Diurnal rhythms of serum and plasma cytokine profiles in healthy elderly individuals assessed using membrane based multiplexed immunoassay.

BACKGROUND: Recent clinical studies suggest that inflammatory mediators have huge potential in individualized therapy and in efficacy screening and can be utilized as biomarkers for a plethora of pathological conditions. The standard approach for detecting and measuring these inflammatory mediators is via blood samples. Nevertheless, there is no scientific report providing solid evidence on the most suitable blood compartment that will give the optimal inflammatory mediator measurement, or regarding the diurnal variation of circulating mediators. In this study, we present the biological variability of circulating cytokines and chemokines from healthy individuals (mean age 59 years) assessed by a novel membrane-based assay. METHODS: Fifteen males and an equal number of females (all above 50 years) with no known inflammatory condition were selected. Through a planar method, named Proteome Profiler™, improved with fluorescence readout into a semi-quantitative multiplex assay, a screening of 36 inflammatory mediators was performed in serum and plasma of morning and afternoon blood withdrawals. RESULTS: The multiplex analysis revealed that the physiological variability of several circulating inflammatory mediators was relatively small within a cohort of 30 healthy aging subjects. There was no substantial gender effect in the inflammatory mediator profile. On the contrary, most of the cytokine/chemokine values measured in the afternoon collection were found to be higher compared to the morning ones, particularly in plasma. CONCLUSIONS: In this study we provide evidence that circulating cytokine and chemokine levels of healthy individuals are elevated when blood is sampled in the afternoon compared to the morning, as influenced by the circulating cortisol levels. Furthermore, we report significant differences between cytokine/chemokine levels measured in serum and plasma. Our results provide essential information for future studies that will focus on examining circulating inflammatory mediator differences between healthy and diseased individuals.

Improving membrane based multiplex immunoassays for semi-quantitative detection of multiple cytokines in a single sample.

BACKGROUND: Inflammatory mediators can serve as biomarkers for the monitoring of the disease progression or prognosis in many conditions. In the present study we introduce an adaptation of a membrane-based technique in which the level of up to 40 cytokines and chemokines can be determined in both human and rodent blood in a semi-quantitative way. The planar assay was modified using the LI-COR (R) detection system (fluorescence based) rather than chemiluminescence and semi-quantitative outcomes were achieved by normalizing the outcomes using the automated exposure settings of the Odyssey readout device. The results were compared to the gold standard assay, namely ELISA. RESULTS: The improved planar assay allowed the detection of a considerably higher number of analytes (n = 30 and n = 5 for fluorescent and chemiluminescent detection, respectively). The improved planar method showed high sensitivity up to 17 pg/ml and a linear correlation of the normalized fluorescence intensity with the results from the ELISA (r = 0.91). CONCLUSIONS: The results show that the membrane-based technique is a semi-quantitative assay that correlates satisfactorily to the gold standard when enhanced by the use of fluorescence and subsequent semi-quantitative analysis. This promising technique can be used to investigate inflammatory profiles in multiple conditions, particularly in studies with constraints in sample sizes and/or budget.

Inhibition of type 1 17ß-hydroxysteroid dehydrogenase impairs the synthesis of 17ß-estradiol in endometriosis lesions.

CONTEXT: Endometriosis affects 10% of the women before menopause and has important personal, professional, and societal economic burdens. Because current medical treatments are aimed at reducing the symptoms only, novel therapeutic targets should be identified. Endometriosis is estrogen dependent and in some patients the endometriosis tissue is able to produce estrogens in an autocrine/paracrine manner. In a number of patients, this is the consequence of the high local activity of the 17ß-hydroxysteroid-dehydrogenases (17ß-HSDs), enzymes able to generate active estrogens from precursors with low activity. OBJECTIVE: The objective of the study was to identify the 17ß-HSD(s) responsible for the high local generation of estrogens in endometriosis and test the possibility to inhibit these enzymes for therapeutic purposes. DESIGN: The expression of different 17ß-HSDs involved in the estrogen metabolism was assessed by real-time PCR in eutopic and ectopic tissue from endometriosis patients (n=14). These biopsies had previously confirmed unbalanced local 17ß-HSD activity, which caused high estrogen generation. The possibility to block the synthesis of estrogens by one inhibitor specific for type 1 17ß-HSD was assessed by HPLC in tissue lysates from endometriosis tissues (n=27). RESULTS: In all but one of the patients, a high type 1 17ß-HSD level is associated with the unbalanced metabolism of estrogens, leading to higher estrogen synthesis in endometriosis than in the endometrium inside the uterus. Inhibition of type 1 17ß-HSD restores to various extents, depending on the patient, the correct metabolism. In 19 of 27 patients analyzed (70%), the 17ß-HSD type 1 inhibitor decreased the generation of 17ß-estradiol by greater than 85%. CONCLUSIONS: Inhibition of 17ß-HSD type 1 can be a potential future treatment option aimed at restoring the correct metabolic balance of estrogens in endometriosis patients with increased local 17ß-HSD type 1 enzyme activity.

Overexpression of 17ß-hydroxysteroid dehydrogenase type 1 increases the exposure of endometrial cancer to 17ß-estradiol.

CONTEXT: The local interconversions between estrone (low activity) and 17ß-estradiol (potent compound) by 17ß-hydroxysteroid dehydrogenases (17ß-HSDs) can lead to high 17ß-estradiol generation in endometrial cancer (EC). OBJECTIVE: Examine the balance between the 17ß-HSDs reducing estrone to 17ß-estradiol (types 1, 5, 12, and 7) and those oxidizing 17ß-estradiol to estrone (2, 4, and 8), in EC. PATIENTS AND METHODS: Reducing and oxidizing 17ß-HSD activities (HPLC) and mRNA level (RT-PCR) were assessed in normal post-menopausal (n = 16), peritumoral endometrium (normal tissue beside cancer, n = 13), and 58 EC (29 grade 1, 18 grade 2, 11 grade 3). RESULTS: Grade 1 EC displayed a shifted estrone reduction/17ß-estradiol oxidation balance in favor of 17ß-estradiol compared with controls. This was more pronounced among estrogen receptor-α (ER-α)-positive biopsies. Type 1 17ß-HSD mRNA (HSD17B1 gene expression, real time PCR) and protein levels (immunohistochemistry) were higher in ER-α-positive grade 1 EC than controls. The mRNA coding for types 4, 5, 7, 8, and 12 17ß-HSD did not vary, whereas that coding for type 2 17ß-HSD was increased in high-grade lesions compared with controls. Three-dimensional ex vivo EC explant cultures demonstrated that 17ß-HSD type 1 generated 17ß-estradiol from estrone and increased tumor cell proliferation. Additional in vitro studies using EC cells confirmed that in the presence of 17ß-HSD type 1, estrone induced estrogen signaling activation similarly to 17ß-estradiol. Therefore, estrone was reduced to 17ß-estradiol. CONCLUSIONS: Type 1 17ß-HSD increases 17ß-estradiol exposure in grade 1 EC, thus supporting tumor growth. This enzyme represents a potential therapeutic target.