Biomarkers of Acute Organ Injury in Pediatric Newly Diagnosed Type 1 Diabetes

Diabetic ketoacidosis (DKA) is a common and potentially life-threatening metabolic complication in children with newly diagnosed type 1 diabetes mellitus (T1DM). In addition to the acute metabolic disturbances, DKA may lead to early or subclinical injury of vital organs, particularly the kidneys and the cardiovascular system, due to dehydration, hypovolemia, metabolic acidosis, electrolyte disturbances, and inflammatory activation.

Recent studies suggest that novel biomarkers may allow early detection of organ dysfunction before conventional clinical indicators become abnormal. Biomarkers such as kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, high-sensitivity troponin (hs-troponin), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have been proposed as sensitive indicators of kidney and myocardial injury. Inflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP) may also reflect systemic inflammatory activation associated with metabolic decompensation.

The aim of this observational cross-sectional study is to investigate and compare biomarkers of acute organ injury and related clinical and echocardiographic parameters in children with newly diagnosed T1DM presenting with DKA, compared with children with newly diagnosed T1DM without DKA and healthy controls.

Participants will be categorized into three groups: (1) children with newly diagnosed T1DM presenting with DKA, (2) children with newly diagnosed T1DM without DKA, and (3) healthy children serving as controls. Blood samples will be collected at hospital admission for measurement of biomarkers including KIM-1, NGAL, hs-troponin, NT-proBNP, IL-6, and CRP, as well as standard laboratory parameters such as serum creatinine, cystatin C, albuminuria, pH, bicarbonate levels, and HbA1c.

All participants with T1DM will undergo cardiological evaluation including clinical examination, electrocardiogram, and transthoracic echocardiography with conventional measurements as well as advanced techniques such as tissue Doppler imaging and speckle-tracking echocardiography. Data collection will be performed at admission and within the first 24-48 hours of hospitalization.

The primary objective of the study is to compare biomarker levels and clinical parameters among the three study groups in order to identify early evidence of acute or subclinical organ dysfunction associated with diabetic ketoacidosis in children with newly diagnosed T1DM.

• Biomarker and Echocardiographic Assessment (Diagnostic test): Blood and urine samples and echocardiographic evaluation performed as part of the clinical assessment of children with newly diagnosed type 1 diabetes.

Primary outcomes

• Neutrophil Gelatinase-Associated Lipocalin [Within 48 hours of hospitalization]: Measurement of neutrophil gelatinase-associated lipocalin (NGAL, ng/mL) as a biomarker of early renal injury in children with newly diagnosed type 1 diabetes.
• Kidney Injury Molecule-1 [Within 48 hours of hospitalization]: Measurement of kidney injury molecule-1 (KIM-1, ng/mL) as a biomarker of renal injury in children with newly diagnosed type 1 diabetes.
• High-Sensitivity Troponin [Within 48 hours of hospitalization]: Measurement of high-sensitivity troponin (hs-troponin, ng/L) as a biomarker of myocardial injury in children with newly diagnosed type 1 diabetes.
• N-terminal pro-B-type Natriuretic Peptide [Within 48 hours of hospitalization]: Measurement of N-terminal pro-B-type natriuretic peptide (NT-proBNP, pg/mL) as a biomarker of cardiac stress in children with newly diagnosed type 1 diabetes.
• Interleukin-6 [Within 48 hours of hospitalization]: Measurement of interleukin-6 (IL-6, pg/mL) as a biomarker of systemic inflammation in children with newly diagnosed type 1 diabetes.
• C-reactive Protein [Within 48 hours of hospitalization]: Measurement of C-reactive protein (CRP, mg/L) as a biomarker of systemic inflammation in children with newly diagnosed type 1 diabetes.

Secondary outcomes

• Serum Creatinine [Within 48 hours of hospitalization]: Measurement of serum creatinine (mg/dL) in children with newly diagnosed type 1 diabetes.
• Cystatin C [Within 48 hours of hospitalization]: Measurement of and cystatin C (mg/L) in children with newly diagnosed type 1 diabetes.
• Left Ventricular Ejection Fraction [Within 48 hours of hospitalization]: Assessment of left ventricular systolic function using left ventricular ejection fraction measured by transthoracic echocardiography.
• Left Ventricular Fractional Shortening [Within 48 hours of hospitalization]: Evaluation of left ventricular systolic function using fractional shortening measured by transthoracic echocardiography.
• E/e' Ratio [Within 48 hours of hospitalization]: Assessment of left ventricular diastolic function using the ratio of transmitral early filling velocity (E) to tissue Doppler early diastolic velocity (e').
• Left Ventricular Global Longitudinal Strain [Within 48 hours of hospitalization]: Assessment of subclinical left ventricular systolic function using global longitudinal strain derived from speckle-tracking echocardiography.
• Glutamic Acid Decarboxylase Antibodies (GAD65) [Within 48 hours of hospitalization]: Measurement of glutamic acid decarboxylase antibodies (GAD65) in children with newly diagnosed type 1 diabetes.
• Insulin Autoantibodies (IAA) [Within 48 hours of hospitalization]: Measurement of insulin autoantibodies (IAA) in children with newly diagnosed type 1 diabetes.
• Islet Antigen-2 Antibodies (IA-2) [Within 48 hours of hospitalization]: Measurement of islet antigen-2 antibodies (IA-2) in children with newly diagnosed type 1 diabetes.
• Zinc Transporter 8 Antibodies (ZnT8) [Within 48 hours of hospitalization]: Measurement of zinc transporter 8 antibodies (ZnT8) in children with newly diagnosed type 1 diabetes.
• Severity of Diabetic Ketoacidosis [Baseline]: Classification of diabetic ketoacidosis severity at hospital admission based on venous blood pH and serum bicarbonate levels according to international pediatric guidelines. Diabetic ketoacidosis will be categorized as mild (pH <7.30, bicarbonate <15 mmol/L), moderate (pH <7.20, bicarbonate <10 mmol/L), or severe (pH <7.10, bicarbonate <5 mmol/L).

Sex: All, ages: 2 Years to 16 Years, accepts healthy volunteers

Inclusion Criteria:

* Children aged 2-16 years
* Newly diagnosed type 1 diabetes mellitus
* Hospital admission for initial evaluation and treatment
* Presence or absence of diabetic ketoacidosis at diagnosis
* Written informed consent from parents or legal guardians

For control group:

\- Age-matched healthy children without diabetes

Exclusion Criteria:

* Previous diagnosis of diabetes mellitus
* Known chronic kidney disease
* Known cardiovascular disease
* Acute infection or inflammatory condition unrelated to diabetes
* Use of medications that may affect renal or cardiac biomarkers

• Athanasios Christoforidis, Principal investigator, Aristotle University Of Thessaloniki