Measurement of circulating lactate is an essential diagnostic tool in pediatric medicine, playing a crucial role in assessing metabolic status and tissue oxygenation. Initially regarded as a byproduct of anaerobic metabolism, recent research has expanded our understanding of lactate’s roles across various physiological systems, from energy metabolism to immune modulation and neurological health. Elevated lactate levels are widely utilized to monitor critical conditions such as sepsis, trauma, and hypoxic–ischemic injury, offering valuable prognostic information in intensive care settings. Notably, lactate dynamics—particularly trends in serial measurements—are more effective than single readings for predicting clinical outcomes, especially in sepsis and trauma. Measurement of circulating lactate in different body fluids (blood, cerebrospinal fluid, and umbilical blood) provides critical insights into neonatal health and central nervous system involvement. However, challenges remain, including the need for non-invasive and rapid point-of-care testing, particularly in neonatal populations. Our aim was to review and synthesize the current literature on the role and particularities of measurement of circulating lactate in pediatric pathology. Emerging technologies, such as machine learning models and small molecule inhibitors, show promise in advancing lactate regulation and predicting hemodynamic instability. As the role of lactate in pediatric pathology continues to evolve, optimizing measurement protocols and exploring new therapeutic strategies will enhance early detection, intervention, and clinical outcomes for critically ill children.

Childhood obesity is a major global health problem, and its management involves a multidisciplinary approach that includes lifestyle changes, dietary interventions, and the use of dietary supplements. In this review, we summarize current findings on the role of amino acids in pediatric obesity, with a particular focus on their involvement in metabolic pathways and weight regulation. The involvement of branched-chain and aromatic amino acids in the pathophysiology and potential management of pediatric obesity is highlighted in recent studies. Both experimental and clinical studies have shown that obese children often exhibit altered plasma amino acid profiles, including increased levels of leucine, isoleucine, valine, phenylalanine, and tyrosine, as well as decreased levels of glycine and serine. These imbalances are correlated with insulin resistance, inflammation, and early metabolic dysfunction. One of the mechanisms through which branched-chain amino acids can promote insulin resistance is the activation of the mammalian target of rapamycin (mTOR) signaling pathway. Metabolomic profiling has demonstrated the potential of specific amino acid patterns to predict obesity-related complications before they become clinically evident. Early identification of these biomarkers could be of great help for individualized interventions. Although clinical studies indicate that changes in dietary amino acids could lead to modest weight loss, improved metabolic profiles, and increased satiety, further studies are needed to establish standardized recommendations.

Metabolically-dysfunction-associated steatotic liver disease (MASLD) represents the most common chronic liver disease in the pediatric population, and its prevalence has doubled over the past decade. The etiology is multifactorial, including genomic risk factors, perinatal and developmental or behavioral factors. Still, many cases of MASLD are associated with being overweight and obesity, particularly in children who have poor dietary habits and sedentary lifestyles that contribute to excessive weight gain. Given the progressive and heterogeneous nature of MASLD, early identification of high-risk patients before the development of severe liver disease is a major clinical priority. Recent studies indicate that disorders of amino acid metabolism are closely linked to both obesity and MASLD, reflecting profound alterations in systemic metabolic homeostasis. The reported data sustain significant changes in circulating amino acid profiles, particularly elevated levels of branched-chain amino acids (BCAAs) and aromatic amino acids. These alterations are thought to reflect fundamental metabolic disturbances, including insulin resistance, compromised mitochondrial activity, and altered hepatic lipid metabolism. Consequently, alterations in amino acid metabolism have been proposed as potential biomarkers for disease progression and metabolic dysfunction in MASLD. This review aims to evaluate the correlation between the amino acid profile and histological changes in pediatric MASLD, including steatosis, steatohepatitis, and fibrosis.