Validity of the copper/zinc ratio as a diagnostic marker for taste disorders associated with zinc deficiency.

Although zinc (Zn) deficiency is often suspected in patients with taste disorders, it may be difficult to diagnose Zn deficiency, especially in patients without any clear risk factors. Accordingly, the aim of the present study was to detect possible markers for taste disorders or zinc deficiency. To achieve this aim, we analyzed data obtained from 122 Japanese men who were not using medicines and had no diseases requiring treatment. We evaluated the following factors: awareness of dysgeusia; salty taste recognition threshold (SRT); the serum concentrations of Zn, copper (Cu), iron, alkaline phosphatase, and albumin; and the Cu/Zn ratio. The serum Cu/Zn ratio was positively correlated with the both the SRT and the awareness of dysgeusia. The serum Zn concentration was not correlated with the SRT or the awareness of dysgeusia in univariate analyses. However, in multivariate logistic regression, the serum Zn concentration was associated with the awareness of dysgeusia. In conclusion, the serum Cu/Zn ratio is a good diagnostic marker for taste disorders and the value of 1.1 may be a threshold level for detecting taste disorders.

Primary sensory neuronal expression of SLURP-1, an endogenous nicotinic acetylcholine receptor ligand.

Secreted mammalian Ly6/urokinase plasminogen activator receptor-related protein-1 (SLURP-1) is a recently identified, endogenous ligand of the alpha7 subunit of nicotinic acetylcholine receptors. SLURP-1 is also the causative gene for an autosomal recessive palmoplantar keratoderma, Mal de Meleda. Although the function of SLURP-1 in keratinocyte development and differentiation has been extensively studied, little is known about its role in the nervous system. In the present study, we analyzed SLURP-1 expression in the spinal cord of rats, as a number of studies suggest spinal nicotinic acetylcholine receptors are important modulators of pain transmission. We detected intense SLURP-1 immunoreactivity in the dorsal horn of the spinal cord, especially in lamina I and outer II. In dorsal root ganglia, SLURP-1 immunoreactivity was detected in small- to medium-sized neurons, where in situ hybridization also revealed the presence of SLURP-1 mRNA. Fluorescent labeling of SLURP-1 partially overlapped that of calcitonin-gene related peptide (CGRP) or substance P (SP) in both the spinal cord dorsal horn and glabrous skin, and electron microscopic analysis revealed colocalization of SLURP-1 with SP or CGRP, in large synaptic vesicles in terminals within the superficial layer of the spinal cord. Finally, sciatic nerve axotomy reduced levels of SLURP-1 immunoreactivity in parallel with that of SP and CGRP in the ipsilateral superficial dorsal horn. These findings suggest that SLURP-1 is expressed in a subset of primary peptidergic sensory neurons.

Expression of SLURP-1, an endogenous alpha7 nicotinic acetylcholine receptor allosteric ligand, in murine bronchial epithelial cells.

Mammalian secreted lymphocyte antigen-6/urokinase-type plasminogen activator receptor-related peptide-1 (SLURP-1) is a positive allosteric ligand for alpha7 nicotinic acetylcholine (ACh) receptors (alpha7 nAChRs) that potentiates responses to ACh and elicits proapoptotic activity in human keratinocytes. Mutations in the gene encoding SLURP-1 have been detected in patients with Mal de Meleda, a rare autosomal recessive skin disorder characterized by transgressive palmoplantar keratoderma. On the basis of these findings, SLURP-1 is postulated to be involved in regulating tumor necrosis factor-alpha (TNF-alpha) release from keratinocytes and macrophages via alpha7 nAChR-mediated pathways. In the present study, we assessed SLURP-1 expression in lung tissue from C57BL/6J mice to investigate the functions of SLURP-1 in pulmonary physiology and pathology. Immunohistochemical and in situ hybridization analyses revealed expression of SLURP-1 protein and mRNA, respectively, exclusively in ciliated bronchial epithelial cells. This was supported by Western blotting showing the presence of the 9.5-kDa SLURP-1 protein in whole-lung tissue and trachea. In addition, high-affinity choline transporter (CHT1) was detected in apical regions of bronchial epithelial cells and in neurons located in the lamina propria of the bronchus, suggesting that bronchial epithelial cells are able to synthesize both SLURP-1 and ACh. We also observed direct contact between F4/80-positive macrophages and bronchial epithelial cells and the presence of invading macrophages in close proximity to CHT1-positive nerve elements. Collectively, these results suggest that SLURP-1 contributes to the maintenance of bronchial epithelial cell homeostasis and to the regulation of TNF-alpha release from macrophages in bronchial tissue.