Haptoglobin phenotypes and structural variants associate with post-exertional malaise and cognitive dysfunction in...

Area of Science:

• Biochemistry
• Immunology
• Neuroscience

Background:

• Myalgic encephalomyelitis (ME) is a complex chronic illness with debilitating post-exertional malaise (PEM) and cognitive dysfunction.
• The underlying molecular mechanisms of ME symptoms, particularly PEM, remain largely unknown.
• Haptoglobin (Hp), a plasma protein, is explored as a potential biomarker for ME severity and cognitive impairment.

Purpose of the Study:

• To investigate the role of haptoglobin (Hp) phenotypes and proteoforms in myalgic encephalomyelitis (ME).
• To assess Hp as a potential biomarker for post-exertional malaise (PEM) severity and cognitive dysfunction in ME patients.
• To explore the association between Hp structure and physiological responses to exertion in ME.

Main Methods:

• A longitudinal case-control study involving 140 ME patients and 44 controls.
• Plasma proteomic profiling and high-performance liquid chromatography (HPLC) were used to analyze Hp levels, phenotypes, and proteoforms.
• Standardized stress protocols were employed to induce PEM and assess cognitive performance.

Main Results:

• ME patients showed reduced Hp levels after exertion, with lower baseline Hp linked to cognitive deficits.
• The Hp2-1 phenotype was more prevalent in ME patients, correlating with increased PEM severity and cognitive impairment.
• Altered Hp proteoform structures, including higher mass forms, were observed in the Hp2-1 subgroup.

Conclusions:

• Hp phenotype and proteoform structure influence the physiological response to exertion in ME, contributing to symptom heterogeneity.
• Hp shows potential as a biomarker for stratifying ME patients and identifying therapeutic targets.
• Targeting Hp may help mitigate oxidative stress and cognitive dysfunction in ME.