MicroRNA miR-155 Activity in Mouse Choline Acetyltransferase-Positive Neurons Is Critical for the Rate of Early and Late Paraplegia After Transient Aortic Cross-Clamping.

Aortic aneurism open repair surgery can cause spinal cord (SC) injury with 5-15% of patients developing paraparesis or paraplegia. Using a mouse model of transient aortic cross-clamping (ACC), we have previously found that the expression of proinflammatory microRNA miR-155 increases in motoneurons (MNs) and endothelial cells (ECs) of ischemic SCs, and that global miR-155 deletion decreases the percentage of paraplegia by 37.4% at 48-h post-ACC. Here, we investigated the cell-specific contribution of miR-155 in choline acetyltransferase-positive (ChAT+) neurons (that include all MNs of the SC) and ECs to SC injury after ACC. Mice lacking miR-155 in ChAT+ neurons (MN-miR-155-KO mice) developed 24.6% less paraplegia than control mice at 48-h post-ACC. In contrast, mice lacking miR-155 in ECs (ECs-miR-155-KO mice) experienced the same percentage of paraplegia as control mice, despite presenting smaller central cord edema. Unexpectedly, mice overexpressing miR-155 in ChAT+ neurons were less likely than control mice to develop early paraplegia during the first day post-ACC, however they reached the same percentage of paraplegia at 48-h. In addition, all mice overexpressing miR-155 in ECs (ECs-miR-155-KI mice) were paraplegic at 48-h post-ACC. Altogether, our results suggest that miR-155 activity in ChAT+ neurons protects the SC against ischemic injury during the first day post-ACC before becoming deleterious during the second day, which indicates that early and late paraplegias arise from different molecular malfunctions. These results point to the need to develop specific protective therapeutics aimed at inhibiting both the early and late deleterious events after open repair surgery of aortic aneurisms.

Successful Anti-SARS-CoV-2 Spike Protein Antibody Response to Vaccination in MAGT1 Deficiency.

BACKGROUND: Novel messenger RNA vaccines against severe acute respiratory syndrome coronavirus (SARS-CoV-2) have been vital in resolving the coronavirus disease-2019 (COVID-19) pandemic. Detection of neutralizing antibodies (NAbs) against the SARS-CoV-2 spike protein (S) confirms immunogenicity with high sensitivity and specificity. Few recent studies with primary and secondary immunodeficient cohorts present adequate or reduced antibody response. We describe the first reported successful response to anti-SARS-CoV-2 S antibody post-vaccination in magnesium transporter 1 (MAGT1) gene deficiency, more commonly recognized as x-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia (XMEN). CASE PRESENTATION: We present a 30-year-old male with selective anti-polysaccharide antibody deficiency, peripheral blood CD5 + /CD19 + B-cell predominance (97%), MAGT1 mutation, and reduced CD16 + CD56 + natural killer- and/or CD8 + T-cell receptor, Group 2, Member D expression. His initial immunological evaluation revealed all seronegative post-vaccination antibody titers but clinically adequate response to protein antigens tetanus and diphtheria anti-toxoids.COVID-19 vaccination and associated serology antibody testing was recommended at this office visit. Anti-SARS-CoV-2 immunoglobulin (Ig)M and IgG antibodies before and after the first BNT162b2 mRNA COVID-19 vaccine doses, as well as nucleocapsid antibody, were negative. S protein total antibody was reactive after the second dose. DISCUSSION: Robust immunological sequelae post-COVID-19 vaccination in the general population are well-documented in the recent literature. Few studies have evaluated COVID-19 vaccination antibody response in immunodeficient patients. The majority positive anti-S antibody detection in most primary immunodeficient (PID) patients among the few studies in the literature, such as the present case, support the safety and efficacy of mRNA COVID-19 vaccination in immunodeficient patients, although larger scale studies are needed. CONCLUSION: We demonstrate successful vaccination in the PID MAGT1 deficiency in this first reported case of reactive anti-S antibody post-COVID-19 vaccination.

Histological Findings After Aortic Cross-Clamping in Preclinical Animal Models.

Spinal cord ischemic injury and paralysis are devastating complications after open surgical repair of thoracoabdominal aortic aneurysms. Preclinical models have been developed to simulate the clinical paradigm to better understand the neuropathophysiology and develop therapeutic treatment. Neuropathological findings in the preclinical models have not been comprehensively examined before. This systematic review studies the past 40 years of the histological findings after open surgical repair in preclinical models. Our main finding is that damage is predominantly in the grey matter of the spinal cord, although white matter damage in the spinal cord is also reported. Future research needs to examine the neuropathological findings in preclinical models after endovascular repair, a newer type of surgical repair used to treat aortic aneurysms.

Endovascular repair and open repair surgery of thoraco-abdominal aortic aneurysms cause drastically different types of spinal cord injury.

Both endovascular repair (EVR) and open repair (OR) surgery of thoraco-abdominal aortic aneurysms cause spinal cord (SC) injury that can lead to paraparesis or paraplegia. It has been assumed that mechanisms responsible for SC damage after EVR are similar to those after OR. This pilot study compared the pathophysiology of SC injury after EVR versus OR using a newly developed EVR dog model. An increasing number of stents similar to those used in patients were inserted in the aorta of three dogs to ensure thoracic or thoracic plus lumbar coverage. The aorta of OR dogs was cross-clamped for 45 min. Behavior assessment demonstrated unique patterns of proprioceptive ataxia and evolving paraparesis in EVR versus irreversible paraplegia in OR. MRI showed posterior signal in lumbar SC after EVR versus central cord edema after OR. Histopathology showed white matter edema in L3-L5 localized to the dorsal column medial lemniscus area associated with loss of myelin basic protein but not neurons after EVR, versus massive neuronal loss in the gray matter in L3-L5 after OR. Metabolome analysis demonstrates a distinctive chemical fingerprint of cellular processes in both interventions. Our results call for the development of new therapeutics tailored to these distinct pathophysiologic findings.