Area Deprivation Index Predicts Mortality for Critically Ill Surgical Patients With Sepsis

Background: The impact of socioeconomic status on outcomes after sepsis has been challenging to define, and no polysocial metric has been shown to predict mortality in sepsis. The primary objective of this study was to evaluate the association between the Area Deprivation Index (ADI) and mortality in patients admitted to the surgical intensive care unit (SICU) with sepsis. Patients and Methods: All patients admitted to the SICU with sepsis (Sequential Organ Failure Assessment [SOFA] score ≥2) were retrospectively reviewed. The ADI scores were obtained and classified as "high ADI" (≥85th percentile, n = 400, representative of high socioeconomic deprivation) and "control ADI" (ADI <85th percentile, n = 976). Baseline demographic and clinical characteristics were compared between groups. The primary outcome was 90-day mortality. Results: High ADI patients were younger (mean age 58.5 vs. 60.8; p = 0.01) and more likely to be non-white (23.7% vs. 10.0%; p < 0.0005) and to present with chronic obstructive pulmonary disease (26.5% vs. 19.0%; p = 0.002). High ADI patients had increased in-hospital (27.3% vs. 21.6%; p = 0.025) and 90-day mortality (35.0% vs. 28.9%; p = 0.03). High ADI patients also had increased rates of renal failure (20.3% vs. 15.3%; p = 0.02). Both cohorts had similar intensive care unit (ICU) lengths of stay and median hospital stay, Charlson comorbidity index, and rate of discharge to home. High ADI is an independent risk factor for 90-day mortality after admission for surgical sepsis (odds ratio [OR], 1.39 ± 0.24; p = 0.014). Conclusions: High ADI is an independent predictor of 90-day mortality in patients with surgical sepsis. Targeted community interventions are needed to reduce sepsis mortality for these at-risk patients.

Microvesicle-Mediated Transfer of DNA Methyltransferase Proteins Results in Recipient Cell Immunosuppression

INTRODUCTION

Patients with sepsis exhibit significant, persistent immunologic dysfunction. Evidence supports the hypothesis that epigenetic regulation of key cytokines plays an important role in this dysfunction. In sepsis, circulating microvesicles (MVs) containing elevated levels of DNA methyltransferase (DNMT) mRNA cause gene methylation and silencing in recipient cells. We sought to examine the functional role of MV DNMT proteins in this immunologic dysfunction.

METHODS

In total, 33 patients were enrolled within 24 h of sepsis diagnosis (23 sepsis, 10 critically ill controls). Blood and MVs were collected on days 1, 3, and 5 of sepsis, and protein was isolated from the MVs. Levels of DNMT protein and activity were quantified. MVs were produced in vitro by stimulating naïve monocytes with lipopolysaccharide. Methylation was assessed using bisulfate site-specific qualitative real-time polymerase chain reaction.

RESULTS

The size of MVs in the patients with sepsis decreased from days 1 to 5 compared to the control group. Circulating MVs contained significantly higher levels of DNMT 1 and 3A, protein. We recapitulated the production of these DNMT-containing MVs in vitro by treating monocytes with lipopolysaccharide. We found that exposing naïve monocytes to these MVs resulted in increased promoter methylation of tumor necrosis factor alpha.

CONCLUSIONS

An analysis of the isolated MVs revealed higher levels of DNMT proteins in septic patients than those in nonseptic patients. Exposing naïve monocytes to DNMT-containing MVs produced in vitro resulted in hypermethylation of tumor necrosis factor alpha, a key cytokine implicated in postsepsis immunosuppression. These results suggest that DNMT-containing MVs cause epigenetic changes in recipient cells. This study highlights a novel role for MVs in the immune dysfunction of patients with sepsis.

Distressed Communities Index Is Not Associated with Mortality for Critically Ill Surgical Patients with Sepsis

Background: The impact of socioeconomic metrics on outcomes after sepsis is unclear. The Distressed Communities Index (DCI) is a composite score quantifying socioeconomic well-being by zip code. The primary objective of this study was to evaluate the association between DCI and mortality in patients with sepsis admitted to the surgical intensive care unit (SICU). Patients and Methods: All patients with sepsis admitted to the SICU (Sequential Organ Failure Assessment [SOFA] score ≥2) were reviewed retrospectively. Composite DCI scores were obtained for each patient and classified into high-distress (DCI ≥75th percentile; n = 331) and control distress (DCI <50th percentile; n = 666) groups. Baseline demographic and clinical characteristics were compared between groups. The primary outcomes were in-hospital and 90-day mortality. Results: The high-distress cohort was younger and more likely to be African American (19.6% vs. 6.2%), transferred from an outside facility (52% vs. 42%), have chronic obstructive pulmonary disease (25.1% vs. 18.8%), and baseline liver disease (8.2% vs. 4.2%). Sepsis presentation was comparable between groups. Compared with the control cohort, high-distress patients had similar in-house (23% vs. 24%) and 90-day mortality (30% vs. 28%) but were associated with longer hospital stay (23 vs. 19 days). High DCI failed to predict in-hospital or 90-day mortality but was an independent risk factor for longer hospital length of stay (odds ratio [OR], 2.83 ± 1.42; p = 0.047). Conclusions: High DCI was not associated with mortality but did independently predict longer length of stay. This may reflect limitations of DCI score in evaluating mortality for patients with sepsis. Future studies should elucidate its association with length of stay, re-admissions, and follow-up.

Characterization of Mortality by Sepsis Source in Patients Admitted to the Surgical Intensive Care Unit

INTRODUCTION

The impact of infectious source on sepsis outcomes for surgical patients is unclear. The objective of this study was to evaluate the association between sepsis sources and cumulative 90-d mortality in patients admitted to the surgical intensive care unit (SICU) with sepsis.

METHODS

All patients admitted to the SICU at an academic institution who met sepsis criteria (2014-2019, n = 1296) were retrospectively reviewed. Classification of source was accomplished through a chart review and included respiratory (RT, n = 144), intra-abdominal (IA, n = 859), skin and soft tissue (SST, n = 215), and urologic (UR, n = 78). Demographics, comorbidities, and clinical presentation were compared. Outcomes included 90-d mortality, respiratory and renal failure, length of stay, and discharge disposition. Cox-proportional regression was used to model predictors of mortality; P < 0.05 was significant.

RESULTS

Patients with SST were younger, more likely to be diabetic and obese, but had the lowest total comorbidities. Median admission sequential organ failure assessment scores were highest for IA and STT and lowest in urologic infections. Cumulative 90-d mortality was highest for IA and RT (35% and 33%, respectively) and lowest for SST (20%) and UR (8%) (P < 0.005). Compared to the other categories, UR infections had the lowest SICU length of stay and the highest discharge-to-home (57%, P < 0.0005). Urologic infections remained an independent negative predictor of 90-d mortality (odds ratio 0.14, 95% confidence interval: 0.1-0.4), after controlling for sequential organ failure assessment.

CONCLUSIONS

Urologic infections remained an independent negative predictor of 90-d mortality when compared to other sources of sepsis. Characterization of sepsis source revealed distinct populations and clinical courses, highlighting the importance of understanding different sepsis phenotypes.

Association of Patient Belief About Success of Antibiotics for Appendicitis and Outcomes: A Secondary Analysis of the CODA Randomized Clinical Trial

Importance

A patient's belief in the likely success of a treatment may influence outcomes, but this has been understudied in surgical trials.

Objective

To examine the association between patients' baseline beliefs about the likelihood of treatment success with outcomes of antibiotics for appendicitis in the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) trial.

Design, Setting, and Participants

This was a secondary analysis of the CODA randomized clinical trial. Participants from 25 US medical centers were enrolled between May 3, 2016, and February 5, 2020. Included in the analysis were participants with appendicitis who were randomly assigned to receive antibiotics in the CODA trial. After informed consent but before randomization, participants who were assigned to receive antibiotics responded to a baseline survey including a question about how successful they believed antibiotics could be in treating their appendicitis.

Interventions

Participants were categorized based on baseline survey responses into 1 of 3 belief groups: unsuccessful/unsure, intermediate, and completely successful.

Main Outcomes and Measures

Three outcomes were assigned at 30 days: (1) appendectomy, (2) high decisional regret or dissatisfaction with treatment, and (3) persistent signs and symptoms (abdominal pain, tenderness, fever, or chills). Outcomes were compared across groups using adjusted risk differences (aRDs), with propensity score adjustment for sociodemographic and clinical factors.

Results

Of the 776 study participants who were assigned antibiotic treatment in CODA, a total of 425 (mean [SD] age, 38.5 [13.6] years; 277 male [65%]) completed the baseline belief survey before knowing their treatment assignment. Baseline beliefs were as follows: 22% of participants (92 of 415) had an unsuccessful/unsure response, 51% (212 of 415) had an intermediate response, and 27% (111 of 415) had a completely successful response. Compared with the unsuccessful/unsure group, those who believed antibiotics could be completely successful had a 13-percentage point lower risk of appendectomy (aRD, -13.49; 95% CI, -24.57 to -2.40). The aRD between those with intermediate vs unsuccessful/unsure beliefs was -5.68 (95% CI, -16.57 to 5.20). Compared with the unsuccessful/unsure group, those with intermediate beliefs had a lower risk of persistent signs and symptoms (aRD, -15.72; 95% CI, -29.71 to -1.72), with directionally similar results for the completely successful group (aRD, -15.14; 95% CI, -30.56 to 0.28).

Conclusions and Relevance

Positive patient beliefs about the likely success of antibiotics for appendicitis were associated with a lower risk of appendectomy and with resolution of signs and symptoms by 30 days. Pathways relating beliefs to outcomes and the potential modifiability of beliefs to improve outcomes merit further investigation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02800785.

Analysis of Outcomes Associated With Outpatient Management of Nonoperatively Treated Patients With Appendicitis

IMPORTANCE

In the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) trial, which found antibiotics to be noninferior, approximately half of participants randomized to receive antibiotics had outpatient management with hospital discharge within 24 hours. If outpatient management is safe, it could increase convenience and decrease health care use and costs.

OBJECTIVE

To assess the use and safety of outpatient management of acute appendicitis.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study, which is a secondary analysis of the CODA trial, included 776 adults with imaging-confirmed appendicitis who received antibiotics at 25 US hospitals from May 1, 2016, to February 28, 2020.

EXPOSURES

Participants randomized to antibiotics (intravenous then oral) could be discharged from the emergency department based on clinician judgment and prespecified criteria (hemodynamically stable, afebrile, oral intake tolerated, pain controlled, and follow-up confirmed). Outpatient management and hospitalization were defined as discharge within or after 24 hours, respectively.

MAIN OUTCOMES AND MEASURES

Outcomes compared among patients receiving outpatient vs inpatient care included serious adverse events (SAEs), appendectomies, health care encounters, satisfaction, missed workdays at 7 days, and EuroQol 5-dimension (EQ-5D) score at 30 days. In addition, appendectomy incidence among outpatients and inpatients, unadjusted and adjusted for illness severity, was compared.

RESULTS

Among 776 antibiotic-randomized participants, 42 (5.4%) underwent appendectomy within 24 hours and 8 (1.0%) did not receive their first antibiotic dose within 24 hours, leaving 726 (93.6%) comprising the study population (median age, 36 years; range, 18-86 years; 462 [63.6%] male; 437 [60.2%] White). Of these participants, 335 (46.1%; site range, 0-89.2%) were discharged within 24 hours, and 391 (53.9%) were discharged after 24 hours. Over 7 days, SAEs occurred in 0.9 (95% CI, 0.2-2.6) per 100 outpatients and 1.3 (95% CI, 0.4-2.9) per 100 inpatients; in the appendicolith subgroup, SAEs occurred in 2.3 (95% CI, 0.3-8.2) per 100 outpatients vs 2.8 (95% CI, 0.6-7.9) per 100 inpatients. During this period, appendectomy occurred in 9.9% (95% CI, 6.9%-13.7%) of outpatients and 14.1% (95% CI, 10.8%-18.0%) of inpatients; adjusted analysis demonstrated a similar difference in incidence (-4.0 percentage points; 95% CI, -8.7 to 0.6). At 30 days, appendectomies occurred in 12.6% (95% CI, 9.1%-16.7%) of outpatients and 19.0% (95% CI, 15.1%-23.4%) of inpatients. Outpatients missed fewer workdays (2.6 days; 95% CI, 2.3-2.9 days) than did inpatients (3.8 days; 95% CI, 3.4-4.3 days) and had similar frequency of return health care visits and high satisfaction and EQ-5D scores.

CONCLUSIONS AND RELEVANCE

These findings support that outpatient antibiotic management is safe for selected adults with acute appendicitis, with no greater risk of complications or appendectomy than hospital care, and should be included in shared decision-making discussions of patient preferences for outcomes associated with nonoperative and operative care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02800785.

Self-selection vs Randomized Assignment of Treatment for Appendicitis

Importance

For adults with appendicitis, several randomized clinical trials have demonstrated that antibiotics are an effective alternative to appendectomy. However, it remains unknown how the characteristics of patients in such trials compare with those of patients who select their treatment and whether outcomes differ.

Objective

To compare participants in the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) randomized clinical trial (RCT) with a parallel cohort study of participants who declined randomization and self-selected treatment.

Design, Setting, and Participants

The CODA trial was conducted in 25 US medical centers. Participants were enrolled between May 3, 2016, and February 5, 2020; all participants were eligible for at least 1 year of follow-up, with all follow-up ending in 2021. The randomized cohort included 1094 adults with appendicitis; the self-selection cohort included patients who declined participation in the randomized group, of whom 253 selected appendectomy and 257 selected antibiotics. In this secondary analysis, characteristics and outcomes in both self-selection and randomized cohorts are described with an exploratory analysis of cohort status and receipt of appendectomy.

Interventions

Appendectomy vs antibiotics.

Main Outcomes and Measures

Characteristics among participants randomized to either appendectomy or antibiotics were compared with those of participants who selected their own treatment.

Results

Clinical characteristics were similar across the self-selection cohort (510 patients; mean age, 35.8 years [95% CI, 34.5-37.1]; 218 female [43%; 95% CI, 39%-47%]) and the randomized group (1094 patients; mean age, 38.2 years [95% CI, 37.4-39.0]; 386 female [35%; 95% CI, 33%-38%]). Compared with the randomized group, those in the self-selection cohort were less often Spanish speaking (n = 99 [19%; 95% CI, 16%-23%] vs n = 336 [31%; 95% CI, 28%-34%]), reported more formal education (some college or more, n = 355 [72%; 95% CI, 68%-76%] vs n = 674 [63%; 95% CI, 60%-65%]), and more often had commercial insurance (n = 259 [53%; 95% CI, 48%-57%] vs n = 486 [45%; 95% CI, 42%-48%]). Most outcomes were similar between the self-selection and randomized cohorts. The number of patients undergoing appendectomy by 30 days was 38 (15.3%; 95% CI, 10.7%-19.7%) among those selecting antibiotics and 155 (19.2%; 95% CI, 15.9%-22.5%) in those who were randomized to antibiotics (difference, 3.9%; 95% CI, -1.7% to 9.5%). Differences in the rate of appendectomy were primarily observed in the non-appendicolith subgroup.

Conclusions and Relevance

This secondary analysis of the CODA RCT found substantially similar outcomes across the randomized and self-selection cohorts, suggesting that the randomized trial results are generalizable to the community at large.

Trial Registration

ClinicalTrials.gov Identifier: NCT02800785.

Lipidomic Profiling of Bronchoalveolar Lavage Fluid Extracellular Vesicles Indicates Their Involvement in Lipopolysaccharide-Induced Acute Lung Injury

Emerging data support the pivotal role of extracellular vesicles (EVs) in normal cellular physiology and disease conditions. However, despite their abundance, there is much less information about the lipid mediators carried in EVs, especially in the context of acute lung injury (ALI). Our data demonstrate that C57BL/6 mice subjected to intranasal Escherichia coli lipopolysaccharide (LPS)-induced ALI release, a higher number of EVs into the alveolar space, compared to saline-treated controls. EVs released during ALI originated from alveolar epithelial cells, macrophages, and neutrophils and carry a diverse array of lipid mediators derived from ω-3 and ω-6 polyunsaturated fatty acids (PUFA). The eicosanoids in EVs correlated with cellular levels of arachidonic acid, expression of cytosolic phospholipase A2, cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome epoxygenase p450 proteins in pulmonary macrophages. Furthermore, EVs from LPS-toll-like receptor 4 knockout (TLR4-/-) mice contained significantly lower amounts of COX and LOX catalyzed eicosanoids and ω-3 PUFA metabolites. More importantly, EVs from LPS-treated wild-type mice increased TNF-α release by macrophages and reduced alveolar epithelial monolayer barrier integrity compared to EVs from LPS-treated TLR4-/- mice. In summary, our study demonstrates for the first time that the EV carried PUFA metabolite profile in part depends on the inflammatory status of the lung macrophages and modulates pulmonary macrophage and alveolar epithelial cell function during LPS-induced ALI.

Patient Factors Associated With Appendectomy Within 30 Days of Initiating Antibiotic Treatment for Appendicitis

IMPORTANCE

Use of antibiotics for the treatment of appendicitis is safe and has been found to be noninferior to appendectomy based on self-reported health status at 30 days. Identifying patient characteristics associated with a greater likelihood of appendectomy within 30 days in those who initiate antibiotics could support more individualized decision-making.

OBJECTIVE

To assess patient factors associated with undergoing appendectomy within 30 days of initiating antibiotics for appendicitis.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study using data from the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) randomized clinical trial, characteristics among patients who initiated antibiotics were compared between those who did and did not undergo appendectomy within 30 days. The study was conducted at 25 US medical centers; participants were enrolled between May 3, 2016, and February 5, 2020. A total of 1552 participants with acute appendicitis were randomized to antibiotics (776 participants) or appendectomy (776 participants). Data were analyzed from September 2020 to July 2021.

EXPOSURES

Appendectomy vs antibiotics.

MAIN OUTCOMES AND MEASURES

Conditional logistic regression models were fit to estimate associations between specific patient factors and the odds of undergoing appendectomy within 30 days after initiating antibiotics. A sensitivity analysis was performed excluding participants who underwent appendectomy within 30 days for nonclinical reasons.

RESULTS

Of 776 participants initiating antibiotics (mean [SD] age, 38.3 [13.4] years; 286 [37%] women and 490 [63%] men), 735 participants had 30-day outcomes, including 154 participants (21%) who underwent appendectomy within 30 days. After adjustment for other factors, female sex (odds ratio [OR], 1.53; 95% CI, 1.01-2.31), radiographic finding of wider appendiceal diameter (OR per 1-mm increase, 1.09; 95% CI, 1.00-1.18), and presence of appendicolith (OR, 1.99; 95% CI, 1.28-3.10) were associated with increased odds of undergoing appendectomy within 30 days. Characteristics that are often associated with increased risk of complications (eg, advanced age, comorbid conditions) and those clinicians often use to describe appendicitis severity (eg, fever: OR, 1.28; 95% CI, 0.82-1.98) were not associated with odds of 30-day appendectomy. The sensitivity analysis limited to appendectomies performed for clinical reasons provided similar results regarding appendicolith (adjusted OR, 2.41; 95% CI, 1.49-3.91).

CONCLUSIONS AND RELEVANCE

This cohort study found that presence of an appendicolith was associated with a nearly 2-fold increased risk of undergoing appendectomy within 30 days of initiating antibiotics. Clinical characteristics often used to describe severity of appendicitis were not associated with odds of 30-day appendectomy. This information may help guide more individualized decision-making for people with appendicitis.

Transfer Status and 90-Day Mortality in ICU Patients with Sepsis: A Propensity Matched Analysis

BACKGROUND

Timely identification and management of sepsis in surgical patients is crucial, and transfer status may delay optimal treatment of these patients. The objective of this study was to compare in-house and 90-day mortality between patients primarily admitted or transferred into the surgical ICU (SICU) at a tertiary referral center.

MATERIAL AND METHODS

All patients admitted to the SICU with a diagnosis of sepsis (Sepsis III) were reviewed at a single institution between 2014 to 2019 (n = 1489). Demographics, comorbidities, and sepsis presentation were compared between transferred (n = 696) and primary patients (n = 793). Primary outcomes evaluated were in-house and 90 day mortality in an unmatched and propensity score matched cohorts. A P value < 0.05 was considered statistically significant.

RESULTS

Transfer patients were more likely to have obesity (60% versus 49%, P < 0.005), a higher median SOFA (6 (4-8) versus 5 (3-8), P = 0.007), and require vasopressors on admission (42% versus 35%, P = 0.004). Compared to primary patients, transfer patients exhibited higher rates of respiratory failure (76% versus 69%, P = 0.003), in-house (30% versus 17%, P < 0.005), and 90 day mortality (36% versus 24%, P < 0.005). After matching, transferred patients were associated with 75% and 83% increased odds of in-house and 90 day mortality after controlling for age, sex, race, comorbidities, BMI, and sepsis severity.

CONCLUSIONS

Transfer status is associated with an over 80% increase in the odds of 90 day mortality for patients admitted to the SICU with sepsis. Aggressive patient identification and earlier transfer of those at higher risk of death may reduce this effect.

Computed Tomography-Measured Psoas Muscle Density as a Predictive Factor for Hypophosphatemia Associated With Refeeding

BACKGROUND

Initiation of parenteral nutrition (PN) after a period of starvation can be complicated by refeeding syndrome (RFS). RFS is associated with electrolyte abnormalities including hypomagnesemia, hyponatremia, and hypophosphatemia. Risk factors include recent weight loss, low body mass index, and electrolyte deficiencies; however, these associations are not strong. We hypothesized that a validated measure of nutrition risk, computed tomography (CT)-measured psoas muscle density, can be used to predict the development of hypophosphatemia associated with RFS.

METHODS

A retrospective analysis of surgical patients initiated on PN with an abdominal CT scan within the past 3 months was conducted. CT-measured psoas muscle density was assessed as a predictive variable for the development of electrolyte abnormalities. Daily electrolyte and clinical outcome measures were recorded.

RESULTS

One hundred nine patients were stratified based on Hounsfield unit average calculation (HUAC). The lowest 25th percentile of patients had HUAC <25. Low HUAC was associated with a significant percent decrease in phosphate levels from baseline to PN day 3 (P < .01) and significant difference in serum phosphate value on PN day 3 (P < .01). The low muscle density quartile also experienced longer days on the mechanical ventilator (P = .01) compared with patients with a higher psoas muscle density.

CONCLUSION

Psoas muscle density predicted the development of hypophosphatemia in patients initiated on PN. This measurement may aid in identifying patients at highest risk of experiencing RFS. A mean psoas HU <25 may prompt additional precautions, including additional phosphate replacement and slower initiation of PN.

Methodological challenges in utilizing miRNAs as circulating biomarkers

MicroRNAs (miRNAs) have emerged as important regulators in the post-transcriptional control of gene expression. The discovery of their presence not only in tissues but also in extratissular fluids, including blood, urine and cerebro-spinal fluid, together with their changes in expression in various pathological conditions, has implicated these extracellular miRNAs as informative biomarkers of disease. However, exploiting miRNAs in this capacity requires methodological rigour. Here, we report several key procedural aspects of miRNA isolation from plasma and serum, as exemplified by research in cardiovascular and pulmonary diseases. We also highlight the advantages and disadvantages of various profiling methods to determine the expression levels of plasma- and serum-derived miRNAs. Attention to such methodological details is critical, as circulating miRNAs become diagnostic tools for various human diseases.

Analyzing the circulating microRNAs in exosomes/extracellular vesicles from serum or plasma by qRT-PCR

Small extracellular vesicles are released from both healthy and disease cells to facilitate cellular communication. They have a wide variety of names including exosomes, microvesicles and microparticles. Depending on their size, very small extracellular vesicles originating from the endocytic pathway have been called exosomes and in some cases nanovesicles. Collectively, extracellular vesicles are important mediators of a wide variety of functions including immune cell development and homeostasis. Encapsulated in the extracellular vesicles are proteins and nucleic acids including mRNA and microRNA molecules. MicroRNAs are small, non-coding RNA molecules implicated in the post-transcriptional control of gene expression that have emerged as important regulatory molecules and are involved in disease pathogenesis including cancer. In some diseases, not only does the quantity and the subpopulations of extracellular vesicles change in the peripheral blood but also microRNAs. Here, we described the analysis of peripheral blood extracellular vesicles by flow cytometry and the RNA extraction from extracellular vesicles isolated from the plasma or serum to profile microRNA expression.