Mecanismo de Prono-supinación

Strategies aimed at reducing RAGE-mediated inflammation, explored specifically via the use of genetically modified mice or the administration of inhibitors, have shown lethality to be reduced in various models of sepsis (Table 8). That most studied has been caecal ligation and puncture (CLP), in which significant survival benefit was demonstrated following administration of anti-RAGE and anti-HMGB1 antibodies, or after administration of pharmacological HMGB1-inhibitors. Similar effects were seen in RAGE-deleted mice [310, 371, 372, 443, 444]. Importantly, the survival benefits associated with anti-RAGE antibodies, anti-HMGB1 antibodies and ethyl pyruvate remain even when they are administered up to 24h after the CLP procedure [371, 372, 443]. The administration of sRAGE was associated with a trend towards improved survival [310]. The efficacy of anti-RAGE strategies is not limited to models of intra-abdominal sepsis, but also those employing systemic Listeria monocytogenes, intra-nasal Streptococcus pneumoniae or influenza A [443, 445, 446]. Targeting relevant ligands to limit RAGE-mediated effects is also associated with substantially improved survival and diminished early bacterial dissemination in mice genetically deprived of S100A8/9 compared to wild-type, both in systemic endotoxaemia and Escherichia coli–induced abdominal sepsis [331, 447]. As discussed in Section 3.2.2, inhibition of HMGB1 also showed beneficial effects in murine models of septic and non- septic systemic inflammation. In addition to anti-HMGB1 antibodies, agents that inhibit the release of HMGB1, such as ethyl pyruvate (EP), stearoyl lysophosphatidylcholine, intravenous immunoglobulin (IVIG), vasoactive intestinal peptide, ghrelin, and nicotine; or those that bind fragments of the HMGB-1 protein (DNA-binding A box), or thrombomodulin have all ameliorated adverse inflammatory responses [373]. The substantially reduced lethality in RAGE-deleted mice, exposed to AGE-rich human albumin solution as

88 resuscitation fluid in septic shock provides compelling evidence for the centrality of RAGE and its ligands [429].

Further evidence of the capacity of sRAGE to reduce inflammation and its adverse sequelae in acute systemic inflammation was seen when administration of sRAGE reduced end-organ damage and levels of pro-inflammatory cytokines and improved mortality in a murine systemic endotoxaemia model; effects also seen in RAGE-deleted mice [311]. The investigators proposed that LPS binding to RAGE mediated the effect of sRAGE. Alternatively sRAGE bound canonical RAGE ligands released in response to endotoxaemia and abrogated receptor-mediated inflammatory responses – RAGE-mediated in the wildtype mice and TLR- mediated in the RAGE-deleted mice.

3.3.1.2. Non-infective SIRS

Studies of RAGE inhibition in non-septic systemic inflammation published to date are summarised in Table 9. In models of haemorrhagic shock and resuscitation, administration of sRAGE attenuated the associated systemic inflammation and RAGE-deleted mice exhibited a protected phenotype [448]. Anti-HMGB1 antibodies prevented death and gut barrier dysfunction [378]. Use of a resuscitation fluid containing the HMGB1-inhibitor EP was associated with complete protection from lethal haemorrhage compared to control fluid [449].

Anti-HMGB1 antibodies reduced systemic inflammation and end-organ damage following bilateral femoral fracture and severe acute pancreatitis (SAP) [376, 377]. EP also limited systemic inflammation and improved survival in rat models of pancreatitis, even when given 12h after onset of SAP [450]. As EP is a small molecule effective at clinically achievable concentrations it seems particularly attractive as a pharmacological inhibitor of HMGB1 release.

89 Treatment group vs. control group

Author and year Model Mode of RAGE inhibition and control

Indication of altered bacterial

dissemination Organ failure Survival difference Yamamoto

2011[311] Intraperitoneal LPS RAGE-deleted, sRAGE Not reported

Less lung and liver damage with sRAGE

Improved survival in RAGE KO vs. WT Improved survival with sRAGE in both RAGE KO and WT

Van Zoelen

2010[451] Intraperitoneal E.Coli

RAGE-deleted vs. wildtype Increased CFU in peritoneal fluid, blood, liver and lungs at 20h

Worse hepatocellular

damage Not assessed

Anti-RAGE IgG vs. control IgG Increased CFU in peritoneal fluid and

distant organs at 20h No change Not assessed Van Zoelen

2009[445]

S. pneumoniae

intranasally RAGE-deleted vs. wildtype Decreased CFU in lung, blood and spleen Less lung inflammation Improved survival Van Zoelen

2009[446]

Influenza A

intranasally RAGE-deleted vs. wildtype Increased clearance of influenza A Not reported Improved survival Zhu 2009[444] CLP Spermine (inhibitor of HMGB1

release) vs. control Not reported Not reported

Improved survival when given early and when given late. Excessive doses given late worsened survival. Table 8 (part I): Summary of major papers assessing effects of RAGE inhibition in murine models of sepsis. sRAGE soluble RAGE, HMGB1 high mobility group box 1, CFU colony forming units, CLP caecal ligation and puncture, LPS lipopolysaccharide, IV intravenous.

90 Treatment group vs. control group

Author and year Model Mode of RAGE inhibition and control Indication of altered bacterial

dissemination Organ failure Survival difference Su 2008[452] Intraperitoneal LPS Ethyl pyruvate vs. placebo Not reported No change Worsened survival

Lutterloh 2007[443]

CLP

RAGE-deleted vs. wildtype No change to CFU in liver, spleen and

peritoneal lavage fluid Not reported Improved survival Anti-RAGE IgG vs. control IgG No change to CFU in liver, spleen and

peritoneal lavage fluid

Less lung and gut injury

Improved survival, even when given as a single dose 24 hours after CLP

Listeria monocytogenes IV RAGE-deleted vs. wildtype No change to CFU in liver or spleen Not reported Improved survival Anti-RAGE IgG vs. control IgG

Vogl 2007[331] Intraperitoneal LPS with

galactosamine S100A9-deleted vs. wildtype Not reported Not reported

Improved survival, returned to normal with IV S100A9.

Liliensiek

2004[310] CLP

RAGE-deleted vs. wildtype (and RAGE over-

expressing mutants) Not reported Less hypotension

Improved survival in RAGE-deleted and no change in over-expressing mutants.

sRAGE intra-peritoneal repeat doses vs. vehicle Not reported Not reported Trend towards improved survival.

Yang 2004[372]

Anti-HMGB1 vs. control Ig, given 24h after onset No change to CFU in spleen Not reported Improved survival

Intraperitoneal LPS

A box subunit of HMGB1 vs. control, given 24h

after onset No change to CFU in spleen Not reported Improved survival

Ulloa 2002[371]

Ethyl pyruvate (40mg/kg) vs. placebo, given

before LPS Not reported Not reported Improved survival

CLP Ethyl pyruvate (40mg/kg) vs. placebo, given

repeatedly from 24h after CLP Not reported Not reported Improved survival Wang 1999[370] Intraperitoneal LPS Anti-HMGB1 IgG intra-peritoneal repeat doses

vs. control IgG Not reported Not reported Improved survival, even when delayed Table 8 (part II): Summary of major papers assessing effects of RAGE inhibition in murine models of sepsis. sRAGE soluble RAGE, HMGB1 high mobility group box 1, CFU colony forming units, CLP caecal ligation and puncture, LPS lipopolysaccharide, IV intravenous

91 Treatment group vs. control group

Author and

year Model

Mode of RAGE inhibition and

control Indication of altered bacterial dissemination Organ failure Survival difference Cai 2009[449]

Haemorrhagic shock and resuscitation

Ethyl pyruvate vs. none Not reported Not reported Dose-dependent, survival benefit Yang 2006[378] HMGB1 AB vs. control Decreased bacterial translocation to mesenteric

lymph nodes Attenuated ileal mucosal hyperpermeability

Survival benefit (90% vs. 46%) Levy 2007[376] Bony fractures HMGB1 AB vs. control Not reported Attenuated hepatic and systemic inflammation Not assessed

Sawa 2006[377]

Severe acute pancreatitis (SAP)

HMGB1 AB vs. control Increased bacterial translocation to pancreas Attenuated pancreatitis and pulmonary and

renal injury Not assessed Yang 2008[450] Delayed ethyl pyruvate vs.

control Not reported

Attenuated hepatic, pulmonary and renal

injury Prolonged survival Raman

2006[448]

Haemorrhagic shock and resuscitation

RAGE-deleted vs. wildtype sRAGE vs. sham

Decreased bacterial translocation to mesenteric

lymph nodes Not reported Not assessed

Table 9: Summary of major papers assessing effects of RAGE inhibition in murine models of non-septic systemic inflammation. AB antibodies, LPS lipopolysaccharide, KO knockout, WT wildtype, LD50 median lethal dose

92

Condition Measurement Association

Nakamura

2011[453] ARDS and sepsis

sRAGE and HMGB1 levels in

blood sRAGE was independently associated with death Jaboudon

2011[454] ARDS ± severe sepsis sRAGE levels in blood sRAGE levels correlated with severity of ARDS, independent of presence of severe sepsis

Cohen 2010[455] Trauma sRAGE levels in blood sRAGE levels were increased early after severe trauma and correlated with the severity of injury, early posttraumatic coagulopathy and hyperfibrinolysis, and endothelial cell activation

Manganelli

2010[383] Major elective surgery

HMGB1 levels in blood and on

monocytes HMGB1 is increased on monocytes early post-operatively, and then concurrent with increases in plasma HMGB1, decreases. Kikkawa

2010[456]

Sepsis, major elective surgery ± ALI

sRAGE and S100A12 plasma

levels sRAGE increases in those who do not develop ALI; S100A12 increases more in those that develop ALI. Agonstoni

2010[457] snCPB sRAGE levels in blood sRAGE increases following snCPB

Kohno 2010[458] Aortic snCPB HMGB1 levels in blood Higher HMGB1 was associated with more severe SIRS and a higher incidence of impaired oxygenation Calfee 2008[459] ALI/ARDS sRAGE levels in blood Levels associated with severity of illness in all. In subset (high tidal volume arm) correlated with mortality Table 10 (Part I): Human studies of the sepsis syndromes relating to measurements of the RAGE axis. BAL broncho-alveolar fluid

93

Condition Measurement Association

Payen 2008[460] Recovery from septic

shock Leukocyte gene expression array One of the greatest changes in expression was S100A8 and A12, with plasma S100A8/9 levels changing in parallel Bopp 2008[461] Sepsis (and ARDS) sRAGE levels in blood Highest levels in non-survivors

Kocsis 2009[462] Severe acute pancreatitis; sepsis

sRAGE and HMGB1 levels in

blood sRAGE highest in those with sepsis, HMGB1 higher in those with severe, compared to mild pancreatitis Makam 2009[463] Cystic fibrosis RAGE on neutrophils from

airways and blood Degree of airway inflammation and extent of RAGE expression on airway neutrophils Determann 2008[464] Major elective surgery sRAGE levels in blood and BAL Blood levels increased without change in BAL levels

Wang 1999[370], Sunden-

Cullberg 2005[392] Sepsis

HMGB1 levels in blood

Levels elevated up to 7 days after admission, without predictable correlation to severity of infection

Angus 2007[409] Community acquired pneumonia

Levels elevated in almost all patients, and although higher circulating HMGB1 were associated with mortality, levels were also persistently elevated in those with uncomplicated recovery

Peltz 2009[400] Trauma Levels elevated as early as one hour after trauma, without relationship to patient outcome Alleva 2005[396] Infection with Falciparum

malariae Levels elevated at admission to hospital and to a greater extent in non-survivors Lantos 2010[397] Burn injury >10% body

surface area Levels elevated, with levels correlating to extent of burns and being higher in non-survivors van Zoelen 2009[447]

Severe sepsis S100A8/9 levels in blood Levels elevated compared with controls, with levels not correlating to severity of illness. Piazza 2007[465]

S100B levels in blood

S100B was significantly elevated, no more so in those with cerebral dysfunction Korfias 2006 [466] Trauma without head

injuries S100B was significantly elevated, in relation to extent of injury and rapidly declined. Table 10 (Part II): Human studies of the sepsis syndromes relating to measurements of the RAGE axis. BAL broncho-alveolar fluid

94

3.3.2. Human studies