In situ deposition of complement in human acute brain ischaemia

Experimental animal models indicate that complement contributes to tissue damage during brain ischaemia and stroke, but limited data are available for a role of the complement in human stroke. We, therefore, evaluated whether acute ischaemia leads to complement activation in human brain. Indirect immunohistochemical staining was performed on paraffin-embedded, formalin-fixed human brain from 10 patients and 10 controls. Complement components C1q, C3c and C4d were detected in all ischaemic lesions, suggesting activation via the classical pathway. C9, C-reactive protein and IgM were detected in necrotic zones. Marked CD59 and weak CD55 expression were found in normal brains, but these complement regulators were virtually absent in ischaemic lesions. Modest amounts of mannose-binding lectin (MBL), MBL-associated serine protease-2 and factor B were found in both ischaemic lesions and controls. These data suggest that increased deposition of complement components combined with decreased expression of complement regulators is a possible mechanism of tissue damage during ischaemia in human brain.

Depression and anxiety amongst multiple sclerosis patients

The aim of this study was to investigate the prevalence of symptoms of depression and anxiety amongst multiple sclerosis (MS) patients, and the associations with demographic and clinical characteristics. The current treatment for depression and anxiety was also evaluated amongst the MS patients. A total of 140 MS patients from Eastern Norway underwent neuropsychiatric and clinical examinations, with registration of symptoms of depression and anxiety (Hopkins Symptom Checklist-25), as well as information about any help seeking for depression were obtained. A total of 31.4% patients reported symptoms of depression, whilst 19.3% reported anxiety; both symptoms were significantly higher than that amongst the general population (P < 0.001). Fatigue and younger age at onset were significantly associated with symptoms of depression, whilst fatigue and pain, lower Expanded Disability Status Scale score and younger age at onset were associated with symptoms of anxiety. The proportion of reported treatment of depression was 15.9% and for anxiety 11.1%. Of untreated patients with symptoms, 18.2% expressed the need for treatment. A greater focus on depression and anxiety amongst MS patients is needed to establish the appropriate treatment for patients suffering from MS.

CD59 efficiently protects human NT2-N neurons against complement-mediated damage

The complement regulatory protein CD59 controls cell survival by the inhibition of C5b-9 formation on the cell membrane. Loss of CD59 increases the susceptibility of cells to complement-mediated damage and lysis. Deposition of IgM can induce complement activation with subsequent cell death. We have previously demonstrated the presence of CD59 on human NT2-N neurons. In this study, we investigated the functional role of CD59 for NT2-N cell survival after IgM-mediated complement activation. Complement activation was induced on NT2-N neurons with human serum following incubation with the IgM monoclonal antibody A2B5 reacting with a neuronal cell membrane epitope. Deposition of C1q and C5b-9 was detected on the cell membrane and sC5b-9 in the culture supernatant. Specific inhibition of complement was obtained by the C3 inhibitor compstatin, and by anti-C5/C5a MoAb. CD59 was blocked by the MoAb BRIC 229. Membrane damage of propidium iodide-stained NT2-N cells was confirmed by immunofluorescence microscopy and degeneration of neuronal processes was shown with crystal violet staining. A2B5, but not the irrelevant control IgM antibody, induced complement activation on NT2-N neurons after incubation with a human serum, as detected by the deposition of C1q. A marked membrane deposition of C5b-9 on NT2-N neurons with accompanying cell death and axonal degeneration was found after the blocking of CD59 with MoAb BRIC 229 but not with an isotype-matched control antibody. Compstatin and anti-C5 monoclonal antibodies which blocked C5 activation efficiently inhibited complement activation. In conclusion, CD59 is essential for protecting human NT2-N neurons against complement-mediated damage, which is known to occur in a number of clinical conditions including stroke.

Systemic complement activation following human acute ischaemic stroke

The brain tissue damage after stroke is mediated partly by inflammation induced by ischaemia-reperfusion injury where the complement system plays a pivotal role. In the present study we investigated systemic complement activation and its relation to C-reactive protein (CRP), a known complement activator, and other inflammatory mediators after acute ischaemic stroke. Sequential plasma samples from 11 acute stroke patients were obtained from the time of admittance to hospital and for a follow-up period of 12 months. Nine healthy gender- and age-matched subjects served as controls. The terminal SC5b-9 complement complex (TCC), CRP, soluble adhesion molecules (L-, E- and P- selectin, ICAM, VCAM) and cytokines [tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-8] were analysed. All parameters were within normal values and similar to the controls the first hours after stroke. Terminal complement complex (TCC) increased significantly from 0.54 to 0.74 AU/ml at 72 h (P = 0.032), reached maximum at 7 days (0.90 AU/ml, P < 0.001), was still significantly increased at 12 days (0.70 AU/ml, P = 0.009) and thereafter normalized. CRP increased significantly from 1.02 to 2.11 mg/l at 24 h (P = 0.023), remained significantly increased for 1 week (2.53-2.94 mg/l, P = 0.012-0.017) and thereafter normalized. TCC and C-reactive protein (CRP) correlated significantly (r = 0.36, P < 0.001). The increase in TCC and CRP correlated to the size of infarction (r = 0.80 and P = 0.017 for TCC; r = 0.72 and P = 0.043 for CRP). No significant changes were seen for adhesion molecules and cytokines. In conclusion, transitory systemic complement activation takes place after stroke. The early rise in CRP and the following TCC increase suggest a possible role for CRP in complement activation, which may contribute to inflammation after stroke.

Pain and sensory complaints in multiple sclerosis

Pain is a frequent and disabling symptom among multiple sclerosis (MS) patients. The importance of this problem was investigated in a hospital based MS population. A total of 142 MS patients underwent neurological examination and a structured interview for registration of pain and sensory symptoms. One-hundred and five patients reported sensory and/or pain symptoms. Pain was reported by 93 patients and was most frequently located in the limbs and lumbar region. The presence of pain was independent of gender, age at onset and examination, disability, disease course and duration. The most frequently reported characteristics of the symptoms were paresthesia, neuralgia and deep muscular aching. About 40% of the patients reported that the symptoms had important influence on daily activities. Only one-third of the patients were treated for their pain. Pain is a frequent and disabling symptom, independent of demographic and clinical variables in MS patients. The low frequency of treatment for these symptoms indicates a need for improved attention to this problem.