Long COVID: Is there a kidney link?

Metabolic causes such as altered bioenergetics and amino acid metabolism may play a major role in Long COVID. Renal-metabolic regulation is an integral part of these pathways but has not been systematically or routinely investigated in Long COVID. Here we discuss the biochemistry of renal tubular injury as it may contribute to Long COVID symptoms. We propose three potential mechanisms that could be involved in Long COVID namely creatine phosphate metabolism, un-reclaimed glomerular filtrate and COVID specific proximal tubule cells (PTC) injury-a tryptophan paradigm. This approach is intended to allow for improved diagnostics and therapy for the long-haul sufferers.

Incorporating age improves the Glasgow Coma Scale score for predicting mortality from traumatic brain injury.

BACKGROUND: The Glasgow Coma Scale (GCS) score has been adapted into categories of severity (mild, moderate, and severe) and are ubiquitous in the trauma setting. This study sought to revise the GCS categories to account for an interaction by age and to determine the discrimination of the revised categories compared with the standard GCS categories. METHODS: The American College of Surgeons National Trauma Data Bank registry was used to identify patients with traumatic brain injury (TBI; ICD-9 codes 850-854.19) who were admitted to participating trauma centers from 2010 to 2015. The primary exposure variables were GCS score and age, categorized by decade (teens, 20s, 30s…, 80s). In-hospital mortality was the primary outcome for examining TBI severity/prognostication. Logistic regression was used to calculate the conditional probability of death by age decade and GCS in a development dataset (75% of patients). These probabilities were used to create a points-based revision of the GCS, categorized as low (mild), moderate, and high (severe). Performance of the revised versus standard GCS categories was compared in the validation dataset using area under the receiver operating characteristic (AUC) curves. RESULTS: The final population included 539,032 patients with TBI. Age modified the performance of the GCS, resulting in a novel categorization schema for each age decile. For patients in their 50s, performance of the revised GCS categories mirrored the standard GCS categorization (3-8, 9-12, 13-15); all other revised GCS categories were heavily modified by age. Model validation demonstrated the revised GCS categories statistically significantly outperformed the standard GCS categories at predicting mortality (AUC: 0.800 vs 0.755, p<0.001). The revised GCS categorization also outperformed the standard GCS categories for mortality within pre-specified subpopulations: blunt mechanism, isolated TBI, falls, non-transferred patients. DISCUSSION: We propose the revised age-adjusted GCS categories will improve severity assessment and provide a more uniform early prognostic indicator of mortality following traumatic brain injury. LEVEL OF EVIDENCE: III epidemiologic/prognostic.

AMP5A modulates Toll-like receptors 7 and 8 single-stranded RNA immune responses in PMA-differentiated THP-1 and PBMC.

Background: Dysregulation of antiviral immunity has been implicated in the progression of acute respiratory syndrome coronavirus 2 infection into severe cases of coronavirus disease of 2019 (COVID-19). Imbalances in the inflammatory response drive the overabundant production of pro-inflammatory cytokines and chemokines. The low molecular weight fraction of 5% human serum albumin commercial preparation (AMP5A) is a novel biologic drug currently under clinical investigation for the treatment of osteoarthritis and the hyperinflammatory response associated with COVID-19. This study aims to elucidate AMP5A effects following the activation of immune cells with agonists of Toll-like receptor (TLR) 7 and/or 8, which detect ssRNA viral sequences. Methods: CXCL10 ELISAs were used to evaluate the dynamics of myeloid cells activated with CL075 and CL307, agonists of TLR7/8 and TLR7, respectively. In addition, enrichment analysis of gene sets generated by ELISA arrays was utilized to gain insight into the biologic processes underlying the identified differentially expressed cytokine profiles. Finally, relative potency (REP) was employed to confirm the involvement of mechanisms of action paramount to AMP5A activity. Results: AMP5A inhibits the release of CXCL10 from both CL075- and CL307-activated PMA-differentiated THP-1 and peripheral blood mononuclear cells. Furthermore, AMP5A suppresses a distinct set of pro-inflammatory cytokines (including IL-1ß, IL-6, IL-12, and CXCL10) associated with COVID-19 and pro-inflammatory NF-κB activation. REP experiments using antagonists specific for the immunomodulatory transcription factors, peroxisome proliferator-activated receptor γ, and aryl hydrocarbon receptor, also indicate that these pathways are involved in the ability of AMP5A to inhibit CXCL10 release. Conclusion: Due to the biphasic course of COVID-19, therapeutic approaches that augment antiviral immunity may be more beneficial early in infection, whereas later interventions should focus on inflammation suppression. In this study, we show that AMP5A inhibits TLR 7/8 signaling in myeloid cells, resulting in a decrease in inflammatory mediators associated with hyperinflammation and autoimmunity. Furthermore, data demonstrating that AMP5A activates immunomodulatory transcription factors found to be protective in lung disease is provided. These findings suggest that the modes and mechanisms of action of AMP5A are well suited to treat conditions involving dysregulated TLR 7/8 activation.

C1 esterase inhibitor-mediated immunosuppression in COVID-19: friend or foe?

From asymptomatic to severe, SARS-CoV-2, causative agent of COVID-19, elicits varying disease severities. Moreover, understanding innate and adaptive immune responses to SARS-CoV-2 is imperative since variants such as Omicron negatively impact adaptive antibody neutralization. Severe COVID-19 is, in part, associated with aberrant activation of complement and Factor XII (FXIIa), initiator of contact system activation. Paradoxically, a protein that inhibits the three known pathways of complement activation and FXIIa, C1 esterase inhibitor (C1-INH), is increased in COVID-19 patient plasma and is associated with disease severity. Here we review the role of C1-INH in the regulation of innate and adaptive immune responses. Additionally, we contextualize regulation of C1-INH and SERPING1, the gene encoding C1-INH, by other pathogens and SARS viruses and propose that viral proteins bind to C1-INH to inhibit its function in severe COVID-19. Finally, we review the current clinical trials and published results of exogenous C1-INH treatment in COVID-19 patients.

A Randomized Controlled Trial to Evaluate the Safety and Efficacy of a Novel Inhaled Biologic Therapeutic in Adults with Respiratory Distress Secondary to COVID-19 Infection.

INTRODUCTION: Inhaled therapeutics may act to directly target and attenuate lung inflammation due to COVID-19. An inhalation form of a novel biologic drug, AMP5A, is being developed as an immunomodulatory agent to treat dysregulated immune responses and is being studied in hospitalized patients to treat respiratory complications due to COVID-19. METHODS: A randomized, controlled, phase I trial was conducted to evaluate hospitalized adults with respiratory distress secondary to COVID-19. Patients received the standard care (SOC) for COVID-19, including respiratory therapy, corticosteroids, and antiviral therapies such as remdesivir. Patients were randomized 1:1 to inhalation treatment with AMP5A as an adjunct to SOC or to SOC alone (control). AMP5A was administered via inhalation daily for 5 days via hand-held nebulizer, non-invasive ventilator, or mechanical ventilation. Safety and clinical efficacy endpoints were evaluated. RESULTS: Forty subjects were enrolled and randomized (n = 19 AMP5A, n = 21 control). Remdesivir was used in fewer AMP5A subjects (26%) than control (52%), and dexamethasone was administered for most subjects (84% AMP5A, 71% control). The study met its primary endpoint with no AMP5A treatment-related adverse events (AEs), and the incidence and severity of AEs were comparable between groups: 18 AEs for control (8 mild, 1 moderate, 9 severe) and 19 AEs for AMP5A (7 mild, 7 moderate, 5 severe). Notably, subjects treated with AMP5A had fewer deaths (5% vs. 24%), shorter hospital stay (8 days vs. 12 days), fewer ICU admissions (21% vs. 33%), and a greater proportion with improved clinical outcomes than control. CONCLUSION: The phase I clinical results indicate inhaled AMP5A is safe, is well tolerated, and could lead to fewer patients experiencing deterioration or death. Based on the treatment effect (i.e., reduced mortality), a phase II trial has been initiated. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04606784.

Multicenter study of US trauma centers examining the effect of the COVID-19 pandemic on injury causes, diagnoses and procedures.

BACKGROUND: The COVID-19 pandemic resulted in nationwide social distancing and shelter-in-place orders meant to curb transmission of the SARS-CoV-2 virus. The effect of the pandemic on injury patterns has not been well described in the USA. The study objective is to determine the effect of the COVID-19 pandemic on the distribution and determinants of traumatic injuries. METHODS: This retrospective multi-institutional cohort study included all hospital admissions for acute traumatic injury at six community level I trauma centers. Descriptive statistics were used to compare injury causes, diagnoses and procedures over two similar time periods: prepandemic (March 11-June 30, 2019) and pandemic (March 11-June 30, 2020). RESULTS: There were 7308 trauma patients included: 3862 (53%) prepandemic and 3446 (47%) during the pandemic. Cause of injury significantly differed by period (p<0.001). During the pandemic, there were decreases in motor vehicle crashes (from 17.0% to 14.0%, p<0.001), worksite injuries (from 5.2% to 4.1%, p=0.02), pedestrian injuries (from 3.0% to 2.2%, p=0.02) and recreational injuries (from 3.0% to 1.7%, p<0.001), while there were significant increases in assaults (6.9% to 8.5%, p=0.01), bicycle crashes (2.8% to 4.2%, p=0.001) and off-road vehicle injuries (1.8% to 3.0%, p<0.001). There was no change by study period in falls, motorcycle injuries, crush/strikes, firearm and self-inflicted injuries, and injuries associated with home-improvement projects. Injury diagnoses differed between time periods; during the pandemic, there were more injury diagnoses to the head (23.0% to 27.3%, p<0.001) and the knee/leg (11.7% to 14.9%, p<0.001). There were also increases in medical/surgical procedures (57.5% to 61.9%, p<0.001), administration of therapeutics/blood products (31.4% to 34.2%, p=0.01) and monitoring (11.0% to 12.9%, p=0.01). DISCUSSION: Causes of traumatic injury, diagnoses, and procedures were significantly changed by the pandemic. Trauma centers must adjust to meet the changing demands associated with altered injury patterns, as they were associated with increased use of hospital resources. LEVEL OF EVIDENCE: III (epidemiological).

Effect of the COVID-19 pandemic on health insurance coverage among trauma patients: a study of six level I trauma centers.

BACKGROUND: Increased unemployment during the COVID-19 pandemic has likely led to widespread loss of employer-provided health insurance. This study examined trends in health insurance coverage among trauma patients during the COVID-19 pandemic, including differences in demographics and clinical characteristics by insurance type. METHODS: This was a retrospective study on adult patients admitted to six level 1 trauma centers between January 1, 2018 and June 30, 2020. The primary exposure was hospital admission date: January 1, 2018 to December 31, 2018 (Period 1), January 1, 2019 to March 15, 2020 (Period 2), and March 16, 2020 to June 30, 2020 (Period 3). Covariates included demographic and clinical variables. χ² tests examined whether the rates of patients covered by each insurance type differed between the pandemic and earlier periods. Mann-Whiney U and χ² tests investigated whether patient demographics or clinical characteristics differed within each insurance type across the study periods. RESULTS: A total of 31 225 trauma patients admitted between January 1, 2018 and June 30, 2019 were included. Forty-one per cent (n=12 651) were admitted in Period 1, 49% (n=15 258) were from Period 2, and 11% (n=3288) were from Period 3. Percentages of uninsured patients increased significantly across the three periods (Periods 1 to 3: 15%, 16%, 21%) (ptrend=0.02); however, there was no accompanying decrease in the percentages of commercial/privately insured patients (Periods 1 to 3: 40%, 39%, 39%) (ptrend=0.27). There was a significant decrease in the percentage of patients on Medicare during the pandemic period (Periods 1 to 3: 39%, 39%, 34%) (p<0.01). DISCUSSION: This study found that job loss during the COVID-19 pandemic resulted in increases of uninsured trauma patients. However, there was not a corresponding decrease in commercial/privately insured patients, as may have been expected; rather, a decrease in Medicare patients was observed. These findings may be attributable to a growing workforce during the study period, in combination with a younger overall patient population during the pandemic. LEVEL OF EVIDENCE: Retrospective, level III study.

Delayed hospital admission for traumatic hip fractures during the COVID-19 pandemic.

BACKGROUND: Concerns of contracting the highly contagious disease COVID-19 have led to a reluctance in seeking medical attention, which may contribute to delayed hospital arrival among traumatic patients. The study objective was to describe differences in time from injury to arrival for patients with traumatic hip fractures admitted during the pandemic to pre-pandemic patients. MATERIALS AND METHODS: This retrospective cohort study at six level I trauma centers included patients with traumatic hip fractures. Patients with a non-fall mechanism and those who were transferred in were excluded. Patients admitted 16 March 2019-30 June 2019 were in the "pre-pandemic" group, patients were admitted 16 March 2020-30 June 2020 were in the "pandemic" group. The primary outcome was time from injury to arrival. Secondary outcomes were time from arrival to surgical intervention, hospital length of stay (HLOS), and mortality. RESULTS: There were 703 patients, 352 (50.1%) pre-pandemic and 351 (49.9%) during the pandemic. Overall, 66.5% were female and the median age was 82 years old. Patients were similar in age, race, gender, and injury severity score. The median time from injury to hospital arrival was statistically shorter for pre-pandemic patients when compared to pandemic patients, 79.5 (56, 194.5) min vs. 91 (59, 420), p = 0.04. The time from arrival to surgical intervention (p = 0.64) was statistically similar between groups. For both groups, the median HLOS was 5 days, p = 0.45. In-hospital mortality was significantly higher during the pandemic, 1.1% vs 3.4%, p = 0.04. CONCLUSIONS: While time from injury to hospital arrival was statistically longer during the pandemic, the difference may not be clinically important. Time from arrival to surgical intervention remained similar, despite changes made to prevent COVID-19 transmission.

Implementing the SNIS recommendations for neurointerventional emergent care in the setting of COVID-19: impact on stroke metrics and patient outcomes.

BACKGROUND: It is not clear whether the COVID-19 pandemic and subsequent Society of Neurointerventional Surgery (SNIS) recommendations affected hospital stroke metrics. METHODS: This retrospective cohort study compared stroke patients admitted to a comprehensive stroke center during the COVID-19 pandemic April 1 2020 to June 30 2020 (COVID-19) to patients admitted April 1 2019 to June 30 2019. We examined stroke admission volume and acute stroke treatment use. RESULTS: There were 637 stroke admissions, 52% in 2019 and 48% during COVID-19, with similar median admissions per day (4 vs 3, P=0.21). The proportion of admissions by stroke type was comparable (ischemic, P=0.69; hemorrhagic, P=0.39; transient ischemic stroke, P=0.10). Acute stroke treatment was similar in 2019 to COVID-19: tPA prior to arrival (18% vs, 18%, P=0.89), tPA treatment on arrival (6% vs 7%, P=0.85), and endovascular therapy (endovascular therapy (ET), 22% vs 25%, P=0.54). The door to needle time was also similar, P=0.12, however, the median time from arrival to groin puncture was significantly longer during COVID-19 (38 vs 43 min, P=0.002). A significantly higher proportion of patients receiving ET were intubated during COVID-19 due to SNIS guideline implementation (45% vs 96%, P<0.0001). There were no differences by study period in discharge mRS, P=0.84 or TICI score, P=0.26. CONCLUSIONS: The COVID-19 pandemic did not significantly affect stroke admission volume or acute stroke treatment utilization. Outcomes were not affected by implementing SNIS guidelines. Although there was a statistical increase in time to groin puncture for ET, it was not clinically meaningful. These results suggest hospitals managing patients efficiently can implement practices in response to COVID-19 without impacting outcomes.

Patterns of alcohol and drug utilization in trauma patients during the COVID-19 pandemic at six trauma centers.

BACKGROUND: Since the national stay-at-home order for COVID-19 was implemented, clinicians and public health authorities worldwide have expressed growing concern about the potential repercussions of drug and alcohol use due to social restrictions. We explored the impact of the national stay-at-home orders on alcohol or drug use and screenings among trauma admissions. METHODS: This was a retrospective cohort study at six Level I trauma centers across four states. Patients admitted during the period after the onset of the COVID-19 restrictions (defined as March 16, 2020-May 31, 2020) were compared with those admitted during the same time period in 2019. We compared 1) rate of urine drug screens and blood alcohol screens; 2) rate of positivity for drugs or alcohol (blood alcohol concentration ≥ 10 mg/dL); 3) characteristics of patients who were positive for drug or alcohol, by period using chi-squared tests or Fisher's exact tests, as appropriate. Two-tailed tests with an alpha of p < 0.05 was used on all tests. RESULTS: There were 4762 trauma admissions across the study period; 2602 (55%) in 2019 and 2160 (45%) in 2020. From 2019 to 2020, there were statistically significant increases in alcohol screens (34% vs. 37%, p = 0.03) and drug screens (21% vs. 26%, p < 0.001). Overall, the rate of alcohol positive patients significantly increased from 2019 to 2020 (32% vs. 39%, p = 0.007), while the rate of drug positive patients was unchanged (57% vs. 52%, p = 0.13). Of the 1025 (22%) patients who were positive for alcohol or drugs, there were significant increases in a history of alcoholism (41% vs. 26%, p < 0.001), and substance abuse (11% vs. 23%, p < 0.001) in the 2020 period. No other statistically significant differences were identified among alcohol or drug positive patients during COVID-19 compared to the same period in 2019. CONCLUSIONS: Our first wave of COVID-19 data suggests that trauma centers were admitting significantly more patients who were alcohol positive, as well those with substance use disorders, potentially due to the impact of social restrictions and guidelines. Further longitudinal research is warranted to assess the alcohol and drug positive rates of trauma patients over the COVID-19 pandemic.

Effect of the COVID-19 pandemic on the ability of level 1 trauma centers to meet American College of Surgeons research requirements.

INTRODUCTION: The COVID-19 pandemic has had major effects on hospitals' ability to perform scientific research while providing patient care and minimizing virus exposure and spread. Many non-COVID-19 research has been halted, and funding has been diverted to COVID-19 research and away from other areas. METHODS: A 28-question survey was administered to all level 1 trauma centers in the USA that included questions about how the pandemic affected the trauma centers' ability to fulfill the volume and research requirements of level 1 verification by the American College of Surgeons (ACS). RESULTS: The survey had a 29% response rate (40/137 successful invitations). Over half of respondents (52%) reported reduced trauma admissions during the pandemic, and 7% reported that their admissions dropped below the volume required for level 1 verification. Many centers diverted resources from research during the pandemic (44%), halted ongoing consenting studies (33%), and had difficulty fulfilling research requirements because of competing clinical priorities (40%). DISCUSSION: Results of this study show a need for flexibility in the ACS verification process during the COVID-19 pandemic, potentially including reduction of the required admissions and/or research publication volumes. LEVEL OF EVIDENCE: Level IV, cross-sectional study.

COVID-19 and trauma: how social distancing orders altered the patient population using trauma services during the 2020 pandemic.

BACKGROUND: Recent studies have reported changes in trauma volumes resulting from the COVID-19 pandemic and social distancing orders (SDOs) implemented by federal and state governments. However, literature is lacking on demographic, injury and outcome patterns. METHODS: This retrospective, cross-sectional study included patients aged ≥18 years at six US level 1 trauma centers. Patients not discharged by the date of data acquisition were excluded. Demographic, injury and outcome variables were assessed across four time periods: period 1 (January 1, 2019-December 31, 2019); period 1b (March 16, 2019-June 30, 2019); period 2 (January 1, 2020-March 15, 2020); and period 3 (March 16, 2020-June 30, 2020). Patients admitted in period 3 were compared with patients presenting during all other periods. Categorical data were compared with χ2 and Fisher's exact tests, and continuous data were assessed with Student's t-tests and Wilcoxon rank-sum tests. RESULTS: We identified 18 567 patients: 12 797 patients in period 1 (including 3707 in period 1b), 2488 in period 2 and 3282 in period 3. Compared with period 1, period 3 had a statistically significant decrease in mean patient volume, increase in portion of penetrating injuries, increase in higher levels of trauma activation, change in emergency department discharge disposition locations, increase in in-hospital mortality and a shorter hospital length of stay. Comparison between period 1b and period 3 demonstrated a decrease in mean patient volume, increase in penetrating injuries, increase in high acuity trauma activations and increase in in-hospital mortality rate. From period 2 to period 3, the penetrating injuries rose from 6.7% to 9.4% (p=0.004), injury severity scale ≥25 increased from 5.9% to 7.7% (p=0.002), full trauma team activations increased from 13.7% to 16.4% (p<0.001), interhospital transfers decreased from 36.7% to 31.6% (p<0.001) and the in-hospital mortality rate increased from 3.3% to 4.2% (p=0.003). DISCUSSION: Beyond altering social interactions among people, the federal SDO is associated with changes in trauma volumes, demographics and injury patterns among patients seeking care at six level 1 hospitals during the pandemic. LEVEL OF EVIDENCE: IV, prognostic and epidemiological.

Examining emergency medical services' prehospital transport times for trauma patients during COVID-19.

INTRODUCTION: Longer prehospital times were associated with increased odds for survival in trauma patients. The purpose of this study was to determine how the COVID-19 pandemic affected emergency medical services (EMS) prehospital times for trauma patients. METHODS: This retrospective cohort study compared trauma patients transported via EMS to six US level I trauma centers admitted 1/1/19-12/31/19 (2019) and 3/16/20-6/30/20 (COVID-19). Outcomes included: total EMS pre-hospital time (dispatch to hospital arrival), injury to dispatch time, response time (dispatch to scene arrival), on-scene time (scene arrival to scene departure), and transportation time (scene departure to hospital arrival). Fisher's exact, chi-squared, or Kruskal-Wallis tests were used, alpha = 0.05. All times are presented as median (IQR) minutes. RESULTS: There were 9400 trauma patients transported by EMS: 79% in 2019 and 21% during the COVID-19 pandemic. Patients were similar in demographics and transportation mode. Emergency room deaths were also similar between 2019 and COVID-19 [0.6% vs. 0.9%, p = 0.13].There were no differences between 2019 and during COVID-19 for total EMS prehospital time [44 (33, 63) vs. 43 (33, 62), p = 0.12], time from injury to dispatch [16 (6, 55) vs. 16 (7, 77), p = 0.41], response time [7 (5, 12) for both groups, p = 0.27], or on-scene time [16 (12-22) vs. 17 (12,22), p = 0.31]. Compared to 2019, transportation time was significantly shorter during COVID-19 [18 (13, 28) vs. 17 (12, 26), p = 0.01]. CONCLUSION: The median transportation time for trauma patients was marginally significantly shorter during COVID-19; otherwise, EMS prehospital times were not significantly affected by the COVID-19 pandemic.

Processes for Trauma Care at Six Level I Trauma Centers During the COVID-19 Pandemic.

INTRODUCTION: As the COVID-19 pandemic spread, patient care guidelines were published and elective surgeries postponed. However, trauma admissions are not scheduled and cannot be postponed. There is a paucity of information available on continuing trauma care during the pandemic. The study purpose was to describe multicenter trauma care process changes made during the COVID-19 pandemic. METHODS: This descriptive survey summarized the response to the COVID-19 pandemic at six Level I trauma centers. The survey was completed in 05/2020. Questions were asked about personal protective equipment, ventilators, intensive care unit (ICU) beds, and negative pressure rooms. Data were summarized as proportions. RESULTS: The survey took an average of 5 days. Sixty-seven percent reused N-95 respirators; 50% sanitized them with 25% using ultraviolet light. One hospital (17%) had regional resources impacted. Thirty-three percent created ventilator allocation protocols. Most hospitals (83%) designated more beds to the ICU; 50% of hospitals designated an ICU for COVID-19 patients. COVID-19 patients were isolated in negative pressure rooms at all hospitals. CONCLUSIONS: In response to the COVID-19 pandemic, Level I trauma centers created processes to provide optimal trauma patient care and still protect providers. Other centers can use the processes described to continue care of trauma patients during the COVID-19 pandemic.

Clinically distinct COVID-19 cases share notably similar immune response progression: A follow-up analysis.

Inflammatory responses to the novel coronavirus SARS-CoV-2, which causes COVID-19, range from asymptomatic to severe. Here we present a follow-up analysis of a longitudinal study characterizing COVID-19 immune responses from a father and son with distinctly different clinical courses. The father required a lengthy hospital stay for severe symptoms, whereas his son had mild symptoms and no fever yet tested positive for SARS-CoV-2 for 29 days. Father and son, as well as another unrelated COVID-19 patient, displayed a robust increase of SERPING1, the transcript encoding C1 esterase inhibitor (C1-INH). We further bolstered this finding by incorporating a serum proteomics dataset and found that serum C1-INH was consistently increased in COVID-19 patients. C1-INH is a central regulator of the contact and complement systems, potentially linking COVID-19 to complement hyperactivation, fibrin clot formation, and immune depression. Furthermore, despite distinct clinical cases, significant parallels were observed in transcripts involved in interferon and B cell signaling. As symptoms were resolving, widespread decreases were seen in immune-related transcripts to levels below those of healthy controls. Our study provides insight into the immune responses of likely millions of people with extremely mild symptoms who may not be aware of their infection with SARS-CoV-2 and implies a potential for long-lasting consequences that could contribute to reinfection risk.

LMWF5A suppresses cytokine release by modulating select inflammatory transcription factor activity in stimulated PBMC.

BACKGROUND: Dysregulation of transcription and cytokine expression has been implicated in the pathogenesis of a variety inflammatory diseases. The resulting imbalance between inflammatory and resolving transcriptional programs can cause an overabundance of pro-inflammatory, classically activated macrophage type 1 (M1) and/or helper T cell type 1 (Th1) products, such as IFNγ, TNFα, IL1-ß, and IL12, that prevent immune switching to resolution and healing. The low molecular weight fraction of human serum albumin (LMWF5A) is a novel biologic drug that is currently under clinical investigation for the treatment of osteoarthritis and the hyper-inflammatory response associated with COVID-19. This study aims to elucidate transcriptional mechanisms of action involved with the ability of LMWF5A to reduce pro-inflammatory cytokine release. METHODS: ELISA arrays were used to identify cytokines and chemokines influenced by LMWF5A treatment of LPS-stimulated peripheral blood mononuclear cells (PBMC). The resulting profiles were analyzed by gene enrichment to gain mechanistic insight into the biologic processes and transcription factors (TFs) underlying the identified differentially expressed cytokines. DNA-binding ELISAs, luciferase reporter assays, and TNFα or IL-1ß relative potency were then employed to confirm the involvement of enriched pathways and TFs. RESULTS: LMWF5A was found to significantly inhibit a distinct set of pro-inflammatory cytokines (TNFα, IL-1ß, IL-12, CXCL9, CXCL10, and CXCL11) associated with pro-inflammatory M1/Th1 immune profiles. Gene enrichment analysis also suggests these cytokines are, in part, regulated by NF-κB and STAT transcription factors. Data from DNA-binding and reporter assays support this with LMWF5A inhibition of STAT1α DNA-binding activity as well as a reduction in overall NF-κB-driven luciferase expression. Experiments using antagonists specific for the immunomodulatory and NF-κB/STAT-repressing transcription factors, peroxisome proliferator-activated receptor (PPAR)γ and aryl hydrocarbon receptor (AhR), indicate these pathways are involved in the LMWF5A mechanisms of action by reducing LMWF5A drug potency as measured by TNFα and IL-1ß release. CONCLUSION: In this report, we provide evidence that LMWF5A reduces pro-inflammatory cytokine release by activating the immunoregulatory transcription factors PPARγ and AhR. In addition, our data indicate that LMWF5A suppresses NF-κB and STAT1α pro-inflammatory pathways. This suggests that LMWF5A acts through these mechanisms to decrease pro-inflammatory transcription factor activity and subsequent inflammatory cytokine production.