Beta-endorphin levels are reduced in peripheral blood mononuclear cells of cluster headache patients

Biomarkers in cluster headache: A systematic review

OBJECTIVE

To systematically investigate previously examined biomarkers in blood, urine, cerebrospinal fluid, tear fluid, and saliva of patients with cluster headache.

BACKGROUND

Cluster headache is a condition with extensive clinical challenges in terms of diagnosis and treatment. Identification of a biomarker with diagnostic implications or as a potential treatment target is highly warranted.

METHODS

We conducted a systematic review including peer reviewed full text of studies that measured biochemical compounds in either blood, urine, cerebrospinal fluid, tear fluid, or saliva of patients with cluster headache diagnosed after the implementation of the International Classification of Headache Disorders (1988) written in English, Danish, Swedish, or Norwegian. Inclusion required a minimum of five participants. The search was conducted in PubMed and EMBASE, in September 2022, and extracted data were screened by two authors. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for reporting systematic reviews were followed. The Newcastle-Ottawa Scale was used to assess the risk of bias in case-controlled studies.

RESULTS

We included 40 studies involving 832 patients with cluster headache and 872 controls, evaluating 80 potential biomarkers. The risk of bias for case-controlled studies was a median of 6 (range: 3-8) and 20 studies out of 40 (50%) were of fair or good quality. Most studies were identified within three groups: hypothalamic-regulated hormones, inflammatory markers, and neuropeptides. Among the hypothalamic hormones, cortisol was the most frequently investigated (N = 7) and was elevated in cluster headache in most of the studies. The most frequently examined inflammatory marker was interleukin 1 (N = 3), but findings were divergent. Calcitonin gene-related peptide was the most investigated neuropeptide (N = 9) and all studies found increased levels during attacks.

CONCLUSION

Biomarker findings have been inconsistent and widely non-specific for cluster headache, which explains why none of the previous studies succeeded in identifying a unique biomarker for cluster headache, but instead contributed to substantiating the underlying pathophysiologic mechanisms. Several of the examined biomarkers could hold promise as markers for disease activity but are unfit for a clear distinction from both controls and other headaches.

Effect of intravenous general anaesthesia with epidural block on the expression of pre-endogenous opioid peptide genes

Objective

To measure the plasma concentrations of three endogenous opioid peptides and the levels of preproenkephalin (PPE) and preprodynorphin (PPD) mRNA in peripheral blood lymphocytes of patients during scheduled surgery performed under intravenous general anaesthesia combined with an epidural block.

Methods

Patients were anaesthetized and arterial blood was collected at 0 (baseline), 20, 40, 60, and 80 min during surgery. The plasma concentrations of β-endorphin, leucine-enkephalin and dynorphin A were measured using radioimmunoassay. Reverse transcription–polymerase chain reaction was used to measure the levels of PPD and PPE mRNA in peripheral blood lymphocytes collected during surgery.

Results

Fifteen patients participated in this prospective study. The plasma concentrations of β-endorphin were significantly lower at all time-points compared with the baseline value. The plasma concentrations of leucine-enkephalin and dynorphin A were significantly lower at 40, 60, and 80 min compared with baseline. The PPD/β-actin ratio was significantly lower at 80 min compared with baseline, while the PPE/β-actin ratio showed no significant change.

Conclusion

The level of mRNA from two pre-endogenous opioid peptide genes either decreased or remained unchanged during surgery under intravenous general anaesthesia with epidural block, suggesting that patients remained pain free during surgery.

Gene Expression Profiling in Cluster Headache: A Pilot Microarray Study

BACKGROUND

Cluster headache (CH) is a primary neurovascular headache disorder characterized by attacks of excruciating pain accompanied by ipsilateral autonomic symptoms. CH pathophysiology is presumed to involve an activation of hypothalamic and trigeminovascular systems, but inflammation and immunological mechanisms have also been hypothesized to be of importance.

OBJECTIVE

To identify differentially expressed genes during different clinical phases of CH, assuming that changes of pathophysiological importance would also be seen in peripheral venous blood.

METHODS

Blood samples were drawn at 3 consecutive occasions from 3 episodic CH patients: during attacks, between attacks and in remission, and at 1 occasion from 3 matched controls. Global gene expression was analyzed with microarray tehnology using the Affymetrix Human Genome U133 2.0 Plus GeneChip Set, covering more than 54,000 gene transcripts, corresponding to almost 22,000 genes. Quantitative RT-PCR on S100P gene expression was analyzed in 6 patients and 14 controls.

RESULTS

Overall, quite small differences were seen intraindividually and large differences interindividually. However, pairwise comparisons of signal values showed upregulation of several S100 calcium binding proteins; S100A8 (calgranulin A), S100A12 (calgranulin C), and S100P during active phase of the disease compared to remission. Also, annexin A3 (calcium-binding) and ICAM3 showed upregulation. BIRC1 (neuronal apoptosis inhibitory protein), CREB5, HLA-DQA1, and HLA-DQB1 were upregulated in patients compared to controls. The upregulation of S100P during attack versus remission was confirmed by quantitative RT-PCR analysis.

CONCLUSIONS

The S100A8 and S100A12 proteins are considered markers of non-infectious inflammatory disease, while the function of S100P is still largely unknown. Furthermore, upregulation of HLA-DQ genes in CH patients may also indicate an inflammatory response. Upregulation of these pro-inflammatory genes during the active phase of CH has not formerly been reported. Data from this pilot microarray study provide a basis for further studies in CH.

Decreased levels of beta-endorphin in circulating mononuclear leukocytes from patients with acute myocardial infarction

Lymphocytes can be activated to produce and release opioid peptides. We investigated the levels of immunoreactive beta-endorphin in peripheral blood mononuclear cells from 11 patients with acute myocardial infarction. The concentrations of beta-endorphin in mononuclear leukocytes of 30.2 +/- 6.9 pg/10(6) cells on admission were in the normal range of 20-40 pg/10(6) cells and decreased significantly to 6.9 +/- 1.9 pg/10(6) cells after 48 h (p < 0.05). Decreased levels of mononuclear leukocyte-associated beta-endorphin in acute myocardial infarction may be due to the release of endogenous opioid after stimulation by stress and acute-phase reactants and play a role in inflammation and pain.

Peripheral mononeuropathy affects hypothalamic and splenocyte beta-endorphin levels but not immune function in the rat

Beta-endorphin and substance P levels were measured in the hypothalamus of rats 14 days after chronic constriction injury of right sciatic nerve. Furthermore, beta-endorphin concentrations in splenocytes, phytoemoagglutinin-induced proliferation of splenocytes, and natural killer activity were assessed. We observed a significant increase of beta-endorphin and substance P hypothalamic levels, and a significant decrease of beta-endorphin concentrations in the immune cells. In contrast, the peripheral mononeuropathy did not affect the immune function. This study presents a picture of central and peripheral peptide changes consistent with a painful condition, but different from what previously observed in rats which underwent peripheral nerve deafferentation or stressful conditions.

Endogenous opiates: 1993

This paper is the sixteenth installment of our annual review of research concerning the opiate system. It is restricted to papers published during 1993 that concern the behavioral effects of the endogenous opiate peptides, and does not include papers dealing only with their analgesic properties. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; development; immunological responses; and other behaviors.