(Pro)renin receptor blocker improves survival of rats with sepsis

The (Pro)renin Receptor - A Regulatory Nodal Point in Disease Networks

Experimental inhibition of the (pro)renin receptor [(P)RR] is a promising therapeutic strategy in different disease models ranging from cardiorenal to oncological entities. Here, we briefly review the direct protein-protein interaction partners of the (P)RR and the plethora of distinct diseases in which the (P)RR is involved. The first structural work on the (P)RR using AlphaFold, which was recently published by Ebihara et al., is the center of this mini-review since it can mechanistically link the protein-protein interaction level with the pathophysiological level. More detailed insights into the 3D structure of the (P)RR and its interaction domains might guide drug discovery on this novel target. Finally, antibody- and small molecule-based approaches to inhibit the (P)RR are shortly discussed.

Myocardial effects of angiotensin II compared to norepinephrine in an animal model of septic shock

BACKGROUND

Angiotensin II is one of the vasopressors available for use in septic shock. However, its effects on the septic myocardium remain unclear. The aim of the study was to compare the effects of angiotensin II and norepinephrine on cardiac function and myocardial oxygen consumption, inflammation and injury in experimental septic shock.

METHODS

This randomized, open-label, controlled study was performed in 20 anesthetized and mechanically ventilated pigs. Septic shock was induced by fecal peritonitis in 16 animals, and four pigs served as shams. Resuscitation with fluids, antimicrobial therapy and abdominal drainage was initiated one hour after the onset of septic shock. Septic pigs were randomly allocated to receive one of the two drugs to maintain mean arterial pressure between 65 and 75 mmHg for 8 h.

RESULTS

There were no differences in MAP, cardiac output, heart rate, fluid balance or tissue perfusion indices in the two treatment groups but myocardial oxygen consumption was greater in the norepinephrine-treated animals. Myocardial mRNA expression of interleukin-6, interleukin-6 receptor, interleukin-1 alpha, and interleukin-1 beta was higher in the norepinephrine than in the angiotensin II group.

CONCLUSIONS

In septic shock, angiotensin II administration is associated with a similar level of cardiovascular resuscitation and less myocardial oxygen consumption, and inflammation compared to norepinephrine.

Renin as a Marker of Tissue Perfusion, Septic Shock and Mortality in Septic Patients: A Prospective Observational Study

Sepsis is a life-threatening organ dysfunction caused by the dysregulation of the host’s response to an infection, where the dominant mechanism is tissue hypoperfusion. Currently, the marker used to define tissue disorders is lactate levels, which may be elevated in other disease states as well. Renin is an essential hormone for the proper functioning of the renin-angiotensin-aldosterone (RASS) system. It is secreted in the glomerular apparatus in response to hypoperfusion. This study aimed to assess the usefulness of renin as a marker of tissue hypoperfusion in patients with sepsis and septic shock. A final group of 48 patients treated for sepsis and septic shock in the intensive care unit was included. Blood samples for renin quantification were collected in the morning as a part of routine blood analysis on the first, third, and fifth days. Sepsis was diagnosed in 19 patients (39.6%), and septic shock was diagnosed in 29 patients (60.4%). There was no significant difference in renin concentration between patients who received and did not receive continuous renal replacement therapy (CRRT) on any study day. Therefore, all samples were analyzed together in subsequent analyses. There was a significant difference in renin concentration between sepsis survivors and non-survivors on the third (31.5 and 119.9 pg/mL, respectively) and fifth (18.2 and 106.7 pg/mL, respectively) days. As a survival marker, renin was characterized by 69% and 71% overall accuracy if determined on the third and fifth days, respectively. There was a significant difference in renin concentration between sepsis and septic shock patients on the first (45.8 and 103.4 pg/mL, respectively) and third (24.7 and 102.1 pg/mL, respectively) days. At an optimal cut-off of 87 pg/mL, renin had very good specificity and a positive likelihood ratio. Renin was a strong predictor of mortality in patients with sepsis and septic shock. Further, the level of renin in patients with septic shock was significantly higher than in patients with sepsis. In combination with the assessment of lactate concentration, renin seems to be the optimal parameter for monitoring tissue hypoperfusion and could be helpful for septic shock diagnosis, as well as for identifying candidate patients for CRRT.

Impact of renin-angiotensin-aldosterone-system inhibitor drugs on mortality in patients with atrial fibrillation and hypertension

BACKGROUND

Renin-angiotensin-aldosterone-system inhibitors markedly play an active role in the primary prevention of atrial fibrillation (AF), but the impact of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) on the mortality of patients with AF remains unclear. This study aimed to examine the relationship between treatment with ACEIs or ARBs and mortality in emergency department (ED) patients with AF and hypertension.

METHODS

This multicenter study enrolled 2016 ED patients from September 2008 to April 2011; 1110 patients with AF and hypertension were analyzed. Patients were grouped according to whether they were treated with ACEI/ARB or not and completed a 1-year follow-up to evaluate outcomes including all-cause death, cardiovascular death, stroke, and major adverse events (MAEs).

RESULTS

Among the 1110 patients with AF and hypertension, 574 (51.7%) received ACEI/ARB treatment. During the 1-year follow-up, 169 all-cause deaths (15.2%) and 100 cardiovascular deaths (9.0%) occurred, while 98 strokes (8.8%) and 255 MAEs (23.0%) occurred. According to the multivariate Cox regression analysis, ACEI/ARB therapy was significantly associated with a reduced risk of all-cause death (HR, 0.605; 95% CI 0.431-0.849; P = 0.004). Moreover, ACEI/ARB therapy was independently associated with a reduced risk of cardiovascular death (HR 0.585; 95% CI 0.372-0.921; P = 0.020) and MAEs (HR 0.651, 95% CI 0.496-0.855, P = 0.002) after adjusting for other risk factors.

CONCLUSIONS

Our results revealed that ACEI/ARB therapy was independently associated with a reduced risk of all-cause death, cardiovascular death, and MAEs in ED patients with AF and hypertension. These results provide evidence for a tertiary preventive treatment for patients with AF and hypertension.

Effects of Renin-Angiotensin-Aldosterone System Inhibitors on Long-Term Major Adverse Cardiovascular Events in Sepsis Survivors

Background Sepsis is known to increase morbidity and duration of hospital stay and is a common cause of mortality worldwide. Renin-angiotensin-aldosterone system inhibitors (RAASis) are commonly used to treat hypertension but are usually discontinued during hospitalization for sepsis because of concerns about renal hypoperfusion. The aim of our study was to investigate whether RAASis should be continued after discharge in sepsis survivors and to identify the effects on the clinical outcomes. Methods and Results A total of 9188 sepsis survivors aged 20 years and older who were discharged from January 1, 2012 to December 31, 2019 were included in our analyses. We further divided sepsis survivors into RAASi users and nonusers. These groups were matched by propensity scores before the outcomes of interest, including all-cause mortality and major adverse cardiac events (MACE), were examined. After propensity score matching, 3106 RAASi users and 3106 RAASi nonusers were included in our analyses. Compared with RAASi nonusers, RAASi users had lower risks of all-cause mortality (hazard ratio [HR], 0.68; 95% CI, 0.62-0.75), MACEs (HR, 0.87; 95% CI, 0.81-0.94), ischemic stroke (HR, 0.85; 95% CI, 0.76-0.96), myocardial infarction (HR, 0.74; 95% CI, 0.61-0.90), and hospitalization for heart failure (HR, 0.84; 95% CI, 0.77-0.92). Subgroup analyses stratified by admission to the ICU and the use of inotropes showed similar results. Conclusions In our study, we found that RAASi users had reduced risks of all-cause mortality and MACEs. These findings suggested a beneficial effect of RAASi use by sepsis survivors after discharge.

Angiotensin aldosterone inhibitors improve survival and ameliorate kidney injury induced by sepsis through suppression of inflammation and apoptosis

Sepsis is an extensive life-threatening illness that occurs due to an abnormal host response that extends through the initial storm of inflammation and oxidative stress and terminates at the late stage of immunosuppression. Among global intensive care units, sepsis-induced acute kidney injury is reported with high mortality rate. The purpose of this study was to evaluate the protective effect of the renin angiotensin aldosterone system (RAAS) inhibition on sepsis outcomes. Cecal ligation and puncture (CLP) procedure was applied for sepsis induction. The experimental design constituted of five groups of rats: sham, CLP-nontreated and CLP-treated with ramipril (10 mg/kg, p.o.), losartan (20 mg/kg, i.p.) and spironolactone (25 mg/kg, p.o.). Twenty-four hours after surgery, rats were euthanized for blood and tissue samples, which were used for assessment of serum inflammatory markers, and oxidative stress parameters, as well as to kidney function parameters. The tissue samples were used for histological and caspase-3 assessment. A survival study was conducted using another set of animals. Our results showed that the different RAAS inhibitors showed protective effects evidenced by enhanced overall survival following sepsis (80% in ramipril and spironolactone-treated and 60% in losartan-treated vs. 10% in the septic group), in addition to improved renal function parameters and reduction of oxidative stress and inflammation. The timely use of RAAS inhibitors during sepsis might represent a new therapeutic approach in septic patient.

Elevated angiotensin II induces platelet apoptosis through promoting oxidative stress in an AT1R-dependent manner during sepsis

Thrombocytopenia is independently related with increased mortality in severe septic patients. Renin‐angiotensin system (RAS) is elevated in septic subjects; accumulating studies show that angiotensin II (Ang II) stimulate the intrinsic apoptosis pathway by promoting reactive oxygen species (ROS) production. However, the mechanisms underlying the relationship of platelet apoptosis and RAS system in sepsis have not been fully elucidated. The present study aimed to elucidate whether the RAS was involved in the pathogenesis of sepsis‐associated thrombocytopenia and explore the underlying mechanisms. We found that elevated plasma Ang II was associated with decreased platelet count in both patients with sepsis and experimental animals exposed to lipopolysaccharide (LPS). Besides, Ang II treatment induced platelet apoptosis in a concentration‐dependent manner in primary isolated platelets, which was blocked by angiotensin II type 1 receptor (AT1R) antagonist losartan, but not by angiotensin II type 2 receptor (AT2R) antagonist PD123319. Moreover, inhibiting AT1R by losartan attenuated LPS‐induced platelet apoptosis and alleviated sepsis‐associated thrombocytopenia. Furthermore, Ang II treatment induced oxidative stress level in a concentration‐dependent manner in primary isolated platelets, which was partially reversed by the AT1R antagonist losartan. The present study demonstrated that elevated Ang II directly stimulated platelet apoptosis through promoting oxidative stress in an AT1R‐dependent manner in sepsis‐associated thrombocytopenia. The results would helpful for understanding the role of RAS system in sepsis‐associated thrombocytopenia.

Therapeutic approaches targeting renin-angiotensin system in sepsis and its complications

Sepsis, caused by the inappropriate host response to infection, is characterized by excessive inflammatory response and organ dysfunction, thus becomes a critical clinical problem. Commonly, sepsis may progress to septic shock and severe complications, including acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), sepsis-induced myocardial dysfunction (SIMD), liver dysfunction, cerebral dysfunction, and skeletal muscle atrophy, which predominantly contribute to high mortality. Additionally, the global pandemic of coronavirus disease 2019 (COVID-19) raised the concern of development of effectve therapeutic strategies for viral sepsis. Renin-angiotensin system (RAS) may represent as a potent therapeutic target for sepsis therapy. The emerging role of RAS in the pathogenesis of sepsis has been investigated and several preclinical and clinical trials targeting RAS for sepsis treatment revealed promising outcomes. Herein, we attempt to review the effects and mechanisms of RAS manipulation on sepsis and its complications and provide new insights into optimizing RAS interventions for sepsis treatment.

Renin and Survival in Patients Given Angiotensin II for Catecholamine-Resistant Vasodilatory Shock. A Clinical Trial

Rationale: Exogenous angiotensin II increases mean arterial pressure in patients with catecholamine-resistant vasodilatory shock (CRVS). We hypothesized that renin concentrations may identify patients most likely to benefit from such therapy.

Objectives: To test the kinetic changes in renin concentrations and their prognostic value in patients with CRVS.

Methods: We analyzed serum samples from patients enrolled in the ATHOS-3 (Angiotensin II for the Treatment of High-Output Shock) trial for renin, angiotensin I, and angiotensin II concentrations before the start of administration of angiotensin II or placebo and after 3 hours.

Measurements and Main Results: Baseline serum renin concentration (normal range, 2.13–58.78 pg/ml) was above the upper limits of normal in 194 of 255 (76%) study patients with a median renin concentration of 172.7 pg/ml (interquartile range [IQR], 60.7 to 440.6 pg/ml), approximately threefold higher than the upper limit of normal. Renin concentrations correlated positively with angiotensin I/II ratios (r = 0.39; P < 0.001). At 3 hours after initiation of angiotensin II therapy, there was a 54.3% reduction (IQR, 37.9% to 66.5% reduction) in renin concentration compared with a 14.1% reduction (IQR, 37.6% reduction to 5.1% increase) with placebo (P < 0.0001). In patients with renin concentrations above the study population median, angiotensin II significantly reduced 28-day mortality to 28 of 55 (50.9%) patients compared with 51 of 73 patients (69.9%) treated with placebo (unstratified hazard ratio, 0.56; 95% confidence interval, 0.35 to 0.88; P = 0.012) (P = 0.048 for the interaction).

Conclusions: The serum renin concentration is markedly elevated in CRVS and may identify patients for whom treatment with angiotensin II has a beneficial effect on clinical outcomes.

Clinical trial registered with www.clinicaltrials.gov (NCT 02338843).

Angiotensin II for the treatment of septic shock in a neutropenic patient with T-cell acute lymphoblastic leukaemia

Mortality remains high in septic shock with few new treatment options. Angiotensin II has been recently approved for use in septic shock due to promising results in the ATHOS-3 trial. However, patients with neutropenia were excluded in the trial. This patient population is becoming increasingly common in the intensive care unit as there is an increase in novel biologic therapies and stem cell transplantations for haematological and solid organ malignancies. We present a case of a patient with T-cell acute lymphoblastic leukaemia who received chemotherapy, resulting in neutropenia and septic shock. There was persistent hypotension despite initiating multiple conventional vasopressors. Angiotensin II was attempted with immediate improvement in the blood pressure which resulted in weaning of other vasopressors. This positive haemodynamic response suggests that angiotensin II can successfully be used in neutropenic patients without increasing the overall catecholamine burden of septic shock.

The (pro)renin receptor in health and disease

The (pro)renin receptor ((P)RR) was first identified as a single-transmembrane receptor in human kidneys and initially attracted attention owing to its potential role as a regulator of the tissue renin-angiotensin system (RAS). Subsequent studies found that the (P)RR is widely distributed in organs throughout the body, including the kidneys, heart, brain, eyes, placenta and the immune system, and has multifaceted functions in vivo. The (P)RR has roles in various physiological processes, such as the cell cycle, autophagy, acid-base balance, energy metabolism, embryonic development, T cell homeostasis, water balance, blood pressure regulation, cardiac remodelling and maintenance of podocyte structure. These roles of the (P)RR are mediated by its effects on important biological systems and pathways including the tissue RAS, vacuolar H⁺-ATPase, Wnt, partitioning defective homologue (Par) and tyrosine phosphorylation. In addition, the (P)RR has been reported to contribute to the pathogenesis of diseases such as fibrosis, hypertension, pre-eclampsia, diabetic microangiopathy, acute kidney injury, cardiovascular disease, cancer and obesity. Current evidence suggests that the (P)RR has key roles in the normal development and maintenance of vital organs and that dysfunction of the (P)RR is associated with diseases that are characterized by a disruption of the homeostasis of physiological functions.

Effect of Renin-Angiotensin-Aldosterone System Inhibitors on Short-Term Mortality After Sepsis: A Population-Based Cohort Study

Antagonists of the renin-angiotensin-aldosterone system (RAAS), including ACEIs (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers), may prevent organ failure. We, therefore, investigated whether specific RAAS inhibitors are associated with reduced mortality in patients with sepsis.We conducted a population-based retrospective cohort study using multivariable propensity score-based regression to control for differences among patients using different RAAS inhibitors. A multivariable-adjusted Cox proportional-hazards regression model was used to determine the association between RAAS inhibitors and sepsis outcomes. To directly compare ACEI users, ARB users, and nonusers, a 3-way propensity score matching approach was performed. Results were pooled with previous evidence via a random-effects meta-analysis. A total of 52 727 patients were hospitalized with sepsis, of whom 7642 were prescribed an ACEI and 4237 were prescribed an ARB. Using propensity score-matched analyses, prior ACEI use was associated with decreased 30-day mortality (hazard ratio, 0.84 [95% CI, 0.75-0.94]) and 90-day mortality (hazard ratio, 0.83 [95% CI, 0.75-0.92]) compared with nonuse. Prior ARB use was associated with an improved 90-day survival (hazard ratio, 0.88 [95% CI, 0.83-0.94]). These results persisted in sensitivity analyses focusing on patients without cancer and patients with hypertension. By contrast, no beneficial effect was found for antecedent β-blockers exposure (hazard ratio, 0.99 [95% CI, 0.94-1.05]). The pooled estimates obtained from the meta-analysis was 0.71 (95% CI, 0.58-0.87) for prior use of ACEI/ARB.The short-term mortality after sepsis was substantially lower among those who were already established on RAAS inhibitor treatment when sepsis occurred.

Implications of Plasma Renin Activity and Plasma Aldosterone Concentration in Critically Ill Patients with Septic Shock

Background

The renin-angiotensin-aldosterone system is closely associated with volume status and vascular tone in septic shock. The present study aimed to assess whether plasma renin activity (PRA) and plasma aldosterone concentration (PAC) measurements compared with conventional severity indicators are associated with mortality in patients with septic shock.

Methods

We evaluated 105 patients who were admitted for septic shock. Plasma levels of the biomarkers PRA and PAC, the PAC/PRA ratio, C-reactive protein (CRP) level, and cortisol level on days 1, 3, and 7 were serially measured. During the intensive care unit stay, relevant clinical information and laboratory results were recorded.

Results

Patients were divided into two groups according to 28-day mortality: survivors (n = 59) and non-survivors (n = 46). The survivor group showed lower PRA, PAC, Acute Physiologic and Chronic Health Evaluation (APACHE) II score, and Sequential Organ Failure Assessment (SOFA) score than did the non-survivor group (all P < 0.05). The SOFA score was positively correlated with PRA (r = 0.373, P < 0.001) and PAC (r = 0.316, P = 0.001). According to receiver operating characteristic analysis, the areas under the curve of PRA and PAC to predict 28-day mortality were 0.69 (95% confidence interval [CI], 0.58 to 0.79; P = 0.001) and 0.67 (95% CI, 0.56 to 0.77; P = 0.003), respectively, similar to the APACHE II scores and SOFA scores. In particular, the group with PRA value ≥3.5 ng ml^-1 h^-1 on day 1 showed significantly greater mortality than did the group with PRA value <3.5 ng ml^-1 h^-1 (log-rank test, P < 0.001). According to multivariate analysis, SOFA score (hazard ratio, 1.11; 95% CI, 1.01 to 1.22), PRA value ≥3.5 ng ml^-1 h^-1 (hazard ratio, 3.25; 95% CI, 1.60 to 6.60), previous history of cancer (hazard ratio, 3.44; 95% CI, 1.72 to 6.90), and coronary arterial occlusive disease (hazard ratio, 2.99; 95% CI, 1.26 to 7.08) were predictors of 28-day mortality.

Conclusions

Elevated PRA is a useful biomarker to stratify the risk of critically ill patients with septic shock and is a prognostic predictor of 28-day mortality.

Angiotensin receptor blockers are not associated with reduced inflammatory markers in the general population

OBJECTIVE

Angiotensin receptor blockers (ARBs) have been suggested to reduce inflammation in randomized controlled trials. We assessed the association between ARBs and inflammatory markers in a general population setting.

METHODS

This is a population-based prospective study conducted in Lausanne, Switzerland. Baseline data from 933 participants on antihypertensive drugs (424 on ARBs) was collected in 2003-2006. Follow-up data from 1120 participants (572 on ARBs) was collected in 2009-2012. C-reactive protein (CRP), interleukins 1β and 6 and tumor necrosis factor alpha (TNF-α) were assessed and categorized in quartiles.

RESULTS

At baseline, no differences were found between participants taking or not taking ARBs for all inflammatory markers studied, and this association persisted after multivariate adjustment: odds ratios (ORs) and (95% confidence interval) for being in the highest quartile of interleukin-1β, interleukin-6, TNF-α and CRP for participants on ARB compared to participants not on ARB were 1.23 (0.89-1.70), 1.26 (0.93-1.70), 1.14 (0.85-1.53) and 1.27 (0.96-1.69) respectively (P > 0.05). These findings were further replicated in the follow-up study: OR and (95% CI) of 1.10 (0.78-1.55), 0.87 (0.64-1.19), 0.83 (0.61-1.14) and 0.91 (0.68-1.22) for interleukin-1β, interleukin-6, TNF-α and CRP respectively (P > 0.05). Finally, no effect of ARBs was found when comparing participants who received ARBs throughout the 5.4-year follow-up with participants on other antihypertensive drugs: OR and (95% CI) of 0.93 (0.61-1.42), 0.80 (0.54-1.17), 0.86 (0.59-1.25) and 0.95 (0.67-1.35) for interleukin-1β, interleukin-6, TNF-α and CRP respectively (P > 0.05).

CONCLUSION

ARBs are not associated with reduced levels of inflammatory markers in the general population.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

Introduction

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

Methods

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

Results

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

Conclusions

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1093-4) contains supplementary material, which is available to authorized users.

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1's multiple functions.