Endothelial Wnt/ß-catenin signaling reduces immune cell infiltration in multiple sclerosis.

Disruption of the blood-brain barrier (BBB) is a defining and early feature of multiple sclerosis (MS) that directly damages the central nervous system (CNS), promotes immune cell infiltration, and influences clinical outcomes. There is an urgent need for new therapies to protect and restore BBB function, either by strengthening endothelial tight junctions or suppressing endothelial vesicular transcytosis. Although wingless integrated MMTV (Wnt)/ß-catenin signaling plays an essential role in BBB formation and maintenance in healthy CNS, its role in BBB repair in neurologic diseases such as MS remains unclear. Using a Wnt/ß-catenin reporter mouse and several downstream targets, we demonstrate that the Wnt/ß-catenin pathway is up-regulated in CNS endothelial cells in both human MS and the mouse model experimental autoimmune encephalomyelitis (EAE). Increased Wnt/ß-catenin activity in CNS blood vessels during EAE progression correlates with up-regulation of neuronal Wnt3 expression, as well as breakdown of endothelial cell junctions. Genetic inhibition of the Wnt/ß-catenin pathway in CNS endothelium before disease onset exacerbates the clinical presentation of EAE, CD4+ T-cell infiltration into the CNS, and demyelination by increasing expression of vascular cell adhesion molecule-1 and the transcytosis protein Caveolin-1 and promoting endothelial transcytosis. However, Wnt signaling attenuation does not affect the progressive degradation of tight junction proteins or paracellular BBB leakage. These results suggest that reactivation of Wnt/ß-catenin signaling in CNS vessels during EAE/MS partially restores functional BBB integrity and limits immune cell infiltration into the CNS.

Intra- and inter-fractional liver and lung tumor motions treated with SBRT under active breathing control.

PURPOSE: To assess intra- and inter-fractional motions of liver and lung tumors using active breathing control (ABC). METHODS AND MATERIALS: Nineteen patients with liver cancer and 15 patients with lung cancer treated with stereotactic body radiotherapy (SBRT) were included in this retrospective study. All patients received a series of three CTs at simulation to test breath-hold reproducibility. The centroids of the whole livers and of the lung tumors from the three CTs were compared to assess intra-fraction variability. For 15 patients (8 liver, 7 lung), ABC-gated kilovoltage cone-beam CTs (kV-CBCTs) were acquired prior to each treatment, and the centroids of the whole livers and of the lung tumors were also compared to those in the planning CTs to assess inter-fraction variability. RESULTS: Liver intra-fractional systematic/random errors were 0.75/0.39 mm, 1.36/0.97 mm, and 1.55/1.41 mm at medial-lateral (ML), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. Lung intra-fractional systematic/random errors were 0.71/0.54 mm (ML), 1.45/1.10 mm (AP), and 3.95/1.93 mm (SI), respectively. Substantial intra-fraction motions (>3 mm) were observed in 26.3% of liver cancer patients and in 46.7% of lung cancer patients. For both liver and lung tumors, most inter-fractional systematic and random errors were larger than the corresponding intra-fractional errors. However, these inter-fractional errors were mostly corrected by the treatment team prior to each treatment based on kV CBCT-guided soft tissue alignment, thereby eliminating their effects on the treatment planning margins. CONCLUSIONS: Intra-fractional motion is the key to determine the planning margins since inter-fractional motion can be compensated based on daily gated soft tissue imaging guidance of CBCT. Patient-specific treatment planning margins instead of recipe-based margins were suggested, which can benefit mostly for the patients with small intra-fractional motions.

Chronic cerebrospinal venous insufficiency: pitfalls and perils of sonographic assessment.

OBJECTIVES: Duplex sonography has been proposed as a diagnostic modality for detection of chronic cerebrovascular venous insufficiency, a recently proposed hypothesis of multiple sclerosis (MS) pathogenesis. We reviewed potential challenges of duplex sonography for diagnosis of chronic cerebrovascular venous insufficiency and used interim pooled data from a study aimed to apply cerebrovascular venous insufficiency criteria to a group of patients with MS and control patients without MS. METHODS: Duplex sonography for chronic cerebrovascular venous insufficiency was performed in patients with MS and controls. Extracranial and deep cerebral veins were studied by using a published chronic cerebrovascular venous insufficiency protocol and criteria. Comparative imaging was performed to explore how physiologic factors and imaging techniques could affect key parameters. The effects of varying definitions on fulfilling chronic cerebrovascular venous insufficiency diagnostic criteria were also explored. RESULTS: Forty-two patients were enrolled. Twenty-five (60%) had a reduction in internal jugular vein cross-sectional area by 50% or more, cross-sectional area of 0.3 cm(2) or less, and/or a B-mode abnormality. No patients had reflux longer than 0.88 seconds in both sitting and supine positions, the presence of duplex sonographic reflux on transcranial Doppler imaging, or a larger internal jugular vein cross-sectional area in the sitting versus supine position. Fourteen patients (33.3%) had either a flap or septum, and 1 had a web. Collateral veins to the vertebral veins were identified in 14 of 42 patients (33.3%). The use of transcranial Doppler imaging versus quality Doppler profiles resulted in fewer patients meeting criteria for chronic cerebrovascular venous insufficiency. CONCLUSIONS: There are several important variables, including physiologic, technical, and criterion definitions, in the application of sonographic assessment of chronic cerebrovascular venous insufficiency that may affect diagnostic accuracy.

A structured evaluation of cryopreservation in generating single-cell transcriptomes from cerebrospinal fluid.

Single-cell transcriptomics allows characterization of cerebrospinal fluid (CSF) cells at an unprecedented level. Here, we report a robust cryopreservation protocol adapted for the characterization of fragile CSF cells by single-cell RNA sequencing (RNA-seq) in moderate- to large-scale studies. Fresh CSF was collected from twenty-one participants at two independent sites. Each CSF sample was split into two fractions: one was processed fresh, while the second was cryopreserved for months and profiled after thawing. B and T cell receptor sequencing was also performed. Our comparison of fresh and cryopreserved data from the same individuals demonstrates highly efficient recovery of all known CSF cell types. We find no significant difference in cell type proportions and cellular transcriptomes between fresh and cryopreserved cells. Results were comparable at both sites and with different single-cell sequencing chemistries. Cryopreservation did not affect recovery of T and B cell clonotype diversity. Our CSF cell cryopreservation protocol provides an important alternative to fresh processing of fragile CSF cells.

Chronic cerebrospinal venous insufficiency as a cause of multiple sclerosis: controversy and reality.

OPINION STATEMENT: Multiple sclerosis (MS) is a relapsing and progressive disorder of the central nervous system. It is characterized most commonly by episodes of clinical worsening, followed by clinical improvement. Pathologically, MS is associated with focal areas of myelin destruction, inflammation, and axonal transection ("demyelinating plaques") in the brain and spinal cord. Traditionally, MS has been considered an autoimmune disorder, with the primary pathophysiology arising from an errant immune system. Recent work has raised the possibility that MS is not caused primarily by an immune abnormality but may instead arise from venous anomalies affecting the jugular and/or azygos venous systems. This condition has been called chronic cerebrospinal venous insufficiency (CCSVI). It has been proposed that CCSVI may be pathogenic in MS, causing venous back pressure and iron deposition, with a secondary immune response. Some investigators have proceeded to unblinded nonrandomized angioplasty and stenting procedures in patients with CCSVI, with anecdotal reports of symptom improvement. Because of conflicting data on the presence of CCSVI and the absence of controlled trials of CCSVI intervention, the current standard of clinical care is neither to evaluate multiple sclerosis (MS) patients for CCSVI anomalies, nor to intervene with procedures to alter such anomalies. There is intense interest and ongoing work to evaluate the presence of venous anomalies in MS patients as well as in normal controls and patients with other neurologic conditions; to characterize such anomalies, if present; and to further understand whether the concept of a "backpressure" pathology is borne out by the evidence. If CCSVI is indeed a pathogenic mechanism for some subset of the MS population, this would dramatically change the focus of attention for therapeutic endeavors and monitoring for this population and would bring MS therapeutics firmly into the area of vascular intervention. On the other hand, the history of MS research contains many novel and potentially paradigm-shifting ideas that were later disproved by other investigators.

Hypogonadism in men with multiple sclerosis: Prevalence and clinical associations.

It has been hypothesized that multiple sclerosis (MS) has hormonal influences, and testosterone may have anti-inflammatory functions in this context. Given prior reports of lower testosterone levels in men with MS in archival serum samples, we evaluated the prevalence of hypogonadism in the clinical setting and its association with disability in men with MS. Subjects were screened for symptoms of hypogonadism using a clinical instrument, and those with positive screens had total and free morning testosterone levels checked. Of the 64 subjects who were screened, 50 (78%) had positive results, and 46 (92%) had morning testosterone levels checked. Among the latter, 5 were found to have testosterone levels below lower limit of normal. Other than the expected inverse relation with BMI, testosterone did not correlate with demographic or disease related factors. Baseline testosterone did not predict risk of EDSS or T25-FW progression or future MRI activity.

Manifestations and impact of the COVID-19 pandemic in neuroinflammatory diseases.

OBJECTIVE: To report initial results of a planned multicenter year-long prospective study examining the risk and impact of COVID-19 among persons with neuroinflammatory disorders (NID), particularly multiple sclerosis (MS). METHODS: In April 2020, we deployed online questionnaires to individuals in their home environment to assess the prevalence and potential risk factors of suspected COVID-19 in persons with NID (PwNID) and change in their neurological care. RESULTS: Our cohort included 1115 participants (630 NID, 98% MS; 485 reference) as of 30 April 2020. 202 (18%) participants, residing in areas with high COVID-19 case prevalence, met the April 2020 CDC symptom criteria for suspected COVID-19, but only 4% of all participants received testing given testing shortages. Among all participants, those with suspected COVID-19 were younger, more racially diverse, and reported more depression and liver disease. PwNID had the same rate of suspected COVID-19 as the reference group. Early changes in disease management included telemedicine visits in 21% and treatment changes in 9% of PwNID. After adjusting for potential confounders, increasing neurological disability was associated with a greater likelihood of suspected COVID-19 (ORadj  = 1.45, 1.17-1.84). INTERPRETATIONS: Our study of real-time, patient-reported experience during the COVID-19 pandemic complements physician-reported MS case registries which capture an excess of severe cases. Overall, PwNID seem to have a risk of suspected COVID-19 similar to the reference population.

Genetic deletion of BACE1 in mice affects remyelination of sciatic nerves.

BACE1 is a promising therapeutic and preventive target for Alzheimer's disease because it is essential for amyloid deposition. However, the recent demonstration of BACE1 in modulating developmental myelination in both peripheral and central nervous systems raises a concern of its effect on myelin maintenance or remyelination, and inhibition of these processes will potentially be detrimental to the BACE1 inhibitor users who are susceptible to myelination diseases such as adult peripheral nerve injury or multiple sclerosis. In this report, we investigated the role of BACE1 during peripheral nerve remyelination in wild-type (WT) and BACE1-null mice. We show here that genetic deletion of BACE1 affects sciatic nerve remyelination. The impaired remyelination appears to stem from the loss of neuregulin-1 cleavage by BACE1. To demonstrate a direct cleavage of neuregulin-1 by BACE1, we have identified a BACE1 cleavage site that turns out be highly conserved among neuregulin-1 paralogues. Moreover, we show that neuregulin-1 family member neuregulin-3 is also cleavable by BACE1. We hypothesize that the BACE1-cleaved extracellular domain of axonal neuregulin-1, perhaps neuregulin-3 as well, binds to Schwann cell ErbB receptors, which in turn regulate remyelination. Pharmacological inhibition of BACE1 should be carefully monitored to avoid alteration of signaling pathway that regulates remyelination.

Esophageal dose tolerance to hypofractionated stereotactic body radiation therapy: risk factors for late toxicity.

PURPOSE: To identify factors associated with grade ≥3 treatment related late esophageal toxicity after lung or liver stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: This was a retrospective review of 52 patients with a planning target volume within 2 cm of the esophagus from a prospective registry of 607 lung and liver SBRT patients treated between 2005 and 2011. Patients were treated using a risk-adapted dose regimen to a median dose of 50 Gy in 5 fractions (range, 37.5-60 Gy in 3-10 fractions). Normal structures were contoured using Radiation Therapy Oncology Group (RTOG) defined criteria. RESULTS: The median esophageal point dose and 1-cc dose were 32.3 Gy (range, 8.9-55.4 Gy) and 24.0 Gy (range, 7.8-50.9 Gy), respectively. Two patients had an esophageal fistula at a median of 8.4 months after SBRT, with maximum esophageal point doses of 51.5 and 52 Gy, and 1-cc doses of 48.1 and 50 Gy, respectively. These point and 1-cc doses were exceeded by 9 and 2 patients, respectively, without a fistula. The risk of a fistula for point doses exceeding 40, 45, and 50 Gy was 9.5% (n=2/21), 10.5% (n=2/19), and 12.5% (n=2/16), respectively. The risk of fistula for 1-cc doses exceeding 40, 45, and 50 Gy was 25% (n=2/9), 50% (n=2/4), and 50% (n=2/4), respectively. Eighteen patients received systemic therapy after SBRT (11 systemic chemotherapy, and 6 biologic agents, and 1 both). Both patients with fistulas had received adjuvant anti-angiogenic (vascular endothelial growth factor) agents within 2 months of completing SBRT. No patient had a fistula in the absence of adjuvant VEGF-modulating agents. CONCLUSIONS: Esophageal fistula is a rare complication of SBRT. In this series, fistula was seen with esophageal point doses exceeding 51 Gy and 1-cc doses greater than 48 Gy. Notably, however, fistula was seen only in those patients who also received adjuvant VEGF-modulating agents after SBRT. The potential interaction of dose and adjuvant therapy should be considered when delivering SBRT near the esophagus.

Hydration status substantially affects chronic cerebrospinal venous insufficiency assessments.

We sought to determine the effect of hydration on the criteria for chronic cerebrospinal venous insufficiency (CCSVI), a proposed hypothesis for the etiology of multiple sclerosis (MS). Sixteen subjects (11 MS and 5 controls) were asked to fast overnight. The following morning, 2 CCSVI ultrasound examinations were performed: 1 in the mildly dehydrated state, and another 30-45 minutes after rehydrating with 1.5 L of Gatorade. Seven subjects fulfilled CCSVI criteria in the dehydrated state. Of these, 5 (71%) no longer fulfilled CCSVI criteria after rehydration. One additional subject met CCSVI criteria only after rehydration. Hydration status has a substantial effect on CCSVI criteria, suggesting that the sonographic findings of CCSVI may represent a physiologic rather than pathologic state.

A technical approach to dissecting and assessing cadaveric veins pertinent to chronic cerebrospinal venous insufficiency in multiple sclerosis.

OBJECTIVE: To establish a detailed technical procedure for studying the anatomical correlates of chronic cerebrospinal venous insufficiency in cadavers of multiple sclerosis and control subjects, and to present our findings of the normal anatomic venous structures, with reference to previous descriptions from the literature. METHODS: This study examined the internal jugular veins (IJVs), the brachiocephalic veins, and the azygos vein from 20 cadavers (10 control and 10 multiple sclerosis). These veins were exposed, isolated by clamps from the rest of the venous system, flushed with water, and then injected with fluid silicone from the superior ends of both IJVs. After the silicone cured to its solid state, the venous tree was removed en bloc and dissected longitudinally to expose the luminal surface. All vein segments were analyzed for anatomic variation. Anatomical analysis for this manuscript focused on normal vein architecture and its variants. RESULTS: Thirty-seven of 40 IJVs contained valves: 29 bicuspid, 6 tricuspid, and 2 unicuspid. The average circumferences of the right and left IJVs were 2·2 and 1·8 cm, respectively. Thirteen of 20 azygos veins contained a valve, located on average 3·6 cm away from the superior vena cava junction. Nine of the 13 azygos valves were bicuspid; four were tricuspid. Only one of the 40 brachiocephalic veins contained a valve. DISCUSSION: We detailed a technical approach for harvesting cadaveric neck and thoracic veins with relevance to chronic cerebrospinal venous insufficiency. The anatomy of the venous system has significant variability, including differing number of valves in different regions and variable characteristics of the valves. Average vein circumference was less than that typically reported in imaging studies of live patients.

The cis-regulatory logic of the mammalian photoreceptor transcriptional network.

The photoreceptor cells of the retina are subject to a greater number of genetic diseases than any other cell type in the human body. The majority of more than 120 cloned human blindness genes are highly expressed in photoreceptors. In order to establish an integrative framework in which to understand these diseases, we have undertaken an experimental and computational analysis of the network controlled by the mammalian photoreceptor transcription factors, Crx, Nrl, and Nr2e3. Using microarray and in situ hybridization datasets we have produced a model of this network which contains over 600 genes, including numerous retinal disease loci as well as previously uncharacterized photoreceptor transcription factors. To elucidate the connectivity of this network, we devised a computational algorithm to identify the photoreceptor-specific cis-regulatory elements (CREs) mediating the interactions between these transcription factors and their target genes. In vivo validation of our computational predictions resulted in the discovery of 19 novel photoreceptor-specific CREs near retinal disease genes. Examination of these CREs permitted the definition of a simple cis-regulatory grammar rule associated with high-level expression. To test the generality of this rule, we used an expanded form of it as a selection filter to evolve photoreceptor CREs from random DNA sequences in silico. When fused to fluorescent reporters, these evolved CREs drove strong, photoreceptor-specific expression in vivo. This study represents the first systematic identification and in vivo validation of CREs in a mammalian neuronal cell type and lays the groundwork for a systems biology of photoreceptor transcriptional regulation.