Relationship between sex steroid hormone levels and CD4 lymphocytes in HIV infected men

The serum concentrations of the steroid, androgens and estrogens, in the HIV-positive male patients were studied. These men belonged to one of the three main behaviour groups: heterosexual (He), drug addicts (DA) and homosexual (Ho) at early stages (II and III) or at advanced stage of AIDS (IVC), classified according to the Centers for Disease Control (CDC). The circulating concentrations of sex steroids were then analysed with reference to the risk factors, absolute CD4 cell count and the progression of HIV infection. Regardless of risk factors, the stage II and III HIV-infected patients had serum dehydro-epiandrosterone sulfate (DHEAs) (+37%, p < 0.03), testosterone (T) (+24%, p < 0.006) and estrone (E1) (+170%, p < 0.0001) levels higher than those of controls. The patients IVC stage had low serum DHEAs (-48%, p < 0.0001) and elevated estradiol (E2) (+200%, p < 0.0001). According to risk factors, there were no significant differences in androgen and estrogen concentrations between the behaviour groups. There were significant positive correlations between the CD4 cell count and the serum concentrations of DHEAs (p < 0.0001), DHEA (p < 0.01) and E1 (p < 0.006). This suggests that there is a relationship between the circulating sex hormone levels, particularly DHEAs, and the progression of immune depression in HIV, whatever the risk factor. The observed association between DHEAs and the progression of HIV infection suggests that this androgen may play a role in the normal function of the immune system.

Alpha-fetoprotein gene expression in early and full-term human trophoblast

Alpha-fetoprotein (AFP) is a major serum glycoprotein synthesized during fetal life mainly by the yolk sac and the fetal liver. At term, it reaches high concentrations in the maternal intervillous blood, which is in direct contact with the placental trophoblastic microvillous membrane, and this suggests the placental origin of the AFP at the fetal-maternal interface. We used several experimental approaches to investigate the expression of AFP gene and fetal protein production in early gestation and term placentas. RT-PCR and immunological studies clearly identified AFP messenger RNA and AFP protein in the placental villi from first trimester of pregnancy. The AFP gene was also expressed in highly purified cytotrophoblasts from early placentas, and enzymo-immunoassay showed that AFP protein was synthesized and secreted by early cytotrophoblasts. AFP was also detected in the cytoplasm of these cells by immuno-cytochemistry. However, none of these methods detected any expression of the AFP gene in full-term placental villi or in cultured trophoblasts. These findings demonstrate that both AFP mRNA and protein are present in trophoblastic cells early in pregnancy. The absence of AFP gene expression in term placental villi also suggests, that the AFP at the fetal-maternal interface is attributable to a notable transplacental passage of AFP from fetal blood in late pregnancy.

Changes in cortisol/DHEA ratio in HIV-infected men are related to immunological and metabolic perturbations leading to malnutrition and lipodystrophy

HIV-1 infection is associated with immune deficiency and metabolic perturbations leading to malnutrition and lipodystrophy. Because immune response and metabolic perturbations (protein and lipid metabolism) are partly regulated by glucocorticoids and DHEA, we determined serum cortisol and DHEA concentrations, and the cortisol/DHEA ratio in HIV-positive men, either untreated or receiving various antiretroviral treatments (ART), including highly active antiretroviral therapy (HAART). Cortisol levels were found increased in all patients, whatever the stage of the disease and independently of the ART treatment. In contrast, serum DHEA was elevated in the asymptomatic stage, and it was below normal values in AIDS patients, either untreated or mono-ART-treated. The DHEA level was low in HAART-treated patients with lipodystrophy (LD+) and highly increased in HAART-treated patients without lipodystrophy (LD-). Consequently, the cortisol/DHEA ratio was similar to controls in asymptomatic untreated or mono-ART-treated patients, but increased in AIDS patients. Interestingly, this ratio was increased in LD+ HAART-treated men, but normalized in LD- HAART-treated patients. Changes in the cortisol/DHEA ratio were negatively correlated with the in vivo CD4 T-cell counts, with the malnutrition markers, such as body-cell mass and fat mass, and with the increased circulating lipids (cholesterol, triglycerides, and apolipoprotein B) associated to the lipodystrophy syndrome. Our observations show that the cortisol/DHEA ratio is dramatically altered in HIV-infected men, particularly during the syndromes of malnutrition and lipodystrophy, and this ratio remains elevated whatever the antiretroviral treatment, including HAART. These findings have practical clinical implications, since manipulation of this ratio could prevent metabolic (protein and lipid) perturbations.

Corticosteroid-binding globulin status at the fetomaternal interface during human term pregnancy

The status of the corticosteroid-binding globulin (CBG) at the fetomaternal interface, especially in the maternal intervillous blood space (I), was investigated and compared to that of CBG in the maternal (M) and fetal (umbilical arteries [A] and vein [V]) peripheral circulations at term. Immunoquantitation of plasma CBG showed that the CBG concentration in I was 30% less than that in M (P < 0.001) and threefold higher than that in umbilical cord blood (P < 0.001). The microheterogeneity of CBG studied by immunoaffinoelectrophoresis in the presence of concanavalin A and Western blotting indicated that the CBG in I was mainly of maternal origin and different from fetal CBG. A CBG mRNA, but no classic 50- to 59-kDa CBG, was found in isolated term trophoblastic cells. The steroid environment of the CBG in I differed greatly from that in the peripheral maternal and fetal circulations, because the progesterone:cortisol molar ratio in I was 75-fold higher than that in M and 7- to 10-fold higher than that in the fetal circulation. Binding studies revealed that the affinity constants of CBG for cortisol in I, A, and V were significantly lower than that in M plasma (P < 0.02) in their respective hormonal contexts. The binding parameters for I-CBG stripped of endogenous steroids and lipids were close to those for M-CBG but different from those of fetal CBG (P < 0.001). These data reflect the physiological relevance of the CBG-steroid interaction, especially with very CBG-loaded progesterone at the fetomaternal interface during late pregnancy.

Effect of the extract of Ginkgo biloba (EGb 761) on the circulating and cellular profiles of polyunsaturated fatty acids: correlation with the anti-oxidant properties of the extract

Ginkgo biloba extract (EGb 761) has beneficial effects on cognitive functions in aging patients, and on various pathologies, including cardiovascular diseases. Although the extract is known to have antioxidant properties and improve membrane fluidity, the cellular mechanisms underlying these effects have not been determined. Here, we examined the in vivo effects of EGb 761 on circulating and cellular lipids. EGb 761 treatment induced significant increases in the levels of circulating polyunsaturated fatty acids (PUFAs), and a decrease in the saturation index SI (saturated/polyunsaturated species). Plasma triglycerides and cholesterol were not affected, while phospholipids were slightly increased at the higher dose of EGb 761. EGb 761 treatment also induced a significant increase in the levels of PUFAs in erythrocyte membranes, especially for the eicosapentaenoic acid (EPA omega 3), and a decrease in the saturation index. Moreover, the response of erythrocytes to oxidative stress was improved in EGb 761-treated animals (H(2)O(2)-induced cell lysis decreased by 50%). Considering that PUFAs are known to improve membrane fluidity and response to oxidative damage, and are precursors of signaling molecules such as prostaglandins, the effects of EGb 761 on circulating and cellular PUFAs may explain some of the pharmacological properties of Ginkgo biloba.

Lipodystrophy defined by a clinical score in HIV-infected men on highly active antiretroviral therapy: correlation between dyslipidaemia and steroid hormone alterations

BACKGROUND

A syndrome of lipodystrophy, associated with hypertriglyceridaemia, hypercholesterolaemia, hyperinsulinaemia and peripheral insulin resistance has been reported in protease inhibitor (PI)-treated HIV-infected patients. Because lipid metabolism, fat mass distribution and insulin resistance are partly regulated by steroid hormones, we questioned whether lipodystrophy is related to hormonal perturbations.

OBJECTIVE

To evaluate serum lipid and steroid hormone concentrations in HIV-positive men on highly active antiretroviral therapy (HAART) in order to determine whether dyslipidaemia, peripheral loss of fatty tissue and central fat accumulation are related to steroid hormone modifications.

DESIGN

A cross-sectional study.

METHODS

Thirty-seven HIV-1-positive men on HAART, 23 of whom had symptoms of lipodystrophy, according to a subjective clinical score of lipodystrophy (SCSL), were tested. Serum concentrations of cholesterol, triglycerides and their subclasses, apolipoproteins and steroid hormones, including cortisol, dehydroepiandrosterone (DHEA), DHEA sulphate, androstenedione, testosterone and dihydrotestosterone were measured.

RESULTS

Serum cholesterol, very low density lipoprotein (VLDL) cholesterol, triglycerides, VLDL triglycerides, high density lipoprotein (HDL) and low density lipoprotein (LDL) triglycerides, apolipoprotein B (ApoB) and atherogenic ratios of cholesterol:HDL cholesterol, LDL cholesterol:HDL cholesterol and ApoB:apolipoprotein A1 (ApoA1) were significantly increased in lipodystrophy-positive compared with lipodystrophy-negative men. The serum cortisol level was similar in lipodystrophy-positive versus lipodystrophy-negative men, but was elevated compared with controls. Serum DHEA was significantly lower in lipodystrophy-positive versus lipodystrophy-negative men and, consequently, the cortisol:DHEA ratio was increased in lipodystrophy-positive patients. A positive correlation was found between the cortisol:DHEA ratio and increased levels of atherogenic lipids. In addition, the SCSL was positively correlated with dyslipidaemia and the cortisol:DHEA ratio.

CONCLUSION

This study demonstrates an association between the cortisol:DHEA ratio, lipid alterations and lipodystrophy. This syndrome might result from an imbalance between peripheral lipolysis and lipogenesis, both regulated by cortisol and DHEA.

Correlation between increased cortisol:DHEA ratio and malnutrition in HIV-positive men

Malnutrition in HIV-infected patients is characterized by a loss of both fat-free mass (FFM) and fat mass (FM). Glucocorticoids and androgens change during the course of the infection and may play a key role in the protein balance. The serum concentrations of cortisol, adrenal (DHEA and DHEA sulfate) and gonadal androgens (androstenedione, testosterone, and dihydrotestosterone) of HIV-positive men were measured and compared with several parameters of body composition as a function of body weight loss (BWL). The patients were assigned to one of five groups according to their BWL: group I (controls, n = 10) < 5%, group II (n = 7) 5-10%, group III (n = 8) 10.1-16%, group IV (n = 9) 16.1-24%, and group V (n = 4) > 24.1%. Correlation analysis showed significant positive or negative relationships between several markers of malnutrition and adrenal androgens and the cortisol:DHEA ratio, but not with cortisol. BWL was negatively correlated with DHEA (r = -0.69, P < 0.0001), DHEA sulfate (r = -0.58, P < 0.0001) and testosterone (r = -0.34, P < 0.03), but positively with the cortisol:DHEA ratio (r = 0.61, P < 0.0001). In contrast, BCM was positively correlated with DHEA (r = 0.34, P < 0.04) and DHEA sulfate (r = 0.36, P < 0.03) and negatively with the cortisol:DHEA ratio (r = -0.58, P < 0.0001). The cortisol:DHEA ratio was also negatively correlated with BMI (body mass index) (r = -0.56, P < 0.01), fat-free mass (r = -0.48, P < 0.004), fat mass (r = -0.39, P < 0.02), and BCM:weight ratio (r = -0.47, P < 0.005) and positively with the extracellular:intracellular water ratio (r = 0.54, P < 0.001). These data indicate that the steroid hormone environment of patients, particularly their cortisol:DHEA ratio, is linked to the malnutrition associated with HIV infection. The decreased DHEA and increased cortisol in patients with the advanced stages of disease could be associated with increased protein catabolism.

Does high polyunsaturated free fatty acid level at the feto-maternal interface alter steroid hormone message during pregnancy?

Polyunsaturated fatty acids (PUFA) are important in pregnancy, fetal development and parturition. We measured free fatty acids (FFA), albumin and alpha-fetoprotein (AFP) in the maternal and fetal circulations of women undergoing elective Caesarean section at term. We also studied the impact of PUFAs on estrogen (ER) and progesterone receptors (PR) binding properties in vitro in the myometria of pregnant women and ex vivo in human myometrial cells in culture. FFA in intervillous blood (I) (feto-maternal interface) and maternal peripheral blood (M) were similar, while those in the umbilical vein (V) and arteries (A) were 2-4 fold lower (P<0.001). PUFA levels were low in M and 3 fold higher in I, A and V (P< 0.001); consequently C20:4 and C22:6 were most abundant in intervillous space. Albumin was uniformly distributed throughout the maternal-fetal unit, but there was a transplacental gradient in AFP. The AFP in the intervillous space had a special conformation (less immuno-reactive, more anionic), suggesting loading with PUFA. Physiological concentrations of C20:4 stimulated estradiol binding, but inhibited progestin binding. C20:4 inhibited progesterone binding by decreasing the number of binding sites, with no change in apparent affinity, in vitro in myometrial tissue and ex vivo in myometrial cells. Thus PUFA may modulate the steroid hormone message, so that the high C20:4 concentration at the maternal-fetal interface at term may help amplify the estrogen signal and inhibit the progesterone signal.

Basal concentrations of various steroids in the nonobese diabetic (NOD) mouse and effect of immobilization stress

The progression of type I diabetes in the NOD mouse is modulated by, among other things, stressful events and steroids. We measured in 2-month-old prediabetic NOD mice various circulating steroids (progesterone, corticosterone, dehydroepiandrosterone, delta4-androstenedione, testosterone, estrone and estradiol) under basal and stressful conditions (1.5h immobilization). Basal progesterone concentrations were low but measurable in randomized cycling NOD females and under the detection limit in NOD males. Immobilization increased progesterone concentrations in both sexes. Serum corticosterone concentrations also increased after immobilization but with the sexual dimorphism normally observed in rodents. Dehydroepiandrosterone concentrations were similar in both sexes and remained unaffected by stress. Testosterone and delta4-androstenedione were drastically reduced after immobilization in NOD males. Serum estrone and estradiol were not found to be statistically different in NOD females and males, but slightly higher to that described in the literature, and immobilization increased estrone concentrations in NOD males. In conclusion, while nonspecific to the NOD mouse, the modulation of circulating corticosteroids, estrogens and androgens induced by environmental factors may be part of the mechanism(s) by which these factors modulate the progression of type I diabetes. The hormonal changes may act in a complex manner at different levels: the immune system, the islet of Langerhans and the other structures involved in glucose homeostasis.

Fatty acids involved in signal cross-talk between cell membrane and nucleus

The results presented underline the fact that the nature and the concentration of the non-esterified fatty acids (NEFAs) liberated from membrane lipids, particularly the essential ones issued from lipid nutrition, clearly belong to a large group of factors (hormones, retinoids, growth factors, cytokines...) which control the shift between cell multiplication and differentiation. NEFAs act on this shift, per se or after being metabolized, by influencing, as second messengers or modulators, the intertwined mechanisms of action of growth factors and steroid hormones. These results may explain the molecular links which exist between endocrinology, oncology and nutrition.

Biological complexity is under the 'strange attraction' of non-esterified fatty acids

It is now clear from numerous data that non-esterified fatty acids (NEFAs) can act without any metabolic modification as second messengers or modulators of the complex signalling network which is characteristic of mammals. This network can respond differently to adapt the organism to the various endogenous and exogenous environmental situations. NEFAs have a wide range of molecular structures, and thus can exert different specific modulatory actions on this signalling network, such as amplification, inhibition or signal redirection. We have chosen the term 'strange attractions' to describe these signalling modulations by analogy with the 'strange attractions' concept introduced in deterministic chaos theory. NEFAs can modulate the functions of mammals at all levels of organization (molecular, cellular, tissue, organ, etc).

Effect of interferon alpha on high serum androgen concentrations in HIV positive men with Kaposi's sarcoma

AIM

To measure serum androgen concentrations in men with HIV related Kaposi's sarcoma (KS) who had been treated with recombinant interferon (IFN) alpha-2a to determine the role of androgens on the development of KS lesions.

METHODS

32 men with HIV related KS who had been treated with IFN were studied: 24 men in complete KS remission and eight not in remission. Serum androgen concentrations were determined before, during, and after IFN treatment and correlated with clinical remission.

RESULTS

All patients in complete KS remission had lower serum androgen concentrations following IFN treatment: -51% for dehydroepiandrosterone (DHEA) (p < 0.0001); -38% for DHEA sulphate (p < 0.002);-39% for androstenedione (p < 0.002); and -44% for testosterone (p < 0.007). These decreases brought the serum concentrations to about normal levels. However, IFN had varying effects on serum androgen concentrations in the men not in remission: a small decrease, a large increase in one androgen, or no change in serum androgens.

CONCLUSIONS

The association between serum androgen levels and the progression or remission of HIV associated KS suggests that androgens affect the development of KS lesions. A clear understanding of the changes in the androgen environment may provide a sound basis for the development of new therapeutic strategies.

High polyunsaturated fatty acid, thromboxane A2, and alpha-fetoprotein concentrations at the human feto-maternal interface

Polyunsaturated fatty acids (PUFA) like arachidonic (C20:4) and docosahexaenoic (C22:6) acids are essential for harmonious fetal development. This study evaluates, at near term, the distributions of free fatty acids (FFA) and their fetal carrier protein, alpha-fetoprotein (AFP) in the maternal (M) and fetal circulation (umbilical arteries (A) and vein (V)), focusing on the feto-material interface where maternal intervillous blood (I) contacts the fetal trophoblast. FFA concentrations in intervillous and maternal blood were similar, while those in umbilical arteries and vein were 2- to 4-fold lower (P < 0.001). There were more saturated FFA in umbilical vein (41%) and arteries (44%) blood than in maternal (30%) and intervillous (32%) blood (P < 0.001). Monounsaturated FFA predominated (P < 0.001) in maternal (43%) blood, but not in intervillous (35%), umbilical vein (33%) and arteries (31%) blood. Di-triunsaturated FFA were similar in intervillous and maternal (25%) blood and lower in umbilical vein and arteries (16%) (P < 0.001). PUFA were low in maternal (2.5%) blood and higher in intervillous and umbilical vein and arteries (9%, P < 0.001); consequently, C20:4 (40 microM) and C22:6 (16 microM) were the most abundant in the intervillous space. The AFP concentrations and AFP lectin-reactive isoforms were similar in intervillous and umbilical vein and arteries blood, but immuno-electrophoresis revealed a particular AFP conformation (less immuno-reactive, more anionic) in the intervillous space, suggesting that AFP is heavily loaded with PUFA at the feto-maternal interface. Prostacyclin derived from C20:4 was similar in all compartments but the thromboxane A2 concentration was 10-fold higher in intervillous blood than in maternal and umbilical vein and arteries blood. Thus the feto-maternal interface has a specific pattern of cell signalling molecules that might critically influence parturition.

What are ago-antagonistic couples? Their role in normal and pathological situations. Therapeutical consequences

Two classes of steroid hormones are successively produced following a microbial infection stress in rat and man. First there are those of attenuation and acceptation, the glucocorticoids and progestins, which correspond to the temporization phase of reaction to stress. Secondly, there are those of rejection or creative reinforcement, namely the adrenal androgens converted in certain circumstances to estrogens by aromatization, which are necessary to fight against or accept the stressor. We suggest that these two classes of signal carrier molecules function as agonistic-antagonistic couples which work to prevent the organism from going too far in the direction of attenuation-acceptation or, on the contrary, in the direction of rejection-reinforcement. The presence of agonistic-antagonistic couples can be identified as regulating numerous other steps in the signal networks. Dysfunctions of such couples result in pathological situations, characterized by an imbalance in the concentration and correspondingly in the biological activity of one of the partners due to a change in the 'equilibrium constant' of the ago-antagonistic couple, changes in the level of synthesis or catabolism of one of the partners, the presence in adequate time and location of the partners, or the deficiency of the receptor of at least one of the partners. Different 'paradoxical' therapeutical strategies are envisaged to reequilibrate the imbalance.

Serum cortisol and DHEA concentrations during HIV infection

The progression of HIV infection is accompanied by severe immunodepression and cachexia, particularly during advanced stages. The immune depression is due largely to a dramatic drop in the number of CD4 cells. The loss of body weight is mainly due to a reduced fat-free mass with no change in adipose tissue. We determined the serum concentrations of cortisol and DHEA and their correlations with absolute CD4 cell counts and changes in body weight of HIV-positive men. The results of five retrospective and prospective studies indicate that the serum concentrations of cortisol and DHEA in HIV-infected patients were different from those of HIV-negative controls. Serum cortisol was elevated at all stages of infection (+20 to +50%, p < .05 to p < .001) particularly in AIDS patients (stage IV C). In contrast, the serum DHEA concentrations were closely correlated with the stage of HIV-infection, being higher in the early stages (stages II and III or > 500 CD4) than in advanced stages (IV C or < 500 CD4)-in the latter being below those of HIV-negative men-or in controls (+40 to 100%, p < .01 to p < .001). There was a negative linear correlation between the CD4 cell counts and cortisol (r = -0.4, p < .02) and a positive linear correlation with DHEA (r = +0.36, p < .01). There was no significant correlation between delta body weight and serum cortisol. In contrast, there was a negative correlation between serum DHEA and delta body weight (%) (r = -0.69, p < .0001) and a positive correlation with the cortisol/DHEA ratio (r = +0.61, p < .0001). There is thus a link between the circulating concentrations of adrenal steroids and the progression of immunosuppression and cachexia during HIV-infection. This raises the question of whether there is a cause-and-effect relationship between clinical progression and circulating steroid concentrations. Further investigations into the relationship between the ratio cortisol/DHEA and the immune response and cachexia should indicate the contributions of these steroids to the etiology of HIV infection and lead to the development of new therapeutic strategies.

Expression and development of a functional plasmalemmal 5-hydroxytryptamine transporter by thyroid follicular cells

5-Hydroxytryptamine (5-HT) is synthesized and secreted by thyroid parafollicular (PF) cells. As all PF granules contain 5-HT, it is released whenever PF cells secrete. Because 5-HT stimulates follicular (F) cells and can modulate their response to TSH, 5-HT has been proposed to be a paracrine PF to F cell transmitter. This role would require a thyroid mechanism to rapidly inactivate 5-HT. A 5-HT transporter (SERT) in the plasma membrane of serotonergic neurons inactivates neuronal 5-HT. We thus tested the hypothesis that this molecule is expressed in the thyroid. Messenger RNA encoding SERT was demonstrated in both the human thyroid and a rat F cell line (FRTL-5). SERT immunoreactivity was detected in rat F, but not PF, cells. Transporter-mediated uptake of [3H]5-HT by F cells arose early in development (E13 in mice) and was maintained in adult life in mice, guinea pigs, bats, and rats (FRTL-5 cells). These observations indicate that a functional SERT is expressed in the thyroid, not by the 5-HT-secreting PF cells, but by their putative F cell targets.

Hypothalamo-pituitary-adrenal function in human immunodeficiency virus-infected men

We prospectively studied adrenal function in 51 human immunodeficiency virus-positive male patients, including heterosexuals, homosexuals, and iv drug users, classified according to 1987 CDC criteria as belonging to stages II/III or IVC. Basal serum concentrations of cortisol (F), progesterone (P4) and 17 alpha-hydroxyprogesterone (17 alpha-OHP4) were determined during the two stages. In stage IVC patients, the circadian rhythms of ACTH and F were assessed, and ovine CRH (oCRH) and immediate cosyntropin-stimulating tests were evaluated. Serum concentrations of hormones were analyzed in relationship to the absolute CD4 cell count in all subjects. The mean serum F concentration in stage IVC patients, the mean P4 concentration in stage II/III and IVC patients, and the mean 17 alpha-OHP4 level in stage II/III patients were significantly increased compared to control values (P < 0.0001, P < 0.0001, and P < 0.002, respectively). The mean serum F concentration in stage IVC patients was significantly increased compared to that in stage II/III patients (P < 0.004), and the mean serum 17 alpha-OHP4 concentration in stage II/III patients was significantly increased compared to that in stage IVC patients (P < 0.02). In the 22 stage IVC patients, the circadian rhythms of ACTH and F were normal in all but 7 for ACTH and 5 for F, whereas oCRH test results indicated that 14 of them had reduced or blunted responses. By contrast, cosyntropin stimulation results were normal. CD4 cell counts were significantly negatively correlated with the serum F concentration (P < 0.02). In conclusion, during human immunodeficiency virus infection, the serum F concentration was negatively correlated with CD4 cell counts. Cosyntropin test results were normal, but 63% of the stage IVC men had abnormal responses to oCRH.

Postprandial free fatty acids stimulate activity of human corticosteroid binding globulin

The effect of postprandial variation of free fatty acids (FFA) on serum corticosteroid binding globulin (CBG) properties and cortisol (hydrocortisone) concentrations were explored in 11 women (20-30 yr) during 8 h after an oral load of tallow (26% C16:0, 18% C18:0, and 43% C18:1), oleic-sunflower (oleic-SF; 73% C18:1), sunflower (SF; 67% C18:2), and mixed oil (MO; 39% C18:1 and 48% C18:2). Serum FFA increased little after SF and MO but more than doubled in the late postprandial period (6 and 8 h) after oleic-SF (due to monounsaturated FFA) or tallow (due to saturated and monounsaturated FFA). CBG concentrations remained unchanged, but in relation with the postprandial elevation of serum FFA, CBG binding activity was increased after tallow or oleic-SF as a result of a combined two- to threefold increase in affinity constant and a 50% reduction in binding sites. Immunological and in vitro binding studies showed the changes in CBG behavior to be conformational and to be mediated mainly by monounsaturated FFA, especially C18:1. The modifications of CBG properties were associated with sustained high concentrations of cortisol (suppression of midday decrease) 6 and 8 h after tallow or oleic-SF. Thus dietary FFA may have an impact on bioavailability of glucocorticoids.

Interactions between phytoestrogens and human sex steroid binding protein

The interactions of human Sex steroid binding protein (SBP) and the lignans [Nordihydrogaiaretic acid (NDGA) enterolactone (Ent), enterodiol (End)] and isoflavonoid phytoestrogens [Equol (Eq), diazein Dad), genistein (Gen)] were studied. The phytoestrogens had different dose-dependent inhibitory effects on steroid binding by SBP. Their relative efficiencies were: Ent> or = NDGA = Eq > Gen for displacing E2 and Eq > Ent > NDGA > Gen for displacing T. End and Dad were much less active. Scatchard analysis suggested that NDGA had similar non- competitive effects on T and E2 binding by reducing the number of binding sites without changing the association constants. But Eq seemed to inhibit E2 binding non-competitively and T binding competitively. NDGA binding to SBP reduced the immunorecognition of SBP by monospecific anti-SBP antibodies, suggesting that NDGA changed SBP immunoreactivity. Unlike NDGA, Eq binding to SBP caused no immunological changes in SBP, indicating qualitative differences in the effects of the lignan and isoflavonoid. Our results indicate that phytoestrogens may modulate the SBP activity and so influence the role of this protein in the delivery of hormonal information to sex steroid-dependent cells.

Differences in androgens of HIV positive patients with and without Kaposi sarcoma

AIM

Since most forms of Kaposi sarcoma are much more common in men than in women, the aim of this study was to examine serum concentrations of sex steroids in HIV positive men with and without Kaposi sarcoma.

METHODS

Blood samples from 34 HIV positive men without Kaposi sarcoma (KS-) and 28 with Kaposi sarcoma (KS+) and from 35 HIV negative men (controls) were analysed for adrenal and gonadal steroids. Further analysis was done in subgroups classified by CD4 lymphocyte counts.

RESULTS

KS+ patients had significantly higher serum dehydroepiandrosterone (DHEA) and testosterone concentrations than the KS- patients, and their DHEA, DHEA sulphate, testosterone, and androstenedione values were higher than in the controls. The KS+ patients with more than 500 CD4 lymphocytes per mm3 had significantly higher serum DHEA, DHEA sulphate, and testosterone than the KS- patients with the same CD4 counts; those with 500-200 CD4 cells/mm3 had higher serum DHEA and testosterone than the equivalent KS- men; and those with < 200 CD4 cells/mm3 had raised DHEA only compared with KS- men. Both KS+ and KS- men had higher serum progesterone and oestradiol than the controls. Glucocorticoids were not significantly altered.

CONCLUSIONS

The high androgen levels in KS+ patients, particularly in the early stages of the disease (> 500 CD4 cells/mm3), may affect the immune system by inducing an abnormal cytokine profile, or by increasing T8 proliferation and activation, or both. This raises the question of the relationship between androgens and Kaposi sarcoma.

Unsaturated fatty acids synergistically enhance glucocorticoid-induced gene expression

Regulation by unsaturated fatty acids of glucocorticoid-sensitive gene transcription was studied in HeLa cells transiently transfected with a mouse mammary tumour virus-luciferase reporter gene. Arachidonic acid and docosahexaenoic acid by themselves had no effect on basal levels of luciferase expression. However, they were able to enhance dexamethasone-induced transcription by 1.4-2.3 times (25-42 times the control levels) in a dose-dependent manner (ED50: 18 and 8 microM) for arachidonic and docosahexaenoic acid, respectively. The glucocorticoid antagonist RU486 effectively antagonized the dexamethasone response as well as the synergistic effect observed in the presence of arachidonic and docosahexaenoic acids, suggesting that the glucocorticoid receptor was an intermediate in the fatty acid synergism of the dexamethasone response. These studies show that fatty acids may be playing a role in modulating the intracellular steroid hormone signalling pathway to co-regulate a glucocorticoid-sensitive promoter.