Plasma neuropeptide Y: a biomarker for symptom severity in chronic fatigue syndrome

Abstract

BackgroundChronic fatigue syndrome (CFS) is a complex, multi-symptom illness with a multisystem pathogenesis involving alterations in the nervous, endocrine and immune systems.Abnormalities in stress responses have been identified as potential triggers or mediators of CFS symptoms. This study focused on the stress mediator neuropeptide Y (NPY). We hypothesized that NPY would be a useful biomarker for CFS.MethodsThe CFS patients (n = 93) were from the Chronic Fatigue and Related Disorders Clinic at the University of Miami and met the 1994 case definition of Fukuda and colleagues. Healthy sedentary controls (n = 100)) were from NIH or VA funded studies. Another fatiguing, multi-symptom illness, Gulf War Illness (GWI), was also compared to CFS. We measured NPY in plasma using a radioimmunoassay (RIA). Psychometric measures, available for a subset of CFS patients included: Perceived Stress Scale, Profile of Mood States, ATQ Positive & Negative Self-Talk Scores, the COPE, the Beck Depression Inventory, Fatigue Symptom Inventory, Cognitive Capacity Screening Examination, Medical Outcomes Survey Short Form-36, and the Quality of Life Scale.ResultsPlasma NPY was elevated in CFS subjects, compared to controls (p = .000) and to GWI cases (p = .000). Receiver operating characteristics (ROC) curve analyses indicated that the predictive ability of plasma NPY to distinguish CFS patients from healthy controls and from GWI was significantly better than chance alone. In 42 patients with CFS, plasma NPY had significant correlations (<0.05) with perceived stress, depression, anger/hostility, confusion, negative thoughts, positive thoughts, general health, and cognitive status. In each case the correlation (+ or -) was in the anticipated direction.ConclusionsThis study is the first in the CFS literature to report that plasma NPY is elevated compared to healthy controls and to a fatigued comparison group, GWI patients. The significant correlations of NPY with stress, negative mood, general health, depression and cognitive function strongly suggest that this peptide be considered as a biomarker to distinguish subsets of CFS.

Dose-dependent effects of neuropeptide Y on the regulation of preadipocyte proliferation and adipocyte lipid synthesis <i>via</i> the PPAR&gamma; pathways

“…The physiological concentration of plasma NPY is approximately 5×10 -11 M ~1.5×10 -10 M [26]. Our experiments demonstrated that at these physiologically relevant concentrations NPY had no significant role or just a weak role on preadipocyte proliferation in vitro.…”

“…Thus, both the central NPY and peripheral NPY especially fat-derived NPY may affect the growth of adipose tissue. Although the serum NPY levels were higher in obese subjects [28], the concentration is remain ranging approximately 1×10 -10 M ~3.4×10 -10 M [26,28], which should have no effect on preadipocytes proliferation based on our data. Nonetheless, the exact level of NPY which produced in adipose tissue remain unclear, we infer that if the adipose tissue could produce supraphysiolagical NPY (even nearly approach 10 -7 M), the growth of adipose tissue may be influenced by high dose of NPY.…”

Disease Mechanisms and Clonidine Treatment in Adolescent Chronic Fatigue Syndrome

“…First, adolescent CFS is associated with enhanced sympathetic nervous activity, low-grade systemic inflammation, attenuated hypothalamus-pituitary-adrenal axis function, slight cognitive impairment, and large activity reduction, but not with common is consistent with a report of high plasma neuropeptide Y levels. 41 Sympathetic enhancement might result from physical deconditioning. In the present study, however, neither plasma norepinephrine level nor heart rate responsiveness was associated with the number of steps per day in patients with CFS (Supplement [eTable 12]).…”

Neuropeptide Y promotes adipogenic differentiation in primary cultured human adipose-derived stem cells

“…Here, we used three concentrations of NPY (10 -7 , 10 -9 and 10 -11 M) to induce hADSCs differentiation. The physiological concentration of NPY in human body is 10-10~10-11 M [22,23]. Before formal experiments, the lower doses of NPY at 10-13 M and 10-15 M which regulated differentiation had been checked and we found that the lower doses had no effects on differentiation.…”