D-lactate in human and ruminant metabolism

Area of Science:

• Biochemistry
• Veterinary Medicine
• Human Physiology

Background:

• D-lactate is a normal blood metabolite at nanomolar levels, arising from methylglyoxal metabolism.
• Millimolar D-lactate concentrations can occur due to excessive gastrointestinal microbial production, leading to D-lactic acidemia.
• Conditions like grain overload in ruminants, short-bowel syndrome in humans, and calf diarrhea present similar neurological symptoms due to D-lactic acidemia.

Purpose of the Study:

• To review recent advancements in understanding D-lactate metabolism in mammals.
• To discuss the pathophysiology of D-lactic acidosis in ruminants and humans.
• To highlight the emerging role of subclinical D-lactate elevation as a biomarker.

Main Methods:

• Literature review of recent studies on D-lactate metabolism and acidosis.
• Analysis of clinical manifestations and biochemical pathways related to D-lactate.
• Examination of diagnostic and prognostic implications of D-lactate levels.

Main Results:

• Mammals possess a significant capacity for D-lactate metabolism, involving a putative D-lactate dehydrogenase.
• D-lactic acidemia, regardless of the underlying cause (e.g., grain overload, short-bowel syndrome), results in comparable neurological effects.
• Subclinical elevations of D-lactate are increasingly recognized as potential indicators of sepsis and trauma.

Conclusions:

• The understanding of D-lactate metabolism has evolved, revealing a higher metabolic capacity in mammals than previously thought.
• D-lactic acidosis presents with consistent neurological signs across different species and etiologies.
• Further research into D-lactate's role in critical illness, sepsis, and trauma is warranted for diagnostic and therapeutic advancements.