Reduced olfactory bulb volume and olfactory sensitivity in patients with acute major depression

Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany.
Neuroscience (Impact Factor: 3.36). 08/2010; 169(1):415-21. DOI: 10.1016/j.neuroscience.2010.05.012
Source: PubMed


The purpose of this study was to assess olfactory function and olfactory bulb volume in patients with acute major depression in comparison to a normal population. Twenty-one patients diagnosed with acute major depressive disorder and 21 healthy controls matched by age, sex and smoking behavior participated in this study. Olfactory function was assessed in a lateralized fashion using measures of odor threshold, discrimination and identification. Olfactory bulb volumes were calculated by manual segmentation of acquired T2-weighted coronal slices according to a standardized protocol. Patients with acute major depressive disorder showed significantly lower olfactory sensitivity and smaller olfactory bulb volumes. Additionally, a significant negative correlation between olfactory bulb volume and depression scores was detected. Their results provide the first evidence, to our knowledge, of decreased olfactory bulb volume in patients with acute major depression. These results might be related to reduced neurogenesis in major depression that could be reflected also at the level of the olfactory bulb.

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Available from: Ilona Croy, Dec 20, 2013
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    • "survival of newly born neurons into adulthood , or is human olfaction conceptionally differently modulated ? Deprivation of neurogenesis in the human olfactory bulb has been implicated in several neurodegenerative diseases that compromise ol - faction and can lead to anosmia ( Turetsky et al . 2000 ; Höglinger et al . 2004 ; Hansson et al . 2010 ; Negoias et al . 2010 ; Winner et al . 2011 ) . How - ever , the limited or absent olfactory bulb neuro - genesis makes it unlikely that the anosmia is a consequence of reduced adult olfactory bulb neurogenesis ."
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    ABSTRACT: Adult neurogenesis appears very well conserved among mammals. It was, however, not until recently that quantitative data on the extent of this process became available in humans, largely because of methodological challenges to study this process in man. There is substantial hippocampal neurogenesis in adult humans, but humans appear unique among mammals in that there is no detectable olfactory bulb neurogenesis but continuous addition of new neurons in the striatum. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.
    Preview · Article · Jul 2015 · Cold Spring Harbor perspectives in biology
    • "The most prominent changes were in the OB volume, enhancement of the glomerular layer, and in the distance between mitral cell layers of both sides of the bulb during degeneration and recovery. Significant reduction in OB volume was previously reported in different MRI studies of neurological disorders such as AD, Parkinson's disease, depression and schizophrenia, which correlates with the disease progression (Turetsky et al., 2000; Thomann et al., 2009; Negoias et al., 2010; Wang et al., 2011). Increase in OB volume was shown following 3 weeks of doxycycline treatment in the present model. "
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    ABSTRACT: Manganese Enhanced MRI (MEMRI) was used to detect specific laminar changes in the olfactory bulb (OB) to follow the progression of amyloid precursor protein (APP)-induced neuronal pathology and its recovery in a reversible olfactory based Alzheimer's disease (AD) mouse model. Olfactory dysfunction is an early symptom of AD, which suggests that olfactory sensory neurons (OSNs) may be more sensitive to AD related factors than neurons in other brain areas. Previously a transgenic mouse model was established that causes degeneration of OSNs by overexpressing humanized APP (hAPP), which results in a disruption of olfactory circuitry with changes in glomerular structure. In the present work, OB volume and manganese enhancement of the glomerular layer in OB were decreased in mutant mice. Turning off APP overexpression with doxycycline produced a significant increase in manganese enhancement of the glomerular layer after only 1 week, and further recovery after 3 weeks, while treatment with Aβ antibody produced modest improvement with MRI measurements. Thus, MEMRI enables a direct tracking of laminar specific neurodegeneration through a non-invasive in vivo measurement. The use of MRI will enable assessment of the ability of different pharmacological reagents to block olfactory neuronal loss and can serve as a unique in vivo screening tool to both identify potential therapeutics and test their efficacy. Copyright © 2015. Published by Elsevier Inc.
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    • "The described procedure was used in multiple studies focusing on OB volumetrics, with consistent results, e.g. (Buschhuter et al. 2008; Croy et al. 2013; Hummel et al. 2013a; Negoias et al. 2010). OB measurements of all data—patients and healthy group members —were performed by the same experimenter (SN) who was blind to the group category of patients and to their respective olfactory test results. "
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    ABSTRACT: The volume of the olfactory bulb (OB) is strongly reduced in patients with major depressive disorder (MDD) and this group exhibits markedly decreased olfactory function. It has been suggested that olfactory input is important for maintaining balance in limbic neurocircuits. The aim of our study was to investigate whether reduced OB volume is associated with response to therapy in MDD. Twenty-four inpatients (all women, age 21-49 years, mean 38 ± 10 years SD) with MDD and 36 healthy controls (all women, age 20-52 years, mean 36 ± 10 years SD) underwent structural MRI. OB volume was compared between responders (N = 13) and non-responders (N = 11) to psychotherapy. Retest of OB volume was performed about 6 months after the end of therapy in nine of the patients. Therapy responders exhibited no significant difference in OB volume compared to healthy controls. However, average OB volume of non-responders was 23 % smaller compared to responders (p = .0011). Furthermore, OB volume was correlated with the change of depression severity (r = .46, p = .024). Volume of the OB did not change in the course of therapy. OB volume may be a biological vulnerability factor for the occurrence and/or maintenance of depression, at least in women.
    Full-text · Article · May 2015 · Brain Imaging and Behavior
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