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Frank C, Albertazzi A, Murphy C. The effect of the apolipoprotein E ε4 allele and olfactory function on odor identification networks. Brain Behav 2024; 14:e3524. [PMID: 38702902 PMCID: PMC11069025 DOI: 10.1002/brb3.3524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 05/06/2024] Open
Abstract
INTRODUCTION The combination of apolipoprotein E ε4 (ApoE ε4) status, odor identification, and odor familiarity predicts conversion to mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS To further understand olfactory disturbances and AD risk, ApoE ε4 carrier (mean age 76.38 ± 5.21) and ε4 non-carrier (mean age 76.8 ± 3.35) adults were given odor familiarity and identification tests and performed an odor identification task during fMRI scanning. Five task-related functional networks were detected using independent components analysis. Main and interaction effects of mean odor familiarity ratings, odor identification scores, and ε4 status on network activation and task-modulation of network functional connectivity (FC) during correct and incorrect odor identification (hits and misses), controlling for age and sex, were explored using multiple linear regression. RESULTS Findings suggested that sensory-olfactory network activation was positively associated with odor identification scores in ε4 carriers with intact odor familiarity. The FC of sensory-olfactory, multisensory-semantic integration, and occipitoparietal networks was altered in ε4 carriers with poorer odor familiarity and identification. In ε4 carriers with poorer familiarity, connectivity between superior frontal areas and the sensory-olfactory network was negatively associated with odor identification scores. CONCLUSIONS The results contribute to the clarification of the neurocognitive structure of odor identification processing and suggest that poorer odor familiarity and identification in ε4 carriers may signal multi-network dysfunction. Odor familiarity and identification assessment in ε4 carriers may contribute to the predictive value of risk for MCI and AD due to the breakdown of sensory-cognitive network integration. Additional research on olfactory processing in those at risk for AD is warranted.
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Stussi Y, Coppin G. Letter to the Editor: Stimulus intensities and sensory modalities constitute two major challenges for online threat conditioning research. Biol Psychol 2024:108805. [PMID: 38679403 DOI: 10.1016/j.biopsycho.2024.108805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/01/2024]
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Throesch BT, Bin Imtiaz MK, Muñoz-Castañeda R, Sakurai M, Hartzell AL, James KN, Rodriguez AR, Martin G, Lippi G, Kupriyanov S, Wu Z, Osten P, Izpisua Belmonte JC, Wu J, Baldwin KK. Functional sensory circuits built from neurons of two species. Cell 2024; 187:2143-2157.e15. [PMID: 38670072 DOI: 10.1016/j.cell.2024.03.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 01/18/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
A central question for regenerative neuroscience is whether synthetic neural circuits, such as those built from two species, can function in an intact brain. Here, we apply blastocyst complementation to selectively build and test interspecies neural circuits. Despite approximately 10-20 million years of evolution, and prominent species differences in brain size, rat pluripotent stem cells injected into mouse blastocysts develop and persist throughout the mouse brain. Unexpectedly, the mouse niche reprograms the birth dates of rat neurons in the cortex and hippocampus, supporting rat-mouse synaptic activity. When mouse olfactory neurons are genetically silenced or killed, rat neurons restore information flow to odor processing circuits. Moreover, they rescue the primal behavior of food seeking, although less well than mouse neurons. By revealing that a mouse can sense the world using neurons from another species, we establish neural blastocyst complementation as a powerful tool to identify conserved mechanisms of brain development, plasticity, and repair.
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Naimi BR, Farquhar D, Duffy AN, Garvey EA, Kelly P, Kahn C, Doshi R, Shah R, Rabinowitz MR, Toskala E, Rosen M, Evans JJ, Nyquist GG. Predictors of Subjective Olfactory Dysfunction and Sinonasal Quality-of-Life After Endoscopic Transsphenoidal Pituitary Surgery. Am J Rhinol Allergy 2024:19458924241243123. [PMID: 38646739 DOI: 10.1177/19458924241243123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
BACKGROUND This is the largest study in North America investigating olfactory outcomes after pituitary surgery to date. OBJECTIVE Characterize factors associated with subjective olfactory dysfunction (OD) and worsened sinonasal quality-of-life (QOL) after endoscopic TSA. METHODS Patients undergoing primary TSA for secreting and non-secreting pituitary adenomas between 2017 and 2021 with pre- and post-operative SNOT-22 scores were included. Subjective OD was determined by the smell/taste dysfunction question on the SNOT-22 (smell-SNOT). RESULTS 159 patients with pre- and post-operative SNOT-22 scores were included. Average total SNOT-22 scores worsened from pre-operative (16.91 ± 16.91) to POM1 (25.15 ± 20.83, P < .001), with no difference from pre-operative (16.40 ± 15.88) to POM6 (16.27 ± 17.92, P = .936) or pre-operative (13.63 ± 13.54) to POM12 (12.60 ± 16.45, P = .651). Average smell-SNOT scores worsened from pre-operative (0.40 ± 1.27) to POM1 (2.09 ± 2.01, P < .001), and pre-operative (0.46 ± 1.29) to POM6 (1.13 ± 2.45, P = .002), with no difference from pre-operative (0.40 ± 1.07) to POM12 (0.71 ± 1.32, P = .100). Female gender had a 0.9-point (95% CI 0.1 to 1.6) P = .021, increase in smell-SNOT at POM1, resolving by POM6 (0.1 [-0.9 to 1.1], P = .800) and POM12 (0.0 [-1.0 to 0.9], P = .942). Septoplasty with tunnel approach had a 1.1 [0.2 to 2.0] out of 5-point (P = .023) increase in smell-SNOT at POM1, resolving by POM6 (0.2 [-1.1 to 1.6], P = .764) and POM12 (0.4 [-0.9 to 1.6], P = .567). Female gender had a 9.5 (4.0 to 15.1)-point (P = .001) increase in SNOT-22 scores at POM1, resolving by POM6 (3.4 [-3.0 to 9.8], P = .292) and POM12 (6.4 [-5.4 to 18.2], P = .276). Intra-operative CSF leak had an 8.6 [2.1 to 15.1]-point (P = .009) increase in SNOT-22 scores at POM1, resolving by POM6 (5.4 [-1.7 to 12.5], P = .135), and POM12 (1.1 [-12.9 to 15.1], P = .873). CONCLUSION Changes in subjective olfaction and sinonasal QOL after TSA may be associated with gender, operative approach, and intra-operative CSF leak, resolving 6-12 months post-operatively.
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Dekeyser A, Huart C, Hummel T, Hox V. Olfactory Loss in Rhinosinusitis: Mechanisms of Loss and Recovery. Int J Mol Sci 2024; 25:4460. [PMID: 38674045 PMCID: PMC11050448 DOI: 10.3390/ijms25084460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/12/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Chronic rhinosinusitis (CRS) is a highly prevalent disease and up to 83% of CRS patients suffer from olfactory dysfunction (OD). Because OD is specifically seen in those CRS patients that present with a type 2 eosinophilic inflammation, it is believed that type 2 inflammatory mediators at the level of the olfactory epithelium are involved in the development of this olfactory loss. However, due to the difficulties in obtaining tissue from the olfactory epithelium, little is known about the true mechanisms of inflammatory OD. Thanks to the COVID-19 pandemic, interest in olfaction has been growing rapidly and several studies have been focusing on disease mechanisms of OD in inflammatory conditions. In this paper, we summarize the most recent data exploring the pathophysiological mechanisms underlying OD in CRS. We also review what is known about the potential capacity of olfactory recovery of the currently available treatments in those patients.
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Modesto T, Neves Gregório B, Marcelino G, Marquet N, Costa RA, Guerreiro PM, Velez Z, Hubbard PC. Anatomy of the olfactory system and potential role for chemical communication in the sound-producing Lusitanian toadfish, Halobatrachus didactylus. JOURNAL OF FISH BIOLOGY 2024. [PMID: 38634148 DOI: 10.1111/jfb.15751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
The current study investigated the structure and function of the olfactory system of the Lusitanian toadfish, Halobatrachus didactylus, using histology and electrophysiology (electro-olfactogram [EOG]), respectively. The olfactory system consists of a digitated anterior peduncle, of unknown function, containing the inhalant nostril. This then leads to a U-shaped olfactory chamber with the olfactory epithelium-identified by Gαolf-immunoreactivity-on the ventral surface. A large lacrimal sac is connected to this tube and is likely involved in generating water movement through the olfactory chamber (this species is largely sedentary). The exhalent nostril lies by the eye and is preceded by a bicuspid valve to ensure one-way flow of water. As do other teleosts, H. didactylus had olfactory sensitivity to amino acids and bile acids. Large-amplitude EOG responses were evoked by fluid from the anterior and posterior testicular accessory glands, and bile and intestinal fluids. Anterior gland and intestinal fluids from reproductive males were significantly more potent than those from non-reproductive males. Male urine and skin mucus proved to be the least potent body fluids tested. These results suggest that chemical communication-as well as acoustic communication-may be important in the reproduction of this species and that this may be mediated by the accessory glands and intestinal fluid.
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Monk AS, Pyati S, Lamb M, Melott N, Benaim EH, Wiesen C, Klatt-Cromwell C, Thorp BD, Ebert CS, Kimple AJ, Senior BA. The relationship between survey-based subjective olfactory awareness and objective olfactory function. Int Forum Allergy Rhinol 2024. [PMID: 38618980 DOI: 10.1002/alr.23355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/14/2024] [Accepted: 04/03/2024] [Indexed: 04/16/2024]
Abstract
KEY POINTS Correlation between symptom-based surveys and objective olfactory testing is variable. For diagnosis and symptom monitoring, surveys should correlate with objective testing. The Odor Awareness Scale (OAS) and Affective Importance of Odor Scale (AIO) showed significant but moderate positive correlations with University of Pennsylvania Scent Identification Test (UPSIT) score.
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Zou Y, Wu W, Luo T, Tang Y, Hu H, Ye A, Xu L, Dai F, Tong X. Disruption of Zfh3 abolishes mulberry-specific monophagy in silkworm larvae. INSECT SCIENCE 2024. [PMID: 38622976 DOI: 10.1111/1744-7917.13354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 01/29/2024] [Accepted: 02/13/2024] [Indexed: 04/17/2024]
Abstract
Feeding behavior is critical for insect survival and fitness. Most researchers have explored the molecular basis of feeding behaviors by identifying and elucidating the function of olfactory receptors (ORs) and gustatory receptors (GRs). Other types of genes, such as transcription factors, have rarely been investigated, and little is known about their potential roles. The silkworm (Bombyx mori) is a well-studied monophagic insect which primarily feeds on mulberry leaves, but the genetic basis of its monophagy is still not understood. In this report, we focused on a transcription factor encoded by the Zfh3 gene, which is highly expressed in the silkworm central and peripheral nervous systems, including brain, antenna, and maxilla. To investigate its function, Zfh3 was abrogated using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) mutagenesis. Since Zfh3 knockout homozygotes are not viable, we studied feeding behavior in heterozygotes, and found that disruption of Zfh3 affects both gustation and olfaction. Mutant larvae lose preference for mulberry leaves, acquire the ability to consume an expanded range of diets, and exhibit improved adaptation to the M0 artificial diet, which contains no mulberry leaves. These results provide the first demonstration that a transcription factor modulates feeding behaviors in an insect.
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Hintschich CA, Ma C, Hähner A, Hummel T. Pronounced Olfactory Habituation with Age. Laryngoscope 2024. [PMID: 38597777 DOI: 10.1002/lary.31442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 03/05/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
OBJECTIVES Olfactory habituation is a transient decrease in olfactory sensitivity caused by prolonged odor exposure, aiding in the discernment of new olfactory stimuli against the background. We explored the impact of subclinical olfactory impairment on odor habituation using age as a proxy. METHODS Before the actual experiment, the individual olfactory threshold for the rose-like odorant phenylethyl alcohol (PEA) was assessed separately for the left and right nostril using the "Sniffin' Sticks" test, and ratings for odor intensity and pleasantness were collected. After applying a nasal clip continuously delivering PEA odor to one nostril for 10 min and 2 h, respectively, threshold, intensity, and pleasantness were reassessed immediately after clip removal. RESULTS In the group of 80 participants (younger adults-mean age 27.7 ± 4.5 years; older adults-mean age 61.5 ± 4.7 years), olfactory thresholds were already significantly elevated after just 10 min, and this habituation was even more pronounced after 2 h. This effect could be observed bilaterally even though significantly more distinct on the exposed side. Older participants generally exhibited a more pronounced habituation on the exposed side after 2 h compared to the younger participants. CONCLUSION The results indicate that older people experience more notable habituation after extended exposure to odors. This is most likely due to the compromised olfactory function in age. Although older and younger subjects scored in the normosmic range when tested with standardized olfactory tests, the stress on the system after exposure to an odor clearly revealed the lower functionality of the aging sense of smell. LEVEL OF EVIDENCE 3 Laryngoscope, 2024.
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Hunter SR, Zola A, Ho E, Kallen M, Adjei-Danquah E, Achenbach C, Smith GR, Gershon R, Reed DR, Schalet B, Parma V, Dalton PH. Using SCENTinel® to predict SARS-CoV-2 infection: insights from a community sample during dominance of Delta and Omicron variants. Front Public Health 2024; 12:1322797. [PMID: 38660364 PMCID: PMC11041634 DOI: 10.3389/fpubh.2024.1322797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/27/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction Based on a large body of previous research suggesting that smell loss was a predictor of COVID-19, we investigated the ability of SCENTinel®, a newly validated rapid olfactory test that assesses odor detection, intensity, and identification, to predict SARS-CoV-2 infection in a community sample. Methods Between April 5, 2021, and July 5, 2022, 1,979 individuals took one SCENTinel® test, completed at least one physician-ordered SARS-CoV-2 PCR test, and endorsed a list of self-reported symptoms. Results Among the of SCENTinel® subtests, the self-rated odor intensity score, especially when dichotomized using a previously established threshold, was the strongest predictor of SARS-CoV-2 infection. SCENTinel® had high specificity and negative predictive value, indicating that those who passed SCENTinel® likely did not have a SARS-CoV-2 infection. Predictability of the SCENTinel® performance was stronger when the SARS-CoV-2 Delta variant was dominant rather than when the SARS-CoV-2 Omicron variant was dominant. Additionally, SCENTinel® predicted SARS-CoV-2 positivity better than using a self-reported symptom checklist alone. Discussion These results indicate that SCENTinel® is a rapid assessment tool that can be used for population-level screening to monitor abrupt changes in olfactory function, and to evaluate spread of viral infections like SARS-CoV-2 that often have smell loss as a symptom.
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Juge AE, Hall NJ, Richeson JT, Cooke RF, Daigle CL. Dogs' ability to detect an inflammatory immune response in cattle via olfaction. Front Vet Sci 2024; 11:1393289. [PMID: 38655536 PMCID: PMC11036545 DOI: 10.3389/fvets.2024.1393289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction Canine olfaction is a potential means for detection of respiratory disease in beef cattle. In a prior study, two dogs were trained to discriminate between nasal swabs from healthy cattle and cattle that developed Bovine Respiratory Disease. Dogs had some ability to identify samples from BRD-affected cattle, but results were ambiguous. The purpose of this study was to evaluate more dogs using better-controlled training and testing procedures. Methods Nasal and saliva swabs were collected from 96 cattle before and after administering a vaccine to induce an inflammatory immune response. Samples were stored at -80°C for up to 11 months before use, and samples from animals with an elevated body temperature at baseline were omitted. An automated olfactometer apparatus was constructed to improve blinding procedures and reduce opportunities for odor contamination. Four dogs were trained to distinguish between swabs from healthy and sickness-model cattle, including the two dogs from the previous study ("Runnels" and "Cheaps") and two inexperienced dogs ("Molokai" and "Amy"). During a seven-month training period, dogs were exposed to samples from 28 animals. Dogs were tested on 59 sets of unfamiliar samples. Results Performance varied among dogs (χ2 = 10.48, p = 0.02). Molokai's performance was above chance (0.73 ± 0.06, p = 0.0006), while Amy (0.44 ± 0.06, p = 0.43), Cheaps (0.53 ± 0.07, p = 0.79), and Runnels (0.56 ± 0.06, p = 0.43) did not respond correctly at a rate different from chance. Accuracy did not differ between nasal swabs (0.63 ± 0.08) and saliva swabs (0.53 ± 0.08, χ2 = 0.81, p = 0.37). Discussion The results of this study indicate that canine olfaction may be an effective means of detecting illness in beef cattle. However, individual dogs' aptitude for this detection task varies.
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Masuda M, Ihara S, Mori N, Koide T, Miyasaka N, Wakisaka N, Yoshikawa K, Watanabe H, Touhara K, Yoshihara Y. Identification of olfactory alarm substances in zebrafish. Curr Biol 2024; 34:1377-1389.e7. [PMID: 38423017 DOI: 10.1016/j.cub.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 12/08/2023] [Accepted: 02/01/2024] [Indexed: 03/02/2024]
Abstract
Escaping from danger is one of the most fundamental survival behaviors for animals. Most freshwater fishes display olfactory alarm reactions in which an injured fish releases putative alarm substances from the skin to notify its shoaling company about the presence of danger. Here, we identified two small compounds in zebrafish skin extract, designated as ostariopterin and daniol sulfate. Ostariopterin is a pterin derivative commonly produced in many freshwater fishes belonging to the Ostariophysi superorder. Daniol sulfate is a novel sulfated bile alcohol specifically present in the Danio species, including zebrafish. Ostariopterin and daniol sulfate activate distinct glomeruli in the olfactory bulb. Zebrafish display robust alarm reactions, composed of darting, freezing, and bottom dwelling, only when they are concomitantly stimulated with ostariopterin and daniol sulfate. These results demonstrate that the fish alarm reaction is driven through a coincidence detection mechanism of the two compounds along the olfactory neural circuitry.
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Wang J, Li H, Wang C, Li D, Zhang Y, Shen M, Xu X, Wu T. Effect of Dl-3-n-Butylphthalide on olfaction in rotenone-induced Parkinson's rats. Front Neurol 2024; 15:1367973. [PMID: 38685946 PMCID: PMC11057415 DOI: 10.3389/fneur.2024.1367973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/18/2024] [Indexed: 05/02/2024] Open
Abstract
Background Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Olfactory dysfunction (OD) is an important nonmotor feature of PD. Dl-3-n-Butylphthalide (NBP) is a synthetic compound isolated from Apium graveolens seeds. The present study was conducted to investigate the effect of NBP on olfaction in rotenone-induced Parkinson's rats to explore the mechanism and pathway of OD in PD. Methods The PD model was established using rotenone-induced SD rats, divided into blank control, model, and treatment groups. A sham group was also established, with 10 rats in each group. The treatment group was given NBP (1 mg/kg, 10 mg/kg, and 100 mg/kg, dissolved in soybean oil) intragastrically for 28 days. Meanwhile, the control group rats were given intra-gastrically soybean oil. After behavioral testing, all rats were executed, and brain tissue was obtained. Proteomics and Proteomic quantification techniques (prm) quantification were used to detect proteomic changes in rat brain tissues. Results Compared with the control group, the model group showed significant differences in behavioral tests, and this difference was reduced after treatment. Proteomics results showed that after treatment with high-dose NBP, there were 42 differentially expressed proteins compared with the model group. Additionally, the olfactory marker (P08523) showed a significant upregulation difference. We then selected 22 target proteins for PRM quantification and quantified 17 of them. Among them, the olfactory marker protein was at least twofold upregulated in the RTH group compared to the model group.
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Li Z, Richter L, Krueger T, Eichwald H, Hähner A, Hummel T. Patients with parosmia respond faster to unpleasant odors than patients with hyposmia: Insights from olfactory event-related potentials. Int Forum Allergy Rhinol 2024. [PMID: 38584570 DOI: 10.1002/alr.23350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/12/2024] [Accepted: 03/22/2024] [Indexed: 04/09/2024]
Abstract
BACKGROUND Diagnosing parosmia is a challenge. The present study aimed to explore the distinctions between hyposmic patients with and without parosmia utilizing electroencephalography-derived olfactory event-related potentials (ERP). METHODS Forty-four patients with hyposmia were enrolled and divided into a group with parosmia (n = 23, mean age ± standard deviation = 48 ± 14 years, seven men) and a group without parosmia (n = 21, age = 52 ± 12 years, seven men) based on the clinical interview. Additionally, 21 healthy controls (mean age = 45 ± 14 years, six men) were included. Various measurements were obtained, including the Sniffin' Stick test, threshold tests for the odorants furfural mercaptan and 2,6-nonadienal, a modified Sniffin' Stick parosmia test, and well-being ratings. Chemosensory ERPs were recorded separately for each nostril using high-precision, computer-controlled air-dilution olfactometry. RESULTS Patients with parosmia had a decreased olfactory function similar to that observed in patients with hyposmia, although the odor sensitivity of patients with severe parosmia remained relatively unaffected. Patients with parosmia reported a decrease in well-being compared to controls. The severity of parosmia was positively correlated with odor sensitivity. Furthermore, patients with severe parosmia exhibited faster responses to unpleasant odors than patients without parosmia. CONCLUSION Overall, the present findings support the idea that parosmia predominantly occurs during olfactory recovery, significantly disturbing patients and warranting the development of effective treatments. Notably, the relatively faster responses of hyposmic patients with severe parosmia suggest that the generation of distorted olfactory responses may involve early stages of the processing of olfactory information.
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Turunen S, Paavilainen S, Vepsäläinen J, Hielm-Björkman A. Scent Detection Threshold of Trained Dogs to Eucalyptus Hydrolat. Animals (Basel) 2024; 14:1083. [PMID: 38612322 PMCID: PMC11010826 DOI: 10.3390/ani14071083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/25/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
Dogs' (Canis lupus familiaris) sense of smell is based on a unique anatomy and physiology that enables them to find and differentiate low concentrations of odor molecules. This ability is exploited when dogs are trained as search, rescue, or medical detection dogs. We performed a three-part study to explore the scent detection threshold of 15 dogs to an in-house-made Eucalyptus hydrolat. Here, decreasing concentrations of the hydrolat were tested using a three-alternative forced-choice method until the first incorrect response, which defined the limit of scent detection for each tested dog. Quantitative proton nuclear magnetic resonance spectroscopy was used to identify and measure the contents of ten commercial Eucalyptus hydrolats, which are used in a dog scent training sport called "nose work". In this study, the dogs' limit of detection initially ranged from 1:104 to 1:1023 but narrowed down to 1:1017-1:1021 after a training period. The results show that, with training, dogs learn to discriminate decreasing concentrations of a target scent, and that dogs can discriminate Eucalyptus hydrolat at very low concentrations. We also detected different concentrations of eucalyptol and lower alcohols in the hydrolat products and highlight the importance of using an identical source of a scent in training a dog for participation in canine scent sport competitions and in olfactory research.
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Brescia FF, Passinger J, Wende RC, Schreiner PR, Zorn H, Fraatz MA. Determining Ultra-Low Organic Molecular Odor Thresholds in Air Helps Identify the Most Potent Fungal Aroma Compound. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:7511-7516. [PMID: 38517735 DOI: 10.1021/acs.jafc.3c08438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
The determination of odor threshold values can be performed in various matrices, including air, and serves as a parameter to compare the potencies of odorous compounds. Typically, the odor thresholds in air are determined by gas chromatography-olfactory (GC-O) and referenced to an internal standard, most often (E)-dec-2-enal. Herein, a direct gas chromatography-flame ionization detector-olfactory analysis method for the determination of odor thresholds in air is reported. As model substrates for this novel approach, naturally occurring substances (R)-1-p-menthene-8-thiol as well as (3S,3aS,6R,7aS)-3,6-dimethyl-3a,4,5,6,7,7a-hexahydro-3H-1-benzofuran-2-one were used. The latter compound was synthesized from (-)-isopulegol and exhibited an extremely low odor recognition threshold of 1.9 × 10-6 ng L-1 air, the lowest value reported for a fungal aroma compound thus far.
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Kahl M, Offner T, Trendel A, Weiss L, Manzini I, Hassenklöver T. S100Z is expressed in a lateral subpopulation of olfactory receptor neurons in the main olfactory system of Xenopus laevis. Dev Neurobiol 2024; 84:59-73. [PMID: 38439531 DOI: 10.1002/dneu.22935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/07/2024] [Accepted: 02/15/2024] [Indexed: 03/06/2024]
Abstract
In contrast to other S100 protein members, the function of S100 calcium-binding protein Z (S100Z) remains largely uncharacterized. It is expressed in the olfactory epithelium of fish, and it is closely associated with the vomeronasal organ (VNO) in mammals. In this study, we analyzed the expression pattern of S100Z in the olfactory system of the anuran amphibian Xenopus laevis. Using immunohistochemistry in whole mount and slice preparations of the larval olfactory system, we found exclusive S100Z expression in a subpopulation of olfactory receptor neurons (ORNs) of the main olfactory epithelium (MOE). S100Z expression was not co-localized with TP63 and cytokeratin type II, ruling out basal cell and supporting cell identity. The distribution of S100Z-expressing ORNs was laterally biased, and their average number was significantly increased in the lateral half of the olfactory epithelium. The axons of S100Z-positive neurons projected exclusively into the lateral and intermediate glomerular clusters of the main olfactory bulb (OB). Even after metamorphic restructuring of the olfactory system, S100Z expression was restricted to a neuronal subpopulation of the MOE, which was then located in the newly formed middle cavity. An axonal projection into the ventro-lateral OB persisted also in postmetamorphic frogs. In summary, S100Z is exclusively associated with the main olfactory system in the amphibian Xenopus and not with the VNO as in mammals, despite the presence of a separate accessory olfactory system in both classes.
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Yusuf N, Monahan K. Epigenetic programming of stochastic olfactory receptor choice. Genesis 2024; 62:e23593. [PMID: 38562011 PMCID: PMC11003729 DOI: 10.1002/dvg.23593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/01/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
The mammalian sense of smell relies upon a vast array of receptor proteins to detect odorant compounds present in the environment. The proper deployment of these receptor proteins in olfactory sensory neurons is orchestrated by a suite of epigenetic processes that remodel the olfactory genes in differentiating neuronal progenitors. The goal of this review is to elucidate the central role of gene regulatory processes acting in neuronal progenitors of olfactory sensory neurons that lead to a singular expression of an odorant receptor in mature olfactory sensory neurons. We begin by describing the principal features of odorant receptor gene expression in mature olfactory sensory neurons. Next, we delineate our current understanding of how these features emerge from multiple gene regulatory mechanisms acting in neuronal progenitors. Finally, we close by discussing the key gaps in our understanding of how these regulatory mechanisms work and how they interact with each other over the course of differentiation.
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Ranabhat S, Domingue MJ, Lebar L, Bingham GV, Zhu KY, Morrison WR. Disruption of semiochemical-mediated movement by the immature Trogoderma variabile Baillon and Trogoderma inclusum Le Conte (Coleoptera: Dermestidae) after exposure to long-lasting insecticide-incorporated netting. PEST MANAGEMENT SCIENCE 2024; 80:1702-1716. [PMID: 38010040 DOI: 10.1002/ps.7903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/29/2023]
Abstract
BACKGROUND Highly mobile stored product insects may be able to readily orient in response to food cues and pheromones to attack durable commodities at each link of the postharvest supply chain. A 0.4% deltamethrin-incorporated long-lasting insecticide-incorporated netting (LLIN) is a successful novel preventative integrated pest management (IPM) tactic to intercept dispersing insects after harvest. However, it is unknown whether exposure to LLIN may affect olfaction and orientation to important semiochemicals by immature stored product dermestids, therefore the aim of this study was to assess whether exposure to LLIN disrupts the normal olfactory and chemotactic behavior of warehouse beetle, Trogoderma variabile Ballion (Coleoptera: Dermestidae), and the larger cabinet beetle, T. inclusum Le Conte (Coleoptera: Dermestidae), larval movement in the presence of important semiochemicals, including food kairomones (e.g., flour) and pheromones, e.g., (Z)-14-methyl-8-hexadecenal. RESULTS The distance moved by the larval population of T. variabile was reduced by 64% after 24-h exposure to LLIN compared to control netting but not immediately after exposure, while T. inclusum larvae movement was reduced by 50% after 24-h exposure to LLIN compared to the control netting. Generally, the olfaction and orientation of larval dermestids were affected after exposure to LLIN compared to control netting. There were species-linked differences in effects on olfaction after the insects were exposed to LLIN. CONCLUSION Our study suggests the use of LLIN may enhance the effectiveness of other concurrent behaviorally-based strategies such as mating disruption when used as part of a comprehensive IPM program in the postharvest environment. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Kamarck ML, Trimmer C, Murphy NR, Gregory KM, Manoel D, Logan DW, Saraiva LR, Mainland JD. Identifying candidate genes underlying isolated congenital anosmia. Clin Genet 2024; 105:376-385. [PMID: 38148624 PMCID: PMC10932857 DOI: 10.1111/cge.14470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/28/2023]
Abstract
An estimated 1 in 10 000 people are born without the ability to smell, a condition known as congenital anosmia, and about one third of those people have non-syndromic, or isolated congenital anosmia (ICA). Despite the significant impact of olfaction for our quality of life, the underlying causes of ICA remain largely unknown. Using whole exome sequencing (WES) in 10 families and 141 individuals with ICA, we identified a candidate list of 162 rare, segregating, deleterious variants in 158 genes. We confirmed the involvement of CNGA2, a previously implicated ICA gene that is an essential component of the olfactory transduction pathway. Furthermore, we found a loss-of-function variant in SREK1IP1 from the family gene candidate list, which was also observed in 5% of individuals in an additional non-family cohort with ICA. Although SREK1IP1 has not been previously associated with olfaction, its role in zinc ion binding suggests a potential influence on olfactory signaling. This study provides a more comprehensive understanding of the spectrum of genetic alterations and their etiology in ICA patients, which may improve the diagnosis, prognosis, and treatment of this disorder and lead to better understanding of the mechanisms governing basic olfactory function.
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Mignot C, Weise S, Podlesek D, Leonhardt G, Bensafi M, Hummel T. What do brain oscillations tell about the human sense of smell? J Neurosci Res 2024; 102:e25335. [PMID: 38634155 DOI: 10.1002/jnr.25335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 04/04/2024] [Accepted: 04/06/2024] [Indexed: 04/19/2024]
Abstract
Brain activity may manifest itself as oscillations which are repetitive rhythms of neuronal firing. These local field potentials can be measured via intracranial electroencephalography (iEEG). This review focuses on iEEG used to map human brain structures involved in olfaction. After presenting the methodology of the review, a summary of the brain structures involved in olfaction is given, followed by a review of the literature on human olfactory oscillations in different contexts. A single case is provided as an illustration of the olfactory oscillations. Overall, the timing and sequence of oscillations found in the different structures of the olfactory system seem to play an important role for olfactory perception.
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Choi NJ, Sykes KJ, Villwock M, Villwock J. Disparities in Olfactory Dysfunction in African Americans. Ann Otol Rhinol Laryngol 2024; 133:406-410. [PMID: 38235801 DOI: 10.1177/00034894231222693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
OBJECTIVES To examine olfactory performance in African Americans (AA) and Whites by comparing individual scent scores on objective olfactory tests to assess potential racial-ethnic differences of scent detection. METHODS Cross-sectional study of healthy participants, age 18+ years, and without sinonasal inflammatory disease from June 2021 to April 2022. Included participants self-identified as AA or White. Patients were recruited from outpatient clinics at University of Kansas Medical Center, and the local community. Two smelling tests were employed: Affordable Rapid Olfactory Measurement Array (AROMA) and Sniffin' Sticks (SST-12). Sino-Nasal Outcome Test (SNOT-22) was used for self-reported olfactory function . Pearson correlation and chi-square tests were used to detect statistical significance. RESULTS Our sample included 102 (46 AA and 56 Whites) participants. AROMA and SST-12 scores were significantly correlated in AA (P < .01, Pearson's Rho = .642) and Whites (P < .05, Pearson's Rho = .297). Mean scores on AROMA were significantly lower for AAs: 64.2 and Whites: 75.5 (P < .01). On AROMA, AA less accurately identified the scents of Licorice, Orange, Lavender, Cinnamon, Clove, and Rosemary (P < .05). Similarly, SST-12 mean scores for AAs: 84.2 were also lower than Whites: 89.9 (P < .01). On SST-12, AA less accurately identified the scent of pineapple Based on SST-12 scoring criteria, 60.9% of AA and 30.4% of Whites were classified as hyposmic (P < .05). SNOT-22 Smell scores were equivalent for both groups. CONCLUSION On both tests of olfaction, AA performed worse than Whites and a greater proportion of AA were considered hyposmic compared to Whites. This is a discrepancy with self-reported olfaction, which showed no difference between Whites and AA. AA performed significantly worse than their White counterparts on several scents, with possible implications regarding cultural appropriateness of scents used in olfactory testing.
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Tepedino MS, Voegels RL, Pezato R, Thamboo A, Kosug EM, Ferrão ACM, Neves RDF, Castilla VMB, Gregório LC. Olfaction and Quality of Life in Patients with Eosinophilic CRS Undergoing Endoscopic Sinus Surgery. Int Arch Otorhinolaryngol 2024; 28:e234-e239. [PMID: 38618594 PMCID: PMC11008929 DOI: 10.1055/s-0043-1772494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/18/2023] [Indexed: 04/16/2024] Open
Abstract
Introduction Chronic rhinosinusitis (CRS) is a common inflammatory disease. This high prevalence leads to high direct and indirect public health costs, which include medical visits, laboratory tests and imaging, pharmacotherapy, hospitalizations, and surgical treatment. Furthermore, CRS has a substantial impact on patient quality of life, affecting productivity and being a common cause of absence from work CRS-associated olfactory dysfunction is highly prevalent, the actual effectiveness of surgical intervention remains inconsistent. Although there are studies evaluating the postoperative course of patients with eosinophilic Chronic rhinosinusitis (eCRS) treated with high-volume budesonide irrigation, there is little objective information regarding the impact of this intervention on olfactory status and quality of life. Objective To conduct a pre- and postoperative analysis of olfaction and quality of life in patients with eCRS treated with surgical intervention followed by high-volume budesonide nasal irrigation. Methods Prospective, descriptive, uncontrolled study of patients with eCRS. All patients underwent pre- and postoperative nasal endoscopy, SNOT-22 questionnaire, and the University of Pennsylvania Smell Identification Text (UPSIT), always by the same previously trained examiner. The SNOT-22 questionnaire and the UPSIT were readministered to all patients at 3 months, 6 months, and 1 year postoperatively, and scores compared with those obtained preoperatively. Results Twenty patients were included in the study, 13 males and 7 females, between the ages of 23 and 65; 8 patients had comorbid asthma. Quantitative evaluation using the UPSIT test showed a significant improvement in olfaction 3 months after surgery, which remained 6 months and 1 year after surgery (p = 0.0063). There was no significant association between eosinophil concentrations in polypoid tissue and postoperative SNOT-22 and UPSIT results. Patients with tissue eosinophils >50 had a lower preoperative UPSIT score. As early as 3 months postoperatively, a significant improvement in quality of life was already noticeable, as represented by a decrease in SNOT-22 values, which persisted through the 1-year postoperative follow-up evaluation (p = 0.0005). Quantitative evaluation using the UPSIT test showed a significant improvement in olfaction 3 months after surgery, which remained 6 months and 1 year after surgery (p = 0.0063). Conclusion Surgery effectively controlled eCRS in patients who adhered to high-volume budesonide nasal irrigation postoperatively. There were significant improvements in quality of life and olfaction, which persisted at least up to one year postoperatively.
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Gellrich J, Zickmüller C, Thieme T, Karpinski C, Fitze G, Smitka M, von der Hagen M, Schriever VA. Olfactory function after mild traumatic brain injury in children-a longitudinal case control study. Cereb Cortex 2024; 34:bhae162. [PMID: 38629798 DOI: 10.1093/cercor/bhae162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/08/2024] [Accepted: 03/27/2024] [Indexed: 04/19/2024] Open
Abstract
The prevalence of posttraumatic olfactory dysfunction in children after mild traumatic brain injury ranges from 3 to 58%, with potential factors influencing this variation, including traumatic brain injury severity and assessment methods. This prospective longitudinal study examines the association between mild traumatic brain injury and olfactory dysfunction in children. Seventy-five pediatric patients with mild traumatic brain injury and an age-matched healthy control group were enrolled. Olfactory function was assessed using the Sniffin' Sticks battery, which focuses on olfactory threshold and odor identification. The study found that children with mild traumatic brain injury had impaired olfactory function compared with healthy controls, particularly in olfactory threshold scores. The prevalence of olfactory dysfunction in the patient group was 33% and persisted for 1 yr. No significant association was found between traumatic brain injury symptoms (e.g. amnesia, loss of consciousness) and olfactory dysfunction. The study highlights the importance of assessing olfactory function in children after mild traumatic brain injury, given its potential impact on daily life. Although most olfactory dysfunction appears transient, long-term follow-up is essential to fully understand the recovery process. The findings add valuable insights to the limited literature on this topic and urge the inclusion of olfactory assessments in the management of pediatric mild traumatic brain injury.
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Hirose A, Nakamura G, Nikaido M, Fujise Y, Kato H, Kishida T. Localized Expression of Olfactory Receptor Genes in the Olfactory Organ of Common Minke Whales. Int J Mol Sci 2024; 25:3855. [PMID: 38612665 PMCID: PMC11012115 DOI: 10.3390/ijms25073855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/13/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
Baleen whales (Mysticeti) possess the necessary anatomical structures and genetic elements for olfaction. Nevertheless, the olfactory receptor gene (OR) repertoire has undergone substantial degeneration in the cetacean lineage following the divergence of the Artiodactyla and Cetacea. The functionality of highly degenerated mysticete ORs within their olfactory epithelium remains unknown. In this study, we extracted total RNA from the nasal mucosae of common minke whales (Balaenoptera acutorostrata) to investigate ORs' localized expression. All three sections of the mucosae examined in the nasal chamber displayed comparable histological structure. However, the posterior portion of the frontoturbinal region exhibited notably high OR expression. Neither the olfactory bulb nor the external skin exhibited the expression of these genes. Although this species possesses four intact non-class-2 ORs, all the ORs expressed in the nasal mucosae belong to class-2, implying the loss of aversion to specific odorants. These anatomical and genomic analyses suggest that ORs are still responsible for olfaction within the nasal region of baleen whales, enabling them to detect desirable scents such as prey and potential mating partners.
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