Machine learning-based evaluation of spontaneous pain and analgesics from cellular calcium signals in the mouse primary somatosensory cortex using explainable features

Introduction

Pain that arises spontaneously is considered more clinically relevant than pain evoked by external stimuli. However, measuring spontaneous pain in animal models in preclinical studies is challenging due to methodological limitations. To address this issue, recently we developed a deep learning (DL) model to assess spontaneous pain using cellular calcium signals of the primary somatosensory cortex (S1) in awake head-fixed mice. However, DL operate like a "black box", where their decision-making process is not transparent and is difficult to understand, which is especially evident when our DL model classifies different states of pain based on cellular calcium signals. In this study, we introduce a novel machine learning (ML) model that utilizes features that were manually extracted from S1 calcium signals, including the dynamic changes in calcium levels and the cell-to-cell activity correlations.

Method

We focused on observing neural activity patterns in the primary somatosensory cortex (S1) of mice using two-photon calcium imaging after injecting a calcium indicator (GCaMP6s) into the S1 cortex neurons. We extracted features related to the ratio of up and down-regulated cells in calcium activity and the correlation level of activity between cells as input data for the ML model. The ML model was validated using a Leave-One-Subject-Out Cross-Validation approach to distinguish between non-pain, pain, and drug-induced analgesic states.

Results and discussion

The ML model was designed to classify data into three distinct categories: non-pain, pain, and drug-induced analgesic states. Its versatility was demonstrated by successfully classifying different states across various pain models, including inflammatory and neuropathic pain, as well as confirming its utility in identifying the analgesic effects of drugs like ketoprofen, morphine, and the efficacy of magnolin, a candidate analgesic compound. In conclusion, our ML model surpasses the limitations of previous DL approaches by leveraging manually extracted features. This not only clarifies the decision-making process of the ML model but also yields insights into neuronal activity patterns associated with pain, facilitating preclinical studies of analgesics with higher potential for clinical translation.

The effect of ginger extract on cisplatin-induced acute anorexia in rats

Cisplatin is a platinum-based chemotherapeutic agent widely used to treat various cancers. However, several side effects have been reported in treated patients. Among these, acute anorexia is one of the most severe secondary effects. In this study, a single oral administration of 100 or 500 mg/kg ginger extract (GE) significantly alleviated the cisplatin-induced decrease in food intake in rats. However, these body weight and water intake decreases were reversed in the 100 mg/kg group rats. To elucidate the underlying mechanism of action, serotonin (5-HT) and 5-HT2C, 3A, and 4 receptors in the nodose ganglion of the vagus nerve were investigated. The results showed that cisplatin-induced increases in serotonin levels in both the blood and nodose ganglion tissues were significantly decreased by100 and 500 mg/kg of GE administration. On 5-HT receptors, 5-HT3A and 4, but not 2C receptors, were affected by cisplatin, and GE 100 and 500 mg/kg succeeded in downregulating the evoked upregulated gene of these receptors. Protein expression of 5-HT3A and 4 receptors were also reduced in the 100 mg/kg group. Furthermore, the injection of 5-HT3A, and 4 receptors antagonists (palonostron, 0.1 mg/kg, i.p.; piboserod, 1 mg/kg, i.p., respectively) in cisplatin treated rats prevented the decrease in food intake. Using high-performance liquid chromatography (HPLC) analysis, [6]-gingerol and [6]-shogaol were identified and quantified as the major components of GE, comprising 4.12% and 2.15% of the GE, respectively. Although [6]-gingerol or [6]-shogaol alone failed to alleviate the evoked anorexia, when treated together, the effect was significant on the cisplatin-induced decrease in food intake. These results show that GE can be considered a treatment option to alleviate cisplatin-induced anorexia.

Global Cerebral Ischemia-induced Depression Accompanies Alteration of Neuronal Excitability in the Infralimbic Cortex Layer 2/3 Pyramidal Neurons

Cerebral ischemia can lead to a range of sequelae, including depression. The pathogenesis of depression involves neuronal change of the medial prefrontal cortex (mPFC). However, how cerebral ischemia-induced changes manifest across subregions and layers of the mPFC is not well understood. In this study, we induced cerebral ischemia in mice via transient bilateral common carotid artery occlusion (tBCCAO) and observed depressive-like behavior. Using whole-cell patch clamp recording, we identified changes in the excitability of pyramidal neurons in the prelimbic cortex (PL) and infralimbic cortex (IL), the subregions of mPFC. Compared to sham control mice, tBCCAO mice showed significantly reduced neuronal excitability in IL layer 2/3 but not layer 5 pyramidal neurons, accompanied by increased rheobase current and decreased input resistance. In contrast, no changes were observed in the excitability of PL layer 2/3 and layer 5 pyramidal neurons. Our results provide a new direction for studying the pathogenesis of depression following ischemic damage by showing that cerebral ischemia induces subregion- and layer-specific changes in the mPFC pyramidal neurons.

Dynamic alteration of intrinsic properties of the cerebellar Purkinje cell during the motor memory consolidation

Intrinsic plasticity of the cerebellar Purkinje cell (PC) plays a critical role in motor memory consolidation. However, detailed changes in their intrinsic properties during memory consolidation are not well understood. Here, we report alterations in various properties involved in intrinsic excitability, such as the action potential (AP) threshold, AP width, afterhyperpolarization (AHP), and sag voltage, which are associated with the long-term depression of intrinsic excitability following the motor memory consolidation process. We analyzed data recorded from PCs before and 1, 4, and 24 h after cerebellum-dependent motor learning and found that these properties underwent dynamic changes during the consolidation process. We further analyzed data from PC-specific STIM1 knockout (STIM1^PKO) mice, which show memory consolidation deficits, and derived intrinsic properties showing distinct change patterns compared with those of wild-type littermates. The levels of memory retention in the STIM1^PKO mice were significantly different compared to wild-type mice between 1 and 4 h after training, and AP width, fast- and medium-AHP, and sag voltage showed different change patterns during this period. Our results provide information regarding alterations in intrinsic properties during a particular period that are critical for memory consolidation.

An Automated Cell Detection Method for TH-positive Dopaminergic Neurons in a Mouse Model of Parkinson's Disease Using Convolutional Neural Networks

Quantification of tyrosine hydroxylase (TH)-positive neurons is essential for the preclinical study of Parkinson's disease (PD). However, manual analysis of immunohistochemical (IHC) images is labor-intensive and has less reproducibility due to the lack of objectivity. Therefore, several automated methods of IHC image analysis have been proposed, although they have limitations of low accuracy and difficulties in practical use. Here, we developed a convolutional neural network-based machine learning algorithm for TH+ cell counting. The developed analytical tool showed higher accuracy than the conventional methods and could be used under diverse experimental conditions of image staining intensity, brightness, and contrast. Our automated cell detection algorithm is available for free and has an intelligible graphical user interface for cell counting to assist practical applications. Overall, we expect that the proposed TH+ cell counting tool will promote preclinical PD research by saving time and enabling objective analysis of IHC images.

Magnolin Inhibits Paclitaxel-Induced Cold Allodynia and ERK1/2 Activation in Mice

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of anti-cancer drugs. The main symptoms often include sensory disturbances and neuropathic pain, and currently there is no effective treatment for this condition. This study aimed to investigate the suppressive effects of magnolin, an extracellular signal-regulated kinase (ERK) inhibitor substance derived from a 95% EtOH extract of the seeds of Magnolia denudata, on the symptoms of CIPN. A taxol-based anti-cancer drug paclitaxel (PTX) was repeatedly injected (2 mg/kg/day, total 8 mg/kg) into mice to induce CIPN. A neuropathic pain symptom was assessed using a cold allodynia test that scores behaviors of licking and shaking paw after plantar administration of acetone drop. Magnolin was administered intraperitoneally (0.1, 1, or 10 mg/kg) and behavioral changes to acetone drop were measured. The effect of magnolin administration on ERK expression in the dorsal root ganglion (DRG) was investigated using western blot analysis. The results showed that the repeated injections of PTX induced cold allodynia in mice. Magnolin administration exerted an analgesic effect on the PTX-induced cold allodynia and inhibited the ERK phosphorylation in the DRG. These results suggest that magnolin could be developed as an alternative treatment to suppress paclitaxel-induced neuropathic pain symptoms.

mGluR1 Regulates the Interspike Interval Threshold for Dendritic Ca2+ Transients in the Cerebellar Purkinje Cells

Ca²⁺+ transients can be observed in the distal dendrites of Purkinje cells (PCs) despite their lack of action potential backpropagation. These Ca²⁺+ events in distal dendrites require specific patterns of PC firing, such as complex spikes (CS) or simple spikes (SS) of burst mode. Unlike CS, which can act directly on voltage-gated calcium channels in the dendrites through climbing fiber inputs, the condition that can produce the Ca²⁺+ events in distal dendrites with burst mode SS is poorly understood. Here, we propose the interspike interval threshold (ISIT) for Ca²⁺+ transients in the distal dendrites of PC. We found that to induce the Ca²⁺+ transients in distal dendrites the frequency of spike firing of PC should reach 250 Hz (3 ms ISI). Metabotropic glutamate receptor 1 (mGluR1) activation significantly relieved the ISIT and established cellular conditions in which spike firing with 50 Hz (19 ms ISI) could induce Ca²⁺+ transients in the distal dendrites. In contrast, blocking T-type Ca²⁺+ channels or depleting the endoplasmic reticulum Ca²⁺+ store resulted in a stricter condition in which spike firing with 333 Hz (2 ms ISI) was required. Our findings demonstrate that the PC has strict ISIT for dendritic Ca²⁺+ transients, and this ISIT can be relieved by mGluR1 activation. This strict restriction of ISIT could contribute to the reduction of the signal-to-noise ratio in terms of collecting information by preventing excessive dendritic Ca²⁺+ transients through the spontaneous activity of PC.

Adoptive therapy with amyloid-β specific regulatory T cells alleviates Alzheimer's disease

Rationale: Neuroinflammation is a primary feature of Alzheimer's disease (AD), for which an increasing number of drugs have been specifically developed. The present study aimed to define the therapeutic impact of a specific subpopulation of T cells that can suppress excessive inflammation in various immune and inflammatory disorders, namely, CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs). Methods: To generate Aβ antigen-specific Tregs (Aβ⁺ Tregs), Aβ 1-42 peptide was applied in vivo and subsequent in vitro splenocyte culture. After isolating Tregs by magnetic bead based purification method, Aβ⁺ Tregs were adoptively transferred into 3xTg-AD mice via tail vein injection. Therapeutic efficacy was confirmed with behavior test, Western blot, quantitative real-time PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry staining (IHC). In vitro suppression assay was performed to evaluate the suppressive activity of Aβ⁺ Tregs using flow cytometry. Thy1.1⁺ Treg trafficking and distribution was analyzed to explore the infused Tregs migration into specific organs in an antigen-driven manner in AD mice. We further assessed cerebral glucose metabolism using ¹⁸F-FDG-PET, an imaging approach for AD biological definition. Subsequently, we evaluated the migration of Aβ⁺ Tregs toward Aβ activated microglia using live cell imaging, chemotaxis, antibody blocking and migration assay. Results: We showed that Aβ-stimulated Tregs inhibited microglial proinflammatory activity and modulated the microglial phenotype via bystander suppression. Single adoptive transfer of Aβ⁺ Tregs was enough to induce amelioration of cognitive impairments, Aβ accumulation, hyper-phosphorylation of tau, and neuroinflammation during AD pathology. Moreover, Aβ-specific Tregs effectively inhibited inflammation in primary microglia induced by Aβ exposure. It may indicate bystander suppression in which Aβ-specific Tregs promote immune tolerance by secreting cytokines to modulate immune responses during neurodegeneration. Conclusions: The administration of Aβ antigen-specific regulatory T cells may represent a new cellular therapeutic strategy for AD that acts by modulating the inflammatory status in AD.

Transcutaneous Auricular Vagus Nerve Stimulation Enhances Cerebrospinal Fluid Circulation and Restores Cognitive Function in the Rodent Model of Vascular Cognitive Impairment

Vascular cognitive impairment (VCI) is a common sequela of cerebrovascular disorders. Although transcutaneous auricular vagus nerve stimulation (taVNS) has been considered a complementary treatment for various cognitive disorders, preclinical data on the effect of taVNS on VCI and its mechanism remain ambiguous. To measure cerebrospinal fluid (CSF) circulation during taVNS, we used in vivo two-photon microscopy with CSF and vasculature tracers. VCI was induced by transient bilateral common carotid artery occlusion (tBCCAO) surgery in mice. The animals underwent anesthesia, off-site stimulation, or taVNS for 20 min. Cognitive tests, including the novel object recognition and the Y-maze tests, were performed 24 h after the last treatment. The long-term treatment group received 6 days of treatment and was tested on day 7; the short-term treatment group received 2 days of treatment and was tested 3 days after tBCCAO surgery. CSF circulation increased remarkably in the taVNS group, but not in the anesthesia-control or off-site-stimulation-control groups. The cognitive impairment induced by tBCCAO was significantly restored after both long- and short-term taVNS. In terms of effects, both long- and short-term stimulations showed similar recovery effects. Our findings provide evidence that taVNS can facilitate CSF circulation and that repetitive taVNS can ameliorate VCI symptoms.

Development of a spontaneous pain indicator based on brain cellular calcium using deep learning

Chronic pain remains an intractable condition in millions of patients worldwide. Spontaneous ongoing pain is a major clinical problem of chronic pain and is extremely challenging to diagnose and treat compared to stimulus-evoked pain. Although extensive efforts have been made in preclinical studies, there still exists a mismatch in pain type between the animal model and humans (i.e., evoked vs. spontaneous), which obstructs the translation of knowledge from preclinical animal models into objective diagnosis and effective new treatments. Here, we developed a deep learning algorithm, designated AI-bRNN (Average training, Individual test-bidirectional Recurrent Neural Network), to detect spontaneous pain information from brain cellular Ca²⁺ activity recorded by two-photon microscopy imaging in awake, head-fixed mice. AI-bRNN robustly determines the intensity and time points of spontaneous pain even in chronic pain models and evaluates the efficacy of analgesics in real time. Furthermore, AI-bRNN can be applied to various cell types (neurons and glia), brain areas (cerebral cortex and cerebellum) and forms of somatosensory input (itch and pain), proving its versatile performance. These results suggest that our approach offers a clinically relevant, quantitative, real-time preclinical evaluation platform for pain medicine, thereby accelerating the development of new methods for diagnosing and treating human patients with chronic pain.

A microscopy technique coupled with an artificial intelligence (AI) platform could help researchers discover new types of pain-relief medicines. A team from South Korea led by Sun Kwang Kim of Kyung Hee University and Sang Jeong Kim of Seoul National University created a machine-learning algorithm that converts calcium signaling data in the brain, as estimated via imaging on genetically engineered mice, into a measurement of pain intensity. The researchers applied the technique to several mouse models of chronic pain and showed that it accurately captured the analgesic effects of known painkillers. They also extended the system to multiple brain regions, cell types and another brain-controlled sensory process, itch. The researchers propose using the AI-based tool to evaluate candidate anti-pain and anti-itch medicines ahead of human trials.

Therapeutics for Chemotherapy-Induced Peripheral Neuropathy: Approaches with Natural Compounds from Traditional Eastern Medicine

Chemotherapy-induced peripheral neuropathy (CIPN) often develops in patients with cancer treated with commonly used anti-cancer drugs. The symptoms of CIPN can occur acutely during chemotherapy or emerge after cessation, and often accompany long-lasting intractable pain. This adverse side effect not only affects the quality of life but also limits the use of chemotherapy, leading to a reduction in the survival rate of patients with cancer. Currently, effective treatments for CIPN are limited, and various interventions are being applied by clinicians and patients because of the unmet clinical need. Potential approaches to ameliorate CIPN include traditional Eastern medicine-based methods. Medicinal substances from traditional Eastern medicine have well-established analgesic effects and are generally safe. Furthermore, many substances can also improve other comorbid symptoms in patients. This article aims to provide information regarding traditional Eastern medicine-based plant extracts and natural compounds for CIPN. In this regard, we briefly summarized the development, mechanisms, and changes in the nervous system related to CIPN, and reviewed the substances of traditional Eastern medicine that have been exploited to treat CIPN in preclinical and clinical settings.

Antioxidant potential and α-glucosidase inhibitory activity of onion (Allium cepa L.) peel and bulb extracts

Allium cepa L. is a commonly consumed vegetable that belongs to the Amaryllidaceae family and contains nutrients and antioxidants in ample amounts. In spite of the valuable food applications of onion bulb, its peel and outer fleshy layers are generally regarded as waste and exploration of their nutritional and therapeutic potential is still in progress with a very slow progression rate. The present study was designed with the purpose of doing a comparative analysis of the antioxidant potential of two parts of Allium cepa, i.g., bulb (edible part) and outer fleshy layers and dry peels (inedible part). Moreover, the inhibitory effect of the onion bulb and peel extracts on rat intestinal α-glucosidase and pancreatic α-amylase of porcine was also evaluated. The antioxidant potential of onion peel and bulb extracts were evaluated using 2,2-diphenyl- 1-picryl hydrazyl (DPPH), ferric-reducing antioxidant power assay (FRAP), 2,2'-azino-bis- 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay, H2O2 radical scavenging activity and Fe2+ chelating activity. Total flavonoids and phenolic content of ethanolic extract of onion peel were significantly greater as compared to that of onion bulb. Ethanolic extract of onion peel also presented better antioxidant and free-radical scavenging activity as compared to the ethanolic extract of bulb, while the aqueous extract of bulb presented weakest antioxidative potential. Onion peel extract's α-glucosidase inhibition potential was also correlated with their phenolic and flavonoid contents. The current findings presented onion peel as a possible source of antioxidative agents and phenolic compounds that might be beneficial against development of various common chronic diseases that might have an association with oxidative stress. Besides, outer dry layers and fleshy peels of onion exhibited higher phenolic content and antioxidant activities, compared to the inner bulb. The information obtained by the present study can be useful in promoting the use of vegetable parts other than the edible mesocarp for several future food applications, rather than these being wasted.

Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set

BACKGROUND

A multi-cancer early detection (MCED) test used to complement existing screening could increase the number of cancers detected through population screening, potentially improving clinical outcomes. The Circulating Cell-free Genome Atlas study (CCGA; NCT02889978) was a prospective, case-controlled, observational study and demonstrated that a blood-based MCED test utilizing cell-free DNA (cfDNA) sequencing in combination with machine learning could detect cancer signals across multiple cancer types and predict cancer signal origin (CSO) with high accuracy. The objective of this third and final CCGA substudy was to validate an MCED test version further refined for use as a screening tool.

PATIENTS AND METHODS

This pre-specified substudy included 4077 participants in an independent validation set (cancer: n = 2823; non-cancer: n = 1254, non-cancer status confirmed at year-one follow-up). Specificity, sensitivity, and CSO prediction accuracy were measured.

RESULTS

Specificity for cancer signal detection was 99.5% [95% confidence interval (CI): 99.0% to 99.8%]. Overall sensitivity for cancer signal detection was 51.5% (49.6% to 53.3%); sensitivity increased with stage [stage I: 16.8% (14.5% to 19.5%), stage II: 40.4% (36.8% to 44.1%), stage III: 77.0% (73.4% to 80.3%), stage IV: 90.1% (87.5% to 92.2%)]. Stage I-III sensitivity was 67.6% (64.4% to 70.6%) in 12 pre-specified cancers that account for approximately two-thirds of annual USA cancer deaths and was 40.7% (38.7% to 42.9%) in all cancers. Cancer signals were detected across >50 cancer types. Overall accuracy of CSO prediction in true positives was 88.7% (87.0% to 90.2%).

CONCLUSION

In this pre-specified, large-scale, clinical validation substudy, the MCED test demonstrated high specificity and accuracy of CSO prediction and detected cancer signals across a wide diversity of cancers. These results support the feasibility of this blood-based MCED test as a complement to existing single-cancer screening tests.

CLINICAL TRIAL NUMBER

NCT02889978.

The Involvement of Central Noradrenergic Pathway in the Analgesic Effect of Bee Venom Acupuncture on Vincristine-Induced Peripheral Neuropathy in Rats

Vincristine is a vinca alkaloid anti-mitotic drug with a broad spectrum of effects on solid and hematologic cancers. The major dose-limiting factor of this anti-cancer regimen is painful peripheral neuropathy. However, no gold-standard analgesic option has been used clinically. In this study, we investigated the effects and mechanism of bee venom acupuncture (BVA) to alleviate peripheral neuropathic pain induced by repeated intraperitoneal infusions of vincristine (1 mg/kg/day, days 1–5 and 8–12) in rats. Subcutaneous injection with bee venom (BV, 1.0 mg/kg) at the ST36 acupoint ameliorated cold and mechanical hypersensitivity (i.e., aberrant withdrawal responses in acetone drop and von Frey hair tests, respectively). In vivo extracellular recording demonstrated that BVA inhibited cutaneous cold (acetone) and mechanical (brush, press, and pinch) stimuli-elicited abnormal hyperexcitation of the spinal wide dynamic range (WDR) neurons in vincristine-treated rats. In addition, the microinjection of lidocaine into the ipsilateral locus coeruleus or the antagonism of the spinal α₂-adrenergic receptors clearly reversed the effects of BVA on cold and mechanical hypersensitivity, indicating a vital role of the descending noradrenergic modulation in analgesia. These findings suggest that BVA could be a potential therapeutic option for vincristine-induced peripheral neuropathy.

Alzheimer's disease: insights for risk evaluation and prevention in the Chinese population and the need for a comprehensive programme in Hong Kong/China

With the ageing of the global population, China is projected to be impacted significantly by the rising number of patients with Alzheimer's disease (AD). A cure for AD is not yet available, so society should be prepared for an increasing AD-related burden. In this review, we examine this impending problem and provide overviews on (a) the magnitude of the problem of AD in Hong Kong/China in the near future; (b) the genetic and lifestyle risk factors that contribute to AD; (c) current diagnostic approaches and the potential of newly discovered genetic biomarkers for early detection; (d) medications, non-pharmacological interventions, and possible preventive measures; and (e) the need for social and psychological care from the community. In Hong Kong, primary care and AD-related support for at-risk individuals, patients, and caregivers are inadequate. A joint effort from the medical community, government, universities, non-governmental organisations/charities, and industry should initiate the development of a long-term programme for AD. Finally, we outline recommendations for the relevant parties to consider.

Metabotropic Glutamate Receptor 5 in the Medial Prefrontal Cortex as a Molecular Determinant of Pain and Ensuing Depression

Pain and depression affect one another, and this bidirectional interaction implies the existence of common or interacting neural pathways. Among the neural circuits relevant to negative affection, the medial prefrontal cortex (mPFC) is known to be involved in both pain and depression. Persistent stress from physical pain and mental distress can evoke maladaptive changes in mPFC circuits to induce depression. Conversely, the unpleasant mood condition alters mPFC circuits to distort the appraisal of aversion and make individuals vulnerable to pain. In this article, recent findings regarding mPFC in chronic pain and/or depression are reviewed, with particular focus on the metabotropic glutamate receptor 5 (mGluR5). Although the involvement of mGluR5 within the mPFC in both pain and depressive disorders has been extensively studied, there are controversies regarding changes in the activity of the mPFC during chronic pain and depression, and the functional roles of mGluR5 on altered mPFC activity. We discuss alterations in the availability of mGluR5 in the mPFC in these disorders, its role in behavioral manifestations, and its possible influence on cellular subpopulations that mediate dysfunction in the mPFC. We also propose molecular mechanisms that may cause expressional changes in mGluR5 within the mPFC circuitry.

TNF-α increases the intrinsic excitability of cerebellar Purkinje cells through elevating glutamate release in Bergmann Glia

For decades, the glial function has been highlighted not only as the ‘structural glue’, but also as an ‘active participant’ in neural circuits. Here, we suggest that tumor necrosis factor α (TNF-α), a key inflammatory cytokine, alters the neural activity of the cerebellar Purkinje cells (PCs) by facilitating gliotransmission in the juvenile male rat cerebellum. A bath application of TNF-α (100 ng/ml) in acute cerebellar slices elevates spiking activity of PCs with no alterations in the regularity of PC firings. Interestingly, the effect of TNF-α on the intrinsic excitability of PCs was abolished under a condition in which the type1 TNF receptor (TNFR1) in Bergmann glia (BG) was genetically suppressed by viral delivery of an adeno-associated virus (AAV) containing TNFR1-shRNA. In addition, we measured the concentration of glutamate derived from dissociated cerebellar cortical astrocyte cultures treated with TNF-α and observed a progressive increase of glutamate in a time-dependent manner. We hypothesised that TNF-α-induced elevation of glutamate from BGs enveloping the synaptic cleft may directly activate metabotropic glutamate receptor1 (mGluR1). Pharmacological inhibition of mGluR1, indeed, prevented the TNF-α-mediated elevation of the intrinsic excitability in PCs. Taken together, our study reveals that TNF-α triggers glutamate release in BG, thereby increasing the intrinsic excitability of cerebellar PCs in a mGluR1-dependent manner.

Upregulation of prefrontal metabotropic glutamate receptor 5 mediates neuropathic pain and negative mood symptoms after spinal nerve injury in rats

Patients with chronic pain easily accompany the negative mood symptoms such as depression and anxiety, and these disturbances in turn affect the aversive perception of pain. However, the underlying mechanisms are largely unknown. We hypothesized that the alteration of metabotropic glutamate receptor 5 (mGluR5) in the brain region underlies such a comorbidity of aversive states. We scanned the brain of chronic neuropathic pain model rats using positron emission tomography (PET) technique with an mGluR5-selective radiotracer [11C] ABP688 and found various brain regions with higher or lower level of mGluR5 compared to control rats. Among the brain areas, a prominent upregulation of mGluR5 was shown in the prelimbic region (PrL) of the medial prefrontal cortex (mPFC) of chronic neuropathic pain animals. A pharmacological blockade of upregulated mGluR5 in the PrL ameliorated the negative symptoms including tactile hypersensitivity and depressive-like behavior, which relieved the subjects from the unpleasant state of chronic neuropathic pain condition. Conversely, lentiviral overexpression of the mGluR5 in the PrL of naïve rats successfully induced comorbid pain and negative moods. Our data provide deeper insight into the shared mechanism of pain perception and negative emotions, identifying a therapeutic target for the treatment of chronic pain and mood disorders.

Simulating real-life exposures to uncover possible risks to human health: A proposed consensus for a novel methodological approach

In real life, consumers are exposed to complex mixtures of chemicals via food, water and commercial products consumption. Since risk assessment usually focuses on individual compounds, the current regulatory approach doesn't assess the overall risk of chemicals present in a mixture. This study will evaluate the cumulative toxicity of mixtures of different classes of pesticides and mixtures of different classes of pesticides together with food additives (FAs) and common consumer product chemicals using realistic doses after long-term exposure. Groups of Sprague Dawley (CD-SD) rats (20 males and 20 females) will be treated with mixtures of pesticides or mixtures of pesticides together with FAs and common consumer product chemicals in 0.0, 0.25 × acceptable daily intake (ADI)/tolerable daily intake (TDI), ADI/TDI and 5 × ADI/TDI doses for 104 weeks. All animals will be examined every day for signs of morbidity and mortality. Clinical chemistry hematological parameters, serum hormone levels, biomarkers of oxidative stress, cardiotoxicity, genotoxicity, urinalysis and echocardiographic tests will be assessed periodically at 6 month intervals. At 3-month intervals, ophthalmological examination, test for sensory reactivity to different types of stimuli, together with assessment of learning abilities and memory performance of the adult and ageing animals will be conducted. After 24 months, animals will be necropsied, and internal organs will be histopathologically examined. If the hypothesis of an increased risk or a new hazard not currently identified from cumulative exposure to multiple chemicals was observed, this will provide further information to public authorities and research communities supporting the need of replacing current single-compound risk assessment by a more robust cumulative risk assessment paradigm.

Extracellular ATP Induces Calcium Signaling in Odontoblasts

Odontoblasts form dentin at the outermost surface of tooth pulp. An increasing level of evidence in recent years, along with their locational advantage, implicates odontoblasts as a secondary role as sensory or immune cells. Extracellular adenosine triphosphate (ATP) is a well-characterized signaling molecule in the neuronal and immune systems, and its potential involvement in interodontoblast communications was recently demonstrated. In an effort to elaborate the ATP-mediated signaling pathway in odontoblasts, the current study performed single-cell reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescent detection to investigate the expression of ATP receptors related to calcium signal in odontoblasts from incisal teeth of 8- to 10-wk-old rats, and demonstrated an in vitro response to ATP application via calcium imaging experiments. While whole tissue RT-PCR analysis detected P2Y₂, P2Y₄, and all 7 subtypes (P2X₁ to P2X₇) in tooth pulp, single-cell RT-PCR analysis of acutely isolated rat odontoblasts revealed P2Y₂, P2Y₄, P2X₂, P2X₄, P2X₆, and P2X₇ expression in only a subset (23% to 47%) of cells tested, with no evidence for P2X₁, P2X₃, and P2X₅ expression. An increase of intracellular Ca²⁺ concentration in response to 100μM ATP, which was repeated after pretreatment of thapsigargin or under the Ca²⁺-free condition, suggested function of both ionotropic and metabotropic ATP receptors in odontoblasts. The enhancement of ATP-induced calcium response by ivermectin and inhibition by 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) confirmed a functional P2X₄ subtype in odontoblasts. Positive calcium response to 2',3'-O-(benzoyl-4-benzoyl)-ATP (BzATP) and negative response to α,β-methylene ATP suggested P2X₂, P2X₄, and P2X₇ as functional subunits in rat odontoblasts. Single-cell RT-PCR analysis of the cells with confirmed calcium response and immunofluorescent detection further corroborated the expression of P2X₄ and P2X₇ in odontoblasts. Overall, this study demonstrated heterogeneous expression of calcium-related ATP receptor subtypes in subsets of individual odontoblasts, suggesting extracellular ATP as a potential signal mediator for odontoblastic functions.

Abstract P5-14-04: A phase 2 study evaluating orteronel, an inhibitor of androgen biosynthesis, in patients with androgen receptor (AR)-expressing metastatic breast cancer: Interim analysis

Background: The frequency of AR expression varies in the different breast cancer subtypes with 88%, 59%, and 32% expression reported in ER+, HER2+, and triple negative tumors, respectively. AR expression is associated with resistance to endocrine therapy in ER+ breast cancer. Androgen levels frequently increase following treatment with aromatase inhibitors suggesting a role for androgen synthesis inhibitors in ER+ breast cancer. AR signaling and expression are seen in triple negative breast cancer (TNBC), and a distinct AR TNBC subtype can be identified by gene expression profiling. AR expression in TNBC offers a potential therapeutic target. Preclinical and clinical studies demonstrated anti-androgen agent activity in breast cancer cell lines; preliminary clinical data suggests activity in TNBC. Orteronel is a novel, oral, selective, nonsteroidal inhibitor of 17, 20-lyase, a key enzyme in androgen biosynthesis that is being evaluated as endocrine therapy in various hormone-sensitive cancers. In this phase 2 study we are evaluating single agent orteronel in AR+ MBC.

Methods: Pts with AR expressing MBC (≥10% staining by central immunohistochemistry) were eligible. Pts were grouped into 2 cohorts for analysis: Cohort 1-TNBC and Cohort 2-ER+ (HER2 could be +/- in this cohort). Pts must have been previously treated with standard therapy for MBC (1-3 chemotherapy regimens for TNBC, 1-3 hormonal therapies + 1 chemotherapy for ER+ patients, ≥2 HER2-targeted regimens for HER2+ patients). A 6 pt lead-in for safety and tolerability of orteronel in AR+ female MBC pts was followed by open enrollment to either cohort. All pts received 300 mg orteronel PO BID over a 4 week cycle and underwent response assessment every 2 cycles. Treatment was continued until disease progression or unacceptable toxicity. The hypothesized response rate for Cohort 1 was 10% and 13% for Cohort 2. We present the results of a protocol-specified interim analysis of the ER+ MBC pts (Cohort 2).

Results: From 3/2014 to 4/2015, a total of 29 pts were enrolled on cohort 2. Median age was 65 years (range, 39-79); 90% ECOG ≤1; 90% HER2-/10% HER2+; median of 7 prior therapies (range 3-11). 93% had prior chemotherapy. Pts received a median of 2 cycles of orteronel treatment (range 1-4) and 3 pts (10%) are still on treatment. Of the 26 pts (90%) pts that have discontinued, 19 (66%) discontinued due to disease progression, 4 (14%) due to pt decision, 2 (7%) due to adverse event (AE), and 1 (3%) due to non-compliance. The most common treatment-related G 3/4 AEs were increased lipase [3 pts (10%)] and hypertension [2 pts (7%)]. There were no treatment-related SAEs or deaths on study. Three pts (10%) had stable disease as their best response. Further response evaluation is underway.

Conclusions: Orteronel monotherapy was well tolerated but appears to have limited single-agent activity in this heavily pre-treated ER+ MBC pt population. The full results from this interim analysis will be presented.

Citation Format: Yardley DA, Peacock N, Young RR, Silber A, Chung G, Webb CD, Jones SF, Shastry M, Midha R, DeBusk LM, Hainsworth JD, Burris HA. A phase 2 study evaluating orteronel, an inhibitor of androgen biosynthesis, in patients with androgen receptor (AR)-expressing metastatic breast cancer: Interim analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-14-04.

Desipramine inhibits salivary Ca(2+) signaling and aquaporin translocation

OBJECTIVE

Desipramine is a tricyclic antidepressant with a negative side effect of dry mouth. The Na(+) /H(+) exchanger was suggested to be a target of desipramine in salivary gland cells. However, it is unclear whether desipramine has other targets in the salivary secretion pathway. Here, we studied the effect of desipramine on salivary Ca(2+) signaling.

MATERIALS AND METHODS

Cytosolic free Ca(2+) concentration ([Ca(2+) ]i ) was determined with the fluorescent Ca(2+) indicator fura-2/AM. Aquaporin translocation was analyzed by Western blotting and immunocytochemistry of confocal microscopy.

RESULTS

Desipramine inhibited the carbachol- and histamine-mediated increase in cytosolic Ca(2+) ([Ca(2+) ]i ) in a concentration-dependent manner. However, desipramine did not affect increases in [Ca(2+) ]i mediated by extracellular ATP, sphingosine-1-phosphate, or thapsigargin. The adrenergic receptor blockers prazosin and propranolol did not reverse the desipramine-mediated inhibition of carbachol- and histamine-induced increases in [Ca(2+) ]i . We also found that desipramine inhibits the increase in membrane aquaporin-5 level triggered by carbachol and histamine treatments.

CONCLUSIONS

These results imply that desipramine blocks muscarinic and histamine receptor-mediated Ca(2+) signaling and the subsequent translocation of aquaporin-5 in human salivary gland cells, suggesting a novel mechanism for the xerogenic effects of desipramine.

Activation of transient receptor potential ankyrin 1 by eugenol

Eugenol is a bioactive plant extract used as an analgesic agent in dentistry. The structural similarity of eugenol to cinnamaldehyde, an active ligand for transient receptor potential ankyrin 1 (TRPA1), suggests that eugenol might produce its effect via TRPA1, in addition to TRPV1 as we reported previously. In this study, we investigated the effect of eugenol on TRPA1, by fura-2-based calcium imaging and patch clamp recording in trigeminal ganglion neurons and in a heterologous expression system. As the result, eugenol induced robust calcium responses in rat trigeminal ganglion neurons that responded to a specific TRPA1 agonist, allyl isothiocyanate (AITC), and not to capsaicin. Capsazepine, a TRPV1 antagonist failed to inhibit eugenol-induced calcium responses in AITC-responding neurons. In addition, eugenol response was observed in trigeminal ganglion neurons from TRPV1 knockout mice and human embryonic kidney 293 cell lines that express human TRPA1, which was inhibited by TRPA1-specific antagonist HC-030031. Eugenol-evoked TRPA1 single channel activity and eugenol-induced TRPA1 currents were dose-dependent with EC50 of 261.5μM. In summary, these results demonstrate that the activation of TRPA1 might account for another molecular mechanism underlying the pharmacological action of eugenol.

Abstract P3-14-02: Patterns of the use of primary systemic therapy in the United States

Background: Primary systemic therapy (PST) is an accepted alternative to adjuvant systemic therapy of breast cancer. It provides equivalent survival, increased breast conservation rates, and prognostic information.

Methods: This analysis assesses patterns of PST use based on information collected by the National Cancer Database (NCDB), a joint project of the American College of Surgeons and the American Cancer Society which captures data on over 70% of all diagnosed breast cancer patients in the U.S. Using the b-participant use file of the NCDB, we evaluated regional, patient, and tumor factors associated with PST use.

Results: The NCDB captured 621,319 patients treated with PST from 2006 to 2010. Of these, 7.4% received systemic therapy pre-operatively, and 3.6% in both the pre- and post-operative settings. Factors correlating with timing of therapy are shown in the table. PST use increased steadily from 7.0% to 7.8% (p<0.001) from 2006 to 2010. PST was significantly more frequently used in younger, African-American, Hispanic, low-income, uninsured patients with larger, node positive tumors, living in large metropolitan areas in the West and treated in academic centers. These factors remained significantly and independently associated with PST on multivariate analysis.

 UnivariateMultivariateFactorPre-opPost-opBothp-valuep-valueYear of Diagnosis   <0.001<0.00120067.0%90.0%3.0%  20077.1%89.5%3.4%  20087.2%89.2%3.6%  20097.6%88.6%3.8%  20107.8%87.7%4.5%  Region   <0.001<0.001Northeast5.7%90.9%3.4%  Atlantic6.7%90.4%2.9%  Southeast8.0%88.2%3.8%  Great Lakes6.5%90.1%3.4%  South7.7%88.4%3.9%  Midwest5.2%90.2%4.6%  West11.4%84.2%4.4%  Mountain8.8%88.7%2.5%  Pacific7.7%88.3%4.0%  Community type (pop):   <0.001<0.001Metro (>1M)7.9%88.3%3.8%  Metro (250K-1M)7.1%89.5%3.4%  Metro (<250K)6.3%90.5%3.2%  Urban, adjacent to a metro area (20K+)6.5%90.0%3.5%  Urban, not adjacent to metro (20K+)6.3%90.5%3.2%  Urban, adjacent to metro (2500-19,999)6.7%89.4%4.0%  Urban, not adjacent to metro (2500-19,999)6.0%90.6%3.4%  Rural/urban pop, adjacent to metro (<2500)6.0%90.3%3.8%  Rural/urban pop, not adjacent to metro (<2500)5.7%90.5%3.8%  Facility type:   <0.001<0.001Community program6.4%90.5%3.1%  Comprehensive community program7.1%89.5%3.5%  Academic/research8.4%87.4%4.2%  Other6.4%90.0%3.6%  Age:   <0.001<0.001<609.4%85.8%4.8%  ≥604.9%92.9%2.3%  Race:   <0.001<0.001Caucasian6.7%89.3%3.5%  African-American11.8%83.3%4.9%  Other8.4%87.5%4.1%  Ethnicity:   <0.001<0.001Non-Hispanic7.2%89.3%3.6%  Hispanic11.2%83.3%5.4%  Median household income:   <0.0010.023<$30K9.0%86.8%4.2%  $30K-$34,9997.7%88.6%3.7%  $35K-$45,9997.2%89.1%3.7%  $46K+6.9%89.6%3.4%  Insurance:   <0.001<0.001Uninsured15.3%78.1%6.6%  Private7.8%88.3%3.9%  Medicaid13.7%79.2%7.2%  Medicare4.8%93.0%2.2%  Military8.2%87.5%4.4%  Clinical T stage:   <0.001<0.001T12.4%96.4%1.2%  T213.6%79.5%6.9%  T3-T435.9%45.3%18.8%  Clinical N stage:   <0.001<0.001N04.8%92.9%2.3%  N1-326.0%60.3%13.7%  pop: population; multivariate OR and 95% CI not shown

Conclusion: PST appears to be underutilized, received by only 7.8% of all patients, 36% of T3-T4 tumors, and 26.0% of clinically node positive patients. However, its rate of use has increased over the past years. There is also significant regional variation in the use of PST, independent of patient and tumor factors.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-02.

Abstract P6-11-03: Follow up of breast cancer patients who underwent gamma knife radiosurgery for a diagnosis of brain metastases: A single institutional experience

Background: Breast cancer (BC) is the second most common cause of brain metastases in the United States. We performed a retrospective analysis of BC patients (pts) in the Yale Gamma Knife Radiosurgery (GKRS) database treated for brain metastases (mets) to report overall survival (OS) from time of GKRS, and to identify factors that predict improved survival outcomes.

Methods: We performed retrospective review of the Yale database of BC pts treated with standard GKRS technique for brain mets from 2000 to May 2013. Treatment doses typically ranged from 16 to 24 Gy prescribed to the 40-85% isodose surfaces. Overall survival (OS) for each patient was calculated from the date of first GKRS treatment of brain metastases. Variables included age, Karnofsky Performance Status (KPS), pre/post whole-brain radiation treatment (WBRT) and/or surgical resection, and # of brain mets treated (1-4 vs ≥5).

Results: A total of 80 BC pts were identified, with a mean age of 56.2 yrs; KPS 40-60 in 8pts (10%), 70-80 in 13 (16%), 90-100 in 41 (51%), unknown in 18 (23%); ER+ in 38 (48%), ER- in 38 (48%), unknown in 4 (5%); HER2 + in 38 (48%), HER2- in 33 (41%), indeterminate in 3 (4%) and unknown in 6 (8%). BC subtypes are Luminal A (ER+/HER2-) in 16 (20%), Luminal B (ER+/HER2+) in 19 (24%), HER-2(ER-/HER2+) in 17 (21%), Basal (ER-/HER2-) in 17 (21%), unknown in 11 (14%). Number of brain mets at time of first GKRS ≥5 in 32 (40%); prior WBRT in 30 (38%); WBRT post GKRS in 9 (11%); surgical resection for brain mets in 13 (16%) prior to GKRS and post GKRS in 9 (11%); 16% had ≥3 GKRS. Median time from primary BC dx to brain mets is 62.8 months (m) (range 46.2-81.6); with no significant difference among subtypes. Median OS from GKRS is 13.1 m (7.6-21.9); median OS from brain mets is 18.8 m (11.7-23.9). On univariate analysis, factors associated with significant improved OS from time of GKRS included HER-2 subtype (p = 0.005), KPS 90-100 (p = 0.008), good control of systemic disease (p = 0.017), pre (p = 0.041) and post GKRS surgical resection (p = 0.02). Age, pre or post WBRT, # of brain mets (1-4 vs. 5) were not significant predictors of OS from time of GKRS. In a multivariate Cox analysis (46 cases), HER-2 subtype remained a significant predictor of improved OS from time of GKRS; (HR) 0.26, 95%CI 0.08 to 0.8, p-value = 0.02. There was a trend in favor of surgical resection of brain mets pre GKRS (HR 0.14, 95% CI 0.02 to 1.15, p-value = 0.067

Conclusion: GKRS offers good local control for BC pts with brain mets, and is a reasonable option for pts with ≥5 brain mets. Our results show no associated survival benefit for administration of WBRT pre/post GKRS. HER-2 subtype is a significant predictor of improved survival in BC pts undergoing GKRS for brain mets.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-03.

Abstract P5-13-05: Richer and wiser: Factors correlated with chemoprevention use in the United States

Introduction: Tamoxifen and raloxifene have been shown to reduce the risk of breast cancer by up to 50%, yet the uptake of these agents remains poor. We sought to determine factors associated with chemoprevention uptake in a nationally representative sample.

Methods: The National Health Interview Survey (NHIS) is a population-based survey conducted annually by the CDC and is designed to be representative of the non-institutionalized civilian population in the United States. We utilized data from the 2010 NHIS cancer supplement to determine factors associated with chemoprevention uptake in women ≥ 35 years of age. Statistical analyses were conducted using SUDAAN software.

Results: In 2010, 10,959 women ≥ 35 years of age were surveyed, representing 83,377,082 people in the population. Of these, 0.21% reported taking chemoprevention, using either tamoxifen or raloxifene. On bivariate analyses, factors correlating with chemoprevention uptake included age, race/ethnicity, education, insurance, income and geographic region (see Table). Interestingly, MRI use, family history of premenopausal breast cancer in first degree relatives, and personal risk perception were not associated with chemoprevention use. On multivariate analysis, education and income remained independent predictors of chemoprevention use.

Conclusion: Approximately 0.2% of women take chemoprevention. It is concerning that sociodemographic factors of education and income are independent predictors of the use of chemopreventive agents for breast cancer, while risk perception and family history do not seem to correlate with uptake rates. These findings are a call to action for improved education and counseling of those who are at greatest risk, and highlight potential disparities in access to appropriate chemoprevention across all sociodemographic groups.

Bivariate and Multivariate Analyses of Factors Correlated with Chemoprevention UptakeFactorBivariate AnalysisMultivariate Analysis Chemoprevention (%)No Chemoprevention (%)p-valueOR (95% CI)p-valueAge  0.0481 0.1087< 40 yr3.2211.93 1.00 40-49 yr5.8726.11 0.78 (0.05-12.44) 50-59 yr11.7024.88 1.44 (0.10-21.43) 60-69 yr23.8218.54 3.15 (0.32-31.41) 70-79 yr44.4110.77 8.62 (0.78-94.75) 80+ yr10.997.77 1.53 (0.10-23.66) Race/ethnicity  0.0006 0.8372Hispanic3.9011.06 00.81 (0.11-5.85) White96.1071.63 1.00 Black011.80 - Asian04.61 - Other00.89 - Education  0.0371 <0.0001< Grade 127.1214.15 1.00 High School25.8627.73 1.86 (0.35-9.75) Some college/Assoc21.4229.97 1.85 (0.36-9.45) Bachelors15.5917.49 1.44 (0.13-16.35) Masters11.708.37 3.23 (0.41-25.14) Prof/Doctorate18.302.28 25.22 (4.30-147.87) Insurance  0.0002 0.0686Not covered012.44 - Medicare72.6129.38 1.00 Medicaid3.224.50 2.38 (0.22-26.15) Military01.74 - Private24.1751.94 0.28 (0.06-1.26) Income  0.0005 0.0306<$35K32.3934.53 1.00 $35K-$74,99926.1131.53 0.97 (0.21-4.42) $75K-$99,999012.08 - $100K+41.6021.86 3.78 (0.94-15.22) Region  0.0441 0.1649Northeast27.9318.62 1.00 Midwest31.6022.88 0.92 (0.32-2.64) South34.4935.66 0.65 (0.21-2.04) West5.9822.84 0.16 (0.03-0.86) Oophorectomy40.1115.160.08132.17 (0.77-6.09)0.1404MRI use2.315.170.2597  Family History2.315.130.2601  Risk Perception  0.1451  High41.5212.50   Average25.8947.49   Low32.5940.01   

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-05.

Pain fiber anesthetic reduces brainstem Fos after tooth extraction

We recently demonstrated that pain-sensing neurons in the trigeminal system can be selectively anesthetized by co-application of QX-314 with the TRPV1 receptor agonist, capsaicin (QX cocktail). Here we examined whether this new anesthetic strategy can block the neuronal changes in the brainstem following molar tooth extraction in the rat. Adult male Sprague-Dawley rats received infiltration injection of anesthetic 10 min prior to lower molar tooth extraction. Neuronal activation was determined by immunohistochemistry for the proto-oncogene protein c-Fos in transverse sections of the trigeminal subnucleus caudalis (Sp5C). After tooth extraction, c-Fos-like immunoreactivity (Fos-LI) detected in the dorsomedial region of bilateral Sp5C was highest at 2 hrs (p < .01 vs. naïve ipsilateral) and declined to pre-injury levels by 8 hrs. Pre-administration of the QX cocktail significantly reduced to sham levels Fos-LI examined 2 hrs after tooth extraction; reduced Fos-LI was also observed with the conventional local anesthetic lidocaine. Pulpal anesthesia by infiltration injection was confirmed by inhibition of the jaw-opening reflex in response to electrical tooth pulp stimulation. Our results suggest that the QX cocktail anesthetic is effective in reducing neuronal activation following tooth extraction. Thus, a selective pain fiber 'nociceptive anesthetic' strategy may provide an effective local anesthetic option for dental patients in the clinic.

Cellular and molecular mechanisms of dental nociception

Due, in part, to the unique structure of the tooth, dental pain is initiated via distinct mechanisms. Here we review recent advances in our understanding of inflammatory tooth pain and discuss 3 hypotheses proposed to explain dentinal hypersensitivity: The first hypothesis, supported by functional expression of temperature-sensitive transient receptor potential channels, emphasizes the direct transduction of noxious temperatures by dental primary afferent neurons. The second hypothesis, known as hydrodynamic theory, attributes dental pain to fluid movement within dentinal tubules, and we discuss several candidate cellular mechanical transducers for the detection of fluid movement. The third hypothesis focuses on the potential sensory function of odontoblasts in the detection of thermal or mechanical stimuli, and we discuss the accumulating evidence that supports their excitability. We also briefly update on a novel strategy for local nociceptive anesthesia via nociceptive transducer molecules in dental primary afferents with the potential to specifically silence pain fibers during dental treatment. Further understanding of the molecular mechanisms of dental pain would greatly enhance the development of therapeutics that target dental pain.

Characterization of Dental Nociceptive Neurons

Selective blockade of nociceptive neurons can be achieved by the delivery of permanently charged sodium channel blockers through the pores of nociceptive ion channels. To assess the feasibility of this application in the dental area, we investigated the electrophysiological and neurochemical characteristics of nociceptive dental primary afferent (DPA) neurons. DPA neurons were identified within trigeminal ganglia labeling with a retrograde fluorescent dye applied to the upper molars of adult rats. Electrophysiological studies revealed that the majority of dental primary afferent neurons showed characteristics of nociceptive neurons, such as sensitivity to capsaicin and the presence of a hump in action potential. Immunohistochemical analysis revealed a large proportion of DPA neurons to be IB4-positive and to express TRPV1 and P2X3. Single-cell RT-PCR revealed mRNA expression of various nociceptive channels, including the temperature-sensitive TRPV1, TRPA1, TRPM8 channels, the extracellular ATP receptor channels P2X2 and P2X3, as well as the nociceptor-specific sodium channel, NaV1.8. In conclusion, DPA neurons have the electrophysiological characteristics of nociceptors and express several nociceptor-specific ion channels. Analysis of these data may assist in the search for a new route of entry for the delivery of membrane-impermeant local anesthetics. Abbreviations: AP, action potential; DiI, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate; DPA, dental primary afferent; FITC, fluorescein 5(6)-isothiocyanate; IB4, isolectin-B4; RT-PCR, reverse-transcription polymerase chain-reaction; TRP, transient receptor potential.

Abstract P3-14-17: Trastuzumab (H) and Rapamycin (R) for Treatment of HER-2 Overexpressing Metastatic Breast Cancer (BC) with Prior Disease Progression on H Based Therapy: Safety and Pharmacodynamic (PD) Results

Background: Preclinical data shows upregulation of the PI3K/AKT pathway and synergistic cytotoxicty between H+R in sensitive and resistant HER-2 overexpressing BC cell lines.

Methods: We designed a phase II clinical trial with an early stopping rule for excess toxicity in the first 4 wks of H+R therapy, defined as ≥3 cases of drug related grade 3 or 4 toxicity observed in the first 9 pts enrolled on trial. We report safety and PD results in 11 pts treated with oral R 6 mg daily + standard dosesand schedule of H. LVEF by ECHO or MUGA was assessed at baseline and every 3 months thereafter; treatment was held for LVEF drop below normal limits or ≥20 percentage points. Pre and post therapy tumor samples were collected when feasible. Circulating tumor (CTC) and endothelial (CEC) cells were collected and analyzed using the Veridex Cell Search System at baseline, wks 1, 2 and 4 and with every restaging.

Results: 11 pts with median age 56 y (range 38-70) treated with H+R were evaluable for safety. Median # cycles was 3 (range 1+ to 12). Non-hematologic grade 3 toxicities in first 4 wks occurred in 3 of the first 9 pts: 1 pt had syncope associated with leucopenia/neutropenia and urinary infection; 1pt had mucositis which responded to dose reduction; 1 pt with known diabetes had grade 3 hyperglycemia, however, this was non-fasting. One pt had grade 3 leucopenia/neutropenia which responded to dose reduction. Grade 3 toxicities for 11 pts in all cycles were as follows: leucopenia/neutropenia (2 pts), non-fasting hyperglycemia (2 pts), syncope (1 pt), hypokalemia (1pt), hyponatremia (1 pt), mucositis (1 pt), rash (2 pts), nail changes (1 pt), thrombosis (1 pt). Infection (urine in 1 pt, skin in 1 pt), anemia (1pt), and elevated PTT (1 pt). One grade 4 non-fasting hyperglycemia occurred in a diabetic pt. LVEF dropped below normal limits and recovered subsequently in 2 pts. Nine pts had baseline and at least one subsequent evaluation for radiographic response by RECIST. Best response was unconfirmed partial response (PR) in 1 pt (8 cycles), stable disease (SD) in 5 pts (12, 6+,6, 3, and 2 cycles) and progression (PD) in 3pts. We combined analysis of AKT pathway markers from 12 baseline and 9 post therapy tissue samples collected on this trial and a phase I study of R +chemotherapy. There were high correlations between baseline AKT pathway markers (mTOR, PTEN, Akt, pAkt, S6K1 and pS6K1; (Spearman's rho-0.401-0.907). This correlation was lost in post therapy samples. Higher mean mTOR levels were seen in non-responders (PD) vs. responders (SD/PR) [p value=0.04]. Eight pts had CTC and CEC results, and were evaluable for response. Baseline CTC levels of &gt;5 cells/7.5 ml were seen in 2/2 pts with PD and 0/6 pts with SD/PR. There was no significant difference in CEC levels between responders and non-responders. Conclusion: R 6 mg daily appears to be well tolerated when combined with standard doses of H. PR in 1 pt and SD for ≥6 months was observed in 2 pts with prior progression on H based therapy. Baseline elevated mTOR level correlates with poor response to R based combinations. Post therapy change in marker expression suggests biologic effect of R.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-14-17.

Adult Rat Odontoblasts Lack Noxious Thermal Sensitivity

Dentin hypersensitivity is a common symptom treated in the dental clinic, yet the underlying cellular and molecular mechanisms are not clear. We hypothesized that odontoblasts detect noxious thermal stimuli by expressing temperature-sensing molecules, and investigated whether temperature-activated TRP channels (thermo-TRP channels), which are known to initiate temperature signaling, mediate temperature sensing in odontoblasts. mRNA expression of dentin sialophosphoprotein and collagenase type 1, odontoblast-specific proteins, was shown in acutely isolated adult rat odontoblasts by single-cell RT-PCR, while TRPV1, TRPV2, TRPM8, and TRPA1 were not detected. Application of noxious temperatures of 42°C and 12°C, as well as capsaicin, menthol, and icilin, agonists of thermo-TRP channels, failed to increase intracellular calcium concentration. Immunohistochemical study also revealed no expression of TRPV1. Thus, it is unlikely that odontoblasts serve as thermal sensors in teeth via thermo-TRP channels.

Modulation of CaV2.3 calcium channel currents by eugenol

Eugenol, a natural congener of capsaicin, is a routine analgesic agent in dentistry. We have recently demonstrated the inhibition of Ca(V)2.2 calcium channel and sodium channel currents to be molecular mechanisms underlying the analgesic effect of eugenol. We hypothesized that Ca(V)2.3 channels are also modulated by eugenol and investigated its mode of action using the whole-cell patch-clamp technique in a heterologous expression system. Eugenol inhibited calcium currents in the E52 cell line, stably expressing the human Ca(V)2.3 calcium channels, where TRPV1 is not endogenously expressed. The extent of current inhibition was not significantly different between naïve E52 cells and TRPV1-expressing E52 cells, suggesting no involvement of TRPV1. In contrast, TRPV1 activation is prerequisite for the inhibition of Ca(V)2.3 calcium channels by capsaicin. The results indicate that eugenol has mechanisms distinct from those of capsaicin for modulating Ca(V)2.3 channels. We suggest that inhibition of Ca(V)2.3 channels by eugenol might contribute to its analgesic effect.

The Centre for Health Informatics at the University of New South Wales - a Clinical Informatics Research Centre

Building a sustainable health system in the 21st Century will require the reinvention of much of the present day system, and the intelligent use of information and communication technologies (ICT) to deliver high quality, safe, efficient and affordable health care. The Centre for Health Informatics (CHI) is Australia’s largest academic research group in this emerging discipline.

Our research is underpinned by a planning process, based on different future scenarios for the health system, which helps us identify longer-term problems needing a sustained research effort. A research competency matrix is used to ensure that the Centre has the requisite core capabilities in the research methods and tools needed to pursue our research program.

The Centre’s work is internationally recognized for its contributions in the development of intelligent search systems to support evidence-based healthcare, developing evaluation methodologies for ICT, and in understanding how communication shapes the safety and quality of health care delivery. Centre researchers also are working on safety models and standards for ICT in healthcare, mining complex gene micro array, medical literature and medical record data, building health system simulation methods to model the impact of health policy changes, and developing novel computational methods to automate the diagnosis of 3-D medical images.

Any individual research group like CHI must necessarily focus on a few areas to allow it to develop sufficient research capacity to make novel and internationally significant contributions. As CHI approaches the end of its first decade, it is becoming clear that developing capacity becomes increasingly challenging as the research territory changes under our feet, and that the Centre will continue to evolve and shift its focus in the years to come.

The Centre for Health Informatics at the University of New South Wales--a clinical informatics research centre

OBJECTIVES

Building a sustainable health system in the 21st Century will require the reinvention of much of the present day system, and the intelligent use of information and communication technologies (ICT) to deliver high quality, safe, efficient and affordable health care. The Centre for Health Informatics (CHI) is Australia's largest academic research group in this emerging discipline.

METHODS

Our research is underpinned by a planning process, based on different future scenarios for the health system, which helps us identify longer-term problems needing a sustained research effort. A research competency matrix is used to ensure that the Centre has the requisite core capabilities in the research methods and tools needed to pursue our research program.

RESULTS

The Centre's work is internationally recognized for its contributions in the development of intelligent search systems to support evidence-based healthcare, developing evaluation methodologies for ICT, and in understanding how communication shapes the safety and quality of health care delivery. Centre researchers also are working on safety models and standards for ICT in healthcare, mining complex gene micro array, medical literature and medical record data, building health system simulation methods to model the impact of health policy changes, and developing novel computational methods to automate the diagnosis of 3-D medical images.

CONCLUSIONS

Any individual research group like CHI must necessarily focus on a few areas to allow it to develop sufficient research capacity to make novel and internationally significant contributions. As CHI approaches the end of its first decade, it is becoming clear that developing capacity becomes increasingly challenging as the research territory changes under our feet, and that the Centre will continue to evolve and shift its focus in the years to come.

Neoadjuvant dose-dense (DD) concurrent doxorubicin (A) and docetaxel (T) for stage III breast cancer (BC)

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Background: The addition of taxanes to anthracycline therapy results in improved disease-free survival (DFS) in the adjuvant setting, and increased pathologic complete response rates (pCR) in the neoadjuvant setting. DD chemotherapy improves DFS and overall survival (OS). We evaluated neoadjuvant DD concurrent AT. Methods: Eligible patients (pts) with stage III BC were treated with AT q 14 days at 1 of 3 dose levels; L1 = 60 mg/m2 for both drugs (4 pts), L2 = A 75 mg/m2 and T 60 mg/m2 (6 pts) or L3 = 75 mg/m2 for both drugs (7 pts) × 6 cycles with G-CSF. Dexrazoxane was given after a cumulative dose of 300 mg/m2 of A. Pts were stratified to post-operative moderate risk (ModR) (≥ partial response, ≤ 3 lymph nodes (LN)) and received adjuvant IV cyclophosphamide (C) 600 mg/m2, methotrexate 40 mg/m2, 5FU 600 mg/m2 IV q 21 d × 6 (CMF), or high risk (HiR) (≤ minor response +/or ≥ 4 LN) and received C 3 gm/m2 q 14 d x 3. Primary endpoints were clinical and pathologic response rates of neoadjuvant AT. Sample size was 42 pts to estimate pCR and provide 90% confidence the true incidence of severe toxicity is <10%. Results: 17 pts with stage III BC were enrolled between 2/1999 and 7/2001; accrual was halted after data on pre-operative trastuzumab were presented. Median age was 50 yrs [range: 34–69]. 3/17 pts (17.6%) had a pCR, and 3 pts had near pCR (residual foci ≤ 1mm), 4/17 (23.5%) had path (-) LN, 7/17 (41%) had a lumpectomy, 7/17 (41%) required dose reductions of AT due to grade 4 neutropenia (5 pts) and grade 3 neuropathy (2 pts). 3 pts required treatment cessation; 1 pt (L2) for prolonged neutropenic fever and 2 pts (L3) for decreased ejection fraction and for acute renal failure. 15 pts were ModR and received adjuvant CMF, 1/2 pts stratified to high dose C declined it and received CMF. Median follow-up is 63 months [range: 28–80] with 13/17 (76.5%) pts surviving, and 12/17 (70.5%) pts surviving and free of disease. Conclusion: Neoadjuvant DD AT every 2 weeks is well-tolerated, with promising activity and survival in locally advanced BC.

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