Objective:To investigate the relationship between niacin skin reaction sensitivity and cognitive function by comparing the difference of niacin skin flushing response and cognitive function between the patients with depression and the normal control group.Method:A cross-sectional study was conducted to recruit 40 patients with depression who met the diagnostic criteria of DSM-Ⅳ (American Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) at The Second People′s Hospital of Zhumadian from July 2018 to August 2019. In the meanwhile, 32 gender-and-education-matched patients were recruited and allocated into the control group. General demographic and clinical data were collected. Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to test individual′s cognitive functions. A Swedish laser Doppler blood flow meter, PeriFlux 5000, was used to test the skin flushing reaction of forearm niacin at eight concentrations (10 -5 mol/L, 10 -4 mol/L, 10 -3.5 mol/L, 10 -3 mol/L, 10 -2.5 mol/L, 10 -2 mol/L, 10 -1.5 mol/L, and 10 -1 mol/L) gradient. The difference of blood flow values in 8 concentration gradients between the two groups was analyzed by repeated measurement multiple comparison and simple effect. The MBF value and LogEC50 were analyzed by non-parametric test. Spearman rank correlation analysis was used to analyze the correlation between LogEC50 and cognitive function scores. Result:In the skin flushing reaction of niacin test, when the concentration of niacin solution was 10 -3.5 mol/L and 10 -3mol/L, there was a significant difference in Blood Flow (BF) between patients with depression and normal subjects ( t=-0.490,-4.626, P<0.01, respectively). The BF value of the normal control group was higher than that of depressed patients. LogEC50 was significantly different between the two groups ( t=4.196, P<0.01). LogEC50 of the normal control group (-3.513±0.848) was lower than that of the depression group (-2.776±0.568). The difference in RBANS between the two groups was tested by independent sample t test. Compared with the normal control group, the scores of the depressed group were significantly lower on the test of list learning ( t=-2.127, P=0.037), coding test ( t=-3.226, P=0, 002), list recall ( t=-3.697, P<0.01), story recall ( t=-2.687, P=0.009), and figure recall ( t=-2.660, P=0.010). There was a negative correlation between list recall ( r=-0.407, P=0.032), story recall ( r=-0.376, P=0.049) and figure recall ( r=-0.455, P=0.015) in the depression group. Maximal blood flow (MBF) was positively correlated with figure copying ( r=0.428, P=0.023). Conclusion:The niacin sensitivity and the score of cognitive function of depression patients are lower than those of the normal control group, and the decrease of cognitive function of depression patients may be related to the disorder of phospholipase A2 (PLA2) signaling pathway.

Objective:To investigate the relationship between niacin skin reaction sensitivity and cognitive function by comparing the difference of niacin skin flushing response and cognitive function between the patients with depression and the normal control group.Method:A cross-sectional study was conducted to recruit 40 patients with depression who met the diagnostic criteria of DSM-Ⅳ (American Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) at The Second People′s Hospital of Zhumadian from July 2018 to August 2019. In the meanwhile, 32 gender-and-education-matched patients were recruited and allocated into the control group. General demographic and clinical data were collected. Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to test individual′s cognitive functions. A Swedish laser Doppler blood flow meter, PeriFlux 5000, was used to test the skin flushing reaction of forearm niacin at eight concentrations (10 -5 mol/L, 10 -4 mol/L, 10 -3.5 mol/L, 10 -3 mol/L, 10 -2.5 mol/L, 10 -2 mol/L, 10 -1.5 mol/L, and 10 -1 mol/L) gradient. The difference of blood flow values in 8 concentration gradients between the two groups was analyzed by repeated measurement multiple comparison and simple effect. The MBF value and LogEC50 were analyzed by non-parametric test. Spearman rank correlation analysis was used to analyze the correlation between LogEC50 and cognitive function scores. Result:In the skin flushing reaction of niacin test, when the concentration of niacin solution was 10 -3.5 mol/L and 10 -3mol/L, there was a significant difference in Blood Flow (BF) between patients with depression and normal subjects ( t=-0.490,-4.626, P<0.01, respectively). The BF value of the normal control group was higher than that of depressed patients. LogEC50 was significantly different between the two groups ( t=4.196, P<0.01). LogEC50 of the normal control group (-3.513±0.848) was lower than that of the depression group (-2.776±0.568). The difference in RBANS between the two groups was tested by independent sample t test. Compared with the normal control group, the scores of the depressed group were significantly lower on the test of list learning ( t=-2.127, P=0.037), coding test ( t=-3.226, P=0, 002), list recall ( t=-3.697, P<0.01), story recall ( t=-2.687, P=0.009), and figure recall ( t=-2.660, P=0.010). There was a negative correlation between list recall ( r=-0.407, P=0.032), story recall ( r=-0.376, P=0.049) and figure recall ( r=-0.455, P=0.015) in the depression group. Maximal blood flow (MBF) was positively correlated with figure copying ( r=0.428, P=0.023). Conclusion:The niacin sensitivity and the score of cognitive function of depression patients are lower than those of the normal control group, and the decrease of cognitive function of depression patients may be related to the disorder of phospholipase A2 (PLA2) signaling pathway.

Objective To investigate the functional connection(FC) between the anterior cingulate cortex (ACC) and other brain regions in unipolar depression(UD) and bipolar depression(BD), and the correlation to the severity of depressive symptoms. Methods 30 patients who met the diagnosis criteria of unipolar depression in DSM?Ⅳ and another 30 patients who met the diagnosis criteria of bipolar depression in DSM?Ⅳ were matched with 32 healthy controls(HC) by gender?, age?, and education. All subjects completed the resting?state functional magnetic resonance scans. After the imaging preprocessing, seed?based functional connectivity analysis was performed on the bilateral ACC. Pearson correlation analysis was performed between the FC values and the severity of depressive symptoms (measured by HAMD17 scores). Results (1) Compared to the health controls, the connectivity between the left ACC (LACC) and the left triangular part of the inferior frontal gyrus(t=3.48) and the connectivity from the LACC to the left inferior parietal gyrus(t=3.15) in patients with unipolar depression significantly increased, so did the connectivity between the right ACC(RACC) and the left triangular part of the inferior frontal gyrus(t=3.52); (2) Compared to the healthy controls, the connectivity from LACC to the right middle temporal gyrus (t=-4.00) in patients with bipolar depression significantly decreased, so did the connectivity between RACC and the other regions induding the left postcentral(t=-3.46), the right superior temporal gyrus(t=-2.86) and the right middle temporal gyrus(t=-3.40);(3)Compared to the patients with bipolar depression,patients with unipolar depression increased connectivity between the LACC and the other regions including the left triangular part of the inferior frontal gyrus(t=3.58), the right triangular part of the inferior frontal gyrus(t=4.06), the right middle temporal gyrus (t=3.25), the left inferior parietal gyrus(t=3.27), and the right inferior parietal gyrus(t=3.99). While the RACC increased its connectivity to the left triangular part of the inferior frontal gyrus(t=3.13), the left inferior parietal gyrus(t=3.42), and the right inferior parietal gyrus(t=3.78) (Alphasim?corr, P<0.001); (4) The severity of depressive symptoms were found uncorrelated to the FC value changes among the different regions(-0.20.05). Conclusion The results suggest that there are much difference in the brain function activity between UD and BD. The connectivity between ACC and other regions is stronger in UD patients, while weaker in BD patients, therefore the FC value could be possibly explored as an independent future biomarker to distinguish BD from UD regardless the symptoms severity.

Objective To investigate the functional connection(FC) between the anterior cingulate cortex (ACC) and other brain regions in unipolar depression(UD) and bipolar depression(BD), and the correlation to the severity of depressive symptoms. Methods 30 patients who met the diagnosis criteria of unipolar depression in DSM?Ⅳ and another 30 patients who met the diagnosis criteria of bipolar depression in DSM?Ⅳ were matched with 32 healthy controls(HC) by gender?, age?, and education. All subjects completed the resting?state functional magnetic resonance scans. After the imaging preprocessing, seed?based functional connectivity analysis was performed on the bilateral ACC. Pearson correlation analysis was performed between the FC values and the severity of depressive symptoms (measured by HAMD17 scores). Results (1) Compared to the health controls, the connectivity between the left ACC (LACC) and the left triangular part of the inferior frontal gyrus(t=3.48) and the connectivity from the LACC to the left inferior parietal gyrus(t=3.15) in patients with unipolar depression significantly increased, so did the connectivity between the right ACC(RACC) and the left triangular part of the inferior frontal gyrus(t=3.52); (2) Compared to the healthy controls, the connectivity from LACC to the right middle temporal gyrus (t=-4.00) in patients with bipolar depression significantly decreased, so did the connectivity between RACC and the other regions induding the left postcentral(t=-3.46), the right superior temporal gyrus(t=-2.86) and the right middle temporal gyrus(t=-3.40);(3)Compared to the patients with bipolar depression,patients with unipolar depression increased connectivity between the LACC and the other regions including the left triangular part of the inferior frontal gyrus(t=3.58), the right triangular part of the inferior frontal gyrus(t=4.06), the right middle temporal gyrus (t=3.25), the left inferior parietal gyrus(t=3.27), and the right inferior parietal gyrus(t=3.99). While the RACC increased its connectivity to the left triangular part of the inferior frontal gyrus(t=3.13), the left inferior parietal gyrus(t=3.42), and the right inferior parietal gyrus(t=3.78) (Alphasim?corr, P<0.001); (4) The severity of depressive symptoms were found uncorrelated to the FC value changes among the different regions(-0.20.05). Conclusion The results suggest that there are much difference in the brain function activity between UD and BD. The connectivity between ACC and other regions is stronger in UD patients, while weaker in BD patients, therefore the FC value could be possibly explored as an independent future biomarker to distinguish BD from UD regardless the symptoms severity.