Discordance Between Invasive and NonInvasive Oxygen Saturation in Critically Ill COVID-19 Patients.

OBJECTIVES: To investigate discordance in oxy-hemoglobin saturation measured both by pulse oximetry (SpO2) and arterial blood gas (ABG, SaO2) among critically ill coronavirus disease 2019 (COVID-19(+)) patients compared to COVID-19(-) patients. METHODS: Paired SpO2 and SaO2 readings were collected retrospectively from consecutive adult admissions to four critical care units in the United States between March and May 2020. The primary outcome was the rate of discordance (|SaO2-SpO2|>4%) in COVID-19(+) versus COVID-19(-) patients. The odds each cohort could have been incorrectly categorized as having a PaO2/FiO2 above or below 150 by their SpO2: Fractional inhaled oxygen ratio (pulse oximetry-derived oxyhemoglobin saturation:fraction of inspired oxygen ratio [SF]) was examined. A multivariate regression analysis assessed confounding by clinical differences between cohorts including pH, body temperature, renal replacement therapy at time of blood draw, and self-identified race. RESULTS: There were 263 patients (173 COVID-19(+)) included. The rate of saturation discordance between SaO2 and SpO2 in COVID-19(+) patients was higher than in COVID-19(-) patients (27.9% vs 16.7%, odds ratio [OR] 1.94, 95% confidence interval [CI]: 1.11 to 2.27). The average difference between SaO2 and SpO2 for COVID-19(+) patients was -1.24% (limits of agreement, -13.6 to 11.1) versus -0.11 [-10.3 to 10.1] for COVID-19(-) patients. COVID-19(+) patients had higher odds (OR: 2.61, 95% CI: 1.14-5.98) of having an SF that misclassified that patient as having a PaO2:FiO2 ratio above or below 150. There was not an association between discordance and the confounders of pH, body temperature, or renal replacement therapy at time of blood draw. After controlling for self-identified race, the association between COVID-19 status and discordance was lost. CONCLUSIONS: Pulse oximetry was discordant with ABG more often in critically ill COVID-19(+) than COVID-19(-) patients. However, these findings appear to be driven by racial differences between cohorts.

Inhibition of the JAK/STAT Pathway Protects Against α-Synuclein-Induced Neuroinflammation and Dopaminergic Neurodegeneration.

UNLABELLED: Parkinson's Disease (PD) is an age-related, chronic neurodegenerative disorder. At present, there are no disease-modifying therapies to prevent PD progression. Activated microglia and neuroinflammation are associated with the pathogenesis and progression of PD. Accumulation of α-synuclein (α-SYN) in the brain is a core feature of PD and leads to microglial activation, inflammatory cytokine/chemokine production, and ultimately to neurodegeneration. Given the importance of the JAK/STAT pathway in activating microglia and inducing cytokine/chemokine expression, we investigated the therapeutic potential of inhibiting the JAK/STAT pathway using the JAK1/2 inhibitor, AZD1480. In vitro, α-SYN exposure activated the JAK/STAT pathway in microglia and macrophages, and treatment with AZD1480 inhibited α-SYN-induced major histocompatibility complex Class II and inflammatory gene expression in microglia and macrophages by reducing STAT1 and STAT3 activation. For in vivo studies, we used a rat model of PD induced by viral overexpression of α-SYN. AZD1480 treatment inhibited α-SYN-induced neuroinflammation by suppressing microglial activation, macrophage and CD4(+) T-cell infiltration and production of proinflammatory cytokines/chemokines. Numerous genes involved in cell-cell signaling, nervous system development and function, inflammatory diseases/processes, and neurological diseases are enhanced in the substantia nigra of rats with α-SYN overexpression, and inhibited upon treatment with AZD1480. Importantly, inhibition of the JAK/STAT pathway prevented the degeneration of dopaminergic neurons in vivo These results indicate that inhibiting the JAK/STAT pathway can prevent neuroinflammation and neurodegeneration by suppressing activation of innate and adaptive immune responses to α-SYN. Furthermore, this suggests the feasibility of targeting the JAK/STAT pathway as a neuroprotective therapy for neurodegenerative diseases. SIGNIFICANCE STATEMENT: α-SYN plays a central role in the pathophysiology of PD through initiation of neuroinflammatory responses. Using an α-SYN overexpression PD model, we demonstrate a beneficial therapeutic effect of AZD1480, a specific inhibitor of JAK1/2, in suppressing neuroinflammation and neurodegeneration. Our findings document that inhibition of the JAK/STAT pathway influences both innate and adaptive immune responses by suppressing α-SYN-induced microglia and macrophage activation and CD4(+) T-cell recruitment into the CNS, ultimately suppressing neurodegeneration. These findings are the first documentation that suppression of the JAK/STAT pathway disrupts the circuitry of neuroinflammation and neurodegeneration, thus attenuating PD pathogenesis. JAK inhibitors may be a viable therapeutic option for the treatment of PD patients.

Signal transducer and activator of transcription-3/suppressor of cytokine signaling-3 (STAT3/SOCS3) axis in myeloid cells regulates neuroinflammation.

Suppressor of cytokine signaling (SOCS) proteins are feedback inhibitors of the JAK/STAT pathway. SOCS3 has a crucial role in inhibiting STAT3 activation, cytokine signaling, and inflammatory gene expression in macrophages/microglia. To determine the role of SOCS3 in myeloid cells in neuroinflammation, mice with conditional SOCS3 deletion in myeloid cells (LysMCre-SOCS3(fl/fl)) were tested for experimental autoimmune encephalomyelitis (EAE). The myeloid-specific SOCS3-deficient mice are vulnerable to myelin oligodendrocyte glycoprotein (MOG)-induced EAE, with a severe, nonresolving atypical form of disease. In vivo, enhanced infiltration of inflammatory cells and demyelination is prominent in the cerebellum of myeloid-specific SOCS3-deficient mice, as is enhanced STAT3 signaling and expression of inflammatory cytokines/chemokines and an immune response dominated by Th1 and Th17 cells. In vitro, SOCS3-deficient macrophages exhibit heightened STAT3 activation and are polarized toward the classical M1 phenotype. SOCS3-deficient M1 macrophages provide the microenvironment to polarize Th1 and Th17 cells and induce neuronal death. Furthermore, adoptive transfer of M2 macrophages into myeloid SOCS3-deficient mice leads to delayed onset and reduced severity of atypical EAE by decreasing STAT3 activation, Th1/Th17 cells, and proinflammatory mediators in the cerebellum. These findings indicate that myeloid cell SOCS3 provides protection from EAE through deactivation of neuroinflammatory responses.

Sperm transfer and reproductive biology in species of hermaphroditic bivalves (Galeommatoidea: Montacutidae).

The histology of the reproductive organs is studied in the protandric hermaphroditic Tellimya ferruginosa. In NW Europe the species reproduces from May through August. Sperm transfer takes place when mature testis follicles are transplanted to the gills or walls of the mantle cavity in recipient hermaphroditic or female bivalves. Transplantation is accompanied by histological changes and sperm cells are released when transplants perish with age. Details are given on the reproduction in Montacuta percompressa which takes place from March through October in North Carolina, USA. All shelled bivalves are females and it is postulated that spermatogenic bodies attached to gills or other surfaces in the female's mantle cavity and previously considered to be dwarf males arise from transplanted larval gonads. The ultrastructure of the euspermatozoa and/or the anucleate paraspermatozoa is described in T. ferruginosa, T. tenella, and M. percompressa. The sperm of the first two species share a number of significant apomorphies with those of another montacutid, Brachiomya stigmatica. In the simultaneous hermaphroditic M. substriata the nucleate paraspermatozoa associate with the euspermatozoa to form spherical spermatozeugmata that are stored in the testis.