Sepsis diagnosis using chemically modified DNA aptamers

Summary Sepsis is a condition in which severe infections are caused by viruses, bacteria, parasites, or fungi, resulting in critical illness that can progress rapidly to multi-organ failure if not treated promptly. Each year, sepsis affects an estimated 49 million people worldwide, including more than 20 million children under age 5 and nearly 5 million older children and adolescents (ages 5-19). Sepsis takes 11 million lives around the world each year, contributing to 20% of all deaths globally and taking more lives than cancer. In the United States, over 1.7 million people are diagnosed with sepsis each year, and an estimated 350,000 adults die from sepsis every year. Sepsis is a “systemic inflammatory response (SIRS) to a microbial infection,” resulting in rapid breathing, rapid heartbeat, fever, or hypothermia. When the body’s overwhelming immune response causes damage to its tissues and organs, it can lead to severe septic shock, resulting in multiple organ failure and death. No single diagnostic test is available to rule out non-infectious inflammation from the onset of sepsis. The culture tests to identify disease-causing infective agents are sent to the laboratory, and preliminary results from cultures may be available within 24 to 48 hours; results take several days. Because of its heterogeneous nature and diverse pathobiological pathways, sepsis diagnosis can be challenging, resulting in over or under-treatment. No single diagnostic test is available that establishes the diagnosis of sepsis or septic shock, and the ability to distinguish sepsis from non- infectious critical illness and to predict outcome is very limited. The known biomarkers, such as CRP, IL6, IL10, CCL2, and CXCL10, lack specificity to rule out infection as the cause of inflammation. The one exception is in the use of procalcitonin or PCT to distinguish sepsis from non-infectious critical illness and to guide the use of antibiotic therapy. However, the consensus is that PCT is not an effective diagnostic measurement to rule in or rule out sepsis from infective inflammation. Therefore, the unmet need exists for a robust and specific sepsis biomarker. Recent studies have shown that pancreatic stone protein (PSP) is a reliable, highly specific, and sensitive biomarker for the early diagnosis of sepsis. Aptus Biosciences is creating picomolar affinity chemically modified aptamers against sepsis biomarkers to develop an ultra-sensitive multi-analyte quantitative test. In the SBIR Phase I Specific Aims 1), we will create chemically modified aptamers with hydrophobic modifications on nucleobases, which are known to deliver aptamers with picomolar affinity and without compromising specificity against specific biomarker PSP, PCT, CRP, and IL6. 2) we will screen select picomolar affinity aptamer for non- competitive binding to target epitopes to develop an aptamer-based sandwich assay using bead-based Quanterix Homebrew technology for ultra-sensitive and rapid detection of sepsis biomarkers. Further, we will demonstrate the feasibility of a multi-analyte aptamer-based sandwich assay to diagnose sepsis vs healthy control samples. This SBIR proposal promises to improve the accurate diagnosis of sepsis from infective inflammation, helping clinicians make timely decisions to prevent complications, unwanted expensive antibiotic therapies, treatment burdens, and hospital costs, saving lives.