Burning mouth syndrome as a trigeminal small fibre neuropathy: Increased heat and capsaicin receptor TRPV1 in nerve fibres correlates with pain score.

Burning mouth syndrome (BMS) is often an idiopathic chronic and intractable pain condition, affecting 1.5-5.5% of middle-aged and elderly women. We have studied the heat and capsaicin receptor TRPV1, and its regulator nerve growth factor (NGF), in BMS. Patients with BMS (n=10) and controls (n=10) were assessed for baseline and post-topical capsaicin pain scores, and their tongue biopsies immunostained for TRPV1, NGF, and structural nerve markers neurofilament and peripherin. Nerve fibres penetrating the epithelium were less abundant in BMS (p<0.0001), indicating a small fibre neuropathy. TRPV1-positive fibres were overall significantly increased in BMS (p=0.0011), as were NGF fibres (p<0.0001) and basal epithelial cell NGF staining (p<0.0147). There was a significant correlation between the baseline pain score and TRPV1 (p=0.0143) and NGF fibres (p=0.0252). A significant correlation was observed between baseline and post-capsaicin pain (p=0.0006). Selective TRPV1 and NGF blockers may provide a new therapy for BMS.     

An animal model of chronic inflammatory pain: pharmacological and temporal differentiation from acute models.

Clinically, inflammatory pain is far more persistent than that typically modelled pre-clinically, with the majority of animal models focussing on short-term effects of the inflammatory pain response. The large attrition rate of compounds in the clinic which show pre-clinical efficacy suggests the need for novel models of, or approaches to, chronic inflammatory pain if novel mechanisms are to make it to the market. A model in which a more chronic inflammatory hypersensitivity phenotype is profiled may allow for a more clinically predictive tool. The aims of these studies were to characterise and validate a chronic model of inflammatory pain. We have shown that injection of a large volume of adjuvant to the intra-articular space of the rat knee results in a prolonged inflammatory pain response, compared to the response in an acute adjuvant model. Additionally, this model also results in a hypersensitive state in the presence and absence of inflammation. A range of clinically effective analgesics demonstrate activity in this chronic model, including morphine (3mg/kg, t.i.d.), dexamethasone (1mg/kg, b.i.d.), ibuprofen (30mg/kg, t.i.d.), etoricoxib (5mg/kg, b.i.d.) and rofecoxib (0.3-10mg/kg, b.i.d.). A further aim was to exemplify the utility of this chronic model over the more acute intra-plantar adjuvant model using two novel therapeutic approaches; NR2B selective NMDA receptor antagonism and iNOS inhibition. Our data shows that different effects were observed with these therapies when comparing the acute model with the model of chronic inflammatory joint pain. These data suggest that the chronic model may be more relevant to identifying mechanisms for the treatment of chronic inflammatory pain states in the clinic.     

Allodynia in rats infected with varicella zoster virus—a small animal model for post-herpetic neuralgia

The most common complication of herpes zoster is post-herpetic neuralgia (PHN), which has been defined as severe pain occurring 1 month after rash onset or persisting for greater than 3 months. PHN is classed as a neuropathic pain that is associated with mechanical allodynia where normally innocuous tactile stimuli are perceived as painful. The development of therapies to treat PHN has been hampered by the lack of animal models, which mimic the clinical situation. We have previously reported that varicella zoster virus (VZV) infection in the rat results in mechanical allodynia and thermal hyperalgesia. Here, we report that following VZV infection of the left footpad rats develop a chronic mechanical allodynia, which is present for longer than 60 days post-infection and which resolves by 100 days PI. The model is robust and reproducible with animals consistently developing allodynia by 3 days PI and continuing to present with symptoms for at least 30 days. The reproducible nature of the induction and course of the allodynia allows the use of this model to determine the effect of various compounds on, and to investigate the pathogenic mechanisms underlying the development of VZV-induced allodynia. Comparative studies using HSV-1 show that the induction of the chronic allodynia is VZV-specific and is not a result is of virus replication-induced tissue damage or accompanying inflammation.Therefore, we propose that the rat VZV infection model could prove useful in studying the mechanisms underlying post-herpetic neuralgia.     

Progressive massive osteolysis secondary to benign squamous epithelial colonisation in chronic osteomyelitis

Although the rare complication of squamous cell carcinoma in chronic osteomyelitis is well known, benign squamous epithelial proliferation can also occur, causing osteolysis and fracture. The radiological and correlated pathological features of osteolysis from this benign complication of chronic osteomyelitis are presented.An erratum to this article can be found at     

Serious diabetes-specific emotional problems and depression in a Croatian-Dutch-English Survey from the European Depression in Diabetes [EDID] Research Consortium

It has been hypothesized that coverage of diabetes-specific issues (e.g. coping with complications, incapacity, pain) during psychotherapy may optimize the likelihood of treatment success for depression in patients with diabetes. However, it is still unclear how often depression is confounded by diabetes-specific emotional problems. We aim to determine the levels of diabetes-specific emotional problems in diabetic individuals with high versus low levels of depression in a sample of 539 outpatients with diabetes (202 Dutch, 185 Croatian and 152 English). Subjects completed the Center for Epidemiological Studies Depression and the Problem Areas in Diabetes scales. Percentages of patients with high depression scores were: 39 and 34% (Croatian men and women), 19 and 21% (Dutch men and women), 19 and 39% (English men and women). Moreover, 79% (Croatian), 47% (Dutch) and 41% (English) of the patients with a severe depression score reported to have four or more serious diabetes-specific emotional problems. For patients with low depression scores, these percentages were: 29% (Croatian), 11% (Dutch) and 1% (English). Serious diabetes-specific emotional problems are particularly prevalent in depressed diabetes patients. Randomized controlled trials are warranted to test whether coverage of diabetes-specific issues during psychotherapy can further improve the treatment of depression in diabetes.     

A gene expression signature associated with metastatic outcome in human leiomyosarcomas

Metastasis is a major factor associated with poor prognosis in cancer, but little is known of its molecular mechanisms. Although the clinical behavior of soft tissue sarcomas is highly variable, few reliable determinants of outcome have been identified. New markers that predict clinical outcome, in particular the ability of primary tumors to develop metastatic tumors, are urgently needed. Here, we have chosen leiomyosarcoma as a model for examining the relationship between gene expression profile and the development of metastasis in soft tissue sarcomas. Using cDNA microarray, we have identified a gene expression signature associated with metastasis in sarcoma that allowed prediction of the future development of metastases of primary tumors (Kaplan-Meier analysis P = 0.001). Our finding may aid the tailoring of therapy for individual sarcoma patients, where the aggressiveness of treatment is affected by the predicted outcome of disease.