Reaction of complement factors and proteasomes in experimental encephalitis

Antisecretory factor in severe traumatic brain injury (AFISTBI): protocol for an exploratory randomized placebo-controlled trial

BACKGROUND

Despite recent advances in neuroimaging and neurocritical care, severe traumatic brain injury (TBI) is still a major cause of severe disability and mortality, with increasing incidence worldwide. Antisecretory factor (AF), commercially available as Salovum®, has been shown to lower intracranial pressure (ICP) in experimental models of, e.g., TBI and herpes encephalitis. The aim of this study is to assess the effect of antisecretory factors in adult patients with severe TBI on ICP and inflammatory mediators in extracellular fluid and plasma.

METHODS/DESIGN

This is a single-center, randomized, placebo-controlled clinical phase 2 trial, investigating the clinical superiority of Salovum® given as a food supplement during 5 days to adults with severe TBI (Glasgow Coma Scale (GCS) < 9), admitted to the neurocritical intensive care unit (NICU) at Skane university hospital, Lund, Sweden. All patients with GCS < 9 and clinical indication for insertion of ICP-monitor and microdialysis catheter will be screened for inclusion and assigned to either the treatment group (n = 10) or placebo group (n = 10). In both groups, the primary outcome will be ICP (mean values and change from baseline during intervention), registered from high-frequency data monitoring for 5 days. Secondary outcomes will be inflammatory mediators in plasma and intracerebral microdialysis perfusate days 1, 3, and 5 during trial treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04117672. Registered on September 17, 2017. Protocol version 6 from October 24, 2023.

Soluble Membrane Attack Complex (sMAC) as a Potential Diagnostic Biomarker Differentiating Acute Viral Encephalitis from Guillain-Barré Syndrome, a Post-infectious Autoimmune State

Acute encephalitis syndrome (AES) presents with the onset of fever, altered sensorium and/or seizures, known to be caused by various infectious and non-infectious aetiological agents, among which viruses are the commonest. The severity of AES prompts rapid diagnosis, which is not met by time-consuming conventional diagnostic techniques. In this study, archived cerebrospinal fluid samples of laboratory-confirmed viral AES, an acute infectious condition and Guillain-Barré Syndrome (GBS), a post-infectious, autoimmune condition was assessed for soluble membrane attack complex (sMAC) using ELISA. Statistical analysis was performed to understand the diagnostic potential of sMAC in AES versus GBS patients. sMAC levels were significantly increased in viral encephalitis compared with GBS samples (43.69 ng/mL vs. 29.33 ng/mL, P < 0.05). The diagnostic potential of sMAC was assessed using the receiver operating characteristic (ROC) curve, which demonstrated excellent diagnostic discrimination between viral AES and GBS (area under curve = 0.8125, 95% CI, P < 0.0001). Using Youden's index, the optimal sMAC cut-off was calculated as 33.6 ng/mL for distinguishing AES from GBS. The findings of our study revealed significant increase in sMAC levels in AES patients in comparison to those with GBS. This underscores the utility of sMAC as a valuable tool in distinguishing between AES and GBS, thereby facilitating more tailored patient management strategies, which varies for acute infectious and post-infectious conditions especially those mediated by autoimmunity.

Antisecretory Factor May Reduce ICP in Severe TBI-A Case Series

Traumatic brain injury (TBI) constitutes a global epidemic. Overall outcome is poor, with mortality ranging from 10 to 70% and significant long-term morbidity. Several experimental reports have claimed effect on traumatic edema, but all clinical trials have failed. Antisecretory factor, an endogenous protein, is commercially available as Salovum®, which is classified as a medical food by the European Union and has been proven effective in experimental trauma models. It has, however, previously not been tested in humans with severe TBI. We hereby report a case series of five adult patients with severe TBI, treated with Salovum. The objective of the intervention was to evaluate safety and, if possible, its effect on intracranial pressure and outcome. Patients received 1 g Salovum per kilo of body weight divided into six doses per 24 h. Each dose was administered through the nasogastric tube. Patients were scheduled for 5 days of treatment with Salovum. Intracranial pressure was controlled in all patients. In three of five patients, intracranial pressure could be controlled with Salovum and deep sedation (no barbiturates), except during periods of gastroparesis. Five of five patients had a favorable short-term outcome, and four of five patients had a favorable long-term outcome. No toxicity was observed. We conclude that at least three of the five treated patients experienced an effect of Salovum with signs of reduction of intracranial pressure and signs of clinical benefit. In order to validate the potential of antisecretory factor in TBI, a prospective, randomized, double-blind, placebo-controlled trial with Salovum has been initiated. Primary outcome for the trial is 30-day mortality; secondary outcomes are treatment intensity level, intracranial pressure, and number of days at the neurointensive care unit.

Increased level of compleasomes in cerebrospinal fluid of patients with herpes simplex encephalitis

Herpes simplex encephalitis (HSE) is a common cause of viral encephalitis (HSV-1) characterised by pronounced inflammation and elevated intracranial pressure. We have shown in a rat model that HSV-1 infection causes an interaction between complement factors and proteasomes, leading to formation of proteasome/complement complexes (compleasomes). Exposure of the proteasome regulatory subunit antisecretory factor 1 (AF1) leads to a decrease in intracranial pressure. The aim of this study was to evaluate the acute and prolonged formation of compleasomes in cerebrospinal fluid (CSF) from patients with HSE. Cerebrospinal fluid samples (n = 55) from 24 HSE patients were analysed for compleasome complexes. Samples from healthy controls (n = 23) and patient controls (n = 27) served as baseline information. Sandwich enzyme-linked immunosorbent assay (ELISA) for proteasomes and their complex formation with complement factor 3 or 4, and Western blot for C3 activation were performed on CSF samples. Increased compleasome formation, both presenting as an initial formation and showing exposure of subunit AF1 in the compleasomes, was found in CSF samples drawn from patients with HSE compared with samples from the control groups (p < 0.0005). The total protein CSF concentration was equal in all groups. The levels were higher in the acute phase compared with late in the disease course (p < 0.0005). Complement 3 breakdown product iC3b was detected in CSF samples of the HSE patients. The early increased formation of compleasomes in CSF suggests that this complex may be involved in host defence against HSE.