Conditioned pain modulation (CPM) (ie, diffuse noxious inhibitory controls) is characterized by reduced perception of pain caused by intense pain in a remote body area. The conditioning stimuli used to trigger CPM causes pain, but also important cardiovascular responses. Higher blood pressure has been associated with reduced pain sensitivity. Descending pain inhibitory mechanisms such as CPM could be involved in this relationship. We investigated the associations between CPM and cardiovascular responses during the cold-pressor test (CPT). Heat pain threshold and tolerance were evaluated in 26 (13 men, 13 women) healthy subjects. CPM was evaluated by comparing pain intensity produced by a 120-second heat stimulation before and after a CPT (5 minutes, 7°C). Heart rate, blood pressure, and baroreflex sensitivity were monitored at rest and during CPT to evaluate cardiovascular responses. We observed a positive relationship between resting blood pressure and heat pain tolerance. The CPT caused important heart rate and blood pressure increases. CPT also reduced pain intensity during the subsequent heat pain-stimulus, indicating effective CPM. A significant positive association was observed between CPM magnitude and the increase in blood pressure during the CPT. These results show that resting blood pressure values are related to acute pain tolerance, while descending pain inhibition is associated with increases in blood pressure. The rise in blood pressure caused by the conditioning stimulus is an important factor predicting the extent of endogenous pain inhibition in healthy subjects.

Bone cancer pain is a common and disruptive symptom in cancer patients. In cancer pain animal models, massive reactive astrogliosis in the dorsal horn of the spinal cord has been reported. Because astrocytes may behave as driving partners for pathological pain, we investigated the temporal development of pain behavior and reactive astrogliosis in a rat bone cancer pain model induced by injecting MRMT-1 rat mammary gland carcinoma cells into the tibia. Along with the development of bone lesions, a gradual mechanical and thermal allodynia and hyperalgesia as well as a reduced use of the affected limb developed in bone cancer-bearing animals, but not in sham-treated animals. Dorsal horn Fos expression after nonpainful palpation of the injected limb was also increased in bone cancer-bearing animals. However, at any time during the evolution of tumor, there was no increase in glial fibrillary acidic protein (GFAP) immunoreactivity in the dorsal horn. Further analysis at 21days after injection of the tumor showed no increase in GFAP and interleukin (IL) 1β transcripts, number of superficial dorsal horn S100β protein immunoreactive astrocytes, or immunoreactivity for microglial markers (OX-42 and Iba-1). In contrast, all these parameters were increased in the dorsal horn of rats 2weeks after sciatic nerve ligation. This suggests that in some cases, bone cancer pain may not be correlated with spinal overexpression of reactive glia markers, whereas neuropathic pain is. Glia may thus play different roles in the development and maintenance of chronic pain in these 2 situations.

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Objective: The dental and periodondal impact of GH/IGF-1 hypersecretion has been poorly investigated until now. Our aim is to precisely describe the oro-dental state of acromegalic patients and to study the impact of GH/IGF-1 hypersecretion on patients' reported oral health related quality of life (OHRQoL). Methods: After collecting characteristics of their disease, acromegalic patients answered the GOHAI questionnaire assessing their OHRQoL, the AcroQoL questionnaire and then benefited from a complete stomatological and radiological examination (orthopantomogram systematically, retro-alveolar radiography or Cone Beam computed tomography if necessary). Results: 29 patients aged 59.1±16.0 years were included. The average DMFT index (sum of Decayed, Missing and Filled Teeth per patient) was 19.0±7.8. 16/29 patients had a gingivitis and 18/29 a mild to moderate chronic periodontitis, but no case of severe chronic periodontitis was found, probably because the frequency of a protective thick gingival biotype was increased (9/29). No case of generalized gingival hypertrophy or diffuse hyper-cementosis was observed. According to the Add-GOHAI score, only 8/26 patients had a satisfactory OHRQoL. This parameter was correlated to the acromegaly-specific quality of life according to the AcroQoL score. Interestingly, 11/29 patients had bulky oral bony outgrowths (OBO) such as large maxillary or mandibular tori and multiple vestibular exostosis. Conclusions: The unsatisfactory OHRQoL reported by acromegalic patients contrasts with a rather good objective oro-dental state and annual oral examination seems relevant in this population. Finally, we report that huge OBO could be helpful signposts for the diagnosis of acromegaly.

Trigeminal neuropathic pain is due to lesion or dysfunction of the nervous system. Dynamic mechanical allodynia is a widespread symptom of neuropathic pain for which mechanisms are still poorly understood. Recent studies demonstrate that forebrain neurons, including neurons in the medial prefrontal cortex (mPFC) are important for the perception of acute and chronic pain. Using the phosphorylation of the extracellular-signal regulated kinase (pERK-1/2) as an anatomical marker of neuronal activation, the present study investigated how dynamic mechanical allodynia is processed in the rat ventral mPFC (prelimbic and infralimbic cortex) after chronic constriction injury to the infraorbital nerve (IoN-CCI). Two weeks after unilateral IoN-CCI, rats showed a dramatic bilateral trigeminal dynamic mechanical allodynia. Light, moving stroking of the infraorbital skin resulted in strong, bilateral upregulation of pERK-1/2 in the ventral mPFC of IoN-CCI animals. pERK-1/2 was located in neuronal cells only. Stimulus-evoked pERK-1/2 immunopositive cell bodies displayed a rostrocaudal gradient and layer-selective distribution in the ventral mPFC, being predominant in the rostral ventral mPFC and in layers II-III and V-VI of the ventral mPFC. In layers II-III, intense pERK-1/2 also extended into distal dendrites, up to layer I. These results demonstrate that trigeminal nerve injury induces a significant alteration in the ventral mPFC processing of tactile stimuli and suggest that ERK phosphorylation contributes to the mechanisms underlying abnormal pain perception under this condition.

Background: Dental cellulitis management is no longer a simple procedure, as more and more patients are needing long-time hospitalization, several surgeries and intensive care follow-up. This prospective study seeks to highlight criteria that can split patients with severe odontogenic infection into two groups: those with simple evolution and those for whom complex management is necessary. Methods: In this observational study, all patients considered with a severe odontogenic infection (which necessitated hospital admission, intravenous antibiotics and general anaesthesia) were enrolled between January 2004 and December 2014 from Clermont-Ferrand University Hospital (France). They were split into two groups: those who needed one surgical intervention with tooth extraction and collection drainage combined with probabilistic antibiotic to treat infection and those who need several surgeries, intensive care unit follow-up or tracheotomy to achieve healing. Results: 653 patients were included, of which 611 (94%) had one surgery, 42 (6%) had more than one surgery before healing. Penicillin allergy (p < 0.001), psychiatric disorders (p = 0.005), oropharyngeal oedema (p = 0.008), floor oedema (p = 0.004), fever (p = 0.04) and trismus (p = 0.018) on admission were the most relevant predictors of complex evolution. A conditional inference tree (CTREE) illustrated the association of prognostic factors and the need of multiple surgery. Conclusions: Besides clinical symptoms of severity, complications of severe odontogenic infection are predicted by measurables and objectives criteria as penicillin allergy, mandibular molar, C-reactive protein level, psychiatric disorders and alcohol abuse. Their specific association potentialize the risks. IRB number: CE-CIC-GREN-12-08.

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