Adipose-derived stem cells decolonize skin by enhancing phagocytic activity of peripheral blood mononuclear cells in the atopic rats.

() is known to induce apoptosis of host immune cells and impair phagocytic clearance, thereby being pivotal in the pathogenesis of atopic dermatitis (AD). Adipose-derived stem cells (ASCs) exert therapeutic effects against inflammatory and immune diseases. In the present study, we investigated whether systemic administration of ASCs restores the phagocytic activity of peripheral blood mononuclear cells (PBMCs) and decolonizes cutaneous under AD conditions.

Common and discrete mechanisms underlying chronic pain and itch: peripheral and central sensitization.

Normally, an obvious antagonism exists between pain and itch. In normal conditions, painful stimuli suppress itch sensation, whereas pain killers often generate itch. Although pain and itch are mediated by separate pathways under normal conditions, most chemicals are not highly specific to one sensation in chronic pathologic conditions.

Adipose Tissue-Derived Stem Cells Alleviate Cold Allodynia in a Rat Spinal Nerve Ligation Model of Neuropathic Pain.

Neuropathic pain caused by lesions or nervous system dysfunction is a neuroimmune disease with limited therapeutic options. Adipose tissue-derived stem cells (ASCs) are multipotent mesenchymal stem cells with potent immunosuppressive properties, and their use as novel cell-based therapeutics have been proposed in many immune diseases. However, the analgesic effect and efficacy of ASCs to treat neuropathic pain remain unclear.

GT1b functions as a novel endogenous agonist of toll-like receptor 2 inducing neuropathic pain.

Spinal cord microglia contribute to nerve injury-induced neuropathic pain. We have previously demonstrated that toll-like receptor 2 (TLR2) signaling is critical for nerve injury-induced activation of spinal cord microglia, but the responsible endogenous TLR2 agonist has not been identified. Here, we show that nerve injury-induced upregulation of sialyltransferase St3gal2 in sensory neurons leads to an increase in expression of the sialylated glycosphingolipid, GT1b.

Natural Killer Cells Degenerate Intact Sensory Afferents following Nerve Injury.

Sensory axons degenerate following separation from their cell body, but partial injury to peripheral nerves may leave the integrity of damaged axons preserved. We show that an endogenous ligand for the natural killer (NK) cell receptor NKG2D, Retinoic Acid Early 1 (RAE1), is re-expressed in adult dorsal root ganglion neurons following peripheral nerve injury, triggering selective degeneration of injured axons. Infiltration of cytotoxic NK cells into the sciatic nerve by extravasation occurs within 3 days following crush injury.

Topical film prepared with Rhus verniciflua extract-loaded pullulan hydrogel for atopic dermatitis treatment.

Atopic dermatitis (AD) is characterized by relapsing pruritus and skin dryness. Due to the pathogenic multiplicity and the adverse effects associated with the current therapeutics, development of transdermal drug delivery system is becoming an area of interest. Here, a novel topical film prepared with Rhus verniciflua extract (RVE)-loaded pullulan hydrogel (RVE@PH) was synthesized and tested its therapeutic efficacy on the AD rats modeled by neonatal capsaicin injection method.

Capsaicin induces atopic dermatitis-like manifestations through dysregulation of proteolytic system and alteration of filaggrin processing in rats.

Atopic dermatitis (AD) is a complex disease featuring pruritic skin inflammation. Many animal models have been developed. In a rat model, subcutaneous capsaicin injection within 48 hours after birth induces AD-like skin manifestations of dermatitis and scratching behaviour 3 weeks after the injection.

Glyoxal-induced exacerbation of pruritus and dermatitis is associated with staphylococcus aureus colonization in the skin of a rat model of atopic dermatitis.

Background: Atopic dermatitis (AD) is a highly pruritic, chronic inflammatory skin disease associated with hyperreactivity to environmental triggers. Among those, outdoor air pollutants such as particulate matter (PM) have been reported to aggravate pre-existing AD. However, underlying mechanisms of air pollution-induced aggravation of AD have hardly been studied.

Effects of Exposure of Formaldehyde to a Rat Model of Atopic Dermatitis Induced by Neonatal Capsaicin Treatment.

Atopic dermatitis is chronically relapsing pruritic eczema and prevails around the world especially in developed countries. Complex interactions between genetic and environmental factors are known to play an important role in the pathophysiology of atopic dermatitis. However, we still lack a detailed picture of the pathogenesis of this disease.

Asthma-like airway inflammation and responses in a rat model of atopic dermatitis induced by neonatal capsaicin treatment.

Recent studies have shown that approximately 70% of patients with severe atopic dermatitis (AD) develop asthma. Development of AD in infancy and subsequent other atopic diseases such as asthma in childhood is referred to as atopic march. However, a causal link between the diseases of atopic march has remained largely unaddressed, possibly due to lack of a proper animal model.

Acute inflammation reveals GABA receptor-mediated nociception in mouse dorsal root ganglion neurons via PGE receptor 4 signaling.

Gamma-aminobutyric acid (GABA) depolarizes dorsal root ganglia (DRG) primary afferent neurons through activation of Cl permeable GABA receptors but the physiologic role of GABA receptors in the peripheral terminals of DRG neurons remains unclear. In this study, we investigated the role of peripheral GABA receptors in nociception using a mouse model of acute inflammation. In vivo, peripheral administration of the selective GABA receptor agonist muscimol evoked spontaneous licking behavior, as well as spinal wide dynamic range (WDR) neuron firing, after pre-conditioning with formalin but had no effect in saline-treated mice.

Formaldehyde-Induced Aggravation of Pruritus and Dermatitis Is Associated with the Elevated Expression of Th1 Cytokines in a Rat Model of Atopic Dermatitis.

Atopic dermatitis is a complex disease of heterogeneous pathogenesis, in particular, genetic predisposition, environmental triggers, and their interactions. Indoor air pollution, increasing with urbanization, plays a role as environmental risk factor in the development of AD. However, we still lack a detailed picture of the role of air pollution in the development of the disease.

Brief Isolation Changes Nociceptive Behaviors and Compromises Drug Tests in Mice.

Herding with a litter is known to comfort rodents, whereas isolation and grouping with noncagemates provoke stress. The effects of stress induced by isolation and grouping with noncagemates on pain responses, and their underlying mechanisms remain elusive. We assessed the effect of isolation, a common condition during behavioral tests, and of grouping on defecation and pain behaviors of mice.

Juvenile obesity aggravates disease severity in a rat model of atopic dermatitis.

Purpose: There is increasing epidemiological evidence of an association between childhood obesity and atopic dermatitis, but little is known about the underlying mechanism(s). In the present study, we used a rat model of atopic dermatitis to assess whether juvenile obesity, induced by reduction of litter size, aggravated the signs of atopic dermatitis and, if so, whether this aggravation was associated with changes in plasma concentration of adipokines, such as leptin and adiponectin.

Methods: Dermatitis was induced by neonatal capsaicin treatment.

HYP-1, a novel diamide compound, relieves inflammatory and neuropathic pain in rats.

In the present study, we investigated whether a novel compound, 2-(2-(4-((4-chlorophenyl)(phenyl)methyl) piperazin-1-yl)-2-oxoethylamino)-N-(3,4,5-trimethoxybenzyl)acetamide (HYP-1), is capable of binding to voltage-gated sodium channels (VGSCs) and evaluated both its inhibitory effect on Na+ currents of the rat dorsal root ganglia (DRG) sensory neuron and its in vivo analgesic activity using rat models of inflammatory and neuropathic pain. HYP-1 showed not only high affinity for rat sodium channel (site 2), but also potent inhibitory activity against the TTX-R Na+ currents of the rat DRG sensory neuron. HYP-1 co-injected with formalin (5%, 50 μl) under the plantar surface of rat hind paw dose-dependently reduced spontaneous pain behaviors during both the early and late phases.

Chronically relapsing pruritic dermatitis in the rats treated as neonate with capsaicin; a potential rat model of human atopic dermatitis.

Background: The pathophysiological mechanisms underlying chronic pruritic skin diseases, e.g. atopic dermatitis (AD), and effective therapies remain elusive due to the paucity of animal models.

The calcium-activated chloride channel anoctamin 1 acts as a heat sensor in nociceptive neurons.

Nociceptors are a subset of small primary afferent neurons that respond to noxious chemical, thermal and mechanical stimuli. Ion channels in nociceptors respond differently to noxious stimuli and generate electrical signals in different ways. Anoctamin 1 (ANO1 also known as TMEM16A) is a Ca(2+)-activated chloride channel that is essential for numerous physiological functions.

TRPV1 in GABAergic interneurons mediates neuropathic mechanical allodynia and disinhibition of the nociceptive circuitry in the spinal cord.

Neuropathic pain and allodynia may arise from sensitization of central circuits. We report a mechanism of disinhibition-based central sensitization resulting from long-term depression (LTD) of GABAergic interneurons as a consequence of TRPV1 activation in the spinal cord. Intrathecal administration of TRPV1 agonists led to mechanical allodynia that was not dependent on peripheral TRPV1 neurons.

Analgesic effect of highly reversible ω-conotoxin FVIA on N type Ca2+ channels.

Background: N-type Ca2+ channels (Ca(v)2.2) play an important role in the transmission of pain signals to the central nervous system. ω-Conotoxin (CTx)-MVIIA, also called ziconotide (Prialt®), effectively alleviates pain, without causing addiction, by blocking the pores of these channels.

A novel rat forelimb model of neuropathic pain produced by partial injury of the median and ulnar nerves.

The vast majority of human peripheral nerve injuries occur in the upper limb, whereas the most animal studies have been conducted using the hindlimb models of neuropathic pain, involving damages of the sciatic or lumbar spinal nerve(s). We attempted to develop a rat forelimb model of peripheral neuropathy by partial injury of the median and ulnar nerves. The halves of each nerve were transected by microscissors at about 5mm proximal from the elbow joint and behavioral signs of neuropathic pain, such as mechanical and cold allodynia, and heat hyperalgesia, were monitored up to 126 days following nerve injury.

Synthesis and T-type calcium channel blocking activity of novel diphenylpiperazine compounds, and evaluation of in vivo analgesic activity.

Novel diphenylpiperazine derivatives were synthesized and evaluated for their inhibitory activity against T-type calcium channel by whole-cell patch clamp recordings on HEK293 cells. Among the test compounds, 2 and 3d were effective in decreasing the response to formalin in both the first and second phases and demonstrated antiallodynic effects in a rat model of neuropathic pain.

Are spinal GABAergic elements related to the manifestation of neuropathic pain in rat?

Impairment in spinal inhibition caused by quantitative alteration of GABAergic elements following peripheral nerve injury has been postulated to mediate neuropathic pain. In the present study, we tested whether neuropathic pain could be induced or reversed by pharmacologically modulating spinal GABAergic activity, and whether quantitative alteration of spinal GABAergic elements after peripheral nerve injury was related to the impairment of GABAergic inhibition or neuropathic pain. To these aims, we first analyzed the pain behaviors following the spinal administration of GABA antagonists (1 microg bicuculline/rat and 5 microg phaclofen/rat), agonists (1 microg muscimol/rat and 0.

Synthesis and bradykinin inhibitory activity of novel non-peptide compounds, and evaluation of in vivo analgesic activity.

A series of novel non-peptide diamide compounds was synthesized and evaluated as antibradykinin agents by utilizing guinea-pig ileum smooth muscle. Among the final compounds, (Z)-4-(4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)-4-oxo-N-(4-phenylbutan-2-yl)but-2-enamide showed most favorable bradykinin inhibitory activity and demonstrated analgesic efficacies in the rat models of inflammatory and neuropathic pain.

Complete Freund's adjuvant-induced intervertebral discitis as an animal model for discogenic low back pain.

Background: Although numerous animal models for low back pain associated with intervertebral disk (IVD) degeneration have been proposed, insufficient data have been provided to make any conclusions regarding pain. Our aim in this study was to determine the reliability of complete Freund's adjuvant (CFA) injection into the rat spine as an animal model representing human discogenic pain.

Methods: We studied IVD degenerative changes with pain development after a 10-microL CFA injection into the L5-6 IVD of adult rats using behavioral, histologic, and biochemical studies.

Membrane-delimited coupling of TRPV1 and mGluR5 on presynaptic terminals of nociceptive neurons.

Transient receptor potential vanilloid subtype 1 (TRPV1) and metabotropic glutamate receptor 5 (mGluR5) located on peripheral sensory terminals have been shown to play critical roles in the transduction and modulation of pain sensation. To date, however, very little is known regarding the significance of functional expression of mGluR5 and TRPV1 on the central terminals of sensory neurons in the dorsal horn of the spinal cord. Here we show that TRPV1 on central presynaptic terminals is coupled to mGluR5 in a membrane-delimited manner, thereby contributing to the modulation of nociceptive synaptic transmission in the substantia gelatinosa neurons of the spinal cord.