George Christodoulakos

Pathogenesis of endometriosis: The role of defective ‘immunosurveillance’

Objective To analyse the aetiopathogenesis and the role of defective ‘immunosurveillance’ in endometriosis. Method Review of studies on the pathogenesis of endometriosis, focusing particularly on novel molecules which express adhesive or proteolytic properties. Hypotheses addressing the role of oxidative stress in endometriosis were also reviewed. Results Endometriosis is a multifactorial disease associated with a general inflammatory response aiming to clear the peritoneal cavity from the ectopic endometriotic cells and tissue. Modern theories suggest that this inflammatory response creates an environment that may promote implantation and proliferation due to defective ‘immunosurveillance’. Conclusion The modern interpretation of the theory of reflux menstruation holds that women destined to develop endometriosis have a deficient immune system, which cannot defend against regurgitated endometrial cells. New findings on genetics, immune modulation, and secreted products of endometriotic lesions of affected women have given insight into the pathogenesis of this disorder and may serve as the background for new treatments of endometriosis-associated pain and infertility.

Thyroid autoimmunity in patients with recurrent spontaneous miscarriages

Recurrent spontaneous miscarriage (RSM) is a multifactorial problem. Auto- and alloimmune parameters have been implicated. Antithyroid antibodies (ATA) were tested in a group of women with RSM. The presence of antipatemal antibodies (APCA) was evaluated as an index of alloimmune contribution. Thirty euthyroid women with RSM (three or more consecutive miscarriages) aged 25–37 years were compared with 15 matched controls. Thyroid peroxidase (TPO) and thyroglobulin antibodies were tested with a chemiluminescence immunoassay and APCA were tested with a cross-match reaction. Results were compared using the chi-squared test. There was a higher frequency of ATA in women with RSM compared to controls (37% versus 13%, p < 0.05). Twenty of the women (67%) with RSM were tested negative for APCA, indicating an alloimmune contribution to their infertility. In this subgroup of women, the frequency of ATA continued to be higher than controls (40% versus 13%, p < 0.05). In conclusion, women with RSM, independent of APCA status, have a higher frequency of ATA. This may represent an additional marker for impaired regulation of the maternal immune system.

Mammographic changes associated with raloxifene and tibolone therapy in postmenopausal women : A prospective study

Objective The prolonged use of estrogen therapy is associated with a slightly increased risk of breast cancer. Alternative therapies that are effective in the prevention of menopause, having associated morbidities but no unwanted effects, are of primary interest in the pharmacologic research. The aim of this study was to evaluate the effect of two alternative to estrogens drugs, the selective estrogen receptor modulator raloxifene and the tissue-specific tibolone, on the mammographic appearance of the breast. Design The study group comprised 131 postmenopausal women aged 41 to 67 years. The women were at least 2 years postmenopausal, free of climacteric symptoms, and at the time of entry to the study had not had therapy for at least 9 months. Women with risk factors for osteoporosis or cardiovascular disease were allocated either to tibolone (n = 56) or raloxifene (n = 48) therapy. Women with no risk factors and women who either did not qualify for or denied treatment (n = 27) served as controls. The study duration was 12 months. Women received a baseline mammogram before commencing therapy and a repeat mammogram at the end of the study period. Mammogram findings were classified according to the modified Wolfe criteria by two expert radiologists. Results No difference was identified between groups with respect to baseline characteristics associated with breast cancer risk. Similarly, no difference was detected between groups concerning the modified Wolfe classification of baseline mammographic findings. In the tibolone group, 10.7% of the women showed an increase in breast density in the 12-month reevaluation. The respective figure in the raloxifene group was 6.3%, whereas no woman in the control group showed an increase in breast density. Differences in the increase in breast density between groups did not, however, reach statistical significance. Accordingly, 10.7% of women in the tibolone group and 18.8% of women in the raloxifene group exhibited involutionary changes in the repeat mammogram, whereas 25.9% of women in the control group revealed a decrease in breast density in the 12-month examination. The percentages were not significantly different between groups. Conclusions Breast density as shown by mammography was stable in a majority of patients and changed in a minority of cases for both tibolone and raloxifene. In most patients, these drugs are not likely to interfere with mammogram interpretation. Larger long-term studies are needed to confirm the impact of prolonged tibolone or raloxifene administration on mammography.

Thoracic Endometriosis Syndrome

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterine cavity and is usually confined to the pelvis. Thoracic endometriosis syndrome (TES) is a rare disorder characterized by the presence of functioning endometrial tissue in the pleura, the lung parenchyma and the airways. TES may present with hemoptysis, due to the shedding of endometrial tissue in the bronchial tree, or spontaneous pneumothorax or hemothorax if the endometrial tissue is localized peripherally. Patients are of reproductive age, often nulliparous, with long-standing symptoms. The crucial issue for establishing the diagnosis is the cyclicity of the symptoms which occur along with the menstrual cycle. TES is virtually a diagnosis of exclusion, established on clinical grounds, since neither CT nor endoscopy are specific for TES. Treatment consists of gonadotropin-releasing hormone analogues, aiming to suppress the hypophyseal-gonadal axis, so as to ensure a regression of the endometrial implants. If medical treatment fails, surgical resection of the endometriomas is suggested, although relapse rate may be high.

The Cardiovascular Effects of Selective Estrogen Receptor Modulators

Abstract:  Coronary artery disease (CAD) is the main contributor of mortality among postmenopausal women. Menopause‐associated estrogen deficiency has both metabolic and vascular consequences that increase the risk for CAD. Hormone therapy (HT) has been reported to have a beneficial effect on metabolic and vascular factors influencing the incidence of CAD. Although observational studies have reported that HT reduces significantly the risk for CAD, randomized clinical trials (WHI, HERS, ERA) have questioned the efficacy of HT in primary and secondary CAD prevention despite confirming the lipid‐lowering effect of HT. In the aftermath of the WHI, increased interest has been given to the action of selective estrogen receptor modulators (SERMs) and their effect on the cardiovascular system. The chemical structure of SERMs, either triphenylethilyn (tamoxifen) or benzothiophene (raloxifene) derivatives, differs from that of estrogens. SERMs are nonsteroidal molecules that bind, with high affinity, to the ER. SERMs induce conformational changes to the ligand‐binding domain of the ER that modulate the ability of the ER to interact with coregulator proteins. The relative balance of coregulators within a cell determines the transcriptional activity of the receptor–ligand complex. SERMs therefore may express an estrogen‐agonist or estrogen‐antagonist effect depending on the tissue targeted. SERMs express variable effects on the metabolic and vascular factors influencing the incidence of CAD. SERMs have been reported to modulate favorably the lipid–lipoprotein profile. Toremifene expresses the most beneficial effect followed by tamoxifene and raloxifene, while ospexifene and HMR‐3339 have the least effect and may even increase triglycerides. Raloxifene and tamoxifene decrease serum homocysteine levels and C‐reactive proteins (CRP), which are both markers of CAD risk. Raloxifene has been reported to increase the nitric oxide (NO)–endothelin (ET)‐1 ratio and, thus, contribute to proper endothelial function and vasodilation. Toremifene has no effect on the NO–ET‐1 ratio. Finally, raloxifene decreases the vascular cell adhesion molecules and the inflammatory cytokines TNF‐α and IL‐6. Of the SERMs, raloxifene has had the most extensive evaluation regarding the effect on the vascular wall of endothelium. Although not confirmed by large clinical trials, raloxifene has been reported to have an effect on the cohesion of the intercellular junction (VE‐cadherin) and the synthesis—degradation of extracellular matrix (MMP‐2). The Multiple Outcomes Raloxifene Evaluation (MORE) study has reported that raloxifene may have a cardioprotective effect when administered to postmenopausal women at high risk for CAD disease.

Role of postmenopausal hormone replacement therapy on body fat gain and leptin levels

During menopause women tend to gain body fat. The increase in adiposity seems to be a consequence of the decline in endogenous estrogens and the reduced energy expenditure. The role of post-menopausal hormone replacement therapy (pHT) in modulating visceral obesity is controversial. Some studies have shown that pHT has no effect on body weight while in other studies pHT increased body weight. Leptin is an adipocyte-derived hormone and its levels reflect the amount of adipose tissue. Obesity is associated with elevated serum leptin levels. The effect of pHT on leptin levels is also controversial. In some studies pHT increased leptin levels while other studies have not confirmed this increasing effect. The major problem encountered during administration of hormone therapy seems to be the timing of pHT initiation which is a strong confounder on the effect of pHT on leptin levels in postmenopausal women.

Effect of hormone replacement therapy, tibolone and raloxifene on serum lipids, apolipoprotein A1, apolipoprotein B and lipoprotein(a) in Greek postmenopausal women

The aim of this study was to assess the effect of estrogen, two regimens of continuous combined hormone replacement therapy (HRT), tibolone and raloxifene on serum lipid, apolipoprotein A1 and B and lipoprotein(a) levels in Greek postmenopausal women. A total of 350 postmenopausal women were studied in a prospective open design. Women were assigned to one of the following regimens depending on the presence of risk factors for osteoporosis, climacteric symptoms and an intact uterus: conjugated equine estrogen 0.625 mg (CEE, n=34), continuous combined CEE 0.625 mg plus medroxyprogesterone acetate (MPA) 5 mg, (n=80), continuous combined 17β-estradiol 2 mg plus norethisterone acetate (NETA) 1 mg (n=58), tibolone 2.5 mg (n=83) and raloxifene HCl 60 mg (n=50). Forty-five postmenopausal women with no indications for HRT served as controls. Total cholesterol (TC), low-density lipoprotein (LDL) cholestrol and high-density lipoprotein (HDL) cholesterol, triglyceride (TG), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and lipoprotein(a) (Lp(a)) levels were assessed in each subject at baseline, and at 6 and 12 months of therapy. All therapy regimens lowered TC levels compared to baseline (4.2-8.0% decrease). This effect was more prominent in the subgoup of women with high baseline TC levels (9.1-20.4% decrease). LDL cholesterol decreased significantly in CEE, CEE/MPA and raloxifene groups (−11.2%, −11.9% and −11.0%, respectively). Hypercholesterolemic women exhibited a steeper decrease in LDL cholesterol (10.6-27.8% in all therapy groups). TG levels increased significantly in the CEE and CEE/MPA groups (23.7% and 21.8%, respectively), while estradiol/NETA had no effect on TG levels. Tibolone decreased TG levels markedly, by 20.6%, while raloxifene had no TG-lowering effect. HDL cholesterol and ApoA1 were increased by CEE and CEE/MPA (HDL cholesterol, 7.4% and 11.8%, respectively; ApoA1, 17.8% and 7.9%, respectively) and decreased by tibolone (HDL cholesterol, −13.6%; and ApoA1, −9.9%). All therapy regimens except raloxifene lowered Lp(a) levels, with tibolone having the more pronounced effect (−13.2 to −29.0%). In conclusion, each therapy regimen had a different effect on lipid-lipoprotein levels, exerting favorable and unfavorable modifications. Hypercholesterolemic women seemed to benefit more from the cholesterol-lowering effect of estrogen replacement therapy/HRT. The choice for a particular regimen should be based on individual needs, indications and lipid-lipoprotein profile.

Apoptosis in Atherosclerosis: A Mini-Review

Apoptosis in atherosclerotic lesions is triggered by inflammatory processes, both via cell-cell contact and by cytokines and oxidized lipids. The role of apoptosis in atherogenesis is dual, depending on the stage of the plaque: In early stages, apoptotic death of smooth muscle--and inflammatory cells, such as lymphocytes and macrophages--may delay atherosclerotic process. However, once the plaque is formed, apoptosis may lead to plaque rupture and thrombosis.

Determinants of serum leptin levels in healthy postmenopausal women

The aim of this study was to evaluate factors that influence leptin levels in postmenopausal women. One hundred and forty-four postmenopausal women were evaluated cross-sectionally. In every woman a complete medical history was obtained, body mass index (BMI) was recorded and morning fasting blood was obtained for the determination of serum leptin, follicle stimulating hormone (FSH), estradiol, testosterone, Δ4androstendione, dehydroepiandrosterone sulphate (DHEAS) and insulin. In univariate analysis, age, BMI and insulin were positively correlated with serum leptin, while DHEAS showed a negative association with leptin concentrations (age r=0.21, p=0.005, BMI r=0.41, p=0.0001, insulin r=0.20, p=0.008, DHEAS r=−0.28, p=0.0001). In stepwise multivariate regression analysis serum leptin could be best predicted from BMI, serum insulin and serum DHEAS [leptin= (1.41 * BMI) −(0.01 * DHEAS) + (3.26 * insulin) −26.3; model r2=0.24, p=0.001]. In conclusion, BMI and serum insulin have a positive while serum DHEAS has a negative impact on serum leptin. Neither endogenous estradiol, nor endogenous testosterone are associated with leptin levels. Further studies are needed to elucidate the role of leptin in determining body weight and composition in postmenopausal women.

Effects of estrogen–progestin and raloxifene therapy on nitric oxide, prostacyclin and endothelin-1 synthesis

This randomized double-blind study was conducted to investigate the effects of 17β-estradiol plus norethisterone acetate, and raloxifene, on nitric oxide (NO), prostacyclin (PGI2) and endothelin-1 (ET-1) serum levels in postmenopausal women. Treatment was initiated after a 28-50 day placebo period. Fourteen women were treated daily with 17β-estradiol 2 mg plus norethisterone acetate 1 mg (E2 + NETA), and 14 with raloxifene HCl 60 mg for a period of 6 months. Serum NO, PGI2 and ET-1 levels were estimated at baseline, after placebo, and at months 3 and 6. E2 + NETA decreased NO levels significantly, while raloxifene did not cause any appreciable change. Both regimens decreased PGI2 levels and ET-1 levels significantly. Finally, E2 + NETA and raloxifene increased the NO/ET-1 ratio by 61.4% and 81.1%, respectively. In conclusion, both regimens may exert a cardioprotective effect by decreasing ET-1 levels and increasing the NO/ET-1 ratio. In contrast, both regimens had a negative influence on PGI2 levels.