R. Clive Landis

R. Clive Landis


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 September 2014 in The Journal of ExtraCorporeal Technology
Verified
Journal Article
Open access
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RLR. Clive Landis
R. Clive Landis
JBJeremiah R. Brown
Jeremiah R. Brown
DFDavid Fitzgerald
David Fitzgerald
DLDonald S. Likosky
Donald S. Likosky
LSLinda Shore-Lesserson
Linda Shore-Lesserson
JHJohn W. Hammon
John W. Hammon
A wide range of pharmacological, surgical, and mechanical pump approaches have been studied to attenuate the systemic inflammatory response to cardiopulmonary bypass, yet no systematically based review exists to cover the scope of anti-inflammatory interventions deployed. We therefore conducted an evidence-based review to capture “self-identified” anti-inflammatory interventions among adult cardiopulmonary bypass procedures. To be included, trials had to measure at least one inflammatory mediator and one clinical outcome, specified in the “Outcomes 2010” consensus statement. Ninety-eight papers satisfied inclusion criteria and formed the basis of the review. The review identified 33 different interventions and approaches to attenuate the systemic inflammatory response. However, only a minority of papers (35 of 98 [35.7%]) demonstrated any clinical improvement to one or more of the predefined outcome measures (most frequently myocardial protection or length of intensive care unit stay). No single intervention was supported by strong level A evidence (multiple randomized controlled trials [RCTs] or meta-analysis) for clinical benefit. Interventions at level A evidence included off-pump surgery, minimized circuits, biocompatible circuit coatings, leukocyte filtration, complement C5 inhibition, preoperative aspirin, and corticosteroid prophylaxis. Interventions at level B evidence (single RCT) for minimizing inflammation included nitric oxide donors, C1 esterase inhibition, neutrophil elastase inhibition, propofol, propionyl-L-carnitine, and intensive insulin therapy. A secondary analysis revealed that suppression of at least one inflammatory marker was necessary but not sufficient to confer clinical benefit. The most effective interventions were those that targeted multiple inflammatory pathways. These observations are consistent with a “multiple hit” hypothesis, whereby clinically effective suppression of the systemic inflammatory response requires hitting multiple inflammatory targets simultaneously. Further research is warranted to evaluate if combinations of interventions that target multiple inflammatory pathways are capable of synergistically reducing inflammation and improving outcomes after cardiopulmonary bypass.

2 May 2013 in International Journal of Inflammation
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Journal Article
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BEBetsy J. Evans
Betsy J. Evans
DHDorian O. Haskard
Dorian O. Haskard
GSGregory Sempowksi
Gregory Sempowksi
RLR. Clive Landis
R. Clive Landis
Cantharidin skin blisters were examined over two days to model the acute and resolving phases of inflammation in human skin. Four blisters were created by topical administration of cantharidin (0.1% v/v) to the forearm of healthy volunteers, with IRB approval. Duplicate skin blisters were aspirated at 16 and 40 hours to model the proinflammatory and resolving phases, respectively. There was a significant increase in leukocyte infiltrate at 40 h with appearance of a “resolving macrophage” phenotype CD14+CD163+by flow cytometry. Neutrophils acquired apoptotic markers at 40 h and were observed to be phagocytosed by macrophagic “Reiter’s” cells. Multiplex cytokine analysis demonstrated that monocyte chemoattractant protein (MCP-1/CCL2), interleukin- (IL-) 6, IL-8/CXCL8, macrophage inflammatory protein (MIP1α/CCL3), MIP-1β/CCL4, tumor necrosis factor- (TNF-)α, and eotaxin (CCL11) were all significantly upregulated at 16 h compared with 40 h. In contrast, immunoregulatory transforming growth factor- (TGF-)β, macrophage-derived chemokine (MDC/CCL22), and interferon-inducible protein (IP-10/CXCL10) were significantly elevated at 40 h. Our results demonstrate that the phases of inflammation and resolution can be discriminated in a two-day model of dermal wound healing. This confirms and extends our understanding of wound repair in humans and provides a powerful research tool for use in clinical settings and to track the molecular benefits of therapeutic intervention.

1 January 2013 in International Journal of Inflammation
Verified
Journal Article
Open access
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RLR. Clive Landis
R. Clive Landis
PPPandelis Philippidis
Pandelis Philippidis
JDJan Domin
Jan Domin
JBJoseph J. Boyle
Joseph J. Boyle
DHDorian O. Haskard
Dorian O. Haskard
Intraplaque hemorrhage causes adaptive remodelling of macrophages towards a protective phenotype specialized towards handling iron and lipid overload, denoted Mhem. The Mhem phenotype expresses elevated levels of hemoglobin (Hb) scavenger receptor, CD163, capable of endocytosing pro-oxidant free Hb complexed to acute phase protein haptoglobin (Hp). It is notable that individuals homozygous for the Hp 2 allele (a poorer antioxidant) are at increased risk of cardiovascular disease compared to the Hp 1 allele. In this study, we examined whether scavenging of polymorphic Hp:Hb complexes differentially generated downstream anti-inflammatory signals in cultured human macrophages culminating in interleukin (IL)-10 secretion. We describe an anti-inflammatory signalling pathway involving phosphatidylinositol-3-kinase activation upstream of Akt phosphorylation (pSer473Akt) and IL-10 secretion. The pathway is mediated specifically through CD163 and is blocked by anti-CD163 antibody or phagocytosis inhibitor. However, levels of pSer473Akt and IL-10 were significantly diminished when scavenging polymorphic Hp2-2:Hb complexes compared to Hp1-1:Hb complexes(P<0.05). Impaired anti-inflammatory macrophage signaling through a CD163/pAkt/IL-10 axis may thus represent a possible Hp2-2 disease mechanism in atherosclerosis.

1 October 2005 in The Heart Surgery Forum
Verified
Journal Article
Closed access
RLR. Clive Landis
R. Clive Landis
JAJoseph E. Arrowsmith
Joseph E. Arrowsmith
RBRobert A. Baker
Robert A. Baker
FSFilip De Somer
Filip De Somer
WDWojciech B. Dobkowski
Wojciech B. Dobkowski
EVEdward D. Verrier
Edward D. Verrier
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1 June 2009 in Seminars in Cardiothoracic and Vascular Anesthesia
Verified
Journal Article
Closed access
RLR. Clive Landis
R. Clive Landis
From the first description of the “systemic inflammatory response” in the early 1990s, it has been recognized that this is a multifaceted response of the body to the combined insult of cardiothoracic surgery with bypass, involving causation by “activation of complement, coagulation, fibrinolytic, and kallikrein cascades, activation of neutrophils with degranulation and protease enzyme release, oxygen radical production, and the synthesis of various cytokines from mononuclear cells.” Yet the intervening 15 years have seen a narrowing of research into individual systems and interventions naively targeted at single pathways without achieving clinically meaningful benefits. The time has come to redefine the systemic inflammatory response so that research can be more productively focused on objectively measuring and interdicting this multisystem disorder. A key concept of this new understanding is that translation into a hard adverse event occurs when the systemic imbalance is combined with a localized trigger. Triggers might be inadvertently provided by transient episodes of ischemia/malperfusion to vulnerable organs or handling trauma to major vessels. Future research should be directed at suppressing systemic activation with combinations of drugs and improved circuit coating, whereas changes in clinical practice and continuous monitoring of perfusion parameters can help eliminate localized triggering events.

21 August 2020 in Pathogens
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Journal Article
Open access
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JTJakob Thannesberger
Jakob Thannesberger
NRNicolas Rascovan
Nicolas Rascovan
AEAnna Eisenmann
Anna Eisenmann
IKIngeborg Klymiuk
Ingeborg Klymiuk
CZCarina Zittra
Carina Zittra
CSChristoph Steininger
Christoph Steininger
Mosquitoes are the most important vectors for arthropod-borne viral diseases. Mixed viral infections of mosquitoes allow genetic recombination or reassortment of diverse viruses, turning mosquitoes into potential virologic mixing bowls. In this study, we field-collected mosquitoes of different species (Aedes aegypti and Culex pipiens complex), from different geographic locations and environments (central Europe and the Caribbean) for highly sensitive next-generation sequencing-based virome characterization. We found a rich virus community associated with a great diversity of host species. Among those, we detected a large diversity of novel virus sequences that we could predominately assign to circular Rep-encoding single-stranded (CRESS) DNA viruses, including the full-length genome of a yet undescribed Gemykrogvirus species. Moreover, we report for the first time the detection of a potentially zoonotic CRESS-DNA virus (Cyclovirus VN) in mosquito vectors. This study expands the knowledge on virus diversity in medically important mosquito vectors, especially for CRESS-DNA viruses that have previously been shown to easily recombine and jump the species barrier.