Long COVID and post-acute sequelae of SARS-CoV-2 pathogenesis and treatment: A Keystone Symposia report

In 2023, the Keystone Symposia held the first international scientific conference convening research leaders investigating the pathology of post-acute sequelae of COVID-19 (PASC) or Long COVID, a growing and urgent public health priority. In this report, we present insights from the talks and workshops presented during this meeting and highlight key themes regarding what researchers have discovered regarding the underlying biology of PASC and directions toward future treatment. Several themes have emerged in the biology, with inflammation and other immune alterations being the most common focus, potentially related to viral persistence, latent virus reactivation, and/or tissue damage and dysfunction, especially of the endothelium, nervous system, and mitochondria. In order to develop safe and effective treatments for people with PASC, critical next steps should focus on the replication of major findings regarding potential mechanisms, disentangling pathogenic mechanisms from downstream effects, development of cellular and animal models, mechanism-focused randomized, placebo-controlled trials, and closer collaboration between people with lived experience, scientists, and other stakeholders. Ultimately, by learning from other post-infectious syndromes, the knowledge gained may help not only those with PASC/Long COVID, but also those with other post-infectious syndromes.

LGG-54. Asthma reduces glioma formation by T cell decorin-mediated inhibition of microglia

To elucidate the mechanisms underlying the reduced incidence of brain tumors in children with Neurofibromatosis type 1 (NF1) and asthma, we leverage optic pathway glioma (Nf1-OPG) mice, human and mouse RNAseq data, and two different experimental asthma models. Following ovalbumin or house dust mite asthma induction at 4-6 weeks of age (WOA), Nf1-OPG mouse optic nerve volumes and proliferation are decreased at 12 and 24 WOA, indicating no tumor development. This inhibition is accompanied by reduced expression of the microglia-produced optic glioma mitogen, Ccl5. Human and murine T cell transcriptome analyses reveal that inhibition of microglia Ccl5 production results from increased T cell expression of decorin, which blocks Ccl4-mediated microglia Ccl5 expression through reduced microglia NFκB signaling. Decorin or NFkB inhibitor treatment of Nf1-OPG mice at 4-6 WOA inhibits tumor formation at 12 WOA, thus establishing a potential mechanistic etiology for the attenuated glioma incidence observed in children with asthma.

"I Want to Do It, But I Want to Make Sure That I Do It Right." Views of Patients with Parkinson's Disease Regarding Early Stem Cell Clinical Trial Participation

Background: First-in-human clinical trials with stem cells for Parkinson's disease (PD) are on the horizon. Their epistemic success depends on ensuring the participation of a sufficient number and appropriately diverse group of patients with PD. Their ethical soundness requires that the research community ensures that subjects' decisions about whether to participate or not are consistent with participants' values, motivations, and goals. We sought to identify PD patients' knowledge, concerns, and expectations regarding early-phase stem cell research in PD. Methods: We conducted five semi-structured focus groups with patients with PD. Group discussions were recorded, transcribed, and coded to identify participants' knowledge, concerns, and expectations regarding participation in early stem cell clinical research in PD. Results: Four themes were generated from our data analysis: (1) participants' skepticism about the potential benefits of these trials; (2) their desire to obtain information about various aspects related to this research; (3) a recognition that accessing available knowledge was often difficult; and (4) the relevance of trusting relationships with various stakeholders. Conclusions: Participants expressed skepticism about the immediate impact of stem cell research. Nonetheless, such skepticism often reflected an appropriate consideration of the risks and potential benefits of participating in high-risk clinical trials. Despite their skepticism, participants were eager to learn more about stem cell research and clinical trials processes. They identified consistently trusted avenues of knowledge on these topics, but they often found it difficult to access relevant information or to determine its value.

Motion monitoring in palliative care using unobtrusive bed sensors

Palliative care needs are growing with the aging population. Ambient sensors offer patients comfortable and discreet point-of-care monitoring. In this study, two palliative care participants were monitored in a sensorized bed. Motion monitoring by a two-tier gross and fine movement detector provided accurate detection and classification of movement, compared to annotations by an observer. However, ascribing the motion to the patient rather than caregivers or visitors would require supplemental sensors. Motion was indicative of pain, with 13% of time spent moving while in pain versus 3% while not noted as in pain.

Circulating TSLP associates with decreased wheezing in non-atopic preschool children: data from the URECA birth cohort

BACKGROUND

Mouse models of atopic march suggest that systemic, skin-derived thymic stromal lymphopoietin (TSLP) mediates progression from eczema to asthma.

OBJECTIVE

We investigated whether circulating TSLP is associated with eczema, allergic sensitization, or recurrent wheezing in young children.

METHODS

A prospective analysis of the relationship between plasma levels of TSLP to allergic sensitization and recurrent wheezing was conducted in the birth cohort from the Urban Environment and Childhood Asthma (URECA) study. Plasma TSLP levels were measured at 1, 2, and 3 years of age and analysed for correlation with clinical parameters in each of the three years. Only those children with consecutive samples for all three years were included in this analysis.

RESULTS

We detected TSLP in 33% of 236 children for whom plasma samples were available for all three years. Overall, a consistently significant association was not found between TSLP and eczema or allergic sensitization. With regard to recurrent wheezing, children with detectable TSLP at one year of age were significantly less likely to experience recurrent wheezing by 3 years compared with those children without detectable TSLP, but this was only seen in children without aeroallergen sensitization at 3 years (P < 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

Contrary to our expectations, circulating TSLP was not significantly associated with eczema, allergen sensitization, or recurrent wheezing during the first three years of life. Early presence of circulating TSLP was significantly associated with reduced incidence of recurrent wheeze in those children not sensitized to aeroallergen. These findings suggest a possible underlying distinction between pathogenesis of developing atopic vs. non-atopic recurrent wheeze.

The role of gap junction protein connexin 43 in Chlamydial pathogenesis (MUC7P.752)

We have shown that Chlamydia-specific CD8 T cells do not significantly affect bacterial clearance but cause oviduct pathology, suggesting that they do not target infected cells efficaciously but cause pathology presumably by targeting uninfected cells. This suggests the possibility that chlamydial peptides are presented to CD8 T cells by uninfected cells, but begs the question: “How do uninfected cells acquire chlamydial peptides”? We hypothesized that gap junction mediated antigen transport (GMAT) via channels formed by connexin (Cx) proteins, predominantly Cx43 expressed on oviduct epithelium, contributes to this effect. We have found that HeLa cells engineered to express Cx43, but not those without, can efficaciously transfer Ova257-264 to co-cultured mouse APC, which subsequently activate CD8+ T cells from Ova primed OT-1 mice. Additionally, using Cre-Lox technology, we generated mice (Foxj1Cre-Cx43flox mice) with a conditional deficiency of Cx43 only in ciliated columnar epithelia, including oviducts. The Foxj1Cre-Cx43flox mice displayed comparable kinetics of vaginal chlamydial clearance, comparable splenic antigen-specific cytokine and serum antibody response, but significantly reduced oviduct pathology compared to WT mice on day 80 after intravaginal chlamydial infection. We have thus demonstrated the role of GMAT in immunopathogenesis of microbial infections.

Consensus guidelines from The American Society of Peritoneal Surface Malignancies on standardizing the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer patients in the United States

BACKGROUND

The American Society of Peritoneal Surface Malignancies (ASPSM) is a consortium of cancer centers performing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). This is a position paper from the ASPSM on the standardization of the delivery of HIPEC.

METHODS

A survey was conducted of all cancer centers performing HIPEC in the United States. We attempted to obtain consensus by the modified method of Delphi on seven key HIPEC parameters: (1) method, (2) inflow temperature, (3) perfusate volume, (4) drug, (5) dosage, (6) timing of drug delivery, and (7) total perfusion time. Statistical analysis was performed using nonparametric tests.

RESULTS

Response rates for ASPSM members (n = 45) and non-ASPSM members (n = 24) were 89 and 33 %, respectively. Of the responders from ASPSM members, 95 % agreed with implementing the proposal. Majority of the surgical oncologists favored the closed method of delivery with a standardized dual dose of mitomycin for a 90-min chemoperfusion for patients undergoing cytoreductive surgery for peritoneal carcinomatosis of colorectal origin.

CONCLUSIONS

This recommendation on a standardized delivery of HIPEC in patients with colorectal cancer represents an important first step in enhancing research in this field. Studies directed at maximizing the efficacy of each of the seven key elements will need to follow.

Surgical management of leiomyosarcoma of the inferior vena cava

INTRODUCTION

Leiomyosarcoma of the inferior vena cava (IVC) is a rare tumor for which en bloc resection offers the only chance of cure. Due to its rarity, however, optimal strategies for the management of the primary tumor and subsequent recurrences are not well defined.

METHODS

We performed a retrospective review of patients who underwent surgical resection of IVC leiomyosarcoma. We evaluated clinical presentations, operative techniques, patterns of recurrence and survival.

RESULTS

From 1990 to 2008, nine patients (four females) were identified. Median age was 55 years (40-76). Presentations included abdominal pain (n = 5), back pain (n = 2), leg swelling (n = 4) and abdominal mass (n = 2). Pre-operative imaging studies showed tumor location to be from the right atrium to renal veins (n = 1), retrohepatic (n = 5), and from hepatic veins to the iliac bifurcations (n = 3). En bloc resection included right nephrectomy (n = 5), right adrenalectomy (n = 4), pancreaticoduodenectomy (n = 1), right hepatic trisectionectomy (n = 1) and right hemicolectomy (n = 1). The IVC was ligated in six patients, and a prosthetic graft was used for IVC reconstruction in three patients. Resection margins were negative in seven cases. Median length of stay was 12 days (range, 6-22 days). Major morbidity included renal failure (n = 1) and there was one post-operative mortality. Five patients had leg edema post-operatively, four of whom had IVC ligation. Median survival was 47 months (range, 1-181 months). Four patients had recurrence and the median time to recurrence was 14 months (range, 3-25 months). Two patients underwent successful resection of recurrence.

CONCLUSIONS

Curative resection of IVC leiomyosarcoma can lead to long-term survival. However, recurrence is common, and effective adjuvant treatments are needed. In selected cases, aggressive surgical treatment of recurrence should be considered.

Age distribution of anginose mononucleosis

The age distribution of anginose infectious mononucleosis in children was analysed retrospectively for the years 1966-85. During that period the disease became significantly more common in children of a young age and less common in older children. This shift could not be attributed either to socioeconomic conditions or to the diagnostic methods used.

Colchicine suppression of local inflammation due to calcinosis in dermatomyositis and progressive systemic sclerosis

Two girls, one with progressive systemic sclerosis and a second with dermatomyositis, developed calcinosis in the skin of the prepatellar area. Calcinosis was accompanied by local inflammation and skin ulceration. Oral colchicine therapy in a dosage of 1 mg per day was followed within two months by significant regression of local inflammation and healing of the skin ulcers.

Calcified subdural haematomas associated with arrested hydrocephalus--late sequelae of shunt operation in infancy

Calcified chronic subdural haematomas (SDH) and features of arrested (compensated) hydrocephalus were demonstrated by skull radiography and cranial computed tomography (CT) in two children who had no neurological deficit. Ventricular surgical drainage had been performed 8 and 11 years prior to admission and the haematomas remained subsequently undetected. The following presentation will serve to illustrate the characteristic radiological features of this entity, the issue of management, and includes a review of the literature.

The effect of chronic anticonvulsant therapy on serum lipids and lipoproteins in epileptic children

We measured serum lipids and lipoproteins in 33 epileptic children who were treated with phenobarbital, valproate, and carbamazepine. High-density lipoprotein cholesterol (HDL-c) was significantly higher in the epileptic children than in two control groups: healthy nonepileptic children, and epileptic children before starting anticonvulsant therapy. Our findings indicate that anticonvulsant drugs should be added to the list of substances that affect serum HDL-c.

Delayed visual maturation

Three infants, recognised as blind during the first 4 months of life, were found to be normal on neurological and ophthalmological examinations. Visual electro-diagnostic studies showed normal retinal responses, but delayed conduction velocities and impaired visually-evoked responses over the occipital cortex. After age 6 months, normal vision developed gradually and all abnormalities disappeared.

Congenital hypertrophic pyloric stenosis: a long-term follow-up of 41 cases

From 1946 to 1977, 228 infants were operated on for congenital hypertrophic pyloric stenosis in the Tel-Aviv Municipal Medical Center, all by the method of Fredet-Ramstedt. An evaluation was made of the late morbidity in 41 patients, ranging in age from 15 to 30 years. The emphasis is on gastrointestinal diseases and their possible connection to the operation. Twenty-four of 41 patients had gastrointestinal symptoms, including dyspepsia, diarrhea, constipation, and abdominal pains. X-ray examination of the stomach was performed in 31 patients, in order to examine the structure and function of the stomach. Five patients showed clear signs of ulcer disease, four in the duodenum and one in the stomach. Another five patients showed mild deformation of the duodenal bulb, and two showed signs of gastritis. No correlation was found between the severity of the congenital pyloric stenosis and the presence of later illness or disturbances.