Association of sex and aspirin use with postoperative bleeding in patients with lower extremity long bone fractures

Objective

The perioperative management of patients on antiplatelet drugs is a rising challenge in orthopedic trauma because antiplatelet drugs are frequently encountered and carry an increased risk of hemorrhagic consequences. The study objective was to examine the effect of aspirin on bleeding outcomes for patients with lower extremity fractures.

Methods

This retrospective study included patients requiring surgical fixation of traumatic hip, femur, and tibia fractures from January 1, 2018, to March 1, 2020. Patients were excluded if they had a significant head injury, were on chronic anticoagulant therapy, or they did not receive venous thromboembolism chemoprophylaxis. Comparisons between aspirin users (patients on aspirin therapy preinjury) and non-aspirin users were examined using χ2 tests, Cochran-Mantel-Haenszel tests, and multivariate logistic regression. The primary outcome was an overt, actionable bleed (eg, blood transfusion for surgical site hemorrhage) within 24 hours postoperative.

Results

There were 864 patients with lower extremity long bone fractures and 24% were aspirin users. The incidence of postoperative bleeding was 8.8% and significantly differed for patients taking aspirin versus not (13.6% vs 7.3%, p=0.01). However, biological sex at birth (M/F) was a significant effect modifier (interaction p=0.04). Among women, there were significantly more postoperative bleeds for aspirin users (17.8% aspirin vs 7.4% no aspirin, adjusted OR (AOR): 2.48 (1.28-4.81), p=0.01). Among men, there were similar postoperative bleeding events by aspirin use (5.6% aspirin vs 7.2% no aspirin, AOR: 0.50 (0.14-1.82), p=0.30). Postoperative hemoglobin values <8 g/dL were more frequent among female aspirin users (21.5% aspirin vs 12.5% no aspirin, p=0.01), but this association was not observed in men (p=0.43).

Conclusion

Women taking aspirin who suffer lower extremity fractures have greater than twofold greater odds of a postoperative bleeding event. These findings suggest adequate perioperative planning to ensure blood availability, and increased awareness to monitor closely for hemorrhage in the 24-hour postoperative window for women taking aspirin preinjury.

Level of evidence

IV.

Hypoxia Dysregulates the Transcription of Myoendothelial Junction Proteins Involved with Nitric Oxide Production in Brain Endothelial Cells

Myoendothelial junctions (MEJs) are structures that allow chemical signals to be transmitted between endothelial cells (ECs) and vascular smooth muscle cells, which control vascular tone. MEJs contain hemoglobin alpha (Hbα) and endothelial nitric oxide synthase (eNOS) complexes that appear to control the production and scavenging of nitric oxide (NO) along with the activity of cytochrome b5 reductase 3 (CYB5R3). The aim of this study was to examine how hypoxia affected the regulation of proteins involved in the production of NO in brain ECs. In brief, human brain microvascular endothelial cells (HBMEC) were exposed to cobalt chloride (CoCl2), a hypoxia mimetic, and a transcriptional analysis was performed using primers for eNOS, CYB5R3, and Hbα2 with ΔΔCt relative gene expression normalized to GAPDH. NO production was also measured after treatment using 4,5-diaminofluorescein diacetate (DAF-DA), a fluorescent NO indicator. When HBMEC were exposed to CoCl2 for 48 h, eNOS and CYB5R3 messenger RNA significantly decreased (up to -17.8 ± 4.30-fold and -10.4 ± 2.8, respectively) while Hbα2 increased to detectable levels. Furthermore, CoCl2 treatment caused a redistribution of peripheral membrane-generated NO production to a perinuclear region. To the best of our knowledge, this is the first time this axis has been studied in brain ECs and these findings imply that hypoxia may cause dysregulation of proteins that regulate NO production in brain MEJs.

Epidemiology of C2 fractures and determinants of surgical management: analysis of a national registry

Objective

Operative management of axis fractures (C2) usually depend on the stability and location of the break and individual patient characteristics. We sought to describe the epidemiology of C2 fractures and hypothesized that determinants for surgery would differ by fracture diagnosis.

Methods

Patients with C2 fractures were identified from the US National Trauma Data Bank from January 1, 2017, to January 1, 2020. Patients were classified by C2 fracture diagnosis: odontoid type II, odontoid types I and III, and non-odontoid fracture (hangman's fracture or fractures through base of the axis). The primary comparison was C2 fracture surgery versus non-operative management. Multivariate logistic regression was used to identify independent associations with surgery. Decision tree-based models were developed to identify determinants for surgery.

Results

There were 38 080 patients; 42.7% had an odontoid type II fracture; 16.5% had an odontoid type I/III fracture; and 40.8% had a non-odontoid fracture. All examined patient demographics, clinical characteristics, outcomes, and interventions differed by C2 fracture diagnosis. Overall, 5292 (13.9%) were surgically managed (17.5% odontoid type II, 11.0% odontoid type I/III, and 11.2% non-odontoid; p<0.001). The following covariates increased odds of surgery for all three fracture diagnoses: younger age, treatment at a level I trauma center, fracture displacement, cervical ligament sprain, and cervical subluxation. Determinants of surgery differed by fracture diagnosis: for odontoid type II, age ≤80 years, a displaced fracture, and cervical ligament sprain were determinants; for odontoid type I/III, age ≤85 years, a displaced fracture, and cervical subluxation were determinants; for non-odontoid fractures, cervical subluxation and cervical ligament sprain were the strongest determinants for surgery, by hierarchy.

Conclusions

This is the largest published study of C2 fractures and current surgical management in the USA. Odontoid fractures, regardless of type, had age and fracture displacement as the strongest determinants for surgical management, whereas associated injuries were determinants of surgery for non-odontoid fractures.

Level of evidence

III.

Findings on Repeat Posttraumatic Brain Computed Tomography Scans in Older Patients With Minimal Head Trauma and the Impact of Existing Antithrombotic Use

STUDY OBJECTIVE

Evaluate the utility of routine rescanning of older, mild head trauma patients with an initial negative brain computed tomography (CT), who is on a preinjury antithrombotic (AT) agent by assessing the rate of delayed intracranial hemorrhage (dICH), need for surgery, and attributable mortality.

METHODS

Participating centers were trained and provided data collection instruments per institutional review board-approved protocols. Data were obtained from manual chart review and electronic medical record download. Adults ≥55 years seen at Level I/II Trauma Centers, between 2017 and 2019 with suspected head trauma, Glasgow Coma Scale 14 to 15, negative initial brain CT, and no other Abbreviated Injury Scale injuries >2 were identified, grouped by preinjury AT therapy (AT- or AT+) and compared on dICH rate, need for operative neurosurgical intervention, and attributable mortality using univariate analysis (α=.05).

RESULTS

A total of 2,950 patients from 24 centers were enrolled; 280 (9.5%) had a repeat brain CT. In those rescanned, the dICH rate was 15/126 (11.9%) for AT- and 6/154 (3.9%) in AT+. Assuming nonrescanned patients did not suffer clinically meaningful dICH, the dICH rate would be 15/2001 (0.7%) for AT- and 6/949 (0.6%) for AT+. No surgical operations were done for dICH. All-cause mortality was 9/2950 (0.3%) and attributable mortality was 1/2950 (0.03%). The attributable death was an AT+, dICH patient whose family declined intervention.

CONCLUSION

In older patients with an initial Glasgow Coma Scale of 14 to 15 and a negative initial brain CT scan, the dICH rate is low (<1%) and of minimal clinical consequence, regardless of AT use. In addition, no patient had operative neurosurgical intervention. Therefore, routine rescanning is not supported based on the results of this study.

Low Prevalence but High Impact of COVID-19 Positive Status in Adult Trauma Patients: A Multi-institutional Analysis of 28 904 Patients

BACKGROUND

Few large investigations have addressed the prevalence of COVID-19 infection among trauma patients and impact on providers. The purpose of this study was to quantify the prevalence of COVID-19 infection among trauma patients by timing of diagnosis, assess nosocomial exposure risk, and evaluate the impact of COVID-19 positive status on morbidity and mortality.

METHODS

Registry data from adults admitted 4/1/2020-10/31/2020 from 46 level I/II trauma centers were grouped by: timing of first positive status (Day 1, Day 2-6, or Day ≥ 7); overall Positive/Negative status; or Unknown if test results were unavailable. Groups were compared on outcomes (Trauma Quality Improvement Program complications) and mortality using univariate analysis and adjusted logistic regression.

RESULTS

There were 28 904 patients (60.7% male, mean age: 56.4, mean injury severity score: 10.5). Of 13 274 (46%) patients with known COVID-19 status, 266 (2%) were Positive Day 1, 119 (1%) Days 2-6, 33 (.2%) Day ≥ 7, and 12 856 (97%) tested Negative. COVID-19 Positive patients had significantly worse outcomes compared to Negative; unadjusted comparisons showed longer hospital length of stay (10.98 vs 7.47;P < .05), higher rates of intensive care unit (57.7% vs 45.7%; P < .05) and ventilation use (22.5% vs 16.9%; P < .05). Adjusted comparisons showed higher rates of acute respiratory distress syndrome (1.7% vs .4%; P < .05) and death (8.1% vs 3.4%; P < .05).

CONCLUSIONS

This multicenter study conducted during the early pandemic period revealed few trauma patients tested COVID-19 positive, suggesting relatively low exposure risk to care providers. COVID-19 positive status was associated with significantly higher mortality and specific morbidity. Further analysis is needed with consideration for care guidelines specific to COVID-19 positive trauma patients as the pandemic continues.

Adherence to Antibiotic Recommendations and Infection Among Patients With Open Long-Bone Fractures: An Examination of Antibiotic Prioritization in Fracture Management

Open fractures are at high risk of infection because of exposure of bone and tissue to the environment. Initiation of intravenous antibiotics is recommended within 1 hour of hospital arrival, although the presence of other severe injuries may lead to delays in fracture management. This retrospective study of adult patients with open long-bone fractures admitted to six level 1 trauma centers between January 1, 2018, and December 31, 2019, aimed to examine adherence to antibiotic recommendations. Associations between receiving recommendation-adherent antibiotics and patient and injury characteristics were investigated univariately and in adjusted regression analyses. The most common fracture locations among the 404 patients included were the tibia (43%) and fibula (26%). Fifty-eight percent of patients received recommendation-adherent antibiotics. After adjustment, patient demographics, comorbidities, cause of injury, and overall injury severity did not show significant associations with adherence to recommendations. Concomitant serious abdominal (adjusted odds ratio [AOR]=0.44) and spinal injuries (AOR=0.23) were associated with lower odds of receiving recommendation-adherent antibiotics. Additionally, fractures of certain locations were associated with increased odds of adherence (humerus: AOR=2.78; fibula: AOR=1.64), as were type 3 fractures (AOR=1.55). The overall infection rate was 4%, and adherence to antibiotic recommendations was not associated with infection (3% vs 5% for nonadherent, P=.34). Results suggest that although full recommendation adherence was somewhat low among this patient population, certain injury characteristics were predictive of adherence rates. Current antibiotic recommendations may benefit from consideration of how antibiotic initiation may fit into the prioritization of injury management, especially in patients with polytrauma with other severe injuries. [Orthopedics. 2023;46(1):54-58.].

C1 esterase inhibitor-mediated immunosuppression in COVID-19: Friend or foe?

From asymptomatic to severe, SARS-CoV-2, causative agent of COVID-19, elicits varying disease severities. Moreover, understanding innate and adaptive immune responses to SARS-CoV-2 is imperative since variants such as Omicron negatively impact adaptive antibody neutralization. Severe COVID-19 is, in part, associated with aberrant activation of complement and Factor XII (FXIIa), initiator of contact system activation. Paradoxically, a protein that inhibits the three known pathways of complement activation and FXIIa, C1 esterase inhibitor (C1-INH), is increased in COVID-19 patient plasma and is associated with disease severity. Here we review the role of C1-INH in the regulation of innate and adaptive immune responses. Additionally, we contextualize regulation of C1-INH and SERPING1, the gene encoding C1-INH, by other pathogens and SARS viruses and propose that viral proteins bind to C1-INH to inhibit its function in severe COVID-19. Finally, we review the current clinical trials and published results of exogenous C1-INH treatment in COVID-19 patients.

Factors associated with delays in medical and surgical open facial fracture management

Objectives

Open fractures are at risk of infection because of exposure of bone and tissue to the environment. Facial fractures are often accompanied by other severe injuries, and therefore fracture management may be delayed until after stabilization. Previous studies in this area have examined timing of multiple facets of care but have tended to report on each in isolation (eg, antibiotic initiation).

Methods

This was a retrospective study of adult patients admitted to five trauma centers from January 1, 2017 to March 31, 2021 with open facial fractures. Variables collected included demographics, injury mechanism, details on facial and non-facial injuries, facial fracture management (irrigation and debridement (I&D), irrigation without debridement, open reduction internal fixation (ORIF), antibiotics), and other hospital events. The study hypothesized that the presence of serious non-facial injuries would be associated with delays in facial fracture management. The primary aims were to describe open facial fracture management practices and examine factors associated with early versus delayed fracture management. A secondary aim was to describe infection rates. Early treatment was defined as within 24 hours of arrival for I&D, irrigation without debridement, and ORIF and within 1 hour for antibiotics.

Results

A total of 256 patients were included. Twenty-seven percent had major trauma (Injury Severity Score ≥16). The presence of serious head injury/traumatic brain injury was associated with delayed I&D (OR_early=0.04, p<0.01), irrigation without debridement (OR_early=0.09, p<0.01), and ORIF (OR_early=0.10, p<0.01). Going to the OR within 24 hours was associated with early I&D (OR_early=377.26, p<0.01), irrigation without debridement (OR_early=13.54, p<0.01), and ORIF (OR_early=154.92, p<0.01). The infection rate was 4%.

Conclusions

In this examination of multiple aspects of open facial fracture management, serious injuries to non-facial regions led to delays in surgical fracture management, consistent with the study hypothesis.

Level of evidence

Level III, prognostic/epidemiological.

Examining trends in gun violence injuries before and during the COVID-19 pandemic across six trauma centers

OBJECTIVES

The onset of the national stay-at-home orders accompanied by a surge in firearm sales has elevated the concerns of clinicians and public health authorities. The purpose of this study was to examine the impact of the stay-at-home orders among gunshot wound (GSW) trauma admissions.

METHODS

This was a retrospective cohort study at six level I trauma centers across four states. Patients admitted after the onset of COVID-19 restrictions (March 16, 2020-June 30, 2020) were compared with those admitted during the same period in 2019. We compared (1) rate of patients with GSW and (2) characteristics of patients with GSW, by period using Χ2 tests or Fisher's exact tests, as appropriate.

RESULTS

There were 6996 trauma admissions across the study period; 3707 (53%) in 2019 and 3289 (47%) in 2020. From 2019 to 2020, there was a significant increase in GSW admissions (4% vs. 6%, p=0.001); 4 weeks specifically had significant increases (March 16-March 23: 4%, April 1-April 8: 5%, April 9-April 16: 6%, and May 11-May 18: 5%). Of the 334 GSWs, there were significant increases in patients with mental illness (5% vs. 11%, p=0.03), alcohol use disorder (2% vs. 10%, p=0.003), substance use disorder (11% vs. 25%, p=0.001), and a significant decrease in mortality (14% vs. 7%, p=0.03) in 2020. No other significant differences between time periods were identified.

CONCLUSION

Our data suggest that trauma centers admitted significantly more patients with GSW following the national guidelines, including an increase in those with mental illness and substance use-related disorders. This could be attributable to the stay-at-home orders.

LEVEL OF EVIDENCE

Level III, retrospective study.

Are trauma research programs in academic and non-academic centers measured by equal standards? A survey of 137 level I trauma centers in the United States

Background

American College of Surgeons level I trauma center verification requires an active research program. This study investigated differences in the research programs of academic and non-academic trauma centers.

Methods

A 28-question survey was administered to ACS-verified level I trauma centers in 11/12/2020–1/7/2021. The survey included questions on center characteristics (patient volume, staff size), peer-reviewed publications, staff and resources dedicated to research, and funding sources.

Results

The survey had a 31% response rate: 137 invitations were successfully delivered via email, and 42 centers completed at least part of the survey. Responding level I trauma centers included 36 (86%) self-identified academic and 6 (14%) self-identified non-academic centers. Academic and non-academic centers reported similar annual trauma patient volume (2190 vs. 2450), number of beds (545 vs. 440), and years of ACS verification (20 vs. 14), respectively. Academic centers had more full-time trauma surgeons (median 8 vs 6 for non-academic centers) and general surgery residents (median 30 vs 7) than non-academic centers. Non-academic centers more frequently ranked trauma surgery (100% vs. 36% academic), basic science (50% vs. 6% academic), neurosurgery (50% vs. 14% academic), and nursing (33% vs. 0% academic) in the top three types of studies conducted. Academic centers were more likely to report non-profit status (86% academic, 50% non-academic) and utilized research funding from external governmental or non-profit grants more often (76% vs 17%).

Conclusions

Survey results suggest that academic centers may have more physician, resident, and financial resources available to dedicate to trauma research, which may make fulfillment of ACS level I research requirements easier. Structural and institutional changes at non-academic centers, such as expansion of general surgery resident programs and increased pursuit of external grant funding, may help ensure that academic and non-academic sites are equally equipped to fulfill ACS research criteria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13037-021-00309-2.

Effect of the COVID-19 pandemic on health insurance coverage among trauma patients: a study of six level I trauma centers

Background

Increased unemployment during the COVID-19 pandemic has likely led to widespread loss of employer-provided health insurance. This study examined trends in health insurance coverage among trauma patients during the COVID-19 pandemic, including differences in demographics and clinical characteristics by insurance type.

Methods

This was a retrospective study on adult patients admitted to six level 1 trauma centers between January 1, 2018 and June 30, 2020. The primary exposure was hospital admission date: January 1, 2018 to December 31, 2018 (Period 1), January 1, 2019 to March 15, 2020 (Period 2), and March 16, 2020 to June 30, 2020 (Period 3). Covariates included demographic and clinical variables. χ² tests examined whether the rates of patients covered by each insurance type differed between the pandemic and earlier periods. Mann-Whiney U and χ² tests investigated whether patient demographics or clinical characteristics differed within each insurance type across the study periods.

Results

A total of 31 225 trauma patients admitted between January 1, 2018 and June 30, 2019 were included. Forty-one per cent (n=12 651) were admitted in Period 1, 49% (n=15 258) were from Period 2, and 11% (n=3288) were from Period 3. Percentages of uninsured patients increased significantly across the three periods (Periods 1 to 3: 15%, 16%, 21%) (p_trend=0.02); however, there was no accompanying decrease in the percentages of commercial/privately insured patients (Periods 1 to 3: 40%, 39%, 39%) (p_trend=0.27). There was a significant decrease in the percentage of patients on Medicare during the pandemic period (Periods 1 to 3: 39%, 39%, 34%) (p<0.01).

Discussion

This study found that job loss during the COVID-19 pandemic resulted in increases of uninsured trauma patients. However, there was not a corresponding decrease in commercial/privately insured patients, as may have been expected; rather, a decrease in Medicare patients was observed. These findings may be attributable to a growing workforce during the study period, in combination with a younger overall patient population during the pandemic.

Level of evidence

Retrospective, level III study.

Incorporating age improves the Glasgow Coma Scale score for predicting mortality from traumatic brain injury

Background

The Glasgow Coma Scale (GCS) score has been adapted into categories of severity (mild, moderate, and severe) and are ubiquitous in the trauma setting. This study sought to revise the GCS categories to account for an interaction by age and to determine the discrimination of the revised categories compared with the standard GCS categories.

Methods

The American College of Surgeons National Trauma Data Bank registry was used to identify patients with traumatic brain injury (TBI; ICD-9 codes 850-854.19) who were admitted to participating trauma centers from 2010 to 2015. The primary exposure variables were GCS score and age, categorized by decade (teens, 20s, 30s…, 80s). In-hospital mortality was the primary outcome for examining TBI severity/prognostication. Logistic regression was used to calculate the conditional probability of death by age decade and GCS in a development dataset (75% of patients). These probabilities were used to create a points-based revision of the GCS, categorized as low (mild), moderate, and high (severe). Performance of the revised versus standard GCS categories was compared in the validation dataset using area under the receiver operating characteristic (AUC) curves.

Results

The final population included 539,032 patients with TBI. Age modified the performance of the GCS, resulting in a novel categorization schema for each age decile. For patients in their 50s, performance of the revised GCS categories mirrored the standard GCS categorization (3-8, 9-12, 13-15); all other revised GCS categories were heavily modified by age. Model validation demonstrated the revised GCS categories statistically significantly outperformed the standard GCS categories at predicting mortality (AUC: 0.800 vs 0.755, p<0.001). The revised GCS categorization also outperformed the standard GCS categories for mortality within pre-specified subpopulations: blunt mechanism, isolated TBI, falls, non-transferred patients.

Discussion

We propose the revised age-adjusted GCS categories will improve severity assessment and provide a more uniform early prognostic indicator of mortality following traumatic brain injury.

Level of evidence

III epidemiologic/prognostic.

Effect of the COVID-19 pandemic on the ability of level 1 trauma centers to meet American College of Surgeons research requirements

Introduction

The COVID-19 pandemic has had major effects on hospitals' ability to perform scientific research while providing patient care and minimizing virus exposure and spread. Many non-COVID-19 research has been halted, and funding has been diverted to COVID-19 research and away from other areas.

Methods

A 28-question survey was administered to all level 1 trauma centers in the USA that included questions about how the pandemic affected the trauma centers' ability to fulfill the volume and research requirements of level 1 verification by the American College of Surgeons (ACS).

Results

The survey had a 29% response rate (40/137 successful invitations). Over half of respondents (52%) reported reduced trauma admissions during the pandemic, and 7% reported that their admissions dropped below the volume required for level 1 verification. Many centers diverted resources from research during the pandemic (44%), halted ongoing consenting studies (33%), and had difficulty fulfilling research requirements because of competing clinical priorities (40%).

Discussion

Results of this study show a need for flexibility in the ACS verification process during the COVID-19 pandemic, potentially including reduction of the required admissions and/or research publication volumes.

Level of evidence

Level IV, cross-sectional study.

Clinically distinct COVID-19 cases share notably similar immune response progression: A follow-up analysis

Inflammatory responses to the novel coronavirus SARS-CoV-2, which causes COVID-19, range from asymptomatic to severe. Here we present a follow-up analysis of a longitudinal study characterizing COVID-19 immune responses from a father and son with distinctly different clinical courses. The father required a lengthy hospital stay for severe symptoms, whereas his son had mild symptoms and no fever yet tested positive for SARS-CoV-2 for 29 days. Father and son, as well as another unrelated COVID-19 patient, displayed a robust increase of SERPING1, the transcript encoding C1 esterase inhibitor (C1–INH). We further bolstered this finding by incorporating a serum proteomics dataset and found that serum C1–INH was consistently increased in COVID-19 patients. C1–INH is a central regulator of the contact and complement systems, potentially linking COVID-19 to complement hyperactivation, fibrin clot formation, and immune depression. Furthermore, despite distinct clinical cases, significant parallels were observed in transcripts involved in interferon and B cell signaling. As symptoms were resolving, widespread decreases were seen in immune-related transcripts to levels below those of healthy controls. Our study provides insight into the immune responses of likely millions of people with extremely mild symptoms who may not be aware of their infection with SARS-CoV-2 and implies a potential for long-lasting consequences that could contribute to reinfection risk.

Effects of propofol on ischemia-reperfusion and traumatic brain injury

Oxidative stress exacerbates brain damage following ischemia-reperfusion and traumatic brain injury (TBI). Management of TBI and critically ill patients commonly involves use of propofol, a sedation medication that acts as a general anesthetic with inherent antioxidant properties. Here we review available evidence from animal model systems and clinical studies that propofol protects against ischemia-reperfusion injury. However, evidence of propofol toxicity in humans exists and manifests as a rare complication, "propofol infusion syndrome" (PRIS). Evidence in animal models suggests that brain injury induces expression of the p75 neurotrophin receptor (p75NTR), which is associated with proapoptotic signaling. p75NTR-mediated apoptosis of neurons is further exacerbated by propofol's superinduction of p75NTR and concomitant inhibition of neurotrophin processing. Propofol is toxic to neurons but not astrocytes, a type of glial cell. Evidence suggests that propofol protects astrocytes from oxidative stress and stimulates astroglial-mediated protection of neurons. One may speculate that in brain injury patients under sedation/anesthesia, propofol provides brain tissue protection or aids in recovery by enhancing astrocyte function. Nevertheless, our understanding of neurologic recovery versus long-term neurological sequelae leading to neurodegeneration is poor, and it is also conceivable that propofol plays a partial as yet unrecognized role in long-term impairment of the injured brain.

The presence of S-sulfonated transthyretin in commercial human serum albumin solutions: Potential contribution to neuropathy

BACKGROUND

Commercial solutions of human serum albumin (HSA) are administered to critically ill patients for the treatment of shock, restoration of blood volume, and the acute management of burns. Previously, conflicting results on the effects of HSA administration have been reported varying from a favorable increase in total plasma antioxidant capacity to a higher mortality rate in traumatic brain injury (TBI) patients. These results could be partially explained due to the known heterogeneity of HSA solutions. We report the discovery of S-sulfonated human transthyretin (hTTR) in HSA solutions.

METHODS

Proteomics was performed on commercially available solutions of 5% HSA by LC-MS analysis. The MS charge envelope for hTTR was deconvolved to the uncharged native hTTR parent mass (13,762 Da). The parent mass was then integrated, and relative proportions of the 2 major species of hTTR, native and S-sulfonated hTTR (13,842 Da), were calculated.

RESULTS

The majority of hTTR found in 5% commercial HSA solutions is in the S-sulfonated form regardless of the age of the HSA solution. S-sulfonation of hTTR at the free cysteine residue in position 10 appears to be the result of a mixed disulfide exchange possibly with S-cysteinylated hTTR or S-cysteinylated HSA. hTTR is a tetramer composed of four identical monomers each containing a reduced cysteine residue in position 10. S-sulfonation of hTTR at this cysteine residue can destabilize the hTTR tetramer, an important step in the formation of TTR-related amyloid fibrils.

CONCLUSIONS

Administration of a commercial HSA solution that already contains S-sulfonated hTTR could potentially contribute to the development of amyloid-related/polyneuropathy in the critically ill.

Stress Hyperglycemia in Critically Ill Patients: Insight Into Possible Molecular Pathways

Severe sepsis, systemic inflammatory response syndrome (SIRS), and traumatic brain injury are frequently associated with hyperglycemia in non-diabetic patients. In patients suffering from any of these conditions, hyperglycemia at admission to an intensive care unit (ICU) is directly correlated with increased mortality or morbidity. Although there was initial enthusiasm for insulin treatment to blood glucose levels below 110 mg/dL in these patients, recent understanding suggests that the potential for hypoglycemic complications make this approach potentially dangerous. More moderate glucose control seems to be more beneficial than the aggressive glucose lowering initially suggested. An important publication has shown that hyperlactatemia accompanying hyperglycemia could be the real culprit in bad outcomes. This suggests that coupling moderate glucose lowering with therapeutic agents which might treat the underlying metabolic disturbances in these conditions may be a better strategy. The key metabolic disturbance in these three conditions seems to be persistent glycolysis as an energy source even in the presence of adequate tissue oxygenation (the Warburg Effect). We look at recent advances in understanding aerobic glycolysis and possibly the action of DPP4 on incretins resulting in insulin dysregulation and suggest key metabolic pathways involved in hyperglycemia regulation.

Clinically relevant redifferentiation of fibroblast-like chondrocytes into functional chondrocytes by the low molecular weight fraction of human serum albumin

OBJECTIVES

Traumatic joint injury induces chondrocyte dysfunction and progressive breakdown of articular cartilage, leading to post-traumatic osteoarthritis (PTOA). In this condition, dysfunctional fibroblast-like chondrocytes (FLCs) no longer express proteins required for cartilage maintenance, such as SOX9 and collagen-type II (COL2). Interleukin-6 (IL-6) has been demonstrated to downregulate expression of these two critical proteins in chondrocytes, and increased IL-6 levels have been measured in patients with PTOA. The <5kDa fraction of human serum albumin (LMWF5A) has been suggested to modulate this pathway, as decreased levels of IL-6 are secreted by immunostimulated LMWF5A-treated macrophages. Our objective was to determine whether LMWF5A induces an in vitro model of FLCs to redifferentiate into functional chondrocytes.

METHODS

SOX9 and COL2 were monitored via western blot, and COL2 was detected with immunofluorescence. Aggrecan and IL-6 were quantified by ELISA. Glycosaminoglycan (GAG) levels were quantified with alcian blue.

RESULTS

We found that LMWF5A significantly increases the principal cartilage transcription factor SOX9 and the SOX9 target protein COL2 in monolayer-cultured FLCs. Multiple LMWF5A treatments of 3-D pellet FLC cultures over 2wks resulted in a significant decrease in IL-6 and significant increases in the major players of articular cartilage mechanics, aggrecan and highly-sulfated GAGs.

CONCLUSIONS

These data support the hypothesis and clinical outcomes of two phase III clinical trials that LMWF5A-treatment induces chondrogenesis and supports functional cartilage. We propose that LMWF5A could maintain articular cartilage integrity in all joints following traumatic injury.

The anti-inflammatory effect of LMWF5A and N-acetyl kynurenine on macrophages: Involvement of aryl hydrocarbon receptor in mechanism of action

After a traumatic insult, macrophages can become activated leading to general inflammation at the site of injury. Activated macrophages are partially regulated by the aryl hydrocarbon receptor (AhR) which when activated suppresses inflammation by limiting the secretion of pro-inflammatory cytokines and promoting the over expression of immuno-modulatory mediators. This study aims to determine whether the low molecular weight fraction of 5% human serum albumin (LMWF5A) and N-acetyl kynurenine (NAK), an N-acetyl tryptophan (NAT) breakdown product in LMWF5A, can regulate inflammation by inhibiting macrophage activation through the AhR since kynurenine is a known AhR agonist. Using LCMS, we demonstrate that NAT is non-enzymatically degraded during accelerated aging of LMWF5A with high heat accelerating degradation. More importantly, NAK is a major degradation product found in LMWF5A. THP-1 monocytes were differentiated into macrophages using phorbol 12-myristate 13-acetate (PMA) and pre-treated with 2-fold dilutions of LMWF5A or synthetic NAK with or without an AhR antagonist (CH223191) prior to overnight stimulation with lipopolysaccharide (LPS). Treatment with LMWF5A caused a 50–70% decrease in IL-6 release throughout the dilution series. A dose-response inhibition of IL-6 release was observed for NAK with maximal inhibition (50%) seen at the highest NAK concentration. Finally, an AhR antagonist partially blocked the anti-inflammatory effect of LMWF5A while completely blocking the effect of NAK. A similar inhibitory effect was observed for CXCL-10, but the AhR antagonist was not effective suggesting additional mechanisms for CXCL-10 release. These preliminary findings suggest that LMWF5A and NAK partially promote the suppression of activated macrophages via the AhR receptor. Therefore, LMWF5A, which contains NAK, is potentially a useful therapeutic in medical conditions where inflammation is prevalent such as trauma, sepsis, and wound healing.

•

LMWF5A contains degradation products of N-acetyl tryptophan (NAT).

•

A major degradation product of NAT in LMWF5A is N-acetyl kynurenine (NAK).

•

LMWF5A and NAK decrease IL-6 and CXCL-10 release from activated macrophages.

•

AhR is partially involved in the mechanism of action for LMWF5A and NAK.

•

The anti-inflammatory properties of LMWF5A are also AhR-independent.

Novel Method Suggests Global Superiority of Short-Duration Antibiotics for Intra-abdominal Infections

Desirability of outcome ranking and response adjusted for duration of antibiotic risk (DOOR/RADAR) are novel and innovative methods of evaluating data in antibiotic trials. We analyzed data from a noninferiority trial of short-course antimicrobial therapy for intra-abdominal infection (STOP-IT), and results suggest global superiority of short-duration therapy for intra-abdominal infections.

Vasopressors in Sepsis

BACKGROUND

Sepsis accounts for 10% of intensive care unit admissions and significant healthcare costs. Although the mortality rate from sepsis has been decreasing with better critical care, early identification of septic patients, and prompt interventions, the mortality rate remains 20%-30%.

METHOD

Review of the English-language literature.

RESULTS

Norepinephrine is the first-line vasopressor in shock and is associated with a lower mortality rate as well as fewer adverse effects. Dopamine has similar actions but is associated with significantly more tachydysrhythmias and should be reserved for patients with bradycardia. Epinephrine and vasopressin are appropriate second-line vasopressors and may enable use of lower doses of norepinephrine while improving hemodynamics. Inotropes may be added in patients with cardiac dysfunction.

CONCLUSION

Appropriate treatment of sepsis includes prompt identification, early antimicrobial drug therapy, appropriate fluid resuscitation, and initiation of vasopressors in the presence of continued septic shock. Further research needs to be done to better understand the ideal timing of the addition of a second agent and the optimal combinations of vasopressors for individual patients.

Longer-Duration Antimicrobial Therapy Does Not Prevent Treatment Failure in High-Risk Patients with Complicated Intra-Abdominal Infections

BACKGROUND

Recent studies have suggested the length of treatment of intra-abdominal infections (IAIs) can be shortened without detrimental effects on patient outcomes. However, data from high-risk patient populations are lacking. We hypothesized that patients at high risk for treatment failure will benefit from a longer course of antimicrobial therapy.

METHODS

Patients enrolled in the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial were evaluated retrospectively to identify risk factors associated with treatment failure, which was defined as the composite outcome of recurrent IAI, surgical site infection, or death. Variables were considered risk factors if there was a positive statistical association with treatment failure. Patients were then stratified according to the presence and number of these risk factors. Univariable analyses were performed using the Kruskal-Wallis, χ², and Fisher exact tests. Logistic regression controlling for risk factors and original randomization group, either a fixed four-day antimicrobial regimen (experimental) or a longer course based on clinical response (control), also was performed.

RESULTS

We identified corticosteroid use, Acute Physiology and Chronic Health Evaluation II score ≥5, hospital-acquired infection, or a colonic source of IAI as risk factors associated with treatment failure. Of the 517 patients enrolled, 263 (50.9%) had one or two risk factors and 16 (3.1%) had three or four risk factors. The rate of treatment failure rose as the number of risk factors increased. When controlling for randomization group, the presence and number of risk factors were independently associated with treatment failure, but the duration of antimicrobial therapy was not.

CONCLUSIONS

We were able to identify patients at high risk for treatment failure in the STOP-IT trial. Such patients did not benefit from a longer course of antibiotic administration. Further study is needed to determine the optimum duration of antimicrobial therapy in high-risk patients.

Patients with Risk Factors for Complications Do Not Require Longer Antimicrobial Therapy for Complicated Intra-Abdominal Infection

A prospective, multicenter, randomized controlled trial found that four days of antibiotics for source-controlled complicated intra-abdominal infection resulted in similar outcomes when compared with a longer duration. We hypothesized that patients with specific risk factors for complications also had similar outcomes. Short-course patients with obesity, diabetes, or Acute Physiology and Chronic Health Evaluation II ≥15 from the STOP-IT trial were compared with longer duration patients. Outcomes included incidence of and days to infectious complications, mortality, and length of stay. Obese and diabetic patients had similar incidences of and days to surgical site infection, recurrent intra-abdominal infection, extra-abdominal infection, and Clostridium difficile infection. Short- and long-course patients had similar incidences of complications among patients with Acute Physiology and Chronic Health Evaluation II ≥15. However, there were fewer days to the diagnosis of surgical site infection (9.5 ± 3.4 vs 21.6 ± 6.2, P = 0.010) and extra-abdominal infection (12.4 ± 6.9 vs 21.8 ± 6.1, P = 0.029) in the short-course group. Mortality and length of stay was similar for all groups. A short course of antibiotics in complicated intra-abdominal infection with source control seems to have similar outcomes to a longer course in patients with diabetes, obesity, or increased severity of illness.

Patients with Risk Factors for Complications Do Not Require Longer Antimicrobial Therapy for Complicated Intra-Abdominal Infection

A prospective, multicenter, randomized controlled trial found that four days of antibiotics for source-controlled complicated intra-abdominal infection resulted in similar outcomes when compared with a longer duration. We hypothesized that patients with specific risk factors for complications also had similar outcomes. Short-course patients with obesity, diabetes, or Acute Physiology and Chronic Health Evaluation II ≥15 from the STOP-IT trial were compared with longer duration patients. Outcomes included incidence of and days to infectious complications, mortality, and length of stay. Obese and diabetic patients had similar incidences of and days to surgical site infection, recurrent intra-abdominal infection, extra-abdominal infection, and Clostridium difficile infection. Short- and long-course patients had similar incidences of complications among patients with Acute Physiology and Chronic Health Evaluation II ≥15. However, there were fewer days to the diagnosis of surgical site infection (9.5 ± 3.4 vs 21.6 ± 6.2, P = 0.010) and extra-abdominal infection (12.4 ± 6.9 vs 21.8 ± 6.1, P = 0.029) in the short-course group. Mortality and length of stay was similar for all groups. A short course of antibiotics in complicated intraabdominal infection with source control seems to have similar outcomes to a longer course in patients with diabetes, obesity, or increased severity of illness.

Inclusion of Vancomycin as Part of Broad-Spectrum Coverage Does Not Improve Outcomes in Patients with Intra-Abdominal Infections: A Post Hoc Analysis

BACKGROUND

Management of complicated intra-abdominal infections (cIAIs) includes broad-spectrum antimicrobial coverage and commonly includes vancomycin for the empiric coverage of methicillin-resistant Staphylococcus aureus (MRSA). Ideally, culture-guided de-escalation follows to promote robust antimicrobial stewardship. This study assessed the impact and necessity of vancomycin in cIAI treatment regimens.

PATIENTS AND METHODS

A post hoc analysis of the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial was performed. Patients receiving piperacillin-tazobactam (P/T) and/or a carbapenem were included with categorization based on use of vancomycin. Univariate and multivariable analyses evaluated effects of including vancomycin on individual and the composite of undesirable outcomes (recurrent IAI, surgical site infection [SSI], or death).

RESULTS

The study cohort included 344 patients with 110 (32%) patients receiving vancomycin. Isolation of MRSA occurred in only eight (2.3%) patients. Vancomycin use was associated with a similar composite outcome, 29.1%, vs. no vancomycin, 22.2% (p = 0.17). Patients receiving vancomycin had (mean [standard deviation]) higher Acute Physiology and Chronic Health Evaluation II scores (13.1 [6.6] vs. 9.4 [5.7], p < 0.0001), extended length of stay (12.6 [10.2] vs. 8.6 [8.0] d, p < 0.001), and prolonged antibiotic courses (9.1 [8.0] vs. 7.1 [4.9] d, p = 0.02). After risk adjustment in a multivariate model, no significant difference existed for the measured outcomes.

CONCLUSIONS

This post hoc analysis reveals that addition of vancomycin occurred in nearly one third of patients and more often in sicker patients. Despite this selection bias, no appreciable differences in undesired outcomes were demonstrated, suggesting limited utility for adding vancomycin to cIAI treatment regimens.

Trial of short-course antimicrobial therapy for intraabdominal infection

BACKGROUND

The successful treatment of intraabdominal infection requires a combination of anatomical source control and antibiotics. The appropriate duration of antimicrobial therapy remains unclear.

METHODS

We randomly assigned 518 patients with complicated intraabdominal infection and adequate source control to receive antibiotics until 2 days after the resolution of fever, leukocytosis, and ileus, with a maximum of 10 days of therapy (control group), or to receive a fixed course of antibiotics (experimental group) for 4±1 calendar days. The primary outcome was a composite of surgical-site infection, recurrent intraabdominal infection, or death within 30 days after the index source-control procedure, according to treatment group. Secondary outcomes included the duration of therapy and rates of subsequent infections.

RESULTS

Surgical-site infection, recurrent intraabdominal infection, or death occurred in 56 of 257 patients in the experimental group (21.8%), as compared with 58 of 260 patients in the control group (22.3%) (absolute difference, -0.5 percentage point; 95% confidence interval [CI], -7.0 to 8.0; P=0.92). The median duration of antibiotic therapy was 4.0 days (interquartile range, 4.0 to 5.0) in the experimental group, as compared with 8.0 days (interquartile range, 5.0 to 10.0) in the control group (absolute difference, -4.0 days; 95% CI, -4.7 to -3.3; P<0.001). No significant between-group differences were found in the individual rates of the components of the primary outcome or in other secondary outcomes.

CONCLUSIONS

In patients with intraabdominal infections who had undergone an adequate source-control procedure, the outcomes after fixed-duration antibiotic therapy (approximately 4 days) were similar to those after a longer course of antibiotics (approximately 8 days) that extended until after the resolution of physiological abnormalities. (Funded by the National Institutes of Health; STOP-IT ClinicalTrials.gov number, NCT00657566.).

Antioxidant oils and Salmonella enterica Typhimurium reduce tumor in an experimental model of hepatic metastasis

Fruit seeds high in antioxidants have been shown to have anticancer properties and enhance host protection against microbial infection. Recently we showed that a single oral dose of Salmonella enterica serovar Typhimurium expressing a truncated human interleukin-2 gene (SalpIL2) is avirulent, immunogenic, and reduces hepatic metastases through increased natural killer cell populations in mice. To determine whether antioxidant compounds enhance the antitumor effect seen in SalpIL2-treated animals, we assayed black cumin (BC), black raspberry (BR), and milk thistle (MT) seed oils for the ability to reduce experimental hepatic metastases in mice. In animals without tumor, BC and BR oil diets altered the kinetics of the splenic lymphocyte response to SalpIL2. Consistent with previous reports, BR and BC seed oils demonstrated independent antitumor properties and moderate adjuvant potential with SalpIL2. MT oil, however, inhibited the efficacy of SalpIL2 in our model. Based on these data, we conclude that a diet high in antioxidant oils promoted a more robust immune response to SalpIL2, thus enhancing its antitumor efficacy.

Attenuated Salmonella typhimurium with interleukin 2 gene prevents the establishment of pulmonary metastases in a model of osteosarcoma

PURPOSE

The current management of osteosarcoma (OS) entails an aggressive preoperative and postoperative chemotherapeutic regimen with limb salvage surgery. Despite these efforts, relapse-free survival is less than 60% in patients with classic OS, whereas most patients relapse with pulmonary metastases. In these studies, we sought to prevent the establishment of pulmonary metastases from OS with a single oral dose of SalpIL2.

METHODS

Mice were administered attenuated Salmonella typhimurium with (SalpIL2) and without a gene for human interleukin 2 (Sal-NG) 7 days before challenge with 2 x 10(5) OS cells via tail vein. Three weeks after injection, mice were harvested for splenic lymphocytes and tumor enumeration.

RESULTS

Prophylaxis with attenuated SalpIL2 significantly reduces pulmonary metastases in number and volume (P < .0001 and P < .0001) with respect to saline controls. Furthermore, splenic natural killer cell populations were increased 396% with SalpIL2 (P < .0007) and 426% with Sal-NG (P < .0003) compared to nontreated groups.

CONCLUSIONS

Host natural killer response is greatly amplified and maybe partially responsible for the effective immune response against the formation of pulmonary metastases. A single oral dose of SalpIL2 may be a novel form of adjuvant therapy for patients after early detection of primary OS.

Attenuated Salmonella typhimurium with IL-2 gene reduces pulmonary metastases in murine osteosarcoma

Historically, osteosarcoma has been a problematic metastatic disease, with 40-80% of patients developing pulmonary metastasis after primary tumor resection. Recent treatment advancements have reduced the occurrence of metastatic lesions to less than 30%. Using attenuated Salmonella typhimurium, we previously demonstrated regression in tumor burden in murine solid tumor and metastatic models. We established a murine model for metastatic osteosarcoma to determine the effect of treatment with a single oral dose of attenuated S. typhimurium with (SalpIL2) and without (Sal-NG) a gene for a truncated human interleukin-2. Female balb/c mice were administered 2 x 10(5) (ATCC K7M2) osteosarcoma cells via tail vein injection from culture and treated by oral gavage of Salmonella species 3 days later. Mice were harvested for splenic lymphocytes and tumor enumeration by intratracheal injection with India ink 21 days after injection. Treatment with attenuated SalpIL2 reduced pulmonary metastases in number and volume compared to saline controls. Furthermore, splenic natural killer cell populations were increased 93% with SalpIL2 and 114% with Sal-NG compared to nontreated groups. This pulmonary metastasis model demonstrates attenuated Salmonella typhimurium with human interleukin-2 reduced metastatic osteosarcoma in mice and confirm the need for further investigation into the immunologic properties of SalpIL2 as a possible treatment for metastatic osteosarcoma.

Sp1 elements regulate transcriptional activity within the murine Toll-like receptor 4 promoter

BACKGROUND AND PURPOSE

Toll-like receptor 4 (TLR4) mediates the innate immune response to lipopolysaccharide (LPS) by a complex intracellular signaling pathway that activates the transcription factor nuclear factor (NF)-kappaB, with subsequent production of inflammatory cytokines. The precise mechanisms involved have not been delineated. We hypothesized that specific regulatory elements exist within the TLR4 promoter.

METHODS

We cloned regions of the murine TLR4 promoter (0.25 kb to 2 kb; -2000 bp to +244 bp) into the pGL3-Basic plasmid containing the firefly luciferase gene and used the resulting constructs to transfect HEK293 or RAW 264.7 cells. After 24 h, we used LPS to stimulate RAW 264.7 cells. We quantified relative light units (RLUs) of cell lysates and secreted tumor necrosis factor (TNF)-alpha. For pairwise comparison, we used Student's t-test. Sequence analysis of the promoter revealed several putative Sp1 sites. We used two constructs showing increased promoter activity, TLR4-750/-1 and TLR4-500/-1, to transfect cells in the presence of a specific Sp1 inhibitor, mithramycin A.

RESULTS

Of the six promoter constructs, four showed greater transcriptional activity (p < 0.05 vs. pGL3-Basic), as measured by luciferase activity. However, we did not observe differences in transcriptional activity of the promoter in five of those six constructs when we stimulated transfected RAW 264.7 cells with 10 ng of LPS. This finding suggests that transcriptional regulation of the promoter is unaffected by cellular changes caused by LPS. Both TLR4-750/-1 and TLR4-500/-1 showed dose-dependent reductions in transcriptional activity in the presence of increasing concentrations of the specific Sp1 inhibitor mithramycin A in both HEK293 and RAW 264.7 cells (p < 0.05 vs. no mithramycin A).

CONCLUSION

At least one Sp1 transcriptional regulatory element is present within the murine TLR4 promoter (range -750 bp to -250 bp). This finding holds promise for manipulating this fundamental inflammatory response.

Postoperative severe microangiopathic hemolytic anemia associated with a giant hepatic cavernous hemangioma

Complications related to liver hemangioma are rare. We herein describe the case of a patient with three giant cavernous hemangiomas of the liver, of which two were resected for symptoms. A significant microangiopathic hemolytic anemia occurred in the early postoperative period, leading to acute renal failure and necessitating blood transfusions. The systematic evaluation of hemolytic processes in the postoperative patient is described. Surgeons should be aware of the potential for hemolytic complications after major surgery when giant hepatic hemangiomas are present.