Maria Laura Fois

Inflammatory biomarkers in blood of patients with acute brain ischemia

Although many failed surrogate markers are provided in the literature, inflammation may contribute to the outcome of ischemic stroke. In 50 consecutive patients with acute ischemic stroke, in the absence of symptoms and signs of concomitant infection, we evaluated a panel of biomarkers reported to be variably associated with brain ischemia, and correlate their serum level with the brain lesion volume and clinical outcome. Infarct size was calculated on computed tomography (CT) scans by means of the Cavalieris method. Neurological impairment was scored by using the Glasgow Coma Scale, Glasgow Outcome Scale and National Institutes of Health (NIH) scales at stroke onset and 3‐month follow‐up. Some markers showed a direct significant correlation with both initial and final NIH scale and with infarct size, particularly tumor necrosis factor alpha (TNF‐α) (P = 0.002), intercellular adhesion molecule‐1 (P < 0.01) and matrix metalloproteinase‐2/9 (P = 0.001). In contrast to previous reports, interleukin‐6 (IL‐6) serum level showed a significant inverse correlation with both final neurological impairment and infarct size (P < 0.001). This novel finding allows us suggesting that IL‐6, in the context of a complex pro‐inflammatory network occurring during stroke, is associated with neuroprotection rather than neurotoxicity in patients with ischemic brain injury.

Seasonal fluctuation of multiple sclerosis births in Sardinia

AbstractStudy results from different geographical areas provide some circumstantial evidence that, when compared with the general population, people who later in life develop multiple sclerosis (MS) have a pattern of birth excess numbers in spring and late summer, which may disclose an association with MS–predisposing environmental agents. To identify the presence of season–related cluster of MS birth in Sardinia we have designed a case–control study in the province of Sassari, Northern Sardinia, insular Italy, an area at veryhigh and increasing risk for MS. Mean birth incidence rate of people with MS (810 cases) on a threeand six–months basis were compared with that of two control populations: the MS unaffected siblings (1069), sharing genetic material with patients, and a representative number of births (247,612) of the general population of the study area. We found that the birth in months peaking in spring significantly represents one risk factor for future MS development. This seasonal deviation of MS births reveals an intriguing epidemiological overlap with common environmental agents, which may open a new scenario of hypothetical explanations for environmental factors perhaps affecting the CNS at the crucial time of myelination or shaping the newborn immune system.

Glatiramer acetate reduces lymphocyte proliferation and enhances IL-5 and IL-13 production through modulation of monocyte-derived dendritic cells in multiple sclerosis

Dendritic cells (DC), as the most effective antigen presenting cells, are protagonists of the complex immune network involved in multiple sclerosis (MS) lesion formation. Glatiramer acetate (GA), a synthetic random copolymer, is thought to exert its therapeutical effect in MS by favouring both Th2 cell development and IL‐10 production from peripheral lymphocytes as well as by systemically affecting the antigen presenting cells. In the present study we further analysed the mechanisms of action of GA by using an autologous DC‐lymphocytes (Ly) coculture system from 11 MS patients and 12 matched healthy controls (HC). We found that, in MS patients, pretreatment with GA significantly decreases the in vitro proliferative effect of DC on lymphocytes as compared to HC and to unpulsed or myelin basic protein (MBP)‐pulsed DC from MS patients (P < 0·05). In addition, GA‐treated DC from both MS patients and HC significantly increase the lymphocyte production of IL‐5 and IL‐13 as compared to MBP‐treated DC (P < 0·05). In conclusion our in vitro study may provide new therapeutical mechanisms of GA on lymphocytes, antiproliferative and Th2‐favouring effects, which are mediated by monocyte‐derived DC.

Multiple sclerosis: reduced proportion of circulating plasmacytoid dendritic cells expressing BDCA-2 and BDCA-4 and reduced production of IL-6 and IL-10 in response to herpes simplex virus type 1

Objective We hypothesized that autoaggressive immune responses observed in multiple sclerosis (MS) could be associated with an imbalance in proportion of immune cell subsets and in cytokine production in response to infection, including viruses. Methods We collected blood mononuclear cells (MNC) from 23 patients with MS and 23 sex- and age-matched healthy controls (HC) from the island of Sardinia, Italy, where the prevalence of MS is extraordinarily high. Using flow cytometry, we studied MNC for expression of blood dendritic cell antigens (BDCA)-2 and BDCA-4 surface markers reflecting the proportion of plasmacytoid dendritic cells (pDC) that produce type I interferons (IFNs) after virus challenge and promote Th2/anti-inflammtory cytokine production. In parallel, pro-inflammatory (interleukin [IL]-2, IL-12, IFN-γ), anti-inflammatory (IL-4, IL-10), and immuno-regulatory/pleiotropic cytokines (type I IFNs including IFN-α and β, IL-6) were measured before and after an in vitro exposure to herpes simplex virus type 1 (HSV-1). Results The subset of lineage negative (lin−), BDCA-2+ cells was lower in patients with MS compared with HC (0.08 ± 0.02% vs 0.24 ± 0.02%; P < 0.001). A similar pattern was observed for lin−BDCA-4+ cells (0.08 ± 0.02% vs 0.17% ± 0.03; P < 0.01). Spontaneous productions of IL-6 (45 ± 10 pg/mL vs 140 ± 26 pg/mL; P < 0.01) and IL-10 (17 ± 0.4 pg/mL vs 21 ± 1 pg/mL; P < 0.05) by MNC were lower in patients with MS compared with HC. Spontaneous production of IL-6 (6.5 ± 0.15 pg/mL vs 21 ± 5 pg/mL; P < 0.01 and IL-10 (11 ± 1 pg/mL vs 14 ± 3 pg/mL; P < 0.05) by pDC was also lower in patients with MS compared with HC. Exposure of MNC to HSV-1 showed, in both patients with MS and HC, increased production of IFN-α, IL-6, and IL-10 but decreased production of IL-4. In response to HSV-1 exposure, productions of IL-6 (165 ± 28 pg/mL vs 325 ± 35 pg/mL; P < 0.01) and IL-10 (27 ± 3 vs 33 ± 3 P < 0.05) by MNC as well as by pDC (IL-6: 28 ± 7 vs 39 ± 12 P < 0.05; IL-10: 14 ± 1 vs 16 ± 3 P < 0.05) were lower in patients with MS compared with HC. Conclusion The results implicate a new evidence for altered immune cells and reduced immune responses in response to viral challenge in MS.

Anti-inflammatory nuclear receptor superfamily in multiple sclerosis patients from Sardinia and Sweden.

Several nuclear hormone receptors have been associated with inflammatory reactions. Particularly, liver X receptors (LXRs) have recently been identified as key transcriptional regulators of genes involved in lipid homeostasis and inflammation. LXRs are negative regulators of macrophage inflammatory gene expression. Multiple sclerosis (MS), a demyelinating disease of the central nervous system of unknown cause, is characterized by recurrent inflammation involving macrophages and their inflammatory mediators. Sweden belongs to the countries with a high MS incidence. In Italy, the MS incidence is lower, except on the island of Sardinia where the incidence is even higher than in Sweden. Subjects from Sardinia are ethnically more homogeneous, and differ from Swedes also regarding genetic background and environment. We studied mRNA expression of several nuclear hormone receptors in blood mononuclear cells (MNC) from female patients with untreated relapsing-remitting MS from Sassari, Sardinia, and Stockholm, Sweden. Sex- and age-matched healthy controls (HC) were from both areas. mRNA expression was evaluated by quantitative real-time PCR. We found altered mRNA expression of LXRs, estrogen receptors (ERs), and androgen receptor (AR) in MS. mRNA expression of both LXRalpha and LXRbeta is lower in MS from Stockholm but not from Sassari. In particular, LXRalpha mRNA expression was significantly lower in MS from Stockholm as compared with all groups in the study including MS from Sassari. Low levels of ERalpha mRNA are seen in MS from both Stockholm and Sassari. The splice variant ERbetacx showed significantly higher mRNA expression in MS from Sassari and Stockholm as compared with corresponding HC. In particular, ERbetacx mRNA in MS from Sassari was remarkably higher as compared with all other groups in the study. Higher levels of AR mRNA are present in HC from Sassari. The findings indicate that the expression levels of anti-inflammatory nuclear receptor superfamily genes in MS appear to reflect both ethnic and environmental influences.

Role of SH Levels and Markers of Immune Response in the Stroke

Background. Sulfhydryl groups (SH) are considered a key factor in redox sensitive reaction of plasma, and their modification could be considered an expression of abnormal generation of oxygen free radicals. Methods. Fifty consecutive patients with acute brain stroke were enclosed in this study. The plasma concentrations of SH groups were correlated to cytokines (IL-1b, IL-6, IL-8, TNF-α), plasma chitotriosidase (Chit), metalloprotease (MMP2–9), intercellular adhesion molecule-1 (ICAM-1). Results. The results demonstrated a significant reduction of SH groups within 24 hours from the onset of an acute ischemic stroke, a reduction of plasma IL-1b, IL-6, and IL-8, and an increase of Chit and TNF-α in relation to the stroke severity. Conclusion. The observation of an intense microenvironment activation that follows the stroke and the correlation between SH levels and markers of immune response suggest that, especially in stroke, is necessary to maintain the redox function to prevent the brain damage. The reduced SH levels represent an attempt to neutralize the abnormal generation of free radicals. Since the reperfusion of brain after ischemic event represents a severe oxidative stress, which must be corrected by regeneration of redox sensitive function, pharmacological intervention could be beneficial in this setting.

Immunological heterogeneity of multiple sclerosis in Sardinia and Sweden

Subjects from Sardinia, Italy, are relatively homogeneous compared to Swedes. Although ethnically distant, both populations have similarly high multiple sclerosis (MS) incidence rates. Pro- and anti-inflammatory cytokines and their receptors, signalling molecules and other immune response-associated factors might influence MS pathogenesis, though definite proof is missing. The study of populations with similar MS incidence but different genetic and environmental background could make possible the definition of factors that relate to such background differences. We selected untreated female MS patients from Sassari, Sardinia, and Stockholm, Sweden, and corresponding sexand age-matched healthy controls (HC), to study blood mononuclear cells (MNC) for mRNA expression of 20 immune response-related genes considered relevant in MS, employing real-time PCR. Higher expression of IL-12p40 mRNA was confined to MS from both Sassari and Stockholm, compared to corresponding HC. MS patients from Sassari, but not Stockholm, expressed higher TNF-a compared to corresponding HC. MS patients from Stockholm, but not Sassari, expressed higher IL-6. Indoleamine 2,3 dioxygenase (IDO), a molecule necessary in tolerance induction, was lower in MS from Stockholm compared to corresponding HC. This was not observed in Sassari. No differences were detected for other members of the IL-12 family, other Th1 and Th2 cytokines, and the signalling molecules Stat 4 and 6. The results corroborate a pro-inflammatory state in MS as reflected by high expression of IL-12, TNF-a and IL-6, although the extent of expression of TNF-a, IL-6 and IDO differs between strictly matched MS patients from different high-incidence areas. This might result from genetic and/or environmental differences. They may account for some of the discrepancies regarding immune response-related molecules previously reported in MS. In conclusion, a pro-inflammatory state exists in MS patients from Sassari as well as Stockholm. The changes of pro-inflammatory and other immune response-related variables differ however between the two MS populations. This may be attributed to the genetic and/or environmental background.