Reduced plasma calcitonin gene-related peptide level identified in cluster headache: A prospective and controlled study

BACKGROUND

The role of calcitonin gene-related peptide (CGRP) in the cyclic pattern of cluster headache is unclear. To acquire biological insight and to comprehend why only episodic cluster headache responds to CGRP monoclonal antibodies, we examined whether plasma CGRP changes between disease states (i.e. bout, remission and chronic) and controls.

METHODS

The present study is a prospective case-control study. Participants with episodic cluster headache were sampled twice (bout and remission). Participants with chronic cluster headache and controls were sampled once. CGRP concentrations were measured in plasma with a validated radioimmunoassay.

RESULTS

Plasma was collected from 201 participants diagnosed with cluster headache according to the International Classification of Headache Disorders, 3rd edition, and from 100 age- and sex-matched controls. Overall, plasma CGRP levels were significantly lower in participants with cluster headache compared to controls (p < 0.05). In episodic cluster headache, CGRP levels were higher in bout than in remission (mean difference: 17.1 pmol/L, 95% confidence interval = 9.8-24.3, p < 0.0001). CGRP levels in bout were not different from chronic cluster headache (p = 0.266).

CONCLUSIONS

Plasma CGRP is unsuitable as a diagnostic biomarker of cluster headache or its disease states. The identified reduced CGRP levels suggest that CGRPs role in cluster headache is highly complex and future investigations are needed into the modulation of CGRP and its receptors.

X-ray microscopy reveals the outstanding craftsmanship of Siberian Iron Age textile dyers

The excellent craftsmanship of ancient Oriental and Central Asian textile dyers is already demonstrated in the remarkable brilliance and fastness of the colours of the so-called Pazyryk carpet, the by far oldest pile carpet found to date. This specimen resembles the advanced craftsmanship of Iron Age Central Asian textile production. We have employed synchrotron-based µ-XRF imaging to detect the distribution of metal organic pigments within individual fibres of the Pazyryk carpet (about 2500 years old) and compare the results to wool fibres, which we prepared according to traditional Anatolian dyeing recipes. We observe congruent pigment distribution within specimens from the Pazyryk carpet and natural wool fibres that we have fermented prior to dyeing. Therefore, we conclude that the superior fermentation technique has been utilized about 2000 years earlier than known so far.

[Pathophysiological role of calcitonin gene-related peptide (CGRP) in migraine and cluster headache]

Calcitonin gene-related peptide (CGRP) is released from trigeminal afferents during migraine and cluster headache attacks and can be detected in the jugular plasma. Infusion of CGRP can induce headache attacks in migraine and cluster patients. Inhibition of the CGRP signal system is therapeutic in migraine and cluster headache. CGRP is a potent dilator of intracranial arteries but does not immediately activate the trigeminal pain system. CGRP may act as a signal molecule between different cells in the trigeminal ganglion and enhances nociceptive transmission in the spinal trigeminal nucleus. Peripheral inhibition of the CGRP system reduces these actions. Outside the trigeminovascular system, CGRP is important for maintaining the perfusion of organs in critical situations, promotes growth and repair functions and is an immunomodulatory factor. These actions should be considered when the CGRP system is suppressed for a long time.

[Pathophysiology of Headaches]

Pathophysiological concepts of primary headache diseases have been developed significantly in the last decades. Nevertheless pathophysiology of single diseases is unexplained. Migraine headache arises from activation and sensibilization of trigeminal nociceptors, essential processes are located at the meninges and the meningeal vessels. Calcitonin gene-related peptide (CGRP) seems to have essential importance concerning migraine and cluster headache. Mechanisms leading to peripheral and central sensitization are relevant in chronification of migraine and tension-type headache. As a higher-level centre the hypothalamus seems to have an essential meaning in the initiation of migraine attacks. Dysbalance between the sympathetic and parasympathetic neural system causes cranial-autonomic symptoms in some headache diseases and can be affected therapeutically.

µ-XRF Studies on the Colour Brilliance in Ancient Wool Carpets

Many handmade ancient and recent oriental wool carpets show outstanding brilliance and persistence of colour that is not achieved by common industrial dyeing procedures. Anthropologists have suggested the influence of wool fermentation prior to dyeing as key technique to achieve the high dyeing quality. By means of μ-XRF elemental mapping of mordant metals we corroborate this view and show a deep and homogenous penetration of colourants into fermented wool fibres. Furthermore we are able to apply this technique and prove that the fermentation process for ancient specimens cannot be investigated by standard methods due to the lack of intact cuticle layers. This finding suggests a broad range of further investigations that will contribute to a deeper understanding of the development of traditional dyeing techniques. Spectroscopic studies add information on the oxidation states of the metal ions within the respective mordant-dye-complexes and suggest a partial charge transfer as basis for a significant colour change when Fe mordants are used.