Low-dose naltrexone for post-COVID fatigue syndrome: a study protocol for a double-blind, randomised trial in British Columbia.

INTRODUCTION: A significant proportion of individuals suffering from post COVID-19 condition (PCC, also known as long COVID) can present with persistent, disabling fatigue similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-viral fatigue syndromes. There remains no clear pharmacological therapy for patients with this subtype of PCC, which can be referred to as post-COVID fatigue syndrome (PCFS). A low dose of the opioid antagonist naltrexone (ie, low-dose naltrexone (LDN)) has emerged as an off-label treatment for treating fatigue and other symptoms in PCC. However, only small, non-controlled studies have assessed LDN in PCC, so randomised trials are urgently required. METHODS AND ANALYSIS: A prospective, randomised, double-blind, parallel arm, placebo-controlled phase II trial will be performed to assess the efficacy of LDN for improving fatigue in PCFS. The trial will be decentralised and open to eligible individuals throughout the Canadian province of British Columbia (BC). Participants will be recruited through the province-wide Post-COVID-19 Interdisciplinary Clinical Care Network (PC-ICCN) and research volunteer platform (REACH BC). Eligible participants will be 19-69 years old, have had a confirmed or physician-suspected SARS-CoV-2 infection at least 3 months prior and meet clinical criteria for PCFS adapted from the Institute of Medicine ME/CFS criteria. Individuals who are taking opioid medications, have a history of ME/CFS prior to COVID-19 or history of significant liver disease will be excluded. Participants will be randomised to an LDN intervention arm (n=80) or placebo arm (n=80). Participants in each arm will be prescribed identical capsules starting at 1 mg daily and follow a prespecified schedule for up-titration to 4.5 mg daily or the maximum tolerated dose. The trial will be conducted over 16 weeks, with assessments at baseline, 6, 12 and 16 weeks. The primary outcome will be fatigue severity at 16 weeks evaluated by the Fatigue Severity Scale. Secondary outcomes will include pain Visual Analogue Scale score, overall symptom severity as measured by the Patient Phenotyping Questionnaire Short Form, 7-day step count and health-related quality of life measured by the EuroQol 5-Dimension questionnaire. ETHICS AND DISSEMINATION: The trial has been authorised by Health Canada and approved by The University of British Columbia/Children's and Women's Health Centre of British Columbia Research Ethics Board. On completion, findings will be disseminated to patients, caregivers and clinicians through engagement activities within existing PCC and ME/CFS networks. Results will be published in academic journals and presented at conferences. TRIAL REGISTRATION NUMBER: NCT05430152.

Fatigue presentation, severity, and related outcomes in a prospective cohort following post-COVID-19 hospitalization in British Columbia, Canada.

Introduction: Increasing evidence on long-term health outcomes following SARS CoV-2 infection shows post-viral symptoms can persist for months. These symptoms are often consistent with those of Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS). The aim of the present study was to examine the prevalence and outcome predictors of post-viral fatigue and related symptoms 3- and 6-months following symptom onset. Methods: A prospective cohort of patients hospitalized with Coronavirus disease (COVID-19) (n = 88) were recruited from a Post-COVID-19 Respiratory Clinic (PCRC) in Vancouver, Canada to examine predictors of long-term fatigue and substantial fatigue. Multivariable mixed effects analyses examined the relationship between patient predictors, including pre-existing comorbidities, patient reported outcome measures, and fatigue and substantial fatigue at follow-up. Results: The number of patients experiencing fatigue or substantial fatigue at 3 months post-infection were 58 (67%) and 14 (16%) respectively. At 6 months these numbers declined to 47 (60%) patients experiencing fatigue and 6 (6%) experiencing substantial fatigue. Adjusted analysis, for sex, age, and time, revealed the number of pre-existing comorbidities to be associated with fatigue (OR 2.21; 95% CI 1.09-4.49; 0.028) and substantial fatigue (OR 1.73; 95% CI 1.06-2.95; 0.033) at 3 months follow-up. Except for shortness of breath, self-care, and follow-up time, all follow-up variables were found to be associated with fatigue and substantial fatigue at 3 months. Conclusion: Fatigue and substantial fatigue are common after COVID-19 infection but often diminish over time. A significant number of patients continue to exhibit long-term fatigue at 6 months follow-up. Further research is needed to clarify the causality of viral infections in the development and severity of fatigue as a symptom and in meeting post-viral fatigue syndrome or ME/CFS diagnostic criteria.

Onset age is a risk factor for refractory pediatric IgA vasculitis: a retrospective cohort study.

BACKGROUND: Though outcome differences between children and adults with immunoglobulin A vasculitis (IgAV) has been well documented, it remains unclear if disease features in pediatric IgAV patients vary with onset age. We aimed to explore clinical features and prognosis of pediatric IgAV stratified by onset age. METHODS: We retrospectively reviewed records of patients under 18 years old diagnosed with IgAV from January 1999 to December 2018 in one tertiary medical center in Taiwan. Patients were grouped by onset age: ≤ 6 years old, 6-12 years old (> 6, ≤ 12), and 12-18 years old (> 12, < 18). Demographics, laboratory data, incidence of gastrointestinal, renal, and joint involvement, corticosteroid dependence, recurrence, and refractory disease were analyzed. Recurrence was defined as disease flare-up after complete remission and discontinuation of all medications for at least 3 months. Corticosteroid dependence was defined by more than 6 weeks of daily oral corticosteroid intake. Refractory disease was defined as not achieving complete remission 6 months after disease onset. Statistical analysis was performed using R software (v3.6.0). RESULTS: There were 484 IgAV patients, with an onset age of 6.10 (4.72-8.58) (median (IQR)) years old. There were 234 (48.3%) patients ≤6 years old, 210 (43.4%) 6-12 years old, and 40 (8.3%) 12-18 years old. One hundred and thirty (26.9%) patients had renal involvement, which was more frequent in older children (≤ 6 years old, 18.4%; 6-12 years old, 31.0%; 12-18 years old, 55.0%; p <  0.001). There were 361 patients (74.6%) with joint involvement; younger children were affected more frequently (≤ 6 years old, 82.1%; 6-12 years old, 71.9%; 12-18 years old, 45.0%; p <  0.001). Gastrointestinal involvement was present in 311 (64.3%) patients, showing no difference among age groups. There were 46 patients (9.5%) with recurrent IgA vasculitis, 136 (28.1%) with corticosteroid dependent and 76 (15.7%) with refractory disease. Corticosteroid dependence and refractory disease occurred more frequently as onset age increased (p <  0.001). CONCLUSION: Pediatric IgAV with different onset ages are associated with distinct clinical manifestations and outcomes. The risk of developing corticosteroid dependence, refractory disease and renal involvement increased with onset age.

Expression of a cryptic secondary sigma factor gene unveils natural competence for DNA transformation in Staphylococcus aureus.

It has long been a question whether Staphylococcus aureus, a major human pathogen, is able to develop natural competence for transformation by DNA. We previously showed that a novel staphylococcal secondary sigma factor, SigH, was a likely key component for competence development, but the corresponding gene appeared to be cryptic as its expression could not be detected during growth under standard laboratory conditions. Here, we have uncovered two distinct mechanisms allowing activation of SigH production in a minor fraction of the bacterial cell population. The first is a chromosomal gene duplication rearrangement occurring spontaneously at a low frequency [≤10(-5)], generating expression of a new chimeric sigH gene. The second involves post-transcriptional regulation through an upstream inverted repeat sequence, effectively suppressing expression of the sigH gene. Importantly, we have demonstrated for the first time that S. aureus cells producing active SigH become competent for transformation by plasmid or chromosomal DNA, which requires the expression of SigH-controlled competence genes. Additionally, using DNA from the N315 MRSA strain, we successfully transferred the full length SCCmecII element through natural transformation to a methicillin-sensitive strain, conferring methicillin resistance to the resulting S. aureus transformants. Taken together, we propose a unique model for staphylococcal competence regulation by SigH that could help explain the acquisition of antibiotic resistance genes through horizontal gene transfer in this important pathogen.

Identification of biomarkers in sequential biopsies of patients with chronic wounds receiving simultaneous acute wounds: a genetic, histological, and noninvasive imaging study.

Chronic wounds are common and lead to significant patient morbidity. A better understanding of their pathogenesis and relevant biomarkers are required. We compared acute and chronic wounds in the same individual using noninvasive imaging including spectrophotometric intracutaneous analysis (SIAscopy) and full-field laser perfusion imaging. Gene expression analysis was also performed on sequential biopsies. Whole genome gene expression microarray analysis (44k), quantitative polymerase chain reaction, and immunohistochemistry were carried out to determine gene expression levels in tissue biopsies. Fifteen Caucasian patients with chronic venous ulcers had biopsies of the wound edges and simultaneously had an acute wound created on their upper arm on days 0, 7, and 14. SIAscopy revealed increased levels of melanin (p < 0.001), reduced levels of collagen (p < 0.001), and hemoglobin (p = 0.022) in chronic wounds. Microarray and subsequent quantitative polymerase chain reaction analysis confirmed an overall differential expression in acute and chronic wounds for several genes. Significantly higher levels of inhibin, beta A (INHBA) expression were confirmed in the dermis of chronic wounds (p < 0.05). Additionally, INHBA and thrombospondin 1 messenger RNA levels significantly correlated with SIAscopy measurements (p < 0.05). This unique study has showed aberrant expression of INHBA in chronic wounds using a sequential biopsy model of chronic vs. acute wounds in the same individual.

Staphylococcus aureus requires cardiolipin for survival under conditions of high salinity.

BACKGROUND: The ability of staphylococci to grow in a wide range of salt concentrations is well documented. In this study, we aimed to clarify the role of cardiolipin (CL) in the adaptation of Staphylococcus aureus to high salinity. RESULTS: Using an improved extraction method, the analysis of phospholipid composition suggested that CL levels increased slightly toward stationary phase, but that this was not induced by high salinity. Deletion of the two CL synthase genes, SA1155 (cls1) and SA1891 (cls2), abolished CL synthesis. The cls2 gene encoded the dominant CL synthase. In a cls2 deletion mutant, Cls1 functioned under stress conditions, including high salinity. Using these mutants, CL was shown to be unnecessary for growth in either basal or high-salt conditions, but it was critical for prolonged survival in high-salt conditions and for generation of the L-form. CONCLUSIONS: CL is not essential for S. aureus growth under conditions of high salinity, but is necessary for survival under prolonged high-salt stress and for the generation of L-form variants.

Morphological changes of short-wavelength cones in the developing S334ter-3 transgenic rat.

The S334ter-3 rat is a transgenic model of retinal degeneration (RD) developed to express a rhodopsin mutation similar to that found in human retinitis pigmentosa. Due to this advantage over other models of RD, a few retina transplant studies have been reported on this animal model. Currently, no information is available on cone photoreceptor changes that occur in the S334ter RD model. In this study, we investigated the effect of RD on the morphology, distribution, and synaptic connectivity of short-wavelength cones (S-cones) during development of S334ter-3 rat retinas. At P21 RD retinas, the outer-nuclear layer was significantly narrower, while S-cones showed shortening of their segments and axons compared to control retinas. From P90 onward, S-opsin-immunoreactive cells appeared at the outer margin of the inner-nuclear layer of RD retinas. Double-labelling experiments showed these cells contained recoverin and cone arrestin. Furthermore, ultra-structure study showed that synaptic ribbons are conserved in the S-cone at P180 RD retinas. Although cell density of S-cones significantly dropped after P90, survival rates depended on the retinal region. Overall, the S334ter-3 RD model shows hallmarks of cone remodelling due to photoreceptor degeneration.