Human Biological Clock



Biological Factors in Mood Disorders — H. K. Manji, MD, of the National Institute of Mental Health, Laboratory of Molecular Pathophysiology, Bethesda, Maryland, discussed the application of molecular biology in order to uncover biological factors involved in the pathophysiology of bipolar disorder. Much of his recent work has focused on using gene-chip array technology and differential display polymerase chain reaction techniques to uncover genes involved in the therapeutic effects of lithium and other mood stabilizing agents. Because drugs such as lithium or the anticonvulsants may induce the expression of a large number of genes unrelated to mood stabilization, multiple selection criteria are used to identify target genes that may be responsible for their therapeutic effects.

One potential set of molecular targets has been suggested by recent work investigating morphologic changes in patients with chronic bipolar or unipolar depression. In a seminal study by Drevets and colleagues,[2] reduced activity was detected in the subgenual prefrontal cortex in both unipolar and bipolar depression. This work suggested cell loss and atrophy may be occurring as a result of prolonged mood disorders. Postmortem studies appear to confirm a decrease in the numbers of neurons and glia, as well as a decrease in cortical thickness in patients suffering from affective disorders.[3] The question remains whether these findings show some degree of specificity for mood disorder and are not just characteristic of a “sick brain.”

There are numerous methodologies employed to identify novel molecular targets that may be involved in affective disorders. In general, laboratory animals are treated with psychotropic medications (eg, lithium, valproate, carbamazepine, etc.) for several weeks. Target brain regions (eg, cortex, hippocampus, amygdala, etc.) are then isolated and genes can be identified by comparing the relative levels of gene expression between animals treated with vehicle or with the drug of interest. By treating animals with drugs possessing different mechanisms of actions (eg, lithium and valproate) that are known to be effective in the management of bipolar disorder, common genes that are regulated by both mood stabilizers can be identified.

One interesting target identified via these methodologies is BAG-1. This gene activates ERK and MAP kinases, which are important intracellular signaling pathways. There is also evidence that BAG-1 potentiates the function of BCL-2. BCL-2 has received a great deal of attention in the cancer literature because it is an antiapoptotic gene that prevents cell death. BAG-1 may also encode a chaperone protein and is involved in modulating the function of the glucocorticoid receptor,[4] which has also been implicated in the pathophysiology of mood disorders. Thus, these data would suggest lithium and valproate may act, in part, by upregulating neurotrophic/neuroprotective genes. Additional preclinical studies have shown that a number of other molecules involved in neurotrophic signaling cascades (CREB, BDNF, BCL-2, GSK-3, MAP kinases) are long-term targets for mood stabilizers.[5] Consistent with these gene expression studies, lithium in particular has shown robust neuroprotective and neurotrophic effects in several preclinical assays.[6-8] Recent human imaging studies have suggested that lithium treatment significantly increased gray matter content in a region-specific manner. Thus, the neurotrophic effects of lithium may counteract some of the neuronal atrophy associated with bipolar disorder.[9]

In conclusion, lithium and other mood stabilization agents may interact with neurotrophic growth cascades. This work has the potential to identify novel mechanisms and, ultimately, suggest novel molecules for the management of bipolar disorder.

Chronobiological Interventions in Mood Disorders[10]

F. Benedetti, of the Istituto Scientifico Ospedale San Raffaele, Neuropsychiatric Sciences, Milano, Italy, has focused his research on chronobiological interventions (ie, disruptions of the normal sleep/wake rhythm) that may, on theoretical grounds, offer a model for the treatment of bipolar disorder. The overall goal is to develop benign alternatives to some of the less well-tolerated treatments used for the management of depression, such as long-term high-dosage medicines or electroconvulsive therapy. Early attempts to use chronobiological methods to treat depression were relatively disappointing because they showed short-lived or no antidepressant effects.

Several different methodologies have been employed to alter chronobiological rhythms in patients with affective disorders. In one treatment regimen, over a 6-day period, patients had 3 days of total sleep deprivation (TSD). This treatment showed some efficacy in the treatment of both unipolar and bipolar depression.[11] A later study combined TSD with light therapy in bipolar patients. In this study, 49 patients were being treated long-term with lithium salts (for at least 6 months), while 66 patients were not taking any psychotropic medication. During the course of treatment, mood was assessed by Visual Analogue Scale 3 times a day. The study demonstrated that both lithium and light therapy significantly increased the effects of TSD on perceived mood, although there was no synergistic effect when lithium and light therapy were combined.[12] A later study was conducted to determine whether sleep phase advance (SPA) could sustain the effects of TSD. The protocol involved 1 day of TSD followed by 3 days of SPA (beginning with sleep allowed from 17:00 until 24:00, with daily backshifts of 2 hours) in consecutively admitted bipolar depressed inpatients.[13] Patients were taking long-term lithium (n = 16) or were psychotropic-free (n = 14). SPA enhanced the acute antidepressant effects of TSDs in patients treated with or without lithium.

A chart review has also been conducted to evaluate the length of hospitalization for 415 unipolar patients and 187 bipolar patients assigned to rooms with eastern or western windows. The windows that faced east received approximately 15,500 lux in the AM whereas patients whose windows faced west received only approximately 1400 lux. Irrespective of treatment modality, the length of hospitalization was lower in bipolar patients on the east side (who received much more morning sunshine) vs the west side. A similar effect was not detected in unipolar patients. This suggests light therapy may be a useful adjunctive therapy in bipolar patients.

Although the exact mechanisms through which TSD, light therapy, and SPA may work remain elusive, some evidence implicates a role for serotonin. In a recent placebo-controlled study, patients with major depression (n = 21) or bipolar disorder (n = 9) were treated with the selective serotonin reuptake inhibitor citalopram and randomized to receive either 400 lux green light treatment in the morning or placebo (exposure to a deactivated negative ion generator) during the first 2 weeks of citalopram treatment.[14] Light therapy was individually tailored to produce a 2-hour phase advance to morning light. Overall, the combination of citalopram with light treatment produced a more rapid improvement than citalopram and placebo (ie, sham light therapy). This may suggest that low-intensity light treatment may be a safe augmentation strategy. A recent study has also suggested that the antidepressant response to serotonergic drug treatments and TSD may be influenced by functional polymorphisms in the serotonin transporter, further suggesting an interaction between chronobiological treatments and the serotonin system. Specifically, TSD showed significantly better mood amelioration in homozygotes for the long variant of 5-HTTLPR than heterozygotes and homozygotes for the short variant.[15] There is also preliminary evidence suggesting that variations in genes supporting the molecular clock (CLOCK and GSK3-b) may influence core features of bipolar disorder, such as age at onset and rate of recurrence.[16]

Overall, these studies provide evidence that chronobiological treatments (SPA/TSD/light therapy) may represent novel and safe augmentation strategies that could contribute to the management of unipolar and bipolar depression.










Purdue researchers have uncovered new evidence that factors other than genes
could cause obesity, finding that genetically identical cells store widely differing
amounts of fat depending on subtle variations in how cells process insulin. Here,
insulin (green) is present in cells with no fat storage and absent in cells with fat
storage at two days after insulin addition. This observation indicates faster insulin processing rates in cells with fat storage. Fluorophore-labeled insulin (green) is visualized with fluorescence imaging, and fat is visualized with coherent
anti-Stokes Raman scattering – or CARS – imaging (red/white). Credit: Weldon School of Biomedical Engineering, Purdue Univ

Purdue University, April 15, 2009, — Researchers have uncovered new evidence suggesting factors other than genes could cause obesity, finding that genetically identical cells store widely differing amounts of fat depending on subtle variations in how cells process insulin.

Learning the precise mechanism responsible for fat storage in cells could lead to methods for controlling obesity.

“Insights from our study also will be important for understanding the precise roles of insulin in obesity or Type II diabetes, and to the design of effective intervention strategies,” said Ji-Xin Cheng, an assistant professor in Purdue University’s Weldon School of Biomedical Engineering and Department of Chemistry.

Findings indicate that the faster a cell processes insulin, the more fat it stores.

Other researchers have suggested that certain “fat genes” might be associated with excessive fat storage in cells. However, the Purdue researchers confirmed that these fat genes were expressed, or activated, in all of the cells, yet those cells varied drastically – from nearly zero in some cases to pervasive in others – in how much fat they stored.

The researchers examined a biological process called adipogenesis, using cultures of a cell line called 3T3-L1, which is often used to study fat cells. In adipogenesis, these cells turn into fat.

“This work supports an emerging viewpoint that not all biological information in cells is encoded in the genetic blueprint,” said Thuc T. Le, a National Institutes of Health postdoctoral fellow at Purdue who is working with Cheng. “We found that the variability in fat storage is dependent on how 3T3-L1 cells process insulin, a hormone secreted by the pancreas after meals to trigger the uptake of glucose from the blood into the liver, muscle or fat cells.”

“This varied capability to store fat among genetically identical cells is a well-observed but poorly understood phenomenon,” Cheng said

The researchers determined that these differences in fat storage depend not on fat-gene expression but on variations in a cascade of events within an “insulin-signaling pathway.” The pathway enables cells to take up glucose from the blood.
“Only one small variation at the beginning of the cascade can lead to a drastic variation in fat storage at the end of the cascade,” Cheng said.

The researchers conducted “single cell profiling” using a combination of imaging techniques to precisely compare fat storage in cloned cells having the same fat genes expressed.

Single cell profiling allows researchers to precisely compare the inner workings of individual cells, whereas the conventional analytical approach in biochemistry measures entire populations of cells and then provides data representing an average.

“In this case, we don’t want an average. We need to find out what causes fat storage at the single-cell level so that we can compare one cell to another, ” Le said. “By profiling multiple events in single cells, we found that variability in fat storage is due to varied rates of insulin processing among cells.”

The cell culture used in the research contains cloned mice fibroblast cells.

“This particular type of cell culture has been used to study the molecular control of obesity for the past 35 years,” Cheng said. “Researchers have observed tremendous variability in how much fat is stored in cells with identical genes, but no one really knows why. Our findings have shed some light on this phenomenon.”

The researchers used a specialized imaging method called coherent anti-Stokes Raman scattering, or CARS, combined with other techniques, including flow cytometry and fluorescence microscopy.

“This multimodal imaging system allows us to correlate different events, like fat storage, gene expression and insulin signaling,” Le said. “We can monitor these different events at the same time, and that’s why we can determine the mechanism at the single-cell level.”

Insulin attaches to binding sites on cell membranes, signaling the cells to take up glucose from the blood. Cells that are said to be resistant to insulin fail to take up glucose, the primary cause of Type II diabetes, a medical condition affecting nearly 24 million Americans. About two-thirds of U.S. adults are overweight, and nearly one-third obese.

The research, which has been funded by the National Institutes of Health, is ongoing. Future work may seek to pinpoint specific events in the insulin-signaling cascade that are responsible for fat storage.

University of Pennsylvania, March/April 2009 — HDL cholesterol, or “good” cholesterol, helps eliminate excess “bad” cholesterol that might otherwise block arteries. As such, individuals with high plasma HDL cholesterol levels have a decreased risk of coronary artery disease.

University of Pennsylvania researchers now show that mutations in the LIPG gene, which codes for the enzyme endothelial lipase, result in high plasma HDL cholesterol levels, providing important human genetic evidence that inhibition of endothelial lipase is likely to raise “good” cholesterol levels.

HDL cholesterol (HDL-C), or “good” cholesterol, carries excess cholesterol – that might otherwise block arteries – from blood vessels back to the liver for processing and elimination. As such, individuals with high plasma HDL-C levels have a decreased risk of developing coronary artery disease.

Genetics contribute to determining a person’s plasma HDL-C level, and in a new JCI study Daniel Rader and colleagues from the University of Pennsylvania show that mutations in the LIPG gene, which codes for an enzyme known as endothelial lipase, result in high plasma HDL-C levels.

The authors examined the LIPG gene in 585 subjects of European ancestry and identified 10 people with previously unreported rare mutated forms of this gene that were unique to subjects with very high HDL-C levels. Further studies revealed that mutations in the LIPG gene that cause loss of endothelial lipase activity were the cause of increased plasma HDL-C levels.

These data provide important human genetic evidence that inhibition of endothelial lipase is likely to raise HDL-C levels in humans. Whether or not the resulting increase in HDL-C level due to this inhibition would impact cardiovascular health requires further study.

Stand Up For Your Health

Physiologists And Microbiologists Find Link Between Sitting And Poor Health — Physiologists analyzing obesity, heart disease, and diabetes found that the act of sitting shuts down the circulation of a fat-absorbing enzyme called lipase. They found that standing up engages muscles and promotes the distribution of lipase, which prompts the body to process fat and cholesterol, independent of the amount of time spent exercising. They also found that standing up uses blood glucose and may discourage the development of diabetes.

You’re probably sitting down right now. Well, by the time you’re done reading this, you may see sitting in a whole new way!

“Chair time is an insidious hazard because people haven’t been told it’s a hazard,” Marc Hamilton, Ph.D., a professor of biomedical sciences at the University of Missouri in Columbia, told Ivanhoe.

That’s right — the time you sit in your chair could be keeping your body’s fat burning in park! More than 47 million adults in the United States have metabolic syndrome, which causes obesity, diabetes and heart disease. Biomedical researchers from the say the reason so many of us have the condition is because we sit too much!

“The existing data, by numerous studies, are starting to show that the rates of heart disease and diabetes and obesity are doubled or sometimes even tripled in people who sit a lot,” Dr. Hamilton explains. One reason, he says, is an enzyme called lipase. When it’s on, fat is absorbed into the muscles, but when we sit down, lipase virtually shuts off.

“Instead, the fat will recirculate in the blood stream and go and be stored as body fat or it can clog arteries and cause diseases,” Dr. Hamilton says. And it’s not a small amount of fat. Plasma samples were taken from the same person after eating the same meal. When they ate sitting down, the sample was cloudy, but when they ate while standing up, it was clear.

“If you can perform a behavior while sitting or standing, I would choose standing,” Dr. Hamilton says. That’s why he swapped his desk chair for a treadmill. Not ready for that step? “You can have just as much fun watching your kids play if you’re standing by the fence, next to a friend who pulls out that aluminum lawn chair and is sitting there,” Dr. Hamilton advises.

You can also limit chair time by taking frequent breaks at work to stand and walk around. Stand up while talking on the phone or even while watching TV.

Standing also helps shrink your waistline! The average person can burn an extra 60 calories an hour just by standing! “But just avoid the chair is the simple recommendation, as much as you can,” Dr. Hamilton says. That’s advice worth a standing ovation!

Another benefit to standing — it improves your HDL or good cholesterol levels. People who sat reduced their good cholesterol levels by 22 percent!

ABOUT TYPE I DIABETES: This is known as an autoimmune disease, because the body destroys its own cells: those that produce insulin. When all those cells have been destroyed, the symptoms of Type I diabetes appear. These include unexplained weight loss; vision problems; more frequent urination; and feeling very hungry, thirsty or tired. Among other long-term complications, Type I diabetes means there is an increased risk of kidney failure, nerve damage, heart disease and blindness.

WHAT IS ARTERY PLAQUE: Plaque doesn’t just grow on your teeth. It can also form inside your arteries — the blood vessels that carry oxygen and blood to the heart, brain and other parts of the body. Arteries have an inner layer of muscle. When it is damaged, plaque can form, sometimes leading to a bulge in the wall of the artery. The bulges can grow big enough to cause the inner lining to rupture. The body responds by sending clotting fibers to the damaged site.

Minerals, especially calcium, can become trapped in the net of fibers, and so can fats like cholesterol. The minerals and fats build up over time, causing the arteries to narrow. Blood can’t flow so easily through the restricted arteries. The arteries can also become clogged, stopping blood flow completely.

Weight Loss Weapon

Carb-cutting Enzyme Stopped By Bean Extract, Endocrinologists Say

UCLA — UCLA researchers have found an extract in white kidney beans that may help the body stop carbs from breaking down into sugars. A digestive enzyme in the body normally acts like scissors, literally cutting starches into little sugars. Phase 2 stops the enzyme from cutting, so the starches stay in the body as long fibers and are burned off quicker. Patients in the clinical studies who took Phase 2 lost body fat, not lean muscle.

Americans are getting fatter. In fact, more than 60 percent are overweight and 18 million have type 2 diabetes. It’s an epidemic that’s becoming more of a problem with each passing year. Now, a new discovery could help you shed those dangerous pounds and live a healthier life.

Pastas … breads … cereals … We know them well. And doctors say it’s carbs like these that are making us fat.

“The problem is that starches are broken down immediately into sugars. When starch breaks down into sugar, it stays in the bloodstream, but is eventually stored as fat,”
Steven Rosenblatt, a family practice doctor in Los Angeles, tells DBIS.

But if you can’t bear to give up your favorite foods, there’s a new option. UCLA researchers have found an extract in white kidney beans may help the body stop carbs from breaking down into sugars.

“By lowering the amount of starches in our diet and the amount of carbohydrates in our diet, we allow the body to slowly start to burn off that stored energy,” says Rosenblatt. He with the bean extract, known as Phase 2, which is sold in pill form and is now even added to certain foods. Here’s how Phase 2 works: A digestive enzyme in the body normally acts like scissors, literally cutting starches into little sugars. Phase 2 stops the enzyme from cutting, so the starches stay in the body as long fibers and are burned off quicker — making losing weight and keeping a normal blood sugar much easier.

Doctors say patients in the clinical studies who took Phase 2 lost body fat, not lean muscle. The extract is not recommended for pregnant women or type one diabetics because their blood sugar could get too low. Mild nausea is the only known side effect. Nora Cosgrove’s struggled with her weight all her life. She admits to probably having been on every diet, but nothing worked. But when her doctor said she was on the fast-track to developing type 2 diabetes, she tried Phase 2.

After three months, she lost 30 pounds and six dress sizes! “I’m not tired anymore,” Cosgrove says. “That’s the main thing.”

The FDA recognizes Phase 2, but doctors say it isn’t a miracle pill. Patients still need to watch what they eat and exercise. But at least they don’t have to give up carbs for good. It is available over the counter at health food stores for about $25 a bottle.

BACKGROUND: Scientists at the University of California, Los Angeles, examines the effect of white kidney bean extract (called Phase 2) on food and Glycemic Index (GI) levels. The research has resulted in the development of many new products for people on special GI diets, including a new pasta. It could especially benefit patients with diabetes, who need to closely monitor and control blood sugar levels, as well as serious athletes and overweight people.
ABOUT THE STUDY: Previous clinical trials found that 1 gram of the Phase 2 kidney bean extract affects blood glucose levels, while the new study shows that 2-3 grams affect GI levels. White kidney bean extract neutralizes the digestive enzyme necessary for starch to turn into glucose. It slows the digestion of starches and sugars, which can cause a rapid rise in blood sugar after eating. A previous UCLA study found that Phase 2 reduced starch absorption by 66%.
THE GLYCEMIC INDEX: Developed in the 1980s, the glycemic index (GI) ranks various foods according to how they affect blood sugar levels two to three hours after eating. Foods high in fat or protein don’t raise levels very much, while certain carbohydrates are so easily broken down in intestine that blood sugar levels rise too quickly. The GI only tells you how rapidly a particular carbohydrate turns into glucose; it doesn’t tell you how much of that carbohydrate is in a given serving of a particular food, or what percentage are ‘available’ carbohydrates, i.e., those that provide energy (starch and sugar, as opposed to fiber). You need to know both to fully understand how a given food affects blood sugar levels. The glycemic load (GL) measures the latter. A GI if 70 or more is high; 56 to 59 is medium; and 55 or less is low. A GL of 20 or more is high; 11 to 19 is medium; and 10 or less is low.
HOW DIGESTION WORKS: Food and drink must be changed into smaller molecules of nutrients to be absorbed into the blood and carried to cells throughout the body. It does this via the digestion process. Food is travels through the esophagus into the stomach, where it is dissolved and emptied into the small intestine. The digested nutrients are absorbed through the intestinal walls, while the rest is expelled as waste.

American Chemical Society, April 15, 2009 — In a potential advance toward a male contraceptive pill and new treatments for infertility, researchers are reporting the identification of key biochemical changes that put sperm “in the mood” for fertilization.

Mark Platt and colleagues note in the new study that sperm cannot fertilize an egg immediately after entering the female reproductive tract. Sperm must acquire this ability after undergoing an activation process called “capacitation.” Scientists have known for years that this process involves phosphorylation. That common biological modification causes cellular activities to be turned “on” by the addition of phosphate molecules to certain amino acids within proteins. However, the specific biochemical details have been a deep mystery.
Using laboratory mice, the researchers compared the extent of phosphorylation in both capacitated and noncapacitated sperm samples. They identified 44 peptides exhibiting differential phosphorylation, on 59 specific amino acids, suggesting that modification of these particular sites is essential for the capacitation process. The relative ratio of phosphorylation between the capacitated and noncapacitated samples were also reported, providing the first biochemical description of what puts sperm “in the mood.”