Download Fujita et al—cAMP Signaling in Brain is Decreased in Unmedicated

Fujita et al—cAMP Signaling in Brain is Decreased in Unmedicated Depressed Patients and
Increased by Treatment with a Selective Serotonin Reuptake Inhibitor
Supplementary Information
Additional Descriptions on Participants. Major depressive disorder MDD patients were
required to be free from psychotropic medications for at least two weeks before the baseline 11C(R)-rolipram PET scan (six weeks for fluoxetine). Healthy controls and patients were excluded if
they had a history of alcohol or substance abuse within the past year or a lifetime history of
alcohol or substance dependence based on DSM-IV. Herbal remedies or use of over-the-counter
medications with known central nervous system effects were not permitted at any time during the
study. MDD patients with serious suicidal ideation or psychosis were excluded from the study,
but those with certain secondary anxiety disorders (generalized anxiety disorder, panic disorder,
social phobia, anxiety disorder not otherwise specified, agoraphobia without panic disorder)
were allowed to participate. In addition, we included patients with a remote history of
posttraumatic stress disorder or obsessive-compulsive disorder but excluded subjects if these
disorders were active at the time of enrollment. All participants underwent a urine drug screen
for amphetamines, benzodiazepines, cocaine metabolites, opiates, and cannabinoids on the day
of each 11C-(R)-rolipram PET scan. Participants were not allowed to ingest caffeine after
midnight on the day before the PET scan.
Statistical Analysis. Age, injection activity, and mass dose per body weight of 11C-(R)-rolipram
were compared between the healthy control and MDD groups using Mann-Whitney U tests. For
the patients who had two PET scans, injection activity and mass dose per body weight were
compared between the two scans using Wilcoxon Signed Rank Tests. These nonparametric tests
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were applied because the Shapiro-Wilk normality test indicated significant deviation from
normal distribution. Clearance of 11C-(R)-rolipram from plasma was compared between controls
and unmedicated patients using two-sample t-tests. For the patients who had two PET scans
(unmedicated at baseline and after eight weeks of treatment with a selective serotonin reuptake
inhibitor (SSRI)), clearance and changes in severity of symptoms were compared between the
two scans using paired sample t-tests. Gender balance and percentage of cigarette smokers were
compared between the two groups using Fisher’s exact test. VT/fP in the 10 brain regions was
compared between control subjects and unmedicated MDD patients and between scans before
and after starting SSRI using repeated measures two-way analysis of variance with regions as the
within-subjects (repeating) factor. The repeated measures two-way analysis of variance was also
performed to study the effect of cigarette smoking, prior medication, and current comorbid
anxiety disorders. The selection of repeated measures two-way analysis of variance was used
because the Shapiro-Wilk normality test did not indicate significant deviation of PET data from
normal distribution. The effect size, Cohen’s d, was calculated by
.
For the PET scans in unmedicated patients at baseline, the correlation between each of
the Montgomery Åsberg Depression Rating Scale (MADRS), 17-item Hamilton Rating Scale for
Depression (HDRS-17), and Hamilton Scale for Anxiety (HAM-A) ratings and VT/fP in the 10
brain regions were investigated using Spearman’s bivariate correlation. In addition, the
correlations were investigated after controlling for age (i.e., by partial correlation). For the
patients who had two PET scans, the bivariate and partial correlation analyses were performed
on the relationship between change in rating scale scores and VT/fP. The relationship between age
and VT/fP was studied with both Pearson and Spearman methods. VT/fP in each voxel from control
subjects and unmedicated MDD patients was compared using SPM8 two-sample t-tests. For both
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baseline rolipram binding in each voxel and its changes after SSRI treatment, the relationship
between rolipram binding and age was examined by an SPM8 regression model. The relationship
between each of the MADRS, HDRS-17, and HAM-A ratings and VT/fP in each voxel of MDD
patients was studied using an SPM8 regression model. All of the SPM analyses were performed
with and without global normalization of proportional scaling.
In the analyses that used binding in the 10 regions, P<.05 was considered statistically
significant. In the SPM analyses, a family-wise error (FWE) corrected P<.05 was considered
statistically significant. One-sided tests to both directions were applied in the SPM analysis to
compare healthy controls and unmedicated patients. One-sided tests were applied to study
correlations between rolipram binding and symptoms, and two-sided tests were applied in the
other analyses. The statistical analyses were performed using IBM SPSS Statistics 22 (Armonk,
New York) for data from the 10 regions or SPM8 for voxel data. Results are shown as mean ±
SD.
Parameters of 11C-(R)-rolipram scans
PET scans were performed with similar injection activity for healthy controls (726±97
MBq), all unmedicated patients at baseline (714±90 MBq), and patients receiving SSRI
treatment (737±38 MBq). No differences were observed between the groups (P>0.14). Mass
dose was also similar between groups (healthy controls: 0.11±0.08, all unmedicated patients at
baseline: 0.12±0.12, and patients taking an SSRI: 0.10±0.08 nmol/kg; P>0.30). At baseline,
clearance did not significantly differ between healthy controls (181±83) and unmedicated
patients (153±61 mL/min, P=0.084). It should be noted that even when clearance differed,
rolipram binding measured as VT/fP from brain and arterial plasma data would not be affected by
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clearance because the data acquisition was long enough to accurately measure equilibrium values
1
. No difference in clearance was observed between baseline and post-SSRI treatment scans
(baseline: 157±68. SSRI: 165±63 mL/min. P=0.72).
Changes in rolipram binding
(Post SSRI - Base)/Base (%)
Fig. S1.
100
50
0
-50
20
30
40
50
Age
Relationship between age and change in 11C-(R)-rolipram binding after treatment with selective
serotonin reuptake inhibitors (SSRIs). Older patients showed significantly greater increases in rolipram
binding after treatment in 10 areas across brain (P<0.001, r=0.69–0.72). The graph shows average brain
data from the 10 areas.
References
1.
Zanotti-Fregonara P, Zoghbi SS, Liow JS, Luong E, Boellaard R, Gladding RL et al.
Kinetic analysis in human brain of [11C](R)-rolipram, a positron emission tomographic
radioligand to image phosphodiesterase 4: a retest study and use of an image-derived
input function. Neuroimage 2011; 54: 1903-1909.
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