Therapeutic plasma exchange for persistent encephalopathy associated with Covid-19

Patients infected with COVID-19 virus, show a highly variable symptomatology which can include central nervous system (CNS) dysfunction. One of the most disabling CNS manifestations is persistent severe encephalopathy seen for weeks after the resolution of the acute viral pneumonia and associated acute systemic illnesses. The precise pathophysiology of this persistent Post COVID Encephalopathy is unknown but may involve direct viral invasion of microvascular endothelium, microvascular thrombosis, toxic neuronal effects of inflammatory products, vasoactive pathology at arteriolar level or leptomeningeal inflammation. Currently, there are no established specific treatments for Post COVID -19 encephalopathy. We present a case series of three patients that underwent Therapeutic Plasma Exchange (TPE) with salinized albumin that suggests a positive therapeutic effect. We believe that the results warrant further evaluation for the role of TPE with a prospective randomized trial in persistent Post COVID -19 encephalopathy syndrome.

Interleukin 6 regulates psoriasiform inflammation-associated thrombosis

Psoriasis patients are at increased risk of heart attack and stroke and have elevated MRP8/14 levels that predict heart attack. The KC-Tie2 psoriasiform mouse model exhibits elevated MRP8/14 and is prothrombotic. Mrp14^-/- mice, in contrast, are protected from thrombosis, but, surprisingly, KC-Tie2xMrp14^-/- mice remain prothrombotic. Treating KC-Tie2xMrp14^-/- mice with anti-IL-23p19 antibodies reversed the skin inflammation, improved thrombosis, and decreased IL-6. In comparison, IL-6 deletion from KC-Tie2 animals improved thrombosis despite sustained skin inflammation, suggesting that thrombosis improvements following IL-23 inhibition occur secondary to IL-6 decreases. Psoriasis patient skin has elevated IL-6 and IL-6 receptor is present in human coronary atheroma, supporting a link between skin and distant vessel disease in patient tissue. Together, these results identify a critical role for skin-derived IL-6 linking skin inflammation with thrombosis, and shows that in the absence of IL-6 the connection between skin inflammation and thrombosis comorbidities is severed.

Racial disparities in melanoma survival

BACKGROUND

Melanoma is a cutaneous malignancy common in the white population but can also occur in other racial groups.

OBJECTIVE

We sought to evaluate survival across racial groups in patients given a diagnosis of malignant melanoma.

METHODS

The Surveillance, Epidemiology, and End Results database was used to populate a cohort of 96,953 patients given a diagnosis of cutaneous melanoma as their primary cancer, from 1992 to 2009.

RESULTS

White patients had the longest survival time (P < .05), followed by Hispanic (P < .05), Asian American/Native American/Pacific Islander (P < .05), and black (P < .05) patients, respectively. Survival stratified by race and stage showed that for stages I and III, blacks had a significantly lower survival (P < .05), and increased hazard ratios (stage I hazard ratio, 3.037 [95% confidence interval, 2.335-3.951]; stage III hazard ratio, 1.864 [95% confidence interval, 1.211-2.87]). The proportion of later stage cutaneous melanoma (stages II-IV) was greater in blacks compared with whites.

CONCLUSION

Despite higher incidence of cutaneous melanoma in whites, overall survival for cutaneous melanoma in non-whites was significantly lower. Our results suggest that more emphasis is needed for melanoma screening and awareness in non-white populations to improve survival outcomes.

Keratinocyte overexpression of IL-17C promotes psoriasiform skin inflammation

IL-17C is a functionally distinct member of the IL-17 family that binds IL-17 receptor E/A to promote innate defense in epithelial cells and regulate Th17 cell differentiation. We demonstrate that IL-17C (not IL-17A) is the most abundant IL-17 isoform in lesional psoriasis skin (1058 versus 8 pg/ml; p < 0.006) and localizes to keratinocytes (KCs), endothelial cells (ECs), and leukocytes. ECs stimulated with IL-17C produce increased TNF-α and KCs stimulated with IL-17C/TNF-α produce similar inflammatory gene response patterns as those elicited by IL-17A/TNF-α, including increases in IL-17C, TNF-α, IL-8, IL-1α/β, IL-1F5, IL-1F9, IL-6, IL-19, CCL20, S100A7/A8/A9, DEFB4, lipocalin 2, and peptidase inhibitor 3 (p < 0.05), indicating a positive proinflammatory feedback loop between the epidermis and ECs. Psoriasis patients treated with etanercept rapidly decrease cutaneous IL-17C levels, suggesting IL-17C/TNF-α-mediated inflammatory signaling is critical for psoriasis pathogenesis. Mice genetically engineered to overexpress IL-17C in KCs develop well-demarcated areas of erythematous, flakey involved skin adjacent to areas of normal-appearing uninvolved skin despite increased IL-17C expression in both areas (p < 0.05). Uninvolved skin displays increased angiogenesis and elevated S100A8/A9 expression (p < 0.05) but no epidermal hyperplasia, whereas involved skin exhibits robust epidermal hyperplasia, increased angiogenesis and leukocyte infiltration, and upregulated TNF-α, IL-1α/β, IL-17A/F, IL-23p19, vascular endothelial growth factor, IL-6, and CCL20 (p < 0.05), suggesting that IL-17C, when coupled with other proinflammatory signals, initiates the development of psoriasiform dermatitis. This skin phenotype was significantly improved following 8 wk of TNF-α inhibition. These findings identify a role for IL-17C in skin inflammation and suggest a pathogenic function for the elevated IL-17C observed in lesional psoriasis skin.

Low vitamin C and increased oxidative stress and cell death in mice that lack the sodium-dependent vitamin C transporter SVCT2

The sodium-dependent vitamin C transporter (SVCT2) is responsible for the transport of vitamin C into cells in multiple organs, from either the blood or the cerebrospinal fluid. Mice null for SVCT2 (SVCT2(-/-)) do not survive past birth but the cause of death has not yet been ascertained. After mating of SVCT2(+/-) males and SVCT2(+/-) females, fewer SVCT2(-/-) and SVCT2(+/-) progeny were observed than would be expected according to Mendelian ratios. Vitamin C levels in SVCT2(-/-), SVCT2(+/-), and SVCT2(+/+) were genotype-dependent. SVCT2(-/-) fetuses had significantly lower vitamin C levels than littermates in placenta, cortex, and lung, but not in liver (the site of vitamin C synthesis). Low vitamin C levels in placenta and cortex were associated with elevations in several markers of oxidative stress: malondialdehyde, isoketals, F(2)-isoprostanes, and F(4)-neuroprostanes. Oxidative stress was not elevated in fetal SVCT2(-/-) lung tissue despite low vitamin C levels. In addition to the expected severe hemorrhage in cortex, we also found hemorrhage in the brain stem, which was accompanied by cell loss. We found evidence of increased apoptosis in SVCT2(-/-) mice and disruption of the basement membrane in fetal brain. Together these data show that SVCT2 is critical for maintaining vitamin C levels in fetal and placental tissues and that the lack of SVCT2, and the resulting low vitamin C levels, results in fetal death and, in SVCT2(-/-) mice that survive the gestation period, in oxidative stress and cell death.

Low ascorbic acid and increased oxidative stress in gulo(-/-) mice during development

Vitamin C (ascorbic acid, AA) depletion during prenatal and postnatal development can lead to oxidative stress in the developing brain and other organs. Such damage may lead to irreversible effects on later brain function. We studied the relationship between AA deficiency and oxidative stress during development in gulonolactone oxidase (gulo) knockout mice that are unable to synthesize their own ascorbic acid. Heterozygous gulo(+/-) mice can synthesize AA and typically have similar tissue levels to wild-type mice. Gulo(+/-) dams were mated with gulo(+/-) males to provide offspring of each possible genotype. Overall, embryonic day 20 (E20) and postnatal day 1 (P1) pups were protected against oxidative stress by sufficient AA transfer during pregnancy. On postnatal day 10 (P10) AA levels were dramatically lower in liver and cerebellum in gulo(-/-) mice and malondialdehyde (MDA) levels were significantly increased. In postnatal day 18 pups (P18) AA levels decreased further in gulo(-/-) mice and oxidative stress was observed in the accompanying elevations in MDA in liver, and F(2)-isoprostanes in cortex. Further, total glutathione levels were higher in gulo(-/-) mice in cortex, cerebellum and liver, indicating that a compensatory antioxidant system was activated. These data show a direct relationship between AA level and oxidative stress in the gulo(-/-) mice. They reinforce the critical role of ascorbic acid in preventing oxidative stress in the developing brain in animals that, like humans, cannot synthesize their own AA.

Vitamin C distribution and retention in the mouse brain

Vitamin C (VC) is a crucial antioxidant in the brain. To assess whether different brain regions vary in their sensitivity to oxidative stress induced by VC depletion, we used the gulonolactone oxidase (gulo) knockout mouse. This mouse, like humans, cannot synthesize VC and thus its tissue VC levels can be varied by dietary VC intake. Gulo knockout mice were fed drinking water containing standard (0.33g/L), low (0.033g/L) or zero (0g/L) VC supplementation levels. After 4weeks, mice were sacrificed and different brain regions removed for assay of VC and malondialdehyde, a marker of lipid peroxidation. Compared to age-matched wild-type controls, the cerebellum, olfactory bulbs and frontal cortex had the highest VC content, whereas the pons and spinal chord had the lowest. However, in mice that did not receive VC, area differences were no longer significant as all values trended towards zero. Malondialdehyde increased in the cortex as VC supplementation was decreased. The same changes were not observed in the cerebellum or pons, suggesting that cortex is more susceptible to oxidative damage from low VC. These results suggest enhanced susceptibility of the cortex to oxidative stress induced by low VC compared to other brain regions.

Ascorbic acid attenuates scopolamine-induced spatial learning deficits in the water maze

Vitamin C (ascorbate) has important antioxidant functions that can help protect against oxidative stress in the brain and damage associated with neurodegenerative disorders such as Alzheimer's disease. When administered parenterally ascorbate can bypass saturable uptake mechanisms in the gut and thus higher tissue concentrations can be achieved than by oral administration. In the present study we show that ascorbate (125 mg/kg) administered intraperitoneally (i.p.) 1-h before testing, partially attenuated scopolamine-induced (1 mg/kg i.p.) cognitive deficits in Morris water maze performance in young mice. Cumulative search error, but not escape latency nor path length, was significantly improved during acquisition in ascorbate plus scopolamine-treated mice although performance did not equal that of control mice. During the probe trial, scopolamine led to increased search error and chance level of time spent in the platform quadrant, whereas mice pre-treated with ascorbate prior to scopolamine did not differ from control mice on these measures. Ascorbate had no effect on unimpaired, control mice and neither did it reduce the peripheral, activity-increasing effects of scopolamine. Ascorbate alone increased acetylcholinesterase activity in the medial forebrain area but had no effect in cortex or striatum. This change, and its action against the amnestic effects of the muscarinic antagonist scopolamine, suggest that ascorbate may be acting in part via altered cholinergic signaling. However, further investigation is necessary to isolate the cognition-enhancing effects of ascorbate.

Cytokine induction of a human acute myelogenous leukemia cell line (KG-1) to a CD1a + dendritic cell phenotype

Dendritic cells (DC) are highly specialized antigen-presenting cells located in many nonlymphoid tissues, and Langerhans cells (LC), a specialized form of DC, are found in the skin. LC as antigen-presenting cells play a critical role in the induction of allergic contact dermatitis. LC research is difficult because few LCs can be isolated from human skin, so efforts have focused on obtaining DCs from alternative sources. Mononuclear cells from peripheral blood and CD34+ stem cells from human cord blood and marrow can be induced to form phenotypic and functional DCs, but experiments of this type are expensive and the DC yield is low. We report here the induction of the myeloid leukemia cell line (KG-1) to a DC morphology and phenotype by culturing the cells in a defined cytokine cocktail. Morphologically, the KG-1-derived DCs are large irregularly shaped cells with prominent dendritic processes and hair-like cytoplasmic projections. Phenotypically, the KG-1-derived DCs lack lineage-specific markers, and express MHC class II, costimulatory molecules CD80 and CD86, and CD83. Functionally, KG-1-derived DCs are capable of phagocytosing latex microspheres and are able to induce a potent allogeneic T-cell response. Within the KG-1-derived DCs, a subpopulation maintains the DC phenotype and morphology described above but further develops CD1a+ marker expression similar to that of resident skin-derived LCs. These findings illustrate that phenotypic, morphologic and functional DCs can be derived from the KG-1 cell line.

Fractionation of Pneumocystis carinii developmental stages by counterflow centrifugal elutriation and sequential filtrations

Immunomagnetic sorting, sequential filtrations, and counterflow centrifugal elutriation were compared for their ability to obtain enriched populations of Pneumocystis carinii developmental stages from infected rat-lung homogenates. Elutriation combined with sequential filtrations resulted in highly (> 95%) enriched populations of P. carinii cysts and trophozoites with excellent viability. This approach offers advantages over previously described methods of obtaining enriched P. carinii cell populations and should have important applications to research on this organism.