disease. Acta Haematol 1993; 90:114-119

El Shafei AM, Dhaliwal JK and Sandhu AK. Pregnancy in sickle cell disease in Bahrain. Br J Obstet Gynaecol 1992; 99: 101-104

Eisenstein MX, Posmer CA and Friedman S. Sickle cell anaemia in pregnancy. Am J Obstet Gynaecol 1956; 72: 622

Emond A, Holman R, Hayes R and Serjeant GR. Priaprism and impotence in homozygous sickle cell disease. Arch Int Med 1980; 140: 1434-1437

Evans E, Mohandas N and Leung A. Static and dynamic rigidities of normal and sickle erythrocytes. Major influence of cell hemoglobin concentration. J Clin Invest 1984; 73: 477-488

Famodu AA and Oduwa D. Platelet count and platelet factor 3 (PF 3) availability in sickle cell disease. Br J Biomed Sc 1995; 52(4): 323-324

Faragher B and Marguerie C. Essential Statistics for Medical Examinations. Fastest Books» Egerton Court, Knutsford, Cheshire, UK 1998

Farmer RD, Lawrenson RA, Rhompson CR, Kennedy JG and Hambleton IR. Population based study of risk of venous thromboembolism associated with various oral contraceptive. Lancet 1997; 349 (9045): 83-88

Farmer RD, Williams XT, Simpson EL and Nightingale AL. Effect of 1995 pill scare on rates of venous thromboembolism among women taking COCP: Analysis of general practice research database. Br Med J 2000; 321(7259): 477-479

Figueiredo MS and Zago MA. Xhe role of irrevesible sickled cells in reducing the osmotic fragility of red cells in sickle cell anaemia. Acta Physiologica et

Pharmacologica Latinoamericana 1985; 35(1): 49-56

Florence AX and Rahman R. Xhe interaction of some oral contraceptive steroids with lipid monolayers and with erythrocytes. J Pharm Pharmac 1972; 24: 942-949

Fogelman I and Blake G. Bone density measurements and therapeutic decision making. Nucl Med Commun 1998; 19(8): 723-725

Fotherby K. Pharmacokinetics of gestagens: some problems. Am J Obstet Gynecol 1990;163:323-328

Fotherby K. Levonorgestrel: clinical pharmacokinetics. Clin Pharmacokin 1995; 28(3): 203-215

Francis RB. Protein S deficiency in sickle cell anaemia. J Lab Clin Med 1998; May: 571-576

Fraser IS, McCarron G and Markham R. A preliminary study of factors influencing perception of menstrual blood loss volume. Am J Obstet Gynecol 1984; 149: 788-793

Freie HMP. Sickle cell disease and hormonal contraception. Acta Obstet Gynecol Scand 1983;62:211-217

Ganong WF. The gonads: development and function of the reproductive system. Review of Medical Physiology. 20* edition. Lange Medical Books/ McGraw Hill, USA 2001: 398-439

Glasier A. Contraception, sterilisation and abortion. In: Shaw RW, Soutter WP and Stanton SL, editors. Gynaecology. 2"^ edition. Churchill Livingstone, London 1997: 393-411

Goldberg MF. The natural history of untreated proliferative sickle retinopathy. Archives of Opthalmology 1971; 85: 428-437

Graham C, Maude GH and Seijeant GR. Delayed menarche in homozygous sickle cell disease. W Ind Med J 1986; 35: 18-22

Granner DK. Hormones of the gonads. In : Murray RK, Granner DK, Mayes PA and Rodwell VW, editors. Harper’s Biochemistry. 24^ edition. Appleton and Lange, Stamford, CT, USA 1996: 566-581

Grudzinkas JG. Hormones: their actions and measurements in gynaecological practice. In: Shaw RW, Soutter WP and Stanton SL, editors. Gynaecology. 2"^ edition. Churchill Livingstone, London 1997: 137-154

Green MA, Noguchi CT, Marwah SS, Keidan AJ and Stuart J. Polymerisation of Hb S and loss of sickle erythrocyte deformability at arterial oxygen tension. Blood 1986; 68 (suppl 1): 62a

Green D and Scott JP. Is sickle cell disease a thrombotic event? Am J Hematol 1986; 23:317-321

Greenwald JG. Stroke in a woman with sickle cell trait taking oral contraceptives. Conn Med 1971; 35: 231-232

Gueri M and Serjeant GR. Leg ulcers in sickle cell anaemia. Trop Georg Med 1974; 22:155

Guillebaud J. Oral contraception- the combined oral contraceptive. Contraception. Your questions answered. 2nd edition. Churchill Livingstone, Singapore 1993: 164

Hallberg L and Nilsson L. Determination of menstrual blood loss. Scand J Clin Lab Invest 1964; 16: 244-248

Hanss M. Erythrocyte filterability measurement by the initial flow rate method. Biorheology 1983; 20: 199-211

Hargus EP, Sheam R and Colon AR. Pulmonary embolism in a female adolescent with sickle cell trait and oral contraceptive use. Am J Obstet Gynecol 1977; 129: 692

Haris PI, Robillard GT, Van Dijk AA and Chapman D. Potential of 13C and 15N labelling for studying protein-protein interactions using Fourier transform infrared spectroscopy. Biochemistry 1992; 31: 6279-6284

Haynes PJ, Hodgson H, Anderson ABM and Turnbull AC. Measurement of menstrual blood loss in patients complaining of menorrhagia. Br J Obstet Gynaecol 1977; 84: 763-768

Haynes RL and Dunn JM. Oral contraceptives, thrombosis and sickle cell hemaglobinopathies. JAMA 1967; 200 : 994

Hebbel RP, Yamada O, Moldow CF, Jacob HS, White JG and Eaton JW. Abnormal adhesiveness of sickle erythrocytes to cultured vascular endothelium: possible mechanism for micro vascular occlusion in sickle cell disease. J Clin Invest 1980; 65:

154-160

Hebbel RP, Boogaerts MAB, Eaton JW and Steinberg MH. Erythrocyte adherence to endothelium in sickle cell anaemia: a possible determinant of disease severity. N Eng J Med 1980; 302: 92-95

Hebbel RP, Schwartz R and Mohandas N. The adhesiveness of sickle erythrocytes: cause and consequence of abnormal interaction with endothelium, monocytes