Determinación de capacidad antioxidante en zumo de oca

L o g a r i t h m i c expr essi on o f me a n± s em levels o f p r o d u c e d T N F a , I L -la , I L - 1/9, IL-2 a n d IL-6 in 2 NC a n d 5 MS p a t i e n t s assessed m on t hl y. In NC v a l ue s w e r e 40I±57, 2.33±1, 90±17, 1.7010.82 a n d 3418.3 p g / m l , in MS p a t i e n t s in r e mi ssi on were 298146, 0.4610.22, 176139, 1.5210.3 a n d 7119.3 p g / m l a n d in MS p a t i en t s in re la ps e we re 351178, 2.1210.81, 274139, 1.7810.82 a n d 9 7 1 2 8 p g / m l f o r T N F a, Il-la , IL-1/9, IL-2 a n d IL-6 respectively. *p<0.05 (Wilcoxon r a n k s u m test) c o m p a r e d to the NC levels. T h e g r a ph ic p r e s e n t a t i o n is in meansls. e.m. , d e s p i t e t he use o f non- p a r a m e t r i c s t at is ti ca l ana lys is test.

response is mediated via the high affinity receptor (Robb et a l . . 1984), the radioligand binding assay used in this study served two purposes: first the assessment of the high affinity receptors on intact cells and secondly the investigation of in vitro interactions between the /3- adrenoceptor and IL-2R expression. Since Gadolinium enhanced MRI lesions indicate an early phase of blood- brain barrier breakdown (Kermode et a l . . 1990) and frequently appear without clinical signs, correlation with immune parameters such as expression of IL-2Rs on PBMCs, could further clarify aspects of the natural history of MS and validate the use of MRI in monitoring disease activity.

Analysis of our findings (Table 3.5.), confirms earlier observations (Miller et al.. 1988) of disease activity without clinical signs, as clinical relapses were recorded on 9 occasions, while MRI activity was present on 15 occasions. The enhanced expression of ^-adrenoceptors correlated more strongly with clinical activity, while that of IL-2RS was more closely associated with MRI activity. Only on 2 occasions was there no correlation with IL-2R expression (patient 5 and 6; Table 3.3.), and in both cases this was associated with disease activity in preceding or following observations. It was of interest that the majority of the observations in which high )3- adrenoceptors and IL-2Rs did not correlate with disease activity belonged to the benign group of patients. From

these limited observations, it would appear that there is greater immunological than clinical or MRI evidence of disease activity in benign MS patients. The more frequent recording of immunological and MRI evidence of disease activity, and the better correlation between MRI activity and IL2-R expression indicate that MRI findings mirror more accurately disease activity in MS.

IL-2R expression in vitro appears to be more tightly controlled than that of ^-adrenoceptors under conditions of mitogenic stimulation, although both are associated with lymphocyte activation. To further clarify the role of ^-adrenoceptors in immunoactivation in MS, we evaluated IL-2R expression following stimulation of the cAMP second messenger system (Feldman et al.. 1987; Anastasiou et al.. 1992) . Suppression of IL-2R expression by isoproterenol (a jS-receptor agonist) was observed on proliferating lymphocytes from NC and MS patients in relapse and remission. However, IL-2R expression after mitogenic stimulation appeared to be lower in remitting MS patients compared to NC and MS patients in relapse possibly indicating a relative immunosuppression during disease remission (Fig 3.7.). Similarly, the proliferation rate of PBMCs was suppressed after stimulation with isoproterenol by 40% in NC and MS patients in remission and by 55% in MS patients in relapse. The higher suppression in MS patients during relapse may mirror the enhanced function of PBMC )S- adrenoceptors in those patients (Fig 3.7.).

It has been suggested that the existence of a high density of ^-adrenoceptors on PBMCs in MS could represent a significant recovery mechanism (Zoukos et al.. 1992a) . This was further supported by in vitro studies in which isoproterenol was found to be effective in reducing the IL-2R density in PBMCs from MS patients in relapse, to within the normal range (Fig 3.9.)• However, the precise timing of these changes during the disease process is of

importance if it is to be exploited therapeutically by adrenergic agonists or antagonists.

Immune activation results in release of various cytokines which can propagate the immunoreactive and inflammatory process. As in vitro studies have demonstrated that leukocyte /3-adrenoceptor density is increased in the presence of interleukins -1 and -2 as well as cortisol, we have assessed the levels of five potentially proinflammatory cytokines. The increase in plasma TNFa in MS patients in relapse confirms other observations (Beck et al.. 1988; Tsukada et al.. 1991), although there is a lack of consensus about the value of plasma cytokines as markers of disease activity in MS. The increased IL-1/9 serum levels, observed in both relapsing and remitting phases of the disease and after stimulation of whole blood in relapsed MS patients, indicate a persisting monocyte activation (Beuscher et al.. 1992). However, the small number of serial plasma level cytokine measurements gives only some indication of pattern

changes, and a larger serial study will be required in order to confirm those changes.

In conclusion this study clearly demonstrates that alterations in expression of lymphocyte ^-adrenoceptors and IL-2RS correlate with disease activity in MS. It appears that ^-adrenoceptor enhanced expression closely follows activation of the lymphocytes. The inhibition of IL-2R expression after ^-adrenoceptor stimulation in vitro suggests that increased number of ^-adrenoceptors could constitute a recovery mechanism in MS. The alterations in peripheral blood in association with central nervous system (CNS) pathology suggests a systemic immunoreactive process in MS, rather than one confined to the CNS. The observed correlations between MRI findings and IL2-R changes on PBMCs indicate that both are useful markers of disease activity.

CHAPTER 4

AUTONOMIC FUNCTION AND EXPRESSION OF ^-ADRENOCEPTORS ON