Olfaction Research Articles

The Effect of Osteopathic Manipulative Treatment on Acute Post COVID-19 Anosmia and Ageusia Symptoms: A Case Report

Abstract Anosmia and ageusia, the loss of sense of smell and taste, respectively, are common symptoms experienced by recovering COVID-19 patients. Thus far, there have been limited proven beneficial treatment options to treat anosmia and ageusia. This case report presents the positive effects of Osteopathic Manipulative Treatment (OMT) on anosmia and ageusia after viral infection by the SARS-CoV-2 virus. OMT focuses on enhancing lymphatic drainage and decreasing inflammation. Techniques treat key somatic dysfunctions to balance the autonomic nervous system and to improve cranial motion and restore motion to improve function. Key cranial bone restrictions including the vomer and nasal bones were addressed in this case. Following treatment, the patient was able to regain the ability to smell and taste, improving patient quality of life. After treatment, his symptoms improved consistently, and he regained his normal sense of smell and taste 4 days after initial treatment. This case presentation serves to demonstrate the potential of incorporating OMT on acute post COVID-19 patients with symptoms of anosmia and ageusia.

Dupilumab improves sense of smell and clinical outcomes in patients with severe chronic rhinosinusitis with nasal polyps with anosmia

Objective Loss of sense of smell is a cardinal symptom of chronic rhinosinusitis with nasal polyps (CRSwNP) and significantly impacts health-related quality of life. Dupilumab significantly improved smell outcomes (loss of smell [LoS] score; University of Pennsylvania Smell Identification Test [UPSIT]) versus placebo in the phase 3 SINUS-24/-52 studies (clinicaltrials.gov, NCT02898454/NCT02912468) in patients with severe CRSwNP. This post hoc analysis investigated the effect of dupilumab on olfaction using UPSIT smell impairment categories. Methods Patients with baseline smell impairment (UPSIT ≤34/≤33 [women/men; score range 0–40] AND LoS score ≥1 [0–3] AND smell/taste item of the 22-item Sinonasal Outcome Test >0 [SNOT-22; 0–5]) treated with dupilumab 300 mg or placebo once every 2 weeks on background intranasal corticosteroids were analyzed. Results Of 724 patients, 665 (91.9%) had smell impairment at baseline; most had anosmia (UPSIT 0–18) (dupilumab/placebo: 80.9%/79.8%). At Week 24, the proportion of dupilumab-treated patients with anosmia decreased to 28.5%, while 14.9% achieved normosmia; most placebo-group patients (79.2%) remained anosmic and only 1.2% achieved normosmia (odds ratio: 17.3 [95% confidence interval: 5.1, 59.0]; p<.0001); results were similar at Week 52. Improvements in Nasal Polyps Score, nasal congestion, and SNOT-22 total score were moderately correlated with improvements in UPSIT at Weeks 24 and 52 (r = −0.38 to −0.50). Conclusion Most patients with severe CRSwNP had anosmia at baseline. Dupilumab treatment significantly improved smell versus placebo, with 14.9% achieving normosmia by Week 24. There was a trend for better clinical outcomes in patients with greater smell improvement.

Anatomical variations and their impact on chronic rhinosinusitis: a retrospective analysis from an Indonesian tertiary hospital

BackgroundChronic rhinosinusitis (CRS) is an inflammation of the paranasal sinus mucosa lasting over 12 weeks. Its etiology includes infections, allergies, immune system failures, anatomical abnormalities, and mucociliary transport disorders. The complex anatomy of the sinonasal region can hinder mucociliary drainage; necessitating CT scans to evaluate predisposing factors and minimize surgical risks. This study aimed to understand the anatomical variations in the paranasal sinuses and their correlation with CRS.ResultsThe study included 128 CRS patients aged 20 to 75, averaging 36.2 years. The most common symptoms were nasal congestion (98%), runny nose (85%), facial pressure (57%), reduced sense of smell (53%), and posterior nasal discharge (43%). Maxillary rhinosinusitis was the most prevalent (88%), followed by ethmoid (84%), frontal (58%), and sphenoid (48%) rhinosinusitis. Anatomical variations were present in 96% of patients, with deviated nasal septum (81.3%), agger nasi pneumatization (73.4%), and frontoethmoidal cells (60.2%) being the most common. Logistic regression indicated a significant association between concha bullosa and maxillary rhinosinusitis (p < 0.05). No significant correlation was found between anatomical variations number and SNOT-22 scores (r = − 0.177, p > 0.05).ConclusionThis study found a high prevalence of anatomical variations in CRS patients, with deviated nasal septum, agger nasi pneumatization, and frontoethmoidal cells being the most common. A significant association was identified between concha bullosa and maxillary rhinosinusitis.

Single-cell RNA sequencing of zebrafish olfactory epithelium reveals cellular heterogeneity and responses to a conspecific alarm substance

Olfaction, the sense of smell, is vital for the survival of many species and serves as an excellent system for investigating the molecular basis of behavior. Fishes possess a well-developed olfactory system that governs various behaviors related to feeding, reproduction, and fear. However, the cellular diversity and heterogeneity of the fish olfactory epithelium remains largely unexplored. This study presents a single-cell atlas of the zebrafish olfactory epithelium using single-cell RNA sequencing (scRNA-seq). Through scRNA-seq analysis of approximately 10,587 ​cells, we identified nine distinct cell types with unique transcriptional profiles, including immature and mature olfactory sensory neurons (OSNs), horizontal basal cells, globose basal cells, and sustentacular cells, as well as lymphocyte and myeloid cells expressing immune signals. Further subcluster analysis revealed selective and combinatorial expression of key components in odorant-mediated signal transduction by distinct OSN populations. Additionally, we discovered transcriptional changes specific to certain OSN populations following exposure to a conspecific alarm substance. The single-cell transcriptional atlas of the zebrafish olfactory epithelium provided in this study serves as a valuable tool for exploring cell diversity and assessing genetic profiles from functional and behavioral perspectives in fish.

Eurasian spruce bark beetle detects lanierone using a highly expressed specialist odorant receptor, present in several functional sensillum types

BackgroundInsects detect odours using odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) in the antennae. Ecologically important odours are often detected by selective and abundant OSNs; hence, ORs with high antennal expression. However, little is known about the function of highly expressed ORs in beetles, since few ORs have been functionally characterized. Here, we functionally characterized the most highly expressed OR (ItypOR36) in the bark beetle Ips typographus L. (Coleoptera, Curculionidae, Scolytinae), a major pest of spruce. We hypothesized that this OR would detect a compound important to beetle fitness, such as a pheromone component. We next investigated the antennal distribution of this OR using single sensillum recordings (SSR) and in situ hybridization, followed by field- and laboratory experiments to evaluate the behavioural effects of the discovered ligand.ResultsWe expressed ItypOR36 in HEK293 cells and challenged it with 64 ecologically relevant odours. The OR responded exclusively to the monoterpene-derived ketone lanierone with high sensitivity. Lanierone is used in chemical communication in North American Ips species, but it has never been shown to be produced by I. typographus, nor has it been studied in relation to this species’ sensory physiology. Single sensillum recordings revealed a novel and abundant lanierone-responsive OSN class with the same specific response as ItypOR36. Strikingly, these OSNs were co-localized in sensilla together with seven different previously described OSN classes. Field experiments revealed that low release rates of lanierone inhibited beetle attraction to traps baited with aggregation pheromone, with strongest effects on males. Female beetles were attracted to lanierone in laboratory walking bioassays.ConclusionsOur study highlights the importance of the so-called ‘reverse chemical ecology’ approach to identify novel semiochemicals for ecologically important insect species. Our discovery of the co-localization pattern involving the lanierone OSN class suggests organizational differences in the peripheral olfactory sense between insect orders. Our behavioural experiments show that lanierone elicits different responses in the two sexes, which also depend on whether beetles are walking in the laboratory or flying in the field. Unravelling the source of lanierone in the natural environment of I. typographus is required to understand these context-dependent behaviours.

Hydrogen and odorized methane blends under variable Reynolds number conditions with and without leaks

Customer-side piping systems involve low Reynolds number flows with prolonged periods under no-flow conditions. In this research, odorized CH4 (methane)/H2 and N2 (nitrogen)/He (helium) blends are investigated experimentally at variable Reynolds number (0 < Red < 5200) to determine if component separation occurs and if the presence of H2 suppresses odorant performance. After prolonged periods under no-flow conditions, all investigated mixtures exhibit varying degrees of component separation. Leak events of odorized CH4/H2 are examined using gas sample analysis. After accounting for gas dilution, leaks of odorized CH4/H2 under no-flow conditions exhibit odorant fade of Tert-Butyl Mercaptan while Methyl Ethyl Sulfide concentrations remain constant. Although odorant fade of Tert-Butyl Mercaptan occurs, measured levels are still approximately 50 times above levels at which the human olfactory sense can either detect or characterize the odorant. For both odorants, suppression due to the presence of H2 is not observed.

Psychometric Functions for α-Ionone in Young Adults

The mathematical relationship between the ability to detect an odorant and its concentration appears for some odorants to be non-monotonic, with reversals (“notches”) in performance appearing at points along the psychometric function. Like visual adaptation curves that reflect the differential sensitivities of cones and rods, such reversals may provide information about underlying olfactory receptor processes. However, the presence of such reversals is rarely acknowledged, few participants and odorants have been tested, and methodological concerns abound. In this study, we examined in detail the psychometric function for the odorant α-ionone using a sizable number of young participants and 10 log-based concentrations of alpha-ionone presented in a random fashion. A trial consisted of the counterbalanced presentation of an odorless mineral oil and a concentration of α-ionone in rapid succession using Snap & Sniff® wands. The participants reported which of the two seemed stronger and indicated their confidence on a 9-point scale. In Study 1, 24 participants completed a single 30-minute test session of 60 trials. In Study 2, 600 trials were obtained from each of nine participants over the course of ten 30-minute sessions. In both studies, notches were consistently found in the psychometric function near the 10−5 and 10−3.5 vol/vol concentrations. Participants’ trial-by-trial confidence judgments corresponded with their detection performance, but their self-rated sense of smell did not. This research definitively demonstrates the presence of reliable reversals in the human α-ionone psychometric function and begs the question as to whether such reversals reflect the recruitment of receptive elements with differing response profiles.

Features of the clinical and functional state of the nose in patients with chronic polypous rhinosinusitis and impaired sense of smell

Introduction. According to EPOS 2020, сhronic rhinosinusitis with nasal polypsis detected in 2–4.3% of the population, in Russia about 1.5 million people suffer from polyposis. In clinical practice, attention is most often paid to indicators of respiratory function. At the same time, the assessment of olfactory impairment characteristic of CRSwNP is carried out only by answering one of the 22 questions of the SNOT-22 questionnaire, and indicators of olfactory function are rarely taken into account when evaluating the results of objective research methods.Aim. To study the features of the clinical and functional state of the nose in patients with chronic rhinosinusitis and impaired sense of smell.Materials and methods. 50 patients with сhronic rhinosinusitis with nasal polypsis were examined. The study included an assessment of the sense of smell using Sniffin Stiks test-12, a study of respiratory function, performing a video endoscopy of the nose, computed tomography of the nose and paranasal sinuses. A comprehensive assessment of the condition was carried out using the SNOT-22 questionnaire.Results. The subjective assessment of the sense of smell by patients with CRSwNP does not always coincide with the results of identification tests. The results of the SNOT-22 questionnaire often depend on the degree of olfactory impairment. Patients with CRSwNP and anosmia are more likely to complain of postnasal congestion, thick nasal discharge and cough than patients with hyposmia, which is consistent with objective research methods.Conclusions. In patients with Ghronic rhinosinusitis with nasal polypsis and varying degrees of olfactory impairment, heterogeneity of the clinical and functional state of the nasal cavity and paranasal sinuses was noted. When interpreting the results of the SNOT-22 questionnaire, it is advisable to use factor analysis, taking into account the patient’s complaints. To plan individual management of patients with CRSwNP, a comprehensive assessment of the sense of smell is necessary, including identification tests, as well as an additional assessment of the results of computed tomography of the nose and paranasal sinuses and a video endoscopic picture of the nose according to generally recognized scales.

Paired and solitary ionocytes in the zebrafish olfactory epithelium.

The sense of smell is generated by electrical currents that are influenced by the concentration of ions in olfactory sensory neurons and mucus. In contrast to the extensive morphological and molecular characterization of sensory neurons, there has been little description of the cells that control ion concentrations in the zebrafish olfactory system. Here, we report the molecular and ultrastructural characterization of zebrafish olfactory ionocytes. Transcriptome analysis suggests that the zebrafish olfactory epithelium contains at least three different ionocyte types, which resemble Na + /K + -ATPase-rich (NaR), Na + /Cl - cotransporter (NCC), and H + -ATPase-rich (HR) cells, responsible for calcium, chloride, and pH regulation, respectively, in the zebrafish skin. NaR-like and HR-like ionocytes are usually adjacent to one another, whereas NCC-like cells are usually solitary. The distinct subtypes are differentially distributed: NaR-like/HR-like cell pairs are found broadly within the olfactory epithelium, whereas NCC-like cells reside within the peripheral non-sensory multiciliated cell zone. Comparison of gene expression and serial-section electron microscopy analysis indicates that the NaR-like cells wrap around the HR-like cells and are connected to them by shallow tight junctions. The development of olfactory ionocyte subtypes is also differentially regulated, as pharmacological Notch inhibition leads to a loss of NaR-like and HR-like cells, but does not affect NCC-like ionocyte number. These results provide a molecular and anatomical characterization of olfactory ionocytes in a stenohaline freshwater teleost. The paired ionocytes suggest that both transcellular and paracellular transport regulate ion concentrations in the olfactory epithelium, while the solitary ionocytes may enable independent regulation of multiciliated cells.

Variants of persistent olfactory dysfunction associated with Novel Coronavirus infection and treatment results

The problem of the occurrence of persistent olfactory dysfunction (OD) associated with Novel Coronavirus infection (COVID-19) has now become relevant, however, a regulated standard of therapy has not been developed. According to the literature, about 60 % of patients report the presence of olfactory disorders that persist for several months or more after recovery from COVID-19. However, no more than 5 % seek medical help for olfactory disorders, which indicates the importance of the problem and the need for treatment in a polyclinic setting. Currently, two main areas of treatment for quantitative and qualitative disorders of the sense of smell are used – drug and non-drug therapy. The article proposes a systematization option based on existing treatment methods with an assessment of their effectiveness. The method of performing olfactory training is described, and the results of treatment of persistent OD are presented.

Transorbital Endoscopic Approach for Managing Challenging Frontal Sinus Lesions: Results and Operative Technique Description

Abstract Objective The aim of this study was to describe our experience using the transorbital endoscopic approach (TEA) in the frontal sinus and the step-by-step technique used. Materials and Methods We reviewed the charts from adult patients who underwent management of frontal sinus lesions with TEA performed from 2017 to 2022. Results Seven patients underwent eight surgeries for frontal sinus lesions using TEA in combination with the endoscopic transnasal approach (ETA), with the majority on the left side (5/8, 62.5%). The average age was 53.9 years, with six male patients and one female patient. Gross total resection (GTR) was achieved in all cases. The most common symptoms leading to surgery were headaches or a sensation of pressure in the forehead (5/8, 62.5%), followed by a decreased sense of smell (3/8, 37.5%), diplopia (3/8, 37.5%), proptosis (2/8, 20%), periorbital cellulitis (2/8, 20%), and decreased visual acuity (1/8, 12.5%). The most common etiology in this case series was mucocele (5/8, 62.5%), followed by osteoid osteoma (2/8, 20%), and inverted papilloma (1/8, 12.5%). The length of stay in all cases was 1 day. The most common complication was mild and transitory V1 numbness, which fully recovered after 6 months (5/8, 62.5%). The average follow-up period was 24.6 months (range of 3–48 months). Conclusion Transoral Endoscopic Approach (TEA) demonstrated being a valuable complement to ETA approaches for treating frontal sinus lesions, especially in challenging regions. The transorbital approach is feasible and can safely achieve GTR for a variety of pathologies while effectively controlling symptoms and resulting in a 1-day hospital stay.

Engineered odorant receptors illuminate the basis of odour discrimination.

How the olfactory system detects and distinguishes odorants with diverse physicochemical properties and molecular configurations remains poorly understood. Vertebrate animals perceive odours through G protein-coupled odorant receptors (ORs)1. In humans, around 400 ORs enable the sense of smell. The OR family comprises two main classes: class I ORs are tuned to carboxylic acids whereas class II ORs, which represent most of the human repertoire, respond to a wide variety of odorants2. A fundamental challenge in understanding olfaction is the inability to visualize odorant binding to ORs. Here we uncover molecular properties of odorant-OR interactions by using engineered ORs crafted using a consensus protein design strategy3. Because such consensus ORs (consORs) are derived from the 17 major subfamilies of human ORs, they provide a template for modelling individual native ORs with high sequence and structural homology. The biochemical tractability of consORs enabled the determination of four cryogenic electron microscopy structures of distinct consORs with specific ligand recognition properties. The structure of a class I consOR, consOR51, showed high structural similarity to the native human receptor OR51E2 and generated a homology model of a related member of the human OR51 family with high predictive power. Structures of three class II consORs revealed distinct modes of odorant-binding and activation mechanisms between class I and class II ORs. Thus, the structures of consORs lay the groundwork for understanding molecular recognition of odorants by the OR superfamily.

Ratting on wildlife crime: training African giant pouched rats to detect illegally trafficked wildlife

The illegal wildlife trade (IWT) is one of the largest global crime economies, directly threatening species and their habitats, and biodiversity, and indirectly the global climate, and countries’ economies. Syndicates operating within the IWT are often involved in trafficking of humans, weapons, and drugs. IWT takes place in large scale through international ports, with wildlife being smuggled inside shipping containers. Current methods to combat IWT and screen these shipping containers, such as X-ray scans, are expensive and time-consuming. Scent-detection animals present an innovative approach to combatting IWT, as animals may be better suited to distinguish between organic materials and less susceptible to visual concealment methods. Previous scent-detection work has largely focused on conservation dogs (Canis lupus familiaris). Here, we present a series of proof-of-principle studies training African giant pouched rats (Cricetomys ansorgei) to detect illegally trafficked wildlife. As initial proof-of-principle within a controlled laboratory environment, we trained rats (n=11) to detect the scent of pangolin scales (Manis spp.) and a threatened African hardwood (Dalbergia melanoxylon). In subsequent experiments, we trained these rats (n=10) to detect rhinoceros horn (family Rhinocerotidae), and elephant tusks (Loxodonta spp.). At the conclusion of these studies, rats (n=7) accurately identified all four target species (although ivory samples may have been cross-contaminated, and results should be interpreted with caution) while correctly rejecting non-target items commonly used by traffickers to conceal the presence of illicit material. Rats detected the presence of wildlife targets even when these were concealed in mixtures among non-target items. These results provide the foundation to train rats for scent-detection of illegally trafficked wildlife to combat IWT. The unique attributes of rats could allow them to complement existing screening technologies in the fight against IWT. Rats have low training and maintenance costs, flexibly work with multiple handlers, have a long lifespan, and a sophisticated sense of smell. Their small size also offers unique capabilities for the screening of shipping containers, such as being able to navigate densely packed areas or be lifted to assess contents of sealed containers by screening ventilation systems. Future directions include assessing operational feasibility of deploying rats at ports.

A Drosophila-inspired intelligent olfactory biomimetic sensing system for gas recognition in complex environments

The olfactory sensory system of Drosophila has several advantages, including low power consumption, high rapidity and high accuracy. Here, we present a biomimetic intelligent olfactory sensing system based on the integration of an 18-channel microelectromechanical system (MEMS) sensor array (16 gas sensors, 1 humidity sensor and 1 temperature sensor), a complementary metal‒oxide‒semiconductor (CMOS) circuit and an olfactory lightweight machine-learning algorithm inspired by Drosophila. This system is an artificial version of the biological olfactory perception system with the capabilities of environmental sensing, multi-signal processing, and odor recognition. The olfactory data are processed and reconstructed by the combination of a shallow neural network and a residual neural network, with the aim to determine the noxious gas information in challenging environments such as high humidity scenarios and partially damaged sensor units. As a result, our electronic olfactory sensing system is capable of achieving comprehensive gas recognition by qualitatively identifying 7 types of gases with an accuracy of 98.5%, reducing the number of parameters and the difficulty of calculation, and quantitatively predicting each gas of 3–5 concentration gradients with an accuracy of 93.2%; thus, these results show superiority of our system in supporting alarm systems in emergency rescue scenarios.

Powerful Patina: The Value of Odors in a Tibetan Buddhist Temple

ABSTRACT In the past decades, attention towards a more sensory perception in the arts and architecture has gained momentum and concerns a variety of disciplines. Nonetheless, hands-on conservation efforts still overwhelmingly concentrate on the visual qualities and values of places. In the following article, I present a case study of a Tibetan–Buddhist temple in Ladakh/India that empirically examines questions of value as they extend to the idea of patina found on wall paintings inside the temple produced by the burning of butter lamps. The layer of soot which obscures these centuries-old wall paintings has particular olfactory qualities. The paper draws from my professional and personal experience as art conservator working with an NGO from 2004 until 2014. It is a methodological re-thinking of our original conservation approach through the framework of Alois Riegl's value model applied to olfactory perceptions of patina. Examined are the meaning of odors concerning heritage values, memory, and the formation of identity. Odors are site-specific, therefore, conservation work at heritage sites needs to include the documentation and value assessment of their olfactory qualities to determine the impact a removal of patina may have on stakeholder communities.

MORPHOLOGYOF OLFACTORIORGAN OFCOMMON PALMCIVET (PARADOXURUS HERMAPHRODITUS)

Common Palm Civet (Paradoxurus hermaphroditus) has a very sharp sense of smell that is a tool for selecting ripe and good quality coffee fruit. This research was aimed to study the morphological characteristics of the olfactory organ of Common palm civet macroscopically and microscopically. In this study, three adult Common palm civet were used. Based on macroscopic observations, Common palm civet had olfactory organs consisting of cavum nasi, nostril, septum nasi, conchae and vomeronasale organs found in the nasale. In the dextra and sinistra cavum nasi, there were conchae (superior, medius and inferior). In the medius and inferior conchae, there a respiratory epithelium in the superior conchae, there was the olfactory epithelium. Hematoxylin-Eosin (HE) staining was used for microscopic observation. Based on microscopic observations, the olfactory epithelium composed of sustentacular cells (supporting cells), receptor cells and basal cells. The respiratory epithelium composed of goblet cells, pseudostratified epithelium and basal cells. The vomeronasale epithelium consists of the sensory and non-sensory epithelium. The sensory epithelium covered the ventral two thirds of the medial side of the vomeronasale, while the non-sensory epithelium covered the lateral side and the dorsal thirded of the medial side of the vomeronasale. The epithelium sensory vomeronasale consisted of three types of cells: supporting, receptors, and basal. Non-sensoryepithelium composed of the pseudostratified epithelium and goblet cells

Enriching Flaws of Scent عطر עטרה A Guava Scent Collection

Abstract This essay is written around the art-action عطر עטרה A Guava scent collection from an artist’s point of view. It connects the decision-making process and manifestations of the scent collection to dominant convictions about the “flaws” of scent and the sense of smell in Western philosophy. According to these convictions, the sense of smell and scent have no relevance to rational thinking and/or scientific knowledge and by implication to a political debate, for three reasons: scent is volatile, the sense of smell is non-verbal, and the sense of smell is too subjective to rely on. By contrast, I argue that the supposed “flaws” of scent and the sense of smell, might, in fact, contribute in a constructive and productive way to a sociopolitical debate, as will be demonstrated by the art installation of the Guava scent collection.

Olfactory Dysfunction in Obesity and Type 2 Diabetes

The article analyzes literature data on the close relationship between energy balance and sense of smell. Olfaction is one of the main modalities of hedonic evaluation of food. Odor is one of the most important sensory signals predicting food quality and plays a key role in food selection and consumption. Appetite can be stimulated by various stimuli, but the leading role belongs to olfactory signals (tasty smells) and levels of hormones that signal hunger and satiety. Olfactory perception is subject to hormonal modulation. In this regard, special attention in the article is paid to the modulating function of insulin. Insulin, one of the main metabolic hormones that controls food intake, has an anorexigenic effect not only at the level of the hypothalamus, but also at the level of the olfactory pathway, especially strong in the olfactory bulb. It has a rate of insulin transport two to eight times higher than in other parts of the brain, and it contains the highest concentration of insulin and the highest density of insulin receptor kinase. Thus, insulin is not only able to penetrate to the site of olfactory information processing, but do so quickly. At the same time, insulin and its receptors are localized in the olfactory epithelium, namely in mature olfactory sensory neurons. Therefore, insulin affects the primary stage of perception of an odorous molecule – odor detection, which occurs at the level of the olfactory epithelium. The sense of smell is impaired up to its complete loss in obesity and type 2 diabetes, worsening the quality of life of such patients. The paper examines the effectiveness of intranasal insulin administration to restore olfactory function in metabolic disorders and other diseases.

Hypogonadotropic hypogonadism as a cause of NOA and its treatment.

Hypogonadotropic hypogonadism (HH) represents a relatively rare cause of nonobstructive azoospermia (NOA), but its knowledge is crucial for the clinical andrologists, as it represents a condition that can be corrected with medical therapy in 3 quarters of cases. There are forms of congenital HH, whether or not associated with an absent sense of smell (anosmic HH or Kallmann syndrome, and normosmic HH, respectively), and forms of acquired HH. In congenital HH, complete absence of pubertal development is characteristic. On the other hand, if the deficit occurs after the time of pubertal development, as in acquired HH patients, infertility and typical symptoms of late-onset hypogonadism are the main reasons for seeking medical assistance. Gonadotropin-releasing hormone (GnRH) or gonadotropin replacement therapy is the mainstay of drug therapy and offers excellent results, although a small but significant proportion of patients do not achieve sufficient responses.

Humans without a sense of smell breathe differently

Olfaction may play a restricted role in human behavior, yet paradoxically, its absence in anosmia is associated with diverse deleterious outcomes, culminating in reduced life expectancy. The mammalian nose serves two purposes: olfaction and breathing. Because respiratory patterns are impacted by odors, we hypothesized that nasal respiratory airflow may be altered in anosmia. We apply a wearable device that precisely logs nasal airflow for 24-hour-long sessions in participants with isolated congenital anosmia and controls. We observe significantly altered patterns of respiratory nasal airflow in anosmia in wake and in sleep. These differences allow classification of anosmia at 83% accuracy using the respiratory trace alone. Patterns of respiratory airflow have pronounced impact on health, emotion and cognition. We therefore suggest that a portion of the deleterious outcomes associated with anosmia may be attributed to altered patterns of respiratory nasal airflow rather than a direct result of lost odor perception per se.