In vitroandin vivoeffect of polycaprolactone nanofiber coating on polyethylene glycol diacrylate scaffolds for intervertebral disc repair

Polyethylene glycol diacrylate (PEGDA) is an important class of photosensitive polymer with many tissue engineering applications. This study compared PEGDA and polycaprolactone (PCL) nanofiber matrix (NFM) coated PEGDA, referred to as PCL-PEGDA, scaffolds for their application in multiple tissue repair such as articular cartilage, nucleus pulposus of the intervertebral disc (IVD). We examined each scaffold morphology, porosity, swelling ratio, degradation, mechanical strength, andin vitrocytocompatibility properties. A defect was created in Sprague Dawley rat tail IVD by scraping native cartilage tissue and disc space, then implanting the scaffolds in the disc space for 4 weeks to evaluatein vivoefficacy of multi-tissue repair. Maintenance of disc height and creation of a new cell matrix was assessed to evaluate each scaffold's ability to repair the tissue defect. Although both PEGDA and PCL-PEGDA scaffolds showed similar porosity ∼73%, we observed distinct topographical characteristics and a higher effect of degradation on the water-absorbing capacity for PEGDA compared to PCL-PEGDA. Mechanical tests showed higher compressive strength and modulus of PCL-PEGDA compared to PEGDA.In vitrocell studies show that the PCL NFM layer covering PEGDA improved osteoblast cell adhesion, proliferation, and migration into the PEGDA layer.In vivostudies concluded that the PEGDA scaffold alone was not ideal for implantation in rat caudal disc space without PCL nanofiber coating due to low compressive strength and modulus.In vivoresults confirm that the PCL-PEGDA scaffold-maintained disc space and created a proteoglycan and collagen-rich new tissue matrix in the defect site after 4 weeks of scaffold implantation. We concluded that our developed PCL-PEGDA has the potential to be used in multi-tissue defect site repair.

THU0336 IMMUNE CHECKPOINT INHIBITOR-RELATED MYOSITIS: A RETROSPECTIVE COHORT STUDY

Background:

Myositis is a rare immune checkpoint inhibitor (ICI)-related adverse event frequently associated with myasthenia gravis (MG) and myocarditis (MC) leading to mortality rates up to 52%.1

Objectives:

To characterize the presentation, course and outcomes of patients with ICI-related myositis alone or with overlap syndrome (myositis with MG or MC or both).

Methods:

We retrospectively identified a cohort of patients treated with ICI at MD Anderson Cancer Center between 2016 and 2019. Suspected myositis was identified using International Classification of Disease version 10 codes and confirmed by electronic medical record review of muscle enzymes, pathology, and other tests, when available. Patients with myositis alone or with overlap syndrome were compared using Fischer’s exact tests and t tests.

Results:

During the study period 8,636 patients received ICI, of which 31 (0.36%) were diagnosed with myositis: 14 (45%) with myositis alone and 17 (55%) with overlap (MG in 5, MC in 4, MG and MC in 8). Twenty patients received programmed death-1 (PD-1) or programmed death-ligand-1 (PDL-1) inhibitors, and 10 received combination PD-1/PDL-1 inhibitor with a cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) inhibitor. One patient received single agent CTLA-4 inhibitor (excluded from pooled data). For the entire cohort the median age at diagnosis was 69 years (range: 40-95 years); the most common presenting symptoms were fatigue in 27 (90%) patients, weakness in 24 (80%), and myalgia in 23 (77%); median CK was 2,236 U/L (range: 23-19,794 U/L). For treatment, 22 of 30 (73%) patients received at least one therapy in addition to steroids: plasmapheresis in 15 (50%) patients, intravenous immune globulin (IVIG) in 12 (40%), biologics in 9 (30%) (rituximab in 6, infliximab in 5, tocilizumab in 3), tacrolimus in 6 (20%), and mycophenolate mofetil in 4 (13%). Median length of exposure to steroids was 47 days (range: 1-250 days). Five (17%) patients were rechallenged with ICI after myositis resolution (3 with myositis alone, 2 with overlap), of which 1 (20%) patient experienced a myositis flare. Twenty-five (83%) patients were not rechallenged on ICI and 3 (12%) of those patients had a flare. Differences between patients with myositis alone compared to those with overlap are shown in Table 1. Patients with overlap more often received a second therapy, specifically plasmapheresis and IVIG, had longer hospitalizations and greater symptom burden at discharge. Overall death between groups was similar; however death attributed to the adverse event occurred only in those with overlap.

Table 1.

Myositis alone vs. Overlap

Myositis alone(N=13)Overlap(N=17)PvalueN(%)/median days [range]Time to symptom onset42 [10-161]22 [9-149]0.234Initial steroid dose (mg/kg day)1.71.80.187Second therapy7 (54)15 (88)0.049 Plasmapheresis3 (23)12 (71)0.025 IVIG1 (8)11 (65)0.002Outcomes Hospitalization length5 [2-50]24 [7-92]0.019 Respiratory failure0 (0)13 (76) Symptoms at discharge0.047 Improved8 (62)6 (35) Resolved3 (23)1 (6)Death Overall8 (62)12 (71)0.706 Adverse event0 (0)7 (41)

Conclusion:

Our results represent the largest cohort of ICI-related myositis to date. Patients with overlap syndrome are treated more aggressively and have worse outcomes than those with myositis alone. Prospective studies are warranted to determine risk factors for developing myositis or overlap syndrome and to determine optimal treatment.

References:

[1]Anquetil BC, Salem LJ-E, Lebrun-Vignes JB, et al. Immune Checkpoint Inhibitor–Associated Myositis: Expanding the Spectrum of Cardiac Complications of the Immunotherapy Revolution.Circulation. 2018;138(7):743-745.

Disclosure of Interests:

None declared

Activation of Stimulator of Interferon Genes (STING) and Sjögren Syndrome

Sjögren syndrome (SS), a chronic autoimmune disorder causing dry mouth, adversely affects the overall oral health in patients. Activation of innate immune responses and excessive production of type I interferons (IFNs) play a critical role in the pathogenesis of this disorder. Recognition of nucleic acids by cytosolic nucleic acid sensors is a major trigger for the induction of type I IFNs. Upon activation, cytosolic DNA sensors can interact with the stimulator of interferon genes (STING) protein, and activation of STING causes increased expression of type I IFNs. The role of STING activation in SS is not known. In this study, to investigate whether the cytosolic DNA sensing pathway influences SS development, female C57BL/6 mice were injected with a STING agonist, dimethylxanthenone-4-acetic acid (DMXAA). Salivary glands (SGs) were studied for gene expression and inflammatory cell infiltration. SG function was evaluated by measuring pilocarpine-induced salivation. Sera were analyzed for cytokines and autoantibodies. Primary SG cells were used to study the expression and activation of STING. Our data show that systemic DMXAA treatment rapidly induced the expression of Ifnb1, Il6, and Tnfa in the SGs, and these cytokines were also elevated in circulation. In contrast, increased Ifng gene expression was dominantly detected in the SGs. The type I innate lymphoid cells present within the SGs were the major source of IFN-γ, and their numbers increased significantly within 3 d of treatment. STING expression in SGs was mainly observed in ductal and interstitial cells. In primary SG cells, DMXAA activated STING and induced IFN-β production. The DMXAA-treated mice developed autoantibodies, sialoadenitis, and glandular hypofunction. Our study demonstrates that activation of the STING pathway holds the potential to initiate SS. Thus, apart from viral infections, conditions that cause cellular perturbations and accumulation of host DNA within the cytosol should also be considered as possible triggers for SS.

Volumetric Analysis from a Harmonized Multisite Brain MRI Study of a Single Subject with Multiple Sclerosis

BACKGROUND AND PURPOSE

MR imaging can be used to measure structural changes in the brains of individuals with multiple sclerosis and is essential for diagnosis, longitudinal monitoring, and therapy evaluation. The North American Imaging in Multiple Sclerosis Cooperative steering committee developed a uniform high-resolution 3T MR imaging protocol relevant to the quantification of cerebral lesions and atrophy and implemented it at 7 sites across the United States. To assess intersite variability in scan data, we imaged a volunteer with relapsing-remitting MS with a scan-rescan at each site.

MATERIALS AND METHODS

All imaging was acquired on Siemens scanners (4 Skyra, 2 Tim Trio, and 1 Verio). Expert segmentations were manually obtained for T1-hypointense and T2 (FLAIR) hyperintense lesions. Several automated lesion-detection and whole-brain, cortical, and deep gray matter volumetric pipelines were applied. Statistical analyses were conducted to assess variability across sites, as well as systematic biases in the volumetric measurements that were site-related.

RESULTS

Systematic biases due to site differences in expert-traced lesion measurements were significant (P < .01 for both T1 and T2 lesion volumes), with site explaining >90% of the variation (range, 13.0-16.4 mL in T1 and 15.9-20.1 mL in T2) in lesion volumes. Site also explained >80% of the variation in most automated volumetric measurements. Output measures clustered according to scanner models, with similar results from the Skyra versus the other 2 units.

CONCLUSIONS

Even in multicenter studies with consistent scanner field strength and manufacturer after protocol harmonization, systematic differences can lead to severe biases in volumetric analyses.

Neuronal Injury and Glial Changes Are Hallmarks of Open Field Blast Exposure in Swine Frontal Lobe

With the rapid increase in the number of blast induced traumatic brain injuries and associated neuropsychological consequences in veterans returning from the operations in Iraq and Afghanistan, the need to better understand the neuropathological sequelae following exposure to an open field blast exposure is still critical. Although a large body of experimental studies have attempted to address these pathological changes using shock tube models of blast injury, studies directed at understanding changes in a gyrencephalic brain exposed to a true open field blast are limited and thus forms the focus of this study. Anesthetized, male Yucatan swine were subjected to forward facing medium blast overpressure (peak side on overpressure 224-332 kPa; n = 7) or high blast overpressure (peak side on overpressure 350-403 kPa; n = 5) by detonating 3.6 kg of composition-4 charge. Sham animals (n = 5) were subjected to all the conditions without blast exposure. After a 3-day survival period, the brain was harvested and sections from the frontal lobes were processed for histological assessment of neuronal injury and glial reactivity changes. Significant neuronal injury in the form of beta amyloid precursor protein immunoreactive zones in the gray and white matter was observed in the frontal lobe sections from both the blast exposure groups. A significant increase in the number of astrocytes and microglia was also observed in the blast exposed sections compared to sham sections. We postulate that the observed acute injury changes may progress to chronic periods after blast and may contribute to short and long-term neuronal degeneration and glial mediated inflammation.

Toxicity and efficacy profiles of intrathecal injection of I-131 NaI via intraventricular (IVent) or intralumbar (Ilumb) route for leptomeningeal metastases (LM) therapy

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Background: LM is a fatal complication occurring in up to 30% of cancer patients. Intrathecal chemotherapy of LM is limited by diffusion while external beam irradiation is limited by neurotoxicity. Radioiodine I-131 may serve as a ablating agent because of its radiations transverse the meningeal thinkness but spare distant underlying nervous tissues. Two phase I studies are designed to determine MTD and to evaluate potential toxicity and efficacy of intrathecal I-131 sodium iodide (NaI) injected via IVent or the ILumb route. Methods: The IVent or Ilumb protocols each accured 5 groups of patients with cytology-confirmed LM from solid tumors. An injection of 15, 30, 60, 90 or 120 mCi of I-131 NaI was performed after thyroid blockade (Lugol solution and perchlorate), via an Ommaya reservoir (IVent) or lumbar puncture (ILumb). Patients underwent whole-body scintigraphy for biodistribution and radiation dosimetry. Follow-up studies consisted of serial CSF cytology, neuropsychology, ophthalmology, and serum tests (TSH and CBC) to 6 months. Results: The IVent and Ilumb studies accured 16 and 15 patients respectively with LM from melanoma, lung, breast and other tumors (13, 8, 6 and 4 of 31 patients). Because of re-entry into the protocols, one patient received a total of 407 mCi; the maximum radiation absorbed doses were estimated at 3716 cGy in the ventricular CSF and 54 cGy in the red marrow. No treatment-related NCI-Grade II/III/IV neurologic, hematologic or thyroid toxicity is noted. Transient improvements up to 6 weeks are noted in neuropsychologic tests (5/16 and 5/15), ophthalomologic test (3/16 and 1/15) and CSF cytology conversion (to negative) in 5/16 and 4/15 patients, respectively. Electrophysiology tests of 2 patients demonstrated normalization of P37 waves measured by somatosensory evoked potentials along with neuropsychologic test improvements. Conclusions: The MTD has not been reached up to 120 mCi on either the IVent or Ilumb protocol. Intrathecal I-131 NaI is likely to be efficacious to eradicate tumors in the CSF for LM therapy. Because of the low toxicity and likely efficacy, a phase II study with higher dosages is needed to fully explore therapeutic potentials of intrathecal I-131 NaI.

No significant financial relationships to disclose.

Imaging of endoleaks

The endovascular repair of abdominal aortic aneurysms is gaining widespread acceptance worldwide. It relies on the exclusion of the aneurysm sac from arterial pressure/blood flow to reduce the pressure within it and therefore prevent the fatal complication of rupture. The presence of an endoleak is clear evidence that communication between the native circulation and the aneurysm sac persists. Unfortunately, direct measurement of the sac pressure is not a practical or safe method for routine detection or follow-up of endoleaks. Therefore, a fast, safe, sensitive, and reproducible method must be available. Although many imaging modalities have been and continue to be investigated, computed tomography angiography remains the gold standard. This article describes the various modalities used for the detection of endoleaks and discusses their imaging characteristics.

Postoperative management: type I and III endoleaks

The purpose of this article is to help the reader understand the importance of imaging findings and treatment strategies for type I and III endoleaks. Although the appearance of these leaks on computed tomography can be somewhat unremarkable and similar in appearance to type II endoleaks, it is critically important for the treating physician to make the correct diagnosis, as these endoleak types signify an incompletely treated aneurysm. Once the diagnosis of a type I or III endoleak is made, the next step in treatment is to identify the cause of the endoleak. Incomplete initial graft expansion, further arterial dilation, endograft migration, component separation, and tears within the graft fabric are all possible causes of type I and III endoleaks. A combination of computed tomography, plain film radiography, and diagnostic angiography may be necessary to make the diagnosis and identify the underlying cause of the complication. Once all of these factors have been determined, a decision has to be made of whether the endoleak can be treated through additional endovascular means or if endovascular therapy has failed for the patient, making open surgical revision necessary to treat the aneurysm. Illustrative cases of all endoleak types and their treatments are the focus of this article.

Correlation between the administered dose of DHEA and serum levels of DHEA and DHEA-S in human volunteers: analysis of published data

OBJECTIVES

Studies from both experimental animals and humans suggest that administration of exogenous DHEA may have beneficial endocrine-metabolic, immunologic and neurologic effects. Several groups have administered DHEA to humans, but to the best of our knowledge, no one at this point has published a summary of the relationship between the administered dose of DHEA and the serum levels of steroids attained.

DESIGN

We summarize the relationship between the administered dose of DHEA and the resulting serum level of DHEA and DHEA-S, in humans, from 18 published articles.

RESULTS

Serum levels of DHEA and DHEA-S increase with increasing doses. Doses above 50 mg/day result in levels that are at or above the upper limit of normal for healthy young adults. At doses above 300 mg/day the increment of serum DHEA and DHEA-S appears to reach a plateau.

CONCLUSIONS

Those wanting to use supplemental DHEA might consider that doses of 300 mg/day are maximal; they clearly result in supraphysiologic concentrations and above this level doses may have increased side effects without significantly increasing the effective level of serum hormone.

A retrospective analysis of the accuracy of T2-weighted images and dynamic gadolinium-enhanced sequences in the detection and characterization of focal hepatic lesions

The aim of this study was to determine the relative ability of T2-weighted and dynamic gadolinium-enhanced T1-weighted gradient-echo sequences to detect and characterize focal hepatic lesions. We retrospectively studied 37 patients with proven focal hepatic lesions using the following sequences: a T1-weighted spin-echo sequence (T1), a T2-weighted sequence (T2), and a series of breath-hold dynamic gadolinium-enhanced T1-weighted gradient-echo sequences (Gd). Two observers were asked to determine retrospectively the number and type of focal hepatic lesions present using images from three combinations of sequences (T1+T2, T1+Gd, T1+T2+Gd). Proof of the number and diagnosis of focal lesions in each patient was established using a consensus read. Both readers detected more focal lesions when both the T2-weighted sequences and the gadolinium-enhanced sequences were available than on either sequence alone, although this improvement reached statistical significance (P<0.05) only for one of the readers. There was no significant difference (P<0.05) in the ability to characterize lesions between any of the sets of sequences. The combination of dynamic gadolinium-enhanced images and T2-weighted images was shown to assess focal hepatic lesions better than either of these sequences alone.

Distribution of distant metastases from newly diagnosed non-small cell lung cancer

BACKGROUND

The purpose of our study was to determine the incidence and locations of M1 disease at presentation in patients with non-small cell lung cancer to help design appropriate preoperative imaging algorithms.

METHODS

All patients with non-small cell lung cancer seen between 1991 and 1993 were identified, and records were reviewed. For patients with M1 disease, the sites of distant metastases and the methods of diagnosis were recorded.

RESULTS

Of 348 patients identified, 276 (79%) had M0 disease and 72 (21%) had M1 disease. In 40 of 72 patients (56%), M1 disease was detected via chest or abdominal computed tomography (CT). Brain, bone, liver, and adrenal glands were the most common sites of metastatic disease, in decreasing order. Brain metastases often occurred as an isolated finding, although isolated liver metastases were uncommon.

CONCLUSIONS

M1 disease was common at presentation, and was often detectable via chest CT. The incremental yield of abdominal CT over chest CT was very small, and therefore abdominal CT is not an effective method of screening for metastases if chest CT has been performed.