scholarly journals Capillary Regression, A Key Pathogenic Feature of COVID-19 Infection?

Author(s):  
George E. Davis ◽  
Courtney T. Griffin

In this brief communication, we propose the concept that capillary regression may represent a primary pathogenic process underlying COVID-19 infection, particularly in the serious and life-threatening manifestations of the disease. We suggest that the marked elevations of pro-inflammatory mediators that are observed in these seriously ill patients may directly induce capillary regression and endothelial cell (EC) loss. Recent autopsy studies are demonstrating EC loss leading to widespread microthrombi and associated tissue damage. Recent work has indicated that interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNFα), and thrombin, individually and in combination, can potently cause capillary tube regression in experimental models in vitro and in vivo. Other pro-inflammatory mediators including interferon gamma (IFNγ), interleukin-4 (IL-4), and interleukin-13 (IL-13) were also shown to be pro-regressive and could be relevant mediators in COVID-19 patients. Interestingly, combinations of pharmacologic agents were identified that reduced capillary regression and protected capillary tube networks against these pro-inflammatory mediators. Such an approach might be an important therapeutic option going forward to treat key disease states where capillary regression plays a major underlying pathogenic role. Finally, if capillary regression is occurring in response to these pro-inflammatory mediators during COVID-19 infection, we suggest that combinations of blocking agents directed to these key pro-regressive mediators might be necessary to appropriately treat patients.

2021 ◽  
Author(s):  
Gaosheng Zhu ◽  
Keze Miao ◽  
Mingwei Dong ◽  
Jie Cai ◽  
Zhihao Shen ◽  
...  

Abstract Osteoarthritis (OA), a prevalent disabling disease, is characterized by irreversible cartilage degradation and persistent inflammation. The etiology as well as pathogenesis of OA are not completely unclear and need further investigation. Gigantol, is a bibenzyl derivative extracted from Dendrobium plants and has been found exhibit multiple effects such as anti-inflammatory effects. Nevertheless, the biological function of gigantol on osteoarthritis (OA) is still uncertain. This study aimed at examining the anti-inflammatory effects and latent mechanisms of gigantol in IL-1β-mediated OA progression. In vitro, we identified that gigantol treatment suppressed tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) in interleukin-1 beta (IL-1β) mediated mouse OA chondrocytes. Gigantol was also shown to dose dependently downregulate the metalloproteinase 13 (MMP13) as well as thrombospondin motifs 5 (ADAMTS5) levels. Moreover, IL-1β-mediated AKT and PI3K phosphorylation as well as NF-κB activation were inhibited by gigantol. Meanwhile, in vivo, we detected that gigantol treatment inhibited degradation of the cartilage degradation and lowered the Osteoarthritis Research Society International scores (OARSI) in OA mouse. Therefore, gigantol is a promising therapeutic option for OA.


Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 412
Author(s):  
Fadia S. Youssef ◽  
Mohamed L. Ashour ◽  
Hesham A. El-Beshbishy ◽  
Abdel Nasser B. Singab ◽  
Michael Wink

LC-ESI-MS (Liquid Chromatography coupled with Electrospray Ionization Mass Spectrometry profiling of a methanol extract from Buddleia indica (BIM) leaves revealed 12 main peaks in which verbascoside and buddlenoid B represent the major compounds. The antioxidant and hepatoprotective activities of BIM were investigated using different in vitro and in vivo experimental models. BIM exhibited substantial in vitro antioxidant properties in DPPH· and HepG2 assays. Regarding CCl4 (carbon tetrachloride) induced hepatotoxicity in a rat model, oxidative stress markers became significantly ameliorated after oral administration of BIM. Lipid peroxide levels showed a 51.85% decline relative to CCl4-treated rats. Super oxide dismutase (SOD), total antioxidant status (TAS), and catalase (CAT) revealed a marked increase by 132.48%, 187.18%, and 114.94% relative to the CCl4 group. In a tamoxifen-induced hepatotoxicity model, BIM showed a considerable alleviation in liver stress markers manifested by a 46.06% and 40% decline in ALT (Alanine Transaminase) and AST (Aspartate Transaminase) respectively. Thiobarbituric acid reactive substances (TBARS) were reduced by 28.57% and the tumor necrosis factor alpha (TNF-α) level by 50%. A virtual screening of major secondary metabolites of BIM to TNF-alpha employing the C-docker protocol showed that gmelinoside H caused the most potent TNF- α inhibition as indicated from their high fitting scores. Thus, BIM exhibited a potent hepatoprotective activity owing to its richness in antioxidant metabolites.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Rodolfo Abarca-Vargas ◽  
Vera L. Petricevich

Background. Different pharmacological properties, such as antioxidant, antiproliferative, and anti-inflammatory properties, have been described among natural products. We previously described that the Bougainvillea xbuttiana (Variety Orange) ethanolic extract (BxbO) has an anti-inflammatory effect; however, this action is not fully understood. In this study, the action of the BxbO extract on the secretion of inflammatory mediators in two experimental models, in vitro and in vivo, after LPS challenge was evaluated. Methods. Peritoneal macrophages were obtained from female BALB/c mice and LPS-challenged with or without the BxbO extract. For the evaluation of mediators, the supernatants at 0, 12, 24, 36, and 48 hours were collected. For in vivo estimation, groups of female BALB/c mice were first intraperitoneously injected with different amounts of LPS and later administered the oral BxbO extract (v.o.) for 144 hours. To understand the mechanism of action, sera obtained from mice were collected at 0, 2, 4, 8, 12, and 24 hours after LPS challenge (with or without BxbO) for the detection of mediators. Results. The results showed that, in both peritoneal macrophages and sera of mice treated with the BxbO extract 1 hour before or together with LPS challenge, proinflammatory cytokines and nitric oxide release were unquestionably repressed. In contrast, in both systems studied here, the IL-10 levels were elevated to 5 to 9 times. At lethal doses of LPS, the BxbO extract treatment was found to protect animals from death. Conclusions. The results revealed that the inhibitory, protective, and benign effects of the BxbO extract were due to its capacity to balance the secretion of mediators.


2016 ◽  
Vol 5 (3) ◽  
pp. 836-847 ◽  
Author(s):  
Crystal S. Lewis ◽  
Luisa Torres ◽  
Jeremy T. Miyauchi ◽  
Cyrus Rastegar ◽  
Jonathan M. Patete ◽  
...  

Abstract Understanding the nature of interactions between nanomaterials, such as commercially ubiquitous hematite (α-Fe2O3) nanorhombohedra (N-Rhomb) and biological systems is of critical importance for gaining insight into the practical applicability of nanomaterials. Microglia represent the first line of defense in the central nervous system (CNS) during severe injury or disease such as Parkinson's and Alzheimer's disease as illustrative examples. Hence, to analyze the potential cytotoxic effect of N-Rhomb exposure in the presence of microglia, we have synthesized Rhodamine B (RhB)-labeled α-Fe2O3 N-Rhomb, with lengths of 47 ± 10 nm and widths of 35 ± 8 nm. Internalization of RhB-labeled α-Fe2O3 N-Rhomb by microglia in the mouse brain was observed, and a dose-dependent increase in the cellular iron content as probed by cellular fluorescence was detected in cultured microglia after nanoparticle exposure. The cells maintained clear functional viability, exhibiting little to no cytotoxic effects after 24 and 48 hours at acceptable, physiological concentrations. Importantly, the nanoparticle exposure did not induce microglial cells to produce either tumor necrosis factor alpha (TNFα) or interleukin 1-beta (IL1β), two pro-inflammatory cytokines, nor did exposure stimulate the production of nitrites and reactive oxygen species (ROS), which are common indicators for the onset of inflammation. Finally, we propose that under the conditions of our experiments, i.e. in the presence of RhB labeled-α-Fe2O3 N-Rhomb maintaining concentrations of up to 100 μg mL−1 after 48 hours of incubation, the in vitro and in vivo internalization of RhB-labeled α-Fe2O3 N-Rhomb are likely to be clathrin-dependent, which represents a conventional mechanistic uptake route for most cells. Given the crucial role that microglia play in many neurological disorders, understanding the potential cytotoxic effects of these nanostructures is of fundamental importance if they are to be used in a therapeutic setting.


Blood ◽  
1993 ◽  
Vol 81 (8) ◽  
pp. 2131-2136
Author(s):  
V Jendrossek ◽  
AM Peters ◽  
S Buth ◽  
J Liese ◽  
U Wintergerst ◽  
...  

Cytokines have been shown to modulate the respiratory burst of polymorphonuclear leukocytes and monocytes from normal controls. We have examined whether monocytes from children with chronic granulomatous disease (CGD) can be primed by cytokines other than interferon-gamma (IFN gamma), which has been demonstrated to improve the production of reactive oxygen species in vivo and in vitro. Monocytes isolated from peripheral blood were cultured without and with IFN gamma (500 U/mL), tumor necrosis factor-alpha (500 U/mL), interleukin-1 beta (IL-1 beta) (100 U/mL), and IL-3 (100 U/mL). After 3 days of culture, the phorbolmyristate acetate (2 ng/mL) and the formyl- methionyl-leucyl-phenylalanine (0.1 mumol/L)-stimulated superoxide- production was determined in a microtiter system. In nearly all of the 14 patients examined (5 autosomal, 5 X-chromosomal, and 4 of unknown inheritance), an improvement of superoxide production could be demonstrated. The most impressive effect with the cytokines newly tested was seen with monocytes from autosomal CGD patients treated with IL-3 and stimulated by phorbolmyristate acetate. In single patients cultivation of monocytes with IL-6 and granulocyte-macrophage colony- stimulating factor resulted in only slight improvement of superoxide production. Our findings indicate that cytokines other than IFN gamma can positively modulate the defective respiratory burst in CGD and that each patient reacts with an individual pattern to different cytokines.


1996 ◽  
Vol 270 (1) ◽  
pp. H183-H193 ◽  
Author(s):  
R. M. Binns ◽  
S. T. Licence ◽  
A. A. Harrison ◽  
E. T. Keelan ◽  
M. K. Robinson ◽  
...  

The endothelial molecule E-selectin binds most leukocyte subsets in vitro. Yet its role in regulating the very different kinetics of inflammatory infiltration of different leukocyte subsets in vivo is unclear. The kinetics of E-selectin upregulation and polymorphonuclear leukocyte (PMN) and blood lymphocyte (PBL) localization in inflammation induced by interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), phytohemagglutinin (PHA), and phorbol myristate acetate (PMA) were investigated in a well-established inbred pig trafficking model. They differed markedly both for these three labeled indicators of inflammation and in each of the four inflammatory processes. In each, E-selectin upregulation correlated with early PMN entry and later with PBL infiltration but was more protracted than both. The importance of E-selectin was confirmed by marked inhibition of PMN and PBL entry (up to > 60%) by F(ab')2 anti-E-selectin. Involvement of other molecules was illustrated by similar or greater inhibition with anti-CD18 F(ab')2. We conclude that, like CD18, E-selectin is necessary for most PMN and PBL infiltration but alone is insufficient, consistent with the involvement of several alternative multistep molecular mechanisms in this entry.


2006 ◽  
Vol 13 (9) ◽  
pp. 1037-1043 ◽  
Author(s):  
Annalisa Ciabattini ◽  
Anna Maria Cuppone ◽  
Rita Pulimeno ◽  
Francesco Iannelli ◽  
Gianni Pozzi ◽  
...  

ABSTRACT Streptococcus gordonii is a bacterial vaccine vector which has previously been shown to activate dendritic cells in vitro and to induce local and systemic immune responses in vivo. In the present study, human monocytes (THP-1 cell line and peripheral blood monocytes) were characterized following interaction with S. gordonii. Treatment of human monocytes with S. gordonii but not latex beads induced a clear up-regulation of CD83, CD40, CD80, and CD54 and the down-regulation of CD14. Furthermore, bacterial treatment stimulated an increased expression of Toll-like receptor 5 (TLR5), TLR6, and TLR7, production of the proinflammatory cytokines tumor necrosis factor alpha and interleukin 1 beta, and reduction of the phagocytic activity. This work shows that the immunostimulatory activity of S. gordonii is not restricted to induction of dendritic-cell maturation but also affects the differentiation process of human monocytes.


1994 ◽  
Vol 76 (5) ◽  
pp. 2177-2185 ◽  
Author(s):  
J. A. Woods ◽  
J. M. Davis ◽  
E. P. Mayer ◽  
A. Ghaffar ◽  
R. R. Pate

Recent evidence suggests that exercise affects macrophage functions and that amount of exercise may be important. We determined effects of moderate (MOD) and exhaustive treadmill running (EXH) on 1) ability of macrophages to become activated for antitumor cytotoxicity after injection of heat-inactivated Propionibacterium acnes in vivo, 2) macrophage responsiveness to activating agents lipopolysaccharide and interferon-gamma, and 3) role of glucocorticoids and various macrophage metabolic products in modulating cytotoxicity in exercised animals. Male C3H/HeN mice were randomly assigned to MOD (18 m/min, 5% grade, 30 min/day) or EXH (18–35 m/min, 5%, 2–4 h) on a motor-driven treadmill. Control animals were kept in simulated treadmill lanes located directly over the runners. In general, both MOD and EXH increased cytotoxicity (42 and 22%, respectively, across all experiments; P < 0.05). Enhanced cytotoxicity was not due to altered macrophage adherence, tumor necrosis factor-alpha, interleukin-1 beta, or reactive oxygen species. Reactive nitrogen species were responsible for enhanced toxicity in EXH only. Macrophage cytotoxicity was further increased by lipopolysaccharide and interferon-gamma to a similar maximal level that was the same in all groups. Plasma corticosterone was elevated two- and fourfold in MOD and EXH, respectively, but there was no correlation between plasma corticosterone and macrophage cytotoxicity when compared across all groups even though cells were sensitive to steroid-mediated suppression in vitro. However, consistent with a corticosterone effect, EXH reduced the number of peritoneal macrophages elicited during P. acnes inflammation and abolished the typical exercise-induced increase in cytotoxicity of activated macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)


1997 ◽  
Vol 17 (10) ◽  
pp. 6184-6190 ◽  
Author(s):  
Z Li ◽  
G J Nabel

A novel member of the I kappaB family has been identified as a protein that associated with the p50 subunit of NF-kappaB in a yeast two-hybrid screen. Similar to previously known I kappaB proteins, this member, I kappaB epsilon, has six consecutive ankyrin repeats. I kappaB epsilon mRNA is widely expressed in different human tissues, with highest levels in spleen, testis, and lung. I kappaB epsilon interacts with different NF-kappaB proteins, including p65 (RelA), c-Rel, p50, and p52, in vitro and in vivo and inhibits the DNA-binding activity of both p50-p65 and p50-c-Rel complexes effectively. Endogenous and transfected NF-kappaB (RelA-dependent) transcriptional activation is inhibited by I kappaB epsilon. I kappaB epsilon mRNA is expressed at different levels in specific cell types and is synthesized constitutively in transformed B-cell lines. It also displays differential induction in response to tumor necrosis factor alpha, interleukin-1, or phorbol ester stimulation compared to I kappaB alpha in non-B-cell lines. Therefore, I kappaB epsilon represents a novel I kappaB family member which provides an alternative mechanism for regulation of NF-kappaB-dependent transcription.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zunpeng Shu ◽  
Na Xing ◽  
Qiuhong Wang ◽  
Xinli Li ◽  
Bingqing Xu ◽  
...  

This study was designed to determine whether the 50% EtOH fraction from AB-8 macroporous resin fractionation of a 70% EtOH extract ofP. Alkekengi(50-EFP) has antibacterial and/or anti-inflammatory activity bothin vivoandin vitroand to investigate the mechanism of 50-EFP anti-inflammatory activity. Additionally, this study sought to define the chemical composition of 50-EFP. Results indicated that 50-EFP showed significant antibacterial activityin vitroand efficacyin vivo. Moreover, 50-EFP significantly reduced nitric oxide (NO), prostaglandin E2(PGE2), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) production in lipopolysaccharide- (LPS-) stimulated THP-1 cells. Nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (examined at the protein level) in THP-1 cells were suppressed by 50-EFP, which inhibited nuclear translocation of p65. Consistent with this anti-inflammatory activityin vitro, 50-EFP reduced inflammation in both animal models. Finally, seventeen compounds (8 physalins and 9 flavones) were isolated as major components of 50-EFP. Our data demonstrate that 50-EFP has antibacterial and anti-inflammatory activities bothin vitroandin vivo. The anti-inflammatory effect appears to occur, at least in part, through the inhibition of nuclear translocation of p65. Moreover, physalins and flavones are probably the active components in 50-EFP that exert antibacterial and anti-inflammatory activities.


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