The role of NIGMS P50 sponsored team science in our understanding of multiple organ failure

The persistent inflammation, immunosuppression, and catabolism syndrome 10 years later

With the implementation of new intensive care unit (ICU) therapies in the 1970s, multiple organ failure (MOF) emerged as a fulminant inflammatory phenotype leading to early ICU death. Over the ensuing decades, with fundamental advances in care, this syndrome has evolved into a lingering phenotype of chronic critical illness (CCI) leading to indolent late post-hospital discharge death. In 2012, the University of Florida (UF) Sepsis Critical Illness Research Center (SCIRC) coined the term Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) to provide a mechanistic framework to study CCI in surgical patients. This was followed by a decade of research into PICS-CCI in surgical ICU patients in order to define the epidemiology, dysregulated immunity, and long-term outcomes after sepsis. Other focused studies were performed in trauma ICU patients and emergency department sepsis patients. Early deaths were surprisingly low (4%); 63% experienced rapid recovery. Unfortunately, 33% progressed to CCI, of which 79% had a poor post-discharge disposition and 41% were dead within one year. These patients had biomarker evidence of PICS, and these biomarkers enhanced clinical prediction models for dismal one-year outcomes. Emergency myelopoiesis appears to play a central role in the observed persistent immune dysregulation that characterizes PICS-CCI. Older patients were especially vulnerable. Disturbingly, over half of the older CCI patients were dead within one year and older CCI survivors remained severely disabled. Although CCI is less frequent (20%) after major trauma, PICS appears to be a valid concept. This review will specifically detail the epidemiology of CCI, PICS biomarkers, effect of site of infection, acute kidney injury, effect on older patients, dysfunctional high-density lipoproteins, sarcopenia/cachexia, emergency myelopoiesis, dysregulated erythropoiesis, and potential therapeutic interventions.

A review of UF SCIRC’s research efforts characterizing CCI, PICS biomarkers, effect of site of infection, acute kidney injury, effects on older patients, dysfunctional high-density lipoproteins, sarcopenia/cachexia, emergency myelopoiesis, and dysregulated erythropoiesis.

The Use of Multiplexing to Identify Cytokine and Chemokine Networks in the Immune-Inflammatory Response to Trauma

Significance: The immunoinflammatory responses that follow trauma contribute to clinical trajectory and patient outcomes. While remarkable advances have been made in trauma services and injury management, clarity on how the immune system in humans responds to trauma is lagging. Recent Advances: Multiplexing platforms have transformed our ability to analyze comprehensive immune mediator responses in human trauma. In parallel, with the establishment of large data sets, computational methods have been adapted to yield new insights based on mediator patterns. These efforts have added an important data layer to the emerging multiomic characterization of the human response to injury. Critical Issues: Outcome after trauma is greatly affected by the host immunoinflammatory response. Excessive or sustained responses can contribute to organ damage. Hence, understanding the pathophysiology behind traumatic injury is of vital importance. Future Directions: This review summarizes our work in the study of circulating immune mediators in trauma patients. Our foundational studies into dynamic patterns of inflammatory mediators represent an important contribution to the concepts and computational challenges that these large data sets present. We hope to see further integration and understanding of multiomics strategies in the field of trauma that can aid in patient endotyping and in potentially identifiying certain therapeutic targets in the future. Antioxid. Redox Signal. 35, 1393-1406.

Biomarker Evidence of the Persistent Inflammation, Immunosuppression and Catabolism Syndrome (PICS) in Chronic Critical Illness (CCI) After Surgical Sepsis

OBJECTIVE

To analyze serial biomarkers of the persistent inflammation, immunosuppression, and catabolism syndrome (PICS) to gain insight into the pathobiology of chronic critical illness (CCI) after surgical sepsis.

BACKGROUND

Although early deaths after surgical intensive care unit sepsis have decreased and most survivors rapidly recover (RAP), one third develop the adverse clinical trajectory of CCI. However, the underlying pathobiology of its dismal long-term outcomes remains unclear.

METHODS

PICS biomarkers over 14 days from 124 CCI and 225 RAP sepsis survivors were analyzed to determine associations and prediction models for (1) CCI (≥14 intensive care unit days with organ dysfunction) and (2) dismal 1-year outcomes (Zubrod 4/5 performance scores). Clinical prediction models were created using PIRO variables (predisposition, insult, response, and organ dysfunction). Biomarkers were then added to determine if they strengthened predictions.

RESULTS

CCI (vs RAP) and Zubrod 4/5 (vs Zubrod 0-3) cohorts had greater elevations in biomarkers of inflammation (interleukin [IL]-6, IL-8, interferon gamma-induced protein [IP-10], monocyte chemoattractant protein 1), immunosuppression (IL-10, soluble programmed death ligand-1), stress metabolism (C-reactive protein, glucagon-like peptide 1), and angiogenesis (angiopoietin-2, vascular endothelial growth factor, vascular endothelial growth factor receptor-1, stromal cell-derived factor) at most time-points. Clinical models predicted CCI on day 4 (area under the receiver operating characteristics curve [AUC] = 0.89) and 1 year Zubrod 4/5 on day 7 (AUC = 0.80). IL-10 and IP-10 on day 4 minimally improved prediction of CCI (AUC = 0.90). However, IL-10, IL-6, IL-8, monocyte chemoattractant protein 1, IP-10, angiopoietin-2, glucagon-like peptide 1, soluble programmed death ligand-1, and stromal cell-derived factor on day 7 considerably improved the prediction of Zubrod 4/5 status (AUC = 0.88).

CONCLUSIONS

Persistent elevations of PICS biomarkers in the CCI and Zubrod 4/5 cohorts and their improved prediction of Zubrod 4/5 validate that PICS plays a role in CCI pathobiology.

Chronic Critical Illness and PICS Nutritional Strategies

The nutritional hallmark of chronic critical illness (CCI) after sepsis is persistent inflammation, immunosuppression, and catabolism syndrome (PICS), which results in global resistance to the anabolic effect of nutritional supplements. This ultimately leaves these patients in a downward phenotypic spiral characterized by cachexia with profound weakness, decreased capacity for rehabilitation, and immunosuppression with the propensity for sepsis recidivism. The persistent catabolism is driven by a pathologic low-grade inflammation with the inability to return to homeostasis and by ongoing increased energy expenditure. Better critical care support systems and advances in technology have led to increased intensive care unit (ICU) survival, but CCI due to PICS with poor long-term outcomes has emerged as a frequent phenotype among ICU sepsis survivors. Unfortunately, therapies to mitigate or reverse PICS-CCI are limited, and recent evidence supports that these patients fail to respond to early ICU evidence-based nutrition protocols. A lack of randomized controlled trials has limited strong recommendations for nutrition adjuncts in these patients. However, based on experience in other conditions characterized by a similar phenotype, immunonutrients aimed at counteracting inflammation, immunosuppression, and catabolism may be important for improving outcomes in PICS-CCI patients. This manuscript intends to review several immunonutrients as adjunctive therapies in treating PICS-CCI.

Older Sepsis Survivors Suffer Persistent Disability Burden and Poor Long-Term Survival

OBJECTIVES

Sepsis has been called a "disease of the elderly," and as in-hospital mortality has decreased, more sepsis survivors are progressing into poorly characterized long-term outcomes. The purpose of this study was to describe the current epidemiology of sepsis in older adults compared with middle-aged and young adults.

DESIGN

Prospective longitudinal study with young (≤45 years), middle-aged (46-64 years), and older (≥65 years) patient groups.

SETTING

University tertiary medical center.

PARTICIPANTS

A total of 328 adult surgical intensive care unit (ICU) sepsis patients.

MEASUREMENTS

Patients were characterized by (1) baseline demographics and predisposition, (2) septic event, (3) hospital outcomes and discharge disposition, (4) 12-month mortality, and (5) Zubrod Performance Status, physical function (Short Physical Performance Battery and handgrip strength), and cognitive function (Hopkins Verbal Learning Test, Controlled Oral Word Association, and Mini-Mental Status Examination) at 3-, 6-, and 12-month follow-up. Loss to follow-up was due to death (in 68), consent withdrawal (in 32), and illness and scheduling difficulties: month 3 (in 51), month 6 (in 29), and month 12 (in 20).

RESULTS

Compared with young and middle-aged patients, older patients had (1) significantly more comorbidities at presentation (eg, chronic renal disease 6% vs 12% vs 21%), intra-abdominal infections (14% vs 25% vs 37%), septic shock (12% vs 25% vs 36%), and organ dysfunctions; (2) higher 30-day mortality (6% vs 4% vs 17%) and fewer ICU-free days (median = 25 vs 23 vs 20); (3) more progression into chronic critical illness (22% vs 34% vs 42%) with higher poor disposition discharge to non-home destinations (19% vs 40% vs 62%); (4) worse 12-month mortality (11% vs 14% vs 33%); and (5) poorer Zubrod Performance Status and objectively measured physical and cognitive functions with only slight improvement over 12-month follow-up.

CONCLUSION

Compared with younger patients, older sepsis survivors suffer both a higher persistent disability burden and 12-month mortality.

Current Epidemiology of Surgical Sepsis: Discordance Between Inpatient Mortality and 1-year Outcomes

OBJECTIVE

We sought to compare traditional inpatient outcomes to long-term functional outcomes and mortality of surgical intensive care unit (SICU) patients with sepsis.

SUMMARY OF BACKGROUND DATA

As inpatient sepsis mortality declines, an increasing number of initial sepsis survivors now progress into a state of chronic critical illness (CCI) and their post-discharge outcomes are unclear.

METHODS

We performed a prospective, longitudinal cohort study of SICU patients with sepsis.

RESULTS

Among this recent cohort of 301 septic SICU patients, 30-day mortality was 9.6%. Only 13 (4%) patients died within 14 days, primarily of refractory multiple organ failure (62%). The majority (n = 189, 63%) exhibited a rapid recovery (RAP), whereas 99 (33%) developed CCI. CCI patients were older, with greater comorbidities, and more severe and persistent organ dysfunction than RAP patients (all P < 0.01). At 12 months, overall cohort performance status was persistently worse than presepsis baseline (WHO/Zubrod score 1.4 ± 0.08 vs 2.2 ± 0.23, P > 0.0001) and mortality was 20.9%. Of note at 12 months, the CCI cohort had persistent severely impaired performance status and a much higher mortality (41.4%) than those with RAP (4.8%) after controlling for age and comorbidity burden (Cox hazard ratio 1.27; 95% confidence interval, 1.14-1.41, P < 0.0001). Among CCI patients, independent risk factors for death by 12 months included severity of comorbidities and persistent organ dysfunction (sequential organ failure assessment ≥6) at day 14 after sepsis onset.

CONCLUSIONS

There is discordance between low inpatient mortality and poor long-term outcomes after surgical sepsis, especially among older adults, increasing comorbidity burden and patients that develop CCI. This represents important information when discussing expected outcomes of surgical patients who experience a complicated clinical course owing to sepsis.

Large publishing consortia produce higher citation impact research but coauthor contributions are hard to evaluate

This paper introduces a simple agglomerative clustering method to identify large publishing consortia with at least 20 authors and 80% shared authorship between articles. Based on Scopus journal articles from 1996–2018, under these criteria, nearly all (88%) of the large consortia published research with citation impact above the world average, with the exceptions being mainly the newer consortia, for which average citation counts are unreliable. On average, consortium research had almost double (1.95) the world average citation impact on the log scale used (Mean Normalised Log Citation Score). At least partial alphabetical author ordering was the norm in most consortia. The 250 largest consortia were for nuclear physics and astronomy, involving expensive equipment, and for predominantly health-related issues in genomics, medicine, public health, microbiology and neuropsychology. For the health-related issues, except for the first and last few authors, authorship seem to primarily indicate contributions to the shared project infrastructure necessary to gather the raw data. It is impossible for research evaluators to identify the contributions of individual authors in the huge alphabetical consortia of physics and astronomy and problematic for the middle and end authors of health-related consortia. For small-scale evaluations, authorship contribution statements could be used when available.

Diagnosis and Management of Polytraumatized Patients With Severe Extremity Trauma

Multiply injured patients with severe extremity trauma are at risk of acute systemic complications and are at high risk of developing longer term orthopaedic complications including soft-tissue infection, osteomyelitis, posttraumatic osteoarthritis, and nonunion. It is becoming increasingly recognized that injury magnitude and response to injury have major jurisdiction pertaining to patient outcomes and complications. The complexities of injury and injury response that affect outcomes present opportunities to apply precision approaches to understand and quantify injury magnitude and injury response on a patient-specific basis. Here, we present novel approaches to measure injury magnitude by adopting methods that quantify both mechanical and ischemic tissue injury specific to each patient. We also present evolving computational approaches that have provided new insight into the complexities of inflammation and immunologic response to injury specific to each patient. These precision approaches are on the forefront of understanding how to stratify individualized injury and injury response in an effort to optimize titrated orthopaedic surgical interventions, which invariably involve most of the multiply injured patients. Finally, we present novel methods directed at mangled limbs with severe soft-tissue injury that comprise severely injured patients. Specifically, methods being developed to treat mangled limbs with volumetric muscle loss have the potential to improve limb outcomes and also mitigate uncompensated inflammation that occurs in these patients.