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Depression and cerebral blood flow

Depression and cerebral blood flow

Maybe a benefit will arise from the current debate about the usefulness of antidepressants in depression, if it draws attention to the published studies concerning reduced regional cerebral blood flow in depression which have failed to influence clinical opinion. Perhaps the relevance of such information can be appreciated by reference to the study by Lucey et al. (1) They showed that in patients with panic disorder with agoraphobia, obsessive compulsive disorder and post traumatic stress disorder, there were regional reductions in cerebral blood flow, but in each disorder in different regions of the brain.

It is proposed that depression is the dysfunctional state arising from inadequate rates of blood flow to deliver the necessary oxygen and nutrient substrates to sustain normal tissue function in specific regions of the brain. This means that the condition would be reversible when there were adequate rates of blood flow.

In 1990, Sackheim et al (2) critically examined what had been written about regional cerebral blood flow in mood disorders. An important contribution was made by Bench et al (3) who reported their findings in a study in which previously scanned patients were rescanned on remission. They concluded, “Thus, recovery from depression is associated with increases in regional cerebral blood flow in the same area in which focal decreases in regional cerebral blood flow are described in the depressed state, in comparison with normal subjects.” Similar findings were reported in another paper (4) which reported that the reduced rate of blood flow in the left frontal region which had been observed during depression, returned to normal during remission. The lack of attention given to such findings probably reflects the current antipathy to reports which imply a role for the flow properties of blood (blood rheology).

It is possible to interpret such changes in blood flow in terms of the effects of poorly deformable red cells, which reflect change in their environment by a reduction in fluidity of the the cell membrane. Normalisation of the cell environment restores normal levels of deformability. So it is not surprising that depression is a frequent problem in chronic disorders which are known to have altered blood rheology manifested as increased blood viscosity and poorly deformable red cells, such as in diabetes for example.

Kamada et al (5) in 1986 reported that sardine oil so increased the fluidity of the membranes of diabetic red cells that they were unable to distinguish such cells from those of non-diabetics. Ten years later Maes et al (6) noted that, ” Major depressed subjects had significantly lower C18-3 omega-3 in cholesteryl esters than normal controls. Major depressed subjects showed significantly lower total omega-3 polyunsaturated fatty acids… than minor depressed subjects and healthy controls.” A later study of the omega-3 fatty acid content in the diet and in red cell membranes of depressed patients (7) noted that, “Lower red blood cell membrane n-3 polyunsaturated fatty acids are associated with the severity of depression,” and concluded, “The findings raise the possibility that depressive symptoms may be relieved by n-3 polyunsaturated fatty acid supplementation.”

Ten years later there is no indication that the significance of such findings have been recognised and therapy for depression has been based upon antidepressants rather that omega-3 rich fish oil which might correct the primary problem. Possibly, if the current debate leads to a more public recognition of the problems of cerebral blood flow in depression, then maybe those who suffer from depression will explore the potential benefits of taking 2 x 1000mg capsules of fish oil, three times daily. Many studies have used 10 capsules daily, and one study reported that the maximal tolerable dose was twenty grams daily. Because of the need for the enzyme delta-6-desaturase to be functional in order to utilise the plant derived alphalinolenic acid, it is safer to use fish oil as a source of omega-3 fatty acids. An alternative would be to increase the dietary intake of omega-3 fatty acids by including sardines or oily fish in meals on a daily basis.

In addition, because regular light exercise has been shown to reduce blood viscosity, an activity such as walking or dancing should be part of the daily programme. A good example was an Australian study involving “pram pushing” which was shown to be beneficial for women with post-partum depression.

HOW D’OXYVA CAN HELP?

D’OXYVA is the only fully noninvasive, completely painless transdermal (over-the-skin) microcirculatory solution that has been clinically tested to significantly improve microcirculation.

The improvement of microcirculation, i.e., blood flow to the smallest blood vessels, benefits one’s health, immune system and overall sense of well-being in a variety of ways.

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Cerebral Blood Flow Predicts Later Cognitive Function in Older Individuals

NEW YORK—Cerebral blood flow (CBF) in healthy older people predicts cognitive function four years later, according to results from an arterial-spin-labeling perfusion-MRI study.

 

“Specifically, we found that brain blood flow measured at the present time can predict a person’s general cognitive ability and, most significantly, memory function,” Dr. Hanzhang Lu from Johns Hopkins University School of Medicine, in Baltimore, Maryland, told Reuters Health by email. “Across different brain regions we studied, we found that the frontal lobe is the most important in determining future cognitive function.”

 

Cognitive abilities decline with age starting from the third decade of life, with the greatest effects on fluid cognition (related to performing tasks). Neuroimaging studies have shown that both brain structure and function deteriorate with age. It remains to be seen, however, whether a particular biomarker can predict future cognitive performance.

 

Dr. Lu’s team examined the relationship between CBF and cognitive function among 309 participants aged 20 to 89 years in the Dallas Lifespan Brain Study.

 

At the year four follow-up, all participants remained free of mild cognitive impairment or dementia, but there were age-related decreases in CBF and cognition. Participants who were older at baseline experienced faster declines in cognitive function, compared with younger subjects.

 

Among participants who were 54 years or older at baseline, higher whole-brain CBF at baseline significantly predicted better fluid cognition (a construct of processing speed, working memory, reasoning, and episodic memory) four years later, the team reports in the Journal of Magnetic Residence Imaging, online January 2.

 

Across the entire group, however, whole-brain CBF did not significantly predict fluid cognition, but it did predict follow-up episodic memory in older individuals and in the entire cohort.

 

Frontal lobe CBF best predicted follow-up fluid cognition, episodic memory, and reasoning in the older group, whereas frontal lobe CBF was only predictive of episodic memory in the entire cohort.

 

In contrast, baseline CBF in the occipital, parietal and temporal lobes was not predictive of any cognitive domains at follow-up.

 

Changes in reasoning ability between baseline and follow-up were dependent on parietal CBF in the older group and whole-brain CBF in the entire group, but there were no other associations between lobar CBF and changes in cognitive functions.

 

“The significance of these findings is that physicians can use some of these measures, including blood flow but also other complementary measures such as amyloid imaging, to identify which of their patients have higher risks for cognitive decline,” Dr. Lu said.

 

“They can then determine the best intervention or treatment strategies for each patient. The physicians can also use these measures to select the best candidates for novel therapies such as those undergoing clinical trials,” he said.

HOW D’OXYVA CAN HELP?

D’OXYVA is the only fully noninvasive, completely painless transdermal (over-the-skin) microcirculatory solution that has been clinically tested to significantly improve microcirculation.

The improvement of microcirculation, i.e., blood flow to the smallest blood vessels, benefits one’s health, immune system and overall sense of well-being in a variety of ways.