Biomarker Enrichment in Sepsis-Associated Acute Kidney Injury: Finding High-Risk Patients in the Intensive Care Unit.

BACKGROUND: Sepsis-associated acute kidney injury (AKI) is a leading comorbidity in admissions to the intensive care unit. While a gold standard definition exists, it remains imperfect and does not allow for the timely identification of patients in the setting of critical illness. This review will discuss the use of biochemical and electronic biomarkers to allow for prognostic and predictive enrichment of patients with sepsis-associated AKI over and above the use of serum creatinine and urine output. SUMMARY: Current data suggest that several biomarkers are capable of identifying patients with sepsis at risk for the development of severe AKI and other associated morbidity. This review discusses these data and these biomarkers in the setting of sub-phenotyping and endotyping sepsis-associated AKI. While not all these tests are widely available and some require further validation, in the near future we anticipate several new tools to help nephrologists and other providers better care for patients with sepsis-associated AKI. KEY MESSAGES: Predictive and prognostic enrichment using both traditional biomarkers and novel biomarkers in the setting of sepsis can identify subsets of patients with either similar outcomes or similar pathophysiology, respectively. Novel biomarkers can identify kidney injury in patients without consensus definition AKI (e.g., changes in creatinine or urine output) and can predict other adverse outcomes (e.g., severe consensus definition AKI, inpatient mortality). Finally, emerging artificial intelligence and machine learning-derived risk models are able to predict sepsis-associated AKI in critically ill patients using advanced learning techniques and several laboratory and vital sign measurements.

[Clinical value of renal artery resistance index and urinary angiotensinogen in early diagnosis of acute kidney injury in patients with sepsis].

OBJECTIVE: To investigate the value of renal artery resistance index (RRI) and urinary angiotensinogen (UAGT) in the early diagnosis of acute kidney injury (AKI) in patients with sepsis. METHODS: A prospective study was conducted. Seventy-eight patients with sepsis admitted to the department of critical care medicine of General Hospital of Ningxia Medical University from January to September 2021 were enrolled. Patients were observed for the development of AKI within 1 week. General data [gender, age, body mass index (BMI), major infection sites and critical illness related scores], laboratory indicators [mean arterial pressure (MAP), central venous pressure (CVP), procalcitonin (PCT), arterial blood lactic acid (Lac), etc.], duration of mechanical ventilation and length of intensive care unit (ICU) stay were recorded. After hemodynamic stabilization of the patients, renal ultrasound was performed to measure the RRI within 24 hours after ICU admission. Urine samples were taken immediately after diagnosis, and the level of UAGT was detected by enzyme-linked immunosorbent assay (ELISA). The above parameters were compared between the two groups. Multivariate Logistic regression was used to analyze the risk factors of AKI in patients with sepsis. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of related indicators for AKI in sepsis. RESULTS: A total of 78 patients were finally enrolled, of which 45 developed AKI and 33 did not. Compared with the non-AKI group, the rates of vasoactive drugs use, 28-day mortality, sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation II (APACHE II) score, PCT, Lac, RRI and UAGT were significantly higher in the AKI group [rates of vasoactive drugs use: 68.9% vs. 39.4%, 28-day mortality: 48.9% vs. 24.2%, SOFA score: 12.0 (10.5, 14.0) vs. 8.0 (7.0, 10.0), APACHE II score: 22.0 (18.0, 27.5) vs. 16.0 (15.0, 18.5), PCT (µg/L): 12.5±2.6 vs. 10.9±2.8, Lac (mmol/L): 2.6 (1.9, 3.4) vs. 1.9 (1.3, 2.6), RRI: 0.74±0.03 vs. 0.72±0.02, UAGT (µg/L): 75.16±19.99 vs. 46.28±20.75, all P < 0.05], the duration of mechanical ventilation and the length of ICU stay were significantly prolonged [duration of mechanical ventilation (days): 8.0 (7.0, 12.0) vs. 5.0 (4.0, 6.0), length of ICU stay (days): 14.0 (10.0, 16.0) vs. 9.0 (8.0, 11.5), both P < 0.01], and MAP was significantly lowered [mmHg (1 mmHg ≈ 0.133 kPa): 68.5±11.2 vs. 74.2±12.8, P < 0.05]. There was no significant difference in other parameters between the two groups. Multivariate Logistic regression analysis showed that SOFA score [odds ratio (OR) = 2.088, 95% confidence interval (95%CI) was 1.322-3.299], APACHE II score (OR = 1.447, 95%CI was 1.134-1.845), RRI (OR = 1.432, 95%CI was 1.103-1.859), and UAGT (OR = 1.077, 95%CI was 1.035-1.121) were independent risk factors for sepsis complicated with AKI (all P < 0.01). ROC curve analysis showed that SOFA score, APACHE II score, RRI and UAGT had certain predictive value for AKI in septic patients, the area under the ROC curve (AUC) were 0.814 (95%CI was 0.716-0.912), 0.804 (95%CI was 0.708-0.901), 0.789 (95%CI was 0.690-0.888), and 0.840 (95%CI was 0.747-0.934), respectively, and the AUC of RRI combined with UAGT was 0.912 (95%CI was 0.849-0.974), which was better than the above single index (all P < 0.05). CONCLUSIONS: RRI combined with UAGT has a high early predictive value for septic AKI.

Combining renal cell arrest and damage biomarkers to predict progressive AKI in patient with sepsis.

BACKGROUND: Sepsis is the most common trigger for AKI and up to 40% of mild or moderate septic AKI would progress to more severe AKI, which is associated with significantly increased risk for death and later CKD/ESRD. Early identifying high risk patients for AKI progression is a major challenge in patients with septic AKI. METHODS: This is a prospective, multicenter cohort study which enrolled adult patients with sepsis and initially developed stage 1 or 2 AKI in the intensive care unit from January 2014 to March 2018. AKI was diagnosed and staged according to 2012 KDIGO-AKI guidelines. Renal cell arrest biomarkers (urinary TIMP2*IGFBP7, u[TIMP-2]*[IGFBP7]) and renal damage biomarkers (urinary KIM-1[uKIM-1] and urinary IL-18 [uIL-18]) were measured at time of AKI clinical diagnosis, and the performance of biomarkers for predicting septic AKI progression alone or in combination were evaluated. The primary outcome was AKI progression defined as worsening of AKI stage. The secondary outcome was AKI progression with subsequent death during hospitalization. RESULTS: Among 433 screened patients, 149 patients with sepsis and stage 1 or 2 AKI were included, in which 63 patients developed progressive AKI and 49 patients subsequently died during hospitalization. u[TIMP-2]*[IGFBP7], uKIM-1 and uIL-18 independently predicted the progression of septic AKI in which u[TIMP-2]*[IGFBP7] showed the greatest AUC (0.745; 95%CI, 0.667-0.823) as compared to uKIM-1 (AUC 0.719; 95%CI 0.638-0.800) and uIL-18 (AUC 0.619; 95%CI 0.525-0.731). Combination of u[TIMP-2]*[IGFBP7] with uKIM-1 improved the performance of predicting septic AKI progression with AUC of 0.752. u[TIMP-2]*[IGFBP7], alone or combined with uKIM-1/uIL-18, improved the risk reclassification over the clinical risk factor model alone both for the primary and secondary outcomes, as evidenced by significant category-free net reclassification index. CONCLUSIONS: Combination of renal cell arrest and damage biomarkers enhanced the prediction of AKI progression in patients with sepsis and improved risk reclassification over the clinical risk factors.

Urinary C3 levels associated with sepsis and acute kidney injury-A pilot study.

Acute kidney injury (AKI) is an abrupt deterioration of renal function often caused by severe clinical disease such as sepsis, and patients require intensive care. Acute-phase parameters for systemic inflammation are well established and used in routine clinical diagnosis, but no such parameters are known for AKI and inflammation at the local site of tissue damage, namely the nephron. Therefore, we sought to investigate complement factors C3a/C3 in urine and urinary sediment cells. After the development of a C3a/C3-specific mouse monoclonal antibody (3F7E2), urine excretion from ICU sepsis patients was examined by dot blot and immunoblotting. This C3a/C3 ELISA and a C3a ELISA were used to obtain quantitative data over 24 hours for 6 consecutive days. Urine sediment cells were analyzed for topology of expression. Patients with severe infections (n = 85) showed peak levels of C3a/C3 on the second day of ICU treatment. The majority (n = 59) showed C3a/C3 levels above 20 µg/ml at least once in the first 6 days after admission. C3a was detectable on all 6 days. Peak C3a/C3 levels correlated negatively with peak C-reactive protein (CRP) levels. No relationship was found between peak C3a/C3 with peak leukocyte count, age, or AKI stage. Analysis of urine sediment cells identified C3a/C3-producing epithelial cells with reticular staining patterns and cells with large-granular staining. Opsonized bacteria were detected in patients with urinary tract infections. In critically ill sepsis patients with AKI, urinary C3a/C3 inversely correlated with serum CRP. Whether urinary C3a/C3 has a protective function through autophagy, as previously shown for cisplatin exposure, or is a by-product of sepsis caused by pathogenic stimuli to the kidney must remain open in this study. However, our data suggest that C3a/C3 may function as an inverse acute-phase parameter that originates in the kidney and is detectable in urine.

An analysis of urine and serum amino acids in critically ill patients upon admission by means of targeted LC-MS/MS: a preliminary study.

Sepsis, defined as a dysregulated host response to infection, causes the interruption of homeostasis resulting in metabolic changes. An examination of patient metabolites, such as amino acids, during the early stage of sepsis may facilitate diagnosing and assessing the severity of the sepsis. The aim of this study was to compare patterns of urine and serum amino acids relative to sepsis, septic shock and survival. Urine and serum samples were obtained from healthy volunteers (n = 15) once or patients (n = 15) within 24 h of a diagnosis of sepsis or septic shock. Concentrations of 25 amino acids were measured in urine and serum samples with liquid chromatography-electrospray mass spectrometry. On admission in the whole cohort, AAA, ABA, mHis, APA, Gly-Pro and tPro concentrations were significantly lower in the serum than in the urine and Arg, Gly, His, hPro, Leu, Ile, Lys, Orn, Phe, Sarc, Thr, Tyr, Asn and Gln were significantly higher in the serum than in the urine. The urine Gly-Pro concentration was significantly higher in septic shock than in sepsis. The serum Cit concentration was significantly lower in septic shock than in sepsis. The urine ABA, mHis and Gly-Pro, and serum Arg, hPro and Orn concentrations were over two-fold higher in the septic group compared to the control group. Urine and serum amino acids measured in septic patients on admission to the ICU may shed light on a patient's metabolic condition during sepsis or septic shock.

A panel of urine-derived biomarkers to identify sepsis and distinguish it from systemic inflammatory response syndrome.

Sepsis is a potentially fatal condition caused by infection. It is frequently difficult to distinguish sepsis from systemic inflammatory response syndrome (SIRS), often resulting in poor prognoses and the misuse of antibiotics. Hence, highly sensitive and specific biomarkers are needed to differentiate sepsis from SIRS. Urine samples were collected and segregated by group (a sepsis group, a SIRS group, and a healthy control group). iTRAQ was used to identify the differentially expressed proteins among the three groups. The identified proteins were measured by ELISA in urine samples. Finally, all the acquired data were analyzed in SPSS. C-reactive protein, leucine-rich alpha glycoprotein-1 and serum amyloid A (SAA) protein were differentially expressed among the three groups. The adjusted median concentrations of urinary C-reactive protein were 1337.6, 358.7, and 2.4 in the sepsis, SIRS, and healthy control groups, respectively. The urinary leucine-rich alpha glycoprotein-1 levels in these three groups were 1614.4, 644.5, and 13.6, respectively, and the levels of SAA were 6.3, 2.9, and 0.07, respectively. For all three of these measures, the sepsis group had higher levels than the SIRS group (P < 0.001), and the SIRS group had higher levels than the healthy control group. When combined, the three biomarkers had a sensitivity of 0.906 and a specificity of 0.896 in distinguishing sepsis from SIRS. Urinary C-reactive protein, urinary leucine-rich alpha glycoprotein-1 and urinary SAA have diagnostic value in cases of sepsis. This initial study suggests the possibility of improved differential diagnosis between sepsis and systemic inflammatory response syndrome; additional confirmation is necessary to corroborate the findings.

Feasibility of Embedding a Scalable, Virtually Enabled Biorepository in the Electronic Health Record for Precision Medicine.

Importance: A cornerstone of precision medicine is the identification and use of biomarkers that help subtype patients for targeted treatment. Such an approach requires the development and subsequent interrogation of large-scale biobanks linked to well-annotated clinical data. Traditional means of creating these data-linked biobanks are costly and lengthy, especially in acute conditions that require time-sensitive clinical data and biospecimens. Objectives: To develop a virtually enabled biorepository and electronic health record (EHR)-embedded, scalable cohort for precision medicine (VESPRE) and compare the feasibility, enrollment, and costs of VESPRE with those of a traditional study design in acute care. Design, Setting, and Participants: In a prospective cohort study, the EHR-embedded screening alert was generated for 3428 patients, and 2199 patients (64%) were eligible and screened. Of these, 1027 patients (30%) were enrolled. VESPRE was developed for regulatory compliance, feasibility, internal validity, and cost in a prospective cohort of 1027 patients (aged ≥18 years) with sepsis-3 within 6 hours of presentation to the emergency department. The VESPRE infrastructure included (1) automated EHR screening, (2) remnant blood collection for creation of a virtually enabled biorepository, and (3) automated clinical data abstraction. The study was conducted at an academic institution in southwestern Pennsylvania from October 17, 2017, to June 6, 2019. Main Outcomes and Measures: Regulatory compliance, enrollment, internal validity of automated screening, biorepository acquisition, and costs. Results: Of the 1027 patients enrolled in the study, 549 were included in the proof-of-concept analysis (305 [56%] men); median (SD) age was 59 (17) years. VESPRE collected 12 963 remnant blood and urine samples and demonstrated adequate feasibility for clinical, biomarker, and microbiome analyses. Over the 20-month test, the total cost beyond the existing operations infrastructure was $39 417.50 ($14 880.00 project management, $22 717.50 laboratory supplies/staff, and $1820.00 data management)-approximately $39 per enrolled patient vs $239 per patient for a traditional cohort study. Conclusions and Relevance: Results of this study suggest that, in a large US health system that collects data using a common EHR platform and centralized laboratory system, VESPRE, a large-scale, inexpensive EHR-embedded infrastructure for precision medicine can be used. Tested in the sepsis setting, VESPRE appeared to capture a high proportion of eligible patients at low incremental cost.

Deregulated microRNA-22-3p in patients with sepsis-induced acute kidney injury serves as a new biomarker to predict disease occurrence and 28-day survival outcomes.

BACKGROUND: Acute kidney injury (AKI) is a common and serious complication of sepsis. MicroRNA-22-3p (miR-22-3p) has been found to be involved in septic AKI progression. The purpose of this study was to analyze both the serum and urinary expression of miR-22-3p in septic AKI patients, and evaluated the clinical value of miR-22-3p in the diagnosis and prognosis of sepsis-induced AKI. METHODS: Serum and urinary expression of miR-22-3p was examined using qRT-PCR. The risk factors related with septic AKI onset were assessed using logistic analysis. A receiver-operating characteristic (ROC) curve was constructed to evaluate the diagnostic performance of miR-22-3p, and the Kaplan-Meier survival curves and Cox regression analysis were used to evaluate the predictive value of miR-22-3p for the 28-day survival of septic AKI patients. RESULTS: Both serum and urinary miR-22-3p expression was decreased and negatively correlated with kidney injury biomarkers in septic AKI patients. MiR-22-3p expression was a risk factor for AKI onset and had diagnostic accuracy in septic AKI patients. The expression of both serum and urinary miR-22-3p was lower in patients who died, and served as a prognostic biomarker to predict 28-day survival in septic AKI patients. CONCLUSION: Serum and urinary miR-22-3p was reduced in sepsis-induced AKI patients, and served as a biomarker to predict AKI occurrence and 28-day survival in sepsis patients.

Discovery and validation of miR-452 as an effective biomarker for acute kidney injury in sepsis.

Rationale: Sepsis is the cause of nearly half of acute kidney injury (AKI) and, unfortunately, AKI in sepsis is associated with unacceptably high rates of mortality. Early detection of AKI would guide the timely intervention and care of sepsis patients. Currently, NephroCheck, based on urinary [TIMP2]*[IGFBP7], is the only FDA approved test for early detection of AKI, which has a relatively low sensitivity for sepsis patients. Methods:In vitro, BUMPT (Boston University mouse proximal tubular cell line) cells were treated with lipopolysaccharides (LPS). In vivo, sepsis was induced in mice by LPS injection or cecal ligation and puncture (CLP). To validate the biomarker potential of miR-452, serum and urinary samples were collected from 47 sepsis patients with AKI, 50 patients without AKI, and 10 healthy subjects. Results: miR-452 was induced in renal tubular cells in septic AKI, and the induction was shown to be mediated by NF-κB. Notably, serum and urinary miR-452 increased early in septic mice following LPS or CLP treatment, prior to detectable renal dysfunction or tissue damage. Sepsis patients with AKI had significantly higher levels of serum and urinary miR-452 than the patients without AKI. Spearman's test demonstrated a remarkable positive correlation between urinary miR-452 and serum creatinine in sepsis patients (r=0.8269). The area under the receiver operating characteristic curve (AUC) was 0.8985 for urinary miR-452. Logistic regression analysis showed a striking 72.48-fold increase of AKI risk for every 1-fold increase of urinary miR-452 in sepsis patients. The sensitivity of urinary miR-452 for AKI detection in sepsis patients reached 87.23%, which was notably higher than the 61.54% achieved by urinary [TIMP2]*[IGFBP7], while the specificity of urinary miR-452 (78.00%) was slightly lower than that of [TIMP2]*[IGFBP7] (87.18%). Conclusions: miR-452 is induced via NF-κB in renal tubular cells in septic AKI. The increase of miR-452, especially that in urine, may be an effective biomarker for early detection of AKI in sepsis patients.

Hypocalcemia in sepsis: analysis of the subcellular distribution of Ca2+ in septic rats and LPS/TNF-α-treated HUVECs.

INTRODUCTION: Hypocalcemia has been widely recognized in sepsis patients. However, the cause of hypocalcemia in sepsis is still not clear, and little is known about the subcellular distribution of Ca2+ in tissues during sepsis. METHODOLOGY: We measured the dynamic change in Ca2+ levels in body fluid and subcellular compartments, including the cytosol, endoplasmic reticulum and mitochondria, in major organs of cecal ligation and puncture (CLP)-operated rats, as well as the subcellular Ca2+ flux in HUVECs which treated by endotoxin and cytokines. RESULTS: In the model of CLP-induced sepsis, the blood and urinary Ca2+ concentrations decreased rapidly, while the Ca2+ concentration in ascites fluid increased. The Ca2+ concentrations in the cytosol, ER, and mitochondria were elevated nearly synchronously in major organs in our sepsis model. Moreover, the calcium overload in CLP-operated rats treated with calcium supplementation was more severe than that in the non-calcium-supplemented rats but was alleviated by treatment with the calcium channel blocker verapamil. Similar subcellular Ca2+ flux was found in vitro in HUVECs and was triggered by lipopolysaccharide (LPS)/TNF-α. CONCLUSIONS: Ca2+ influx from the blood into the intercellular space and Ca2+ release into ascites fluid may cause hypocalcemia in sepsis and that this process may be due to the synergistic effect of endotoxin and cytokines.

The evaluation of early predictive factors for urosepsis in patients with negative preoperative urine culture following mini-percutaneous nephrolithotomy.

PURPOSE: To identify early predictive factors for urosepsis secondary to mini-percutaneous nephrolithotomy (MPCNL) in patients with negative preoperative urine culture (UC). METHODS: A total of 786 patients with baseline negative UC who underwent MPCNL between January 2017 and June 2019 were retrospectively analyzed. Urosepsis was defined according to the Sepsis-3 definition. Subsequently, perioperative potential risk factors were compared between non-urosepsis and urosepsis groups. RESULTS: Despite negative UC in all patients, the rate of positive stone culture (SC) was 16.0%; the rate of pelvic urine culture (PUC) was 7.5%; 23 cases (2.9%) developed urosepsis after MPCNL. Univariate analysis showed that urosepsis was associated with the female gender, BMI, stone burden, diabetes mellitus and preoperative urine test. Multivariate logistic regression analysis suggested that urine test with positive nitrite and white blood cells and leukocyte esterase (N+WBC+LE+) (OR 17.51, 95% CI 6.75-45.38, P < 0.001) and operative time > 120 min (OR 3.53, 95% CI 1.41-8.85, P = 0.007) were independent risk factors for urosepsis. Additionally, receiver operating characteristic curve analysis of N+WBC+LE+ showed that the area under the curve was 0.785 for predicting the occurrence of urosepsis. Further analysis showed that N+WBC+LE+ provided an efficient prediction of SC+/PUC+ (SC+ or PUC+) with 61.7% sensitivity and 97.3% specificity. CONCLUSIONS: In spite of the baseline negative preoperative UC, 2.9% of patients developed urosepsis after MPCNL. N+WBC+LE + was determined to be an early and efficient prediction of intraoperative bacterial status and urosepsis following MPCNL. Nevertheless, further studies are needed to confirm the results.

New Approaches to Identify Sepsis Biomarkers: The Importance of Model and Sample Source for Mass Spectrometry.

Septic shock is a systemic inflammatory response syndrome associated with circulatory failure leading to organ failure with a 40% mortality rate. Early diagnosis and prognosis of septic shock are necessary for specific and timely treatment. However, no predictive biomarker is available. In recent years, improvements in proteomics-based mass spectrometry have improved the detection of such biomarkers. This approach can be performed on different samples such as tissue or biological fluids. Working directly from human samples is complicated owing to interindividual variability. Indeed, patients are admitted at different stages of disease development and with signs of varying severity from one patient to another. All of these elements interfere with the identification of early, sensitive, and specific septic shock biomarkers. For these reasons, animal models of sepsis, although imperfect, are used to control the kinetics of the development of the pathology and to standardise experimentation, facilitating the identification of potential biomarkers. These elements underline the importance of the choice of animal model used and the sample to be studied during preclinical studies. The aim of this review is to discuss the relevance of different approaches to enable the identification of biomarkers that could indirectly be relevant to the clinical setting.

Effect of Furosemide on Urinary Oxygenation in Patients with Septic Shock.

BACKGROUND: Renal medullary hypoxia precedes the development of acute kidney injury in experimental sepsis and can now be assessed by continuous measurement of urinary oxygen tension (PuO2). OBJECTIVES: We aimed to test if PuO2 measurements in patients with septic shock would be similar to those shown in experimental sepsis and would detect changes induced by the administration of furosemide. METHOD: Pilot prospective observational cohort study in a tertiary intensive care unit (ICU). Seven adult patients with septic shock admitted to ICU had PuO2 measurements recorded minutely. There were 29 episodes of intravenous furosemide (20 mg n = 19; 40 mg n = 10). RESULTS: The median pre-furosemide PuO2 was low at 21.2 mm Hg (interquartile range [IQR] 17.73-24.86) and increased to 26 mm Hg (IQR 20.27-29.95) at 20 min (p < 0.01), to 27.5 mm Hg (IQR 24.06-33.18) at 40 min (p < 0.01) and to 28.5 mm Hg (IQR 22.65-31.03) at 60 min (p < 0.01). The increase in PuO2 was greater in episodes with a diuretic response >2 mL/kg/h than during episodes without such a response (p < 0.01). CONCLUSIONS: PuO2 measurements in patients are reflective of the low values reported in experimental models of sepsis. PuO2 values increased following furosemide administration with a response independently associated with greater diuresis.

Rapid Detection of Sepsis using CESDA: the Caenorhabditis elegans Sepsis Detection Assay.

INTRODUCTION: The nematode Caenorhabditis elegans was used as a biological sensor to detect the urine of sepsis patients (CESDA assay). METHODS: C. elegans was aliquoted onto the center of assay plates and allowed to migrate towards sepsis (T) or control (C) urine samples spotted on the same plate. The number of worms found in either (T) or (C) was scored at 10-minute intervals over a 60-minute period. RESULTS: The worms were able to identify the urine (<48 hours) of sepsis patients rapidly within 20 minutes (AUROC=0.67, p=0.012) and infection within 40 minutes (AUROC=0.80, p=0.016). CONCLUSIONS: CESDA could be further explored for sepsis diagnosis.

LncRNA TapSAKI promotes inflammation injury in HK-2 cells and urine derived sepsis-induced kidney injury.

OBJECTIVE: To explore the possible mechanism of lncRNA TapSAKI in urine derived sepsis-induced kidney injury. MATERIALS AND METHODS: In vivo urine-derived sepsis (US) rat model and in vitro LPS-induced HK-2 cells were established, and TapSAKI, miR-22, PTEN, TLR4 and p-p65 expressions were detected by qRT-PCR and western blot. RNA precipitation and RNA pull-down were performed to confirm the interaction between TapSAKI and miR-22. RESULTS: TapSAKI was up-regulated, miR-22 was down-regulated, PTEN, TLR4 and p-p65 expressions, and inflammatory factors TNF-α and IL-6 levels were up-regulated in kidney tissue of US rats and LPS-induced HK-2 cells. In addition, TapSAKI interacted with miR-22, and negatively modulate miR-22 expression. We also observed TapSAKI promoted PTEN expression, TLR4/NF-κB pathway related proteins TLR4 and p-p65, and apoptosis protein cleaved-caspase-3 through negatively regulating miR-22. Further experiments proved TapSAKI/miR-22/TLR4/NF-κB pathway could promote HK-2 cell apoptosis. Finally, in vivo experiments showed TapSAKI knockdown negatively regulated miR-22 and positively regulate PTEN, decreased renal function indicators blood urea nitrogen and serum creatinine, and reduced TNF-α and IL-6. CONCLUSION: TapSAKI was elevated in urine derived sepsis-induced kidney injury, and promoted HK-2 cell apoptosis and inflammatory response through miR-22/PTEN/TLR4/NF-κB pathway.

Rapid detection of sepsis using cesda: the caenorhabditis elegans sepsis detection assay

Abstract INTRODUCTION The nematode Caenorhabditis elegans was used as a biological sensor to detect the urine of sepsis patients (CESDA assay). METHODS C. elegans was aliquoted onto the center of assay plates and allowed to migrate towards sepsis (T) or control (C) urine samples spotted on the same plate. The number of worms found in either (T) or (C) was scored at 10-minute intervals over a 60-minute period. RESULTS The worms were able to identify the urine (<48 hours) of sepsis patients rapidly within 20 minutes (AUROC=0.67, p=0.012) and infection within 40 minutes (AUROC=0.80, p=0.016). CONCLUSIONS CESDA could be further explored for sepsis diagnosis.

Matrix Metalloproteinase-9 and Tissue Inhibitor of Matrix Metalloproteinase-1 in Sepsis after Major Abdominal Surgery.

BACKGROUND: The role of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in sepsis after major abdominal surgery and sepsis-associated organ dysfunction is unexplored. MATERIALS AND METHODS: Fifty-three patients with sepsis after major abdominal surgery were compared to 50 operated and 50 nonoperated controls. MMP-9, TIMP-1, biomarkers of inflammation, kidney and liver injury, coagulation, and metabolic disorders were measured daily during 96 h following diagnosis of sepsis and once in controls. MMP-9/TIMP-1 ratios and disease severity scores were calculated. Use of vasopressors/inotropes, mechanical ventilation, and survival were recorded. RESULTS: Septic patients had lower MMP-9 and MMP-9/TIMP-1 ratios but higher TIMP-1 levels compared to controls. AUC-ROC for diagnosis of sepsis was 0.940 and 0.854 for TIMP-1 and 0.924 and 0.788 for MMP-9/TIMP-1 ratio (sepsis versus nonoperated and sepsis versus operated controls, resp.). Lower MMP-9 and MMP-9/TIMP-1 ratio and higher TIMP-1 levels were associated with shorter survival. MMP-9, TIMP-1, and MMP-9/TIMP-1 ratio correlated with biomarkers of inflammation, kidney and liver injury, coagulation, metabolic disorders, and disease severity scores. Use of vasopressors/inotropes was associated with higher TIMP-1 levels. CONCLUSIONS: MMP-9, TIMP-1, and MMP-9/TIMP ratio were good diagnostic or prognostic biomarkers of sepsis after major abdominal surgery and were linked to sepsis-associated organ dysfunction.

Biomarkers of Sepsis-Induced Acute Kidney Injury.

Sepsis, an infection-induced systemic disease, leads to pathological, physiological, and biochemical abnormalities in the body. Organ dysfunction is caused by a dysregulated host response to infection during sepsis which is a major contributing factor to acute kidney injury (AKI) and the mortality rate for sepsis doubles due to coincidence of AKI. Sepsis-induced AKI is strongly associated with increased mortality and other adverse outcomes. More timely diagnosis would allow for earlier intervention and could improve patient outcomes. Sepsis-induced AKI is characterized by a distinct pathophysiology compared with other diseases and may also have unique patterns of plasma and urinary biomarkers. This concise review summarizes properties and perspectives of the biomarkers for their individual clinical utilization.

Urinary Mitochondrial DNA Identifies Renal Dysfunction and Mitochondrial Damage in Sepsis-Induced Acute Kidney Injury.

BACKGROUND: Recent animal studies have shown that mitochondrial dysfunction initiates and accelerates renal injury in sepsis, but its role in sepsis remains unknown. Mitochondrial stress or dying cells can lead to fragmentation of the mitochondrial genome, which is considered a surrogate marker of mitochondrial dysfunction. Therefore, we evaluated the efficiency of urinary mitochondrial DNA (UmtDNA) as a marker of renal dysfunction during sepsis-induced acute kidney injury (AKI). METHODS: We isolated DNA from plasma and urine of patients. mtDNA levels were quantified by quantitative PCR. Sepsis patients were divided into no AKI, mild AKI, and severe AKI groups according to RIFLE criteria. Additionally, cecal ligation and puncture (CLP) was established in rats to evaluate the association between UmtDNA and mitochondrial function. RESULTS: A total of 52 (49.5%) developed AKI among enrolled sepsis patients. Increased systemic mtDNA did not correlate with systemic inflammation or acute renal dysfunction in sepsis patients, while AKI did not have an additional effect on circulating mtDNA levels. In contrast, UmtDNA was significantly enriched in severe AKI patients compared with that in the mild AKI or no AKI group, positively correlated with plasma creatinine, urinary neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1, and inversely with the estimated glomerular filtration rate. Additionally, UmtDNA increased in rats following CLP-induced sepsis. UmtDNA was predictive of AKI development and correlated with plasma creatinine and blood urea nitrogen in the rat sepsis model. Finally, the UmtDNA level was inversely correlated with the cortical mtDNA copy number and relative expression of mitochondrial gene in the kidney. CONCLUSION: An elevated UmtDNA level correlates with mitochondrial dysfunction and renal injury in sepsis patients, indicating renal mitochondrial injury induced by sepsis. Therefore, UmtDNA may be regarded as a valuable biomarker for the occurrence of AKI and the development of mitochondria-targeted therapies following sepsis-induced AKI.