Possible role of endocannabinoids in olfactory and taste dysfunctions in Alzheimer’s and Parkinson’s patients and volumetric changes in the brain

Petekkaya, Emine; Kuş, Berna; Doğan, Serdar; Bayaroğulları, Hanifi; Mutlu, Turay; Melek, İsmet; Arpacı, Abdullah

doi:10.1016/j.jocn.2022.03.047

Cited by 5 publications

(7 citation statements)

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“…study was based on indirect questionnaires obtained by caregivers; 2) the results of one study did not include a comparison with healthy control subjects; and 3) one study was written in French, and the raw data could not be obtained. Finally, 12 studies were included in this systematic review and meta-analysis (Figure 1, Table 1) (5,10,16,(18)(19)(20)(21)(22)(23)(24)(25)(26) . No studies were found to have a high risk of bias after performing a quality assessment using the Newcastle-Ottawa Quality Assessment Scale (Supplementary Table 1).…”

Section: Search Resultsmentioning

confidence: 99%

Association of gustatory dysfunction and Alzheimer's disease: a systematic review and meta-analysis

Kwak,

Kim,

Min

2023

Rhin

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BACKGROUND: Chemosensory dysfunction (olfaction, taste, and trigeminal) affects quality of life, potentially impacting eating behaviors. We investigated which factors are associated with weight loss in patients with smell and taste disorders. METHODS: Retrospective study of consecutive adult patients seen in the smell and taste clinic during a 10-year period. Patients were asked about smell, flavor and taste impairment. Psychophysically, smell was assessed with Sniffin' Sticks, flavor with a retronasal test, and taste with Taste Strips. RESULTS: A total of 554 patients (313 females) were included with a median age of 51 years (IQR 23). Seventy-six (13.7%) reported involuntary weight loss (median 6 kg, IQR 6) due to chemosensory disorders. The odds of losing weight were 2.1 times higher when patients reported subjective changes in flavor perception. Parosmia was a significant predictor of weight loss. Patients with symptoms lasting longer than two years were less likely to present with weight loss. Post-traumatic chemosensory dysfunction was a significant predictor of losing weight. On psychophysical testing, the probability of a patient losing weight increased by 8% for every 1-unit reduction in Taste Strips score. CONCLUSION: Factors associated with weight loss were self-reported changes in flavor perception, parosmia, duration of symptoms for less than two years, head injury, and psychophysically measured low Taste Strips score. These data help to identify patients at risk of weight loss from smell or taste impairment.

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Section: Search Resultsmentioning

confidence: 99%

Association of gustatory dysfunction and Alzheimer's disease: a systematic review and meta-analysis

Kwak,

Kim,

Min

2023

Rhin

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“…However, the lack of such a relationship in other areas where EC receptors are located indicates that factors other than ECs may also be effective here. In a recent study, it was found that EC levels were also increased in Alzheimer’s patients (Petekkaya et al 2022 ). Recent studies have stated that there are Alzheimer-like changes in the brains of COVID-19 patients (Reiken et al 2022 ) and that Alzheimer’s and COVID-19 have common genetic risk factors (Magusali et al 2021 ).…”

Section: Discussionmentioning

confidence: 98%

Possible Role of Endocannabinoids in Olfactory and Taste Dysfunctions in COVID-19 Patients and Volumetric Changes in the Brain

et al. 2022

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Introduction COVID-19 infection develops neurologic symptoms such as smell and taste loss. We aimed to determine the volumetric changes in the brain and correlation of possible related biochemical parameters and endocannabinoid levels after COVID-19 recovery. Methods Brain magnetic resonance images of recovered COVID-19 patients and healthy volunteers, whose olfactory and gustatory scores were obtained through a questionnaire, were taken, and the volumes of the brain regions associated with taste and smell were measured by automatic and semiautomatic methods. Endocannabinoids (EC), which are critical in the olfactory system, and vitamin B12, zinc, iron, ferritin, thyroid-stimulating hormone (TSH), and thyroxine (T4) levels, which are reported to have possible roles in olfactory disorders, were measured in peripheral blood. Results Taste and smell disorder scores and EC levels were found to be higher in recovered COVID-19 patients compared to controls. EC levels were negatively correlated with bilateral entorhinal cortex (ENT) volumes in the COVID-19 group. Subgenual anterior cingulate cortex volumes showed correlations with gustatory complaints and ferritin in recovered COVID-19 patients. Conclusions The critical finding of our study is the high EC levels and negative correlation between EC levels and left ENT volumes in recovered COVID-19 patients. Implications It is possible that ECs are potential neuromodulators in many conditions leading to olfactory disorders, including COVID-19.

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“…39,[52][53][54][55] These observations provide a rationale for conducting studies to evaluate potential attentional and cognitive deficit in patients with persistent OD. Furthermore, It is known that smell loss is one of the prodromal symptoms of many neurodegenerative diseases including Alzheimer's and Parkinson's diseases 56 and disorders with impaired attentional capacity, 57,58 with mechanisms of OD being yet to be elucidated. Despite there is no evidence yet that patients with post-COVID-19 olfactory loss are at higher risk for neurodegenerative diseases, the existence of a relevant fraction of patients with persistent long-term OD should be enough to consider that hypothesis and design studies to investigate these aspects.…”

Section: Discussionmentioning

confidence: 99%

Psychophysical assessment of olfactory and gustatory function in post‐mild COVID‐19 patients: A matched case‐control study with 2‐year follow‐up

Boscolo‐Rizzo

Hummel

Invitto

et al. 2023

Int Forum Allergy Rhinol

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BackgroundThe aim of this study was to psychophysically evaluate the prevalence of smell and taste dysfunction 2 years after mildly symptomatic severe acute respiratory syndrome–coronavirus‐2 (SARS‐CoV‐2) infection compared to that observed at 1‐year follow‐up and while considering the background of chemosensory dysfunction in the no‐coronavirus disease 2019 (COVID‐19) population.MethodThis is a prospective case‐control study on 93 patients with polymerase chain reaction (PCR)‐positive SARS‐CoV‐2 infection and 93 matched controls. Self‐reported olfactory and gustatory dysfunction was assessed by 22‐item Sino‐Nasal‐Outcome Test (SNOT‐22), item “Sense of smell or taste.” Psychophysical orthonasal and retronasal olfactory function and gustatory performance were estimated using the extended Sniffin’ Sticks test battery, 20 powdered tasteless aromas, and taste strips test, respectively. Nasal trigeminal sensitivity was assessed by sniffing a 70% solution of acetic acid.ResultsThe two psychophysical assessments of chemosensory function took place after a median of 409 days (range, 366–461 days) and 765 days (range, 739–800 days) from the first SARS‐CoV‐2–positive swab, respectively. At 2‐year follow‐up, cases exhibited a decrease in the prevalence of olfactory (27.9% vs. 42.0%; absolute difference, −14.0%; 95% confidence interval [CI], −21.8% to −2.6%; p = 0.016) and gustatory dysfunction (14.0% vs. 25.8%; absolute difference, −11.8%; 95% CI, −24.2% to 0.6%; p = 0.098). Subjects with prior COVID‐19 were more likely than controls to have an olfactory dysfunction (27.9% vs. 10.8 %; absolute difference, 17.2%; 95% CI, 5.2% to 28.8%) but not gustatory dysfunction (14.0% vs. 9.7%; absolute difference, 4.3%; 95% CI, −5.8% to 14.4% p = 0.496) still 2 years after the infection. Overall, 3.2% of cases were still anosmic 2 years after the infection.ConclusionsAlthough a proportion of subjects recovered from long‐lasting smell/taste dysfunction more than 1 year after COVID‐19, cases still exhibited a significant excess of olfactory dysfunction 2 years after SARS‐CoV‐2 infection when compared to matched controls.

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Possible role of endocannabinoids in olfactory and taste dysfunctions in Alzheimer’s and Parkinson’s patients and volumetric changes in the brain

Cited by 5 publications

References 38 publications

Association of gustatory dysfunction and Alzheimer's disease: a systematic review and meta-analysis

Association of gustatory dysfunction and Alzheimer's disease: a systematic review and meta-analysis

Possible Role of Endocannabinoids in Olfactory and Taste Dysfunctions in COVID-19 Patients and Volumetric Changes in the Brain

Psychophysical assessment of olfactory and gustatory function in post‐mild COVID‐19 patients: A matched case‐control study with 2‐year follow‐up

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