Urinary Actin, as a Potential Marker of Sepsis-related Acute Kidney Injury

Study Overview
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Brief Summary
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In our study, 17 septic, 43 sepsis-related acute kidney injury and 24 control patients were enrolled. Blood and urine samples were collected at the intensive care unit from acutely diagnosed septic and sepsis-related acute kidney injury patients at three time points (T1-3): T1: within 24 hours after admission; T2: second day morning; T3: third day morning of follow-up. Patients with malignancies needing palliative care, end-stage renal disease or kidney transplantation were excluded. Not more than one sample (venous blood, midstream spot urine) was collected from control patients. Serum and urinary actin levels were determined by quantitative Western blot. Urinary actin concentrations were expressed as µg/L, while serum actin levels were expressed as mg/L. Data were compared with laboratory and clinical parameters. Patients were categorized by the Sepsis-3 definitions and 30-day mortality data were investigated.

Detailed Description
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Actin is a globular protein present in every cell with a 42 kilodalton molecular mass. It plays an important role in muscle contraction while being an essential component of the cytoskeleton as well. Several proteins (e.g. gelsolin, Gc-globulin) bind actin in the circulation during the physiological cell turnover, thus making its urinary appearance unlikely. However, recent studies indicate that actin could be detected in the urine of kidney-transplant patients with acute kidney injury. Therefore, the main focus of our research was the detection and measurement of actin in the blood and urine in patients with sepsis or sepsis-related acute kidney injury, as the early recognition of kidney injury - especially in sepsis - is essential in the aspect of therapy and survival.

Official Title
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Urinary Actin, as a Potential Marker of Sepsis-related Acute Kidney Injury: a Pilot Study

Conditions
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Acute Kidney Injury Due to Sepsis, Sepsis

Intervention / Treatment
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* Other: Sepsis therapy
* Other: Sepsis-related acute kidney injury therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Sepsis Sepsis-related acute kidney injury Exclusion Criteria: malignancies needing palliative care end-stage renal disease kidney transplantation under 18 years of age unobtainable consent

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sepsis<br>Patients receive sepsis therapy. | Other: Sepsis therapy<br>* Patients receiving sepsis therapy followed the international guidelines of the 2016 Surviving Sepsis Campaign regarding fluid resuscitation, feeding, vasopressor, respiratory, anticoagulation and hydrocortisone therapy, along with ulcer prophylaxis and sedation. Blood and urine samples were collected at the intensive care unit from this patient group at three time points (T1-3): T1: within 24 hours after admission; T2: second day morning; T3: third day morning of follow-up. 24 patients were documented without sepsis and acute kidney injury as a control group.<br>|
| Sepsis-related acute kidney injury<br>Patients receive sepsis and sepsis-related acute kidney injury therapy. | Other: Sepsis-related acute kidney injury therapy<br>* Patient management of sepsis and sepsis-related acute kidney injury followed the international guidelines of the 2016 Surviving Sepsis Campaign regarding fluid resuscitation, feeding, vasopressor, respiratory, anticoagulation and hydrocortisone therapy, along with ulcer prophylaxis, sedation and renal replacement therapy (if needed). In this patient group, blood and urine sampling was performed at three time points (T1-3): T1: within 24 hours after admission; T2: second day morning; T3: third day morning of follow-up.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urinary actin concentrations | Urine samples were centrifuged (10 min, 1500 g) and supernatants were treated with electrophoresis sample buffer then heated at 100 °C for 5 minutes. Urinary actin was determined by quantitative Western blot. Native and denatured sample aliquots were stored at -70 °C until analysis. | 3 days | 
| Serum actin concentrations | Clotted blood samples were centrifuged (10 min, 1500 g) and supernatants were treated with electrophoresis sample buffer then heated at 100 °C for 5 minutes. Serum actin was determined by quantitative Western blot. Native and denatured sample aliquots were stored at -70 °C until analysis. | 3 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| U-actin/u-creatinine concentrations | U-actin values were determined by quantitative Western blot, while U-creatinine concentrations were measured using automated routine laboratory procedures, therefore U-actin/u-creatinine ratios could be calculated. | 5 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sepsis-3, Acute Kidney Injury, Urinary actin, Western blot