Correlation between the human fecal microbiota and depression.

BACKGROUND: Depression is a chronic syndrome with a pathogenesis linked to various genetic, biological, and environmental factors. Several links between gut microbiota and depression have been established in animal models. In humans, however, few correlations have yet been demonstrated. The aim of our work was therefore to identify potential correlations between human fecal microbiota (as a proxy for gut microbiota) and depression. METHODS: We analyzed fecal samples from 55 people, 37 patients, and 18 non-depressed controls. Our analyses were based on data generated by Illumina deep sequencing of 16S rRNA gene amplicons. KEY RESULTS: We found several correlations between depression and fecal microbiota. The correlations, however, showed opposite directions even for closely related Operational Taxonomic Units (OTU's), but were still associated with certain higher order phylogroups. The order Bacteroidales showed an overrepresentation (p = 0.05), while the family Lachnospiraceae showed an underrepresentation (p = 0.02) of OTU's associated with depression. At low taxonomic levels, there was one clade consisting of five OTU's within the genus Oscillibacter, and one clade within Alistipes (consisting of four OTU's) that showed a significant association with depression (p = 0.03 and 0.01, respectively). CONCLUSIONS & INFERENCES: The Oscillibacter type strain has valeric acid as its main metabolic end product, a homolog of neurotransmitter GABA, while Alistipes has previously been shown to be associated with induced stress in mice. In conclusion, the taxonomic correlations detected here may therefore correspond to mechanistic models.

Quantitative EEG in type 1 diabetic adults with childhood exposure to severe hypoglycaemia: a 16 year follow-up study.

AIMS/HYPOTHESIS: In diabetic children and adolescents, a history of severe hypoglycaemia (SH) has been associated with increased slow EEG activity and reduced cognition, possibly due to harmful effects of SH on the developing brain. In a group of type 1 diabetic patients with early exposure to SH, who had EEG abnormalities and reduced cognition in childhood, we have recently demonstrated that the reduced cognition may persist into adulthood. We have now assessed whether the reduced cognition was accompanied by lasting EEG abnormalities. METHODS: In 1992-1993, we studied EEG and cognition in 28 diabetic children and 28 matched controls. 16 years later, we re-investigated the same participants, with 96% participation rate. Diabetic participants were classified as with (n = 9) or without (n = 18) early SH, defined as episodes with convulsions or loss of consciousness by 10 years of age. For each EEG band (delta, theta, alpha and beta) and cerebral region (frontocentral, temporal, and parietooccipital), we calculated relative amplitudes and amplitude asymmetry. We also calculated occipital alpha mean frequency, alpha peak frequency at maximum amplitude, alpha peak width, and theta regional mean frequencies. We examined whether these EEG measures, relative to age- and sex-matched controls, differed between diabetic participants with and without early SH. RESULTS: We found no association of early SH with any of the EEG measures. CONCLUSIONS/INTERPRETATION: Childhood SH was not associated with EEG abnormalities in young type 1 diabetic adults. Our findings suggest that the reduced adulthood cognition associated with childhood exposure to SH is not accompanied by lasting EEG abnormalities.

Low blood pressure is a better predictor of cognitive deficits than the apolipoprotein e4 allele in the oldest old.

OBJECTIVE: To study the correlates of cognitive deficits in persons 80 years and older. MATERIALS AND METHODS: Data from 271 individuals between 80 and 102 years of age, drawn from a central registrar (response rate 50%) were analyzed regarding e apolipoprotein E (Apo-E) polymorphism, blood pressure (BP), homocysteine, sex, age and education as predictors for low score on Mini Mental Status Examination (MMSE). RESULTS: Low systolic and diastolic BP were highly associated with low score on the MMSE, followed by age and Apo-E e4. No relationship was found between Apo-E allele groups and BP. Homocysteine, sex, and education were only of marginal importance. CONCLUSIONS: Hypotension is an important factor for performance on the MMSE. To some extent, this was also true for having the Apo-E e4 allele. A combined effect on cognition for these two factors was not found.

Neuropsychological deficits in HIV-1 seropositive and seronegative intravenous drug users (IVDUs): a follow-up study.

Human immunodeficiency virus type 1 (HIV-1) seropositive AIDS free and HIV-1 seronegative intravenous drug users were tested twice with a comprehensive neuropsychological test battery. Only minor group differences were found. Memory difficulties were the most pronounced difference with lower scores in the HIV-1 seropositive group. The memory difficulties were to some degree associated with emotional difficulties, that is, anxiety. The HIV-1 seropositive subjects were tested a third time and there was no further decline in any test with memory content at this testing. The only test that showed a significant decline in the HIV-1 seropositive group was the Trail Making Test.

Cognitive sequelae of repeated head injury in a population of intravenous drug users.

The relationship between closed head injury and performance on neuropsychological (NP) tests was investigated in a group of intravenous drug users (IVDUs). Subjects with repeated head traumas involving loss of consciousness (LOC) performed worse than both a control group without LOC and reference group with only a single episode of LOC. There were no significant differences between the last two groups. Performance on tests of memory, attention, and motor performance was significantly worse in the group with repeated head injury. The average time since the last episode of LOC was more than 11 years. We conclude from these findings that a single episode of LOC does not result in significant cognitive impairment in this population. Two or more episodes, however, are more likely to produce chronic cognitive impairment.

Psychological difficulties related to human immunodeficiency virus-1 infection in intravenous drug users.

Psychopathology and emotional changes were examined over a 9-month period in this study of human immunodeficiency virus-1 (HIV-1) infection in seronegative and seropositive intravenous drug users. The HIV-1-seropositive group showed more psychological difficulties and emotional distress at both testings. For the HIV-1-seronegative subjects, a trend for less psychopathology and psychological distress was found. At the second testing, the difference between groups was increased due to improvement of the HIV-1-seronegative group. A more chronic course of psychological distress was found in the HIV-1-seropositive group.

Neuropsychological deficits in HIV-1 seropositive and seronegative intravenous drug users.

A battery of neuropsychological tests was administered to detoxified HIV-1 seropositive and seronegative intravenous drug users. There were few problems related to administering the test battery to the groups in question. Of the total sample, 28% obtained an Halstead-Reitan Impairment Index > .4, indicating central nervous system deficits. Both groups performed below comparable normative levels on the variables studied. The HIV-1 infection per se could not explain the neuropsychological impairment.

Regional brain atrophy in HIV-1 infection: association with specific neuropsychological test performance.

Quantified magnetic resonance imaging (MRI) was related to neuropsychological (NP) test scores in an asymptomatic HIV-1 seropositive group, a non-demented AIDS/ARC group, a group of subjects with HIV-1 dementia, and a seronegative control group. The MRIs were quantified using three planimetric measures of brain structure: the bicaudate ratio (a measure of caudate region atrophy), the bifrontal ratio (a measure of frontal region atrophy), and the ventricle to brain ratio (a measure of overall cerebral atrophy). Cognitive performance was assessed with standard NP tests. Significant correlations between the MRI ratios and many of the NP tests were observed. Of the tests grooved pegboard, part B of the trail making test, the verbal fluency test, and the digit span forward were associated with MRI abnormalities. The bicaudate ratio was most closely associated with the NP tests. These findings indicate that ventricular enlargement, especially in the region of the caudate, is closely related to poor NP test performance in HIV-1 infection.

[HIV and the central nervous system]. / HIV og sentralnervesystemet.

It is well documented that human immunodeficiency virus (HIV) can infect the central nervous system. Neurological dysfunction occurs frequently in acquired immunodeficiency syndrome (AIDS) and most commonly in the form of a subacute HIV-encephalitis. The pathological abnormalities in patients with subacute HIV-encephalitis are most prominent in subcortical structures, notably in the cerebral white and deep gray matter. The patients frequently develop abnormalities in cognitive, motor and behavioral functions. The infected cells are predominant lymphocytes and macrophages. The production of cytokines by these cells appears to be a central factor in the pathogenesis of subacute HIV-encephalitis. The central nervous system can function as a reservoir of HIV infection. Neuropsychological assessment is a sensitive method for documentation of early brain involvement by HIV infection. The HIV-associated neurological abnormalities may be partially ameliorated by administration of zidovudine (AZT).