Dysfunction in a gene that can lead to attention deficit hyperactivity disorder (ADHD) schizophrenia, bipolar disorder and depression has been identified.
People with attention deficits have difficulty focussing and often display compulsive behaviour.
The study suggests that these symptoms could be due to dysfunction in ErbB4 gene, that helps different brain regions communicate.
ErbB4 is also a risk factor for psychiatric disorders and is required to maintain healthy neurotransmitter levels in the brain.
“And since ErbB4 is a risk factor for schizophrenia, bipolar disorder, and major depression, the results provide insights into mechanisms of these disorders,” said Lin Mei, Professor Case Western Reserve University School of Medicine in Cleveland.
In the findings, published in the journal Neuron, researchers showed mice lacking ErbB4 activity in specific brain regions performed poorly on timed attention tasks.
The mice struggled to pay attention and remember visual cues associated with food. Neuroscientists describe the kind of thought-driven attention required for the tasks as “top-down attention”.
Top-down attention is goal-oriented and related to focus. People who lack efficient top-down attention are at a higher risk for ADHD.
The study is the first to connect ErbB4 to top-down attention.
“The results reveal a mechanism for top-down attention, which could go wrong in attention disorders,” Mei said.
The study found that when a protein (neuregulin-1) attaches to the ErbB4 receptor, it triggers a chain reaction that ultimately determines neurotransmitter levels in the prefrontal cortex and hippocampus.
Without ErbB4, neurotransmitter levels go awry.
The results showed that mice lacking ErbB4 have low levels of a particular neurotransmitter GABA, or gamma-aminobutyric acid, in the brain.
This further led to impaired top-down attention in the prefrontal cortex and impairs how the prefrontal cortex can efficiently coordinate with the hippocampus, a region that supports memory and attention.
Diabetes patients at higher risk of liver disease:study
While analysing 18 million people living with type-2 diabetes, a study led by Queen Mary University of London and the University of Glasgow found that diabetics are at a particular risk of developing deadly liver cirrhosis and liver cancer.
Non-alcoholic fatty liver disease (NAFLD) affects up to a quarter of people in the West and is closely associated with obesity and type-2 diabetes. Its rise is reflective of the social problems of poor diets and sedentary lifestyles. Since general practitioners are often unaware of the condition, patients mostly go undiagnosed.
NAFLD is a benign condition for the majority but one-in-six people will go on to develop the aggressive form of the disease, called non-alcoholic steatohepatitis (NASH), leading to liver injury, scarring and eventually in some cases, cirrhosis, liver failure and even liver cancer.
Published in the journal of BMC Medicine, the team combined the healthcare records of 18 million European adults from the UK, Netherlands, Italy and Spain. They matched each NAFLD patient to 100 patients who did not have a recorded diagnosis, and looked to see who developed liver cirrhosis and liver cancer over time.
“We were surprised that the number of patients with recorded diagnoses of non-alcoholic fatty liver was much less than expected, meaning that many patients are actually undiagnosed in primary care. Even over the short time frame of the study, some patients progressed to more advanced, life threatening stages of disease, suggesting that they are being diagnosed very late,” said lead researcher Dr William Alazawi from Queen Mary University of London.
Naveed Sattar from the University of Glasgow said, “Doctors treating patients with diabetes already have a lot to check on – eyes, kidneys, heart risks – but these results remind us that we should not neglect the liver, nor forget to consider the possibility of NASH. They also remind us that perhaps more efforts are needed to help our patients with diabetes lose weight and cut alcohol.”
In India, prevalence of NAFLD is estimated to be around 9-32 per cent in the general Indian population, with a higher incidence rate among obese and diabetic patients. In fact, type-2 diabetes surges the risk of liver associated death by up to 22-fold in patients with NAFLD, as per National Center for Biotechnology.
Notably, a 2017-study, ‘Prevalence of non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus and its correlation with coronary artery disease (CAD)’, in India found that the prevalence of NAFLD was 41.2 per cent in the study group and was higher in females.
NAFLD in the younger age group was also significantly higher than that in the older age group. Elevated liver enzymes, elevated HbA1C, duration of diabetes, obesity, acanthosis nigricans and metabolic syndrome were all significantly associated with NAFLD.
How chronic stress promotes breast cancer development
Chinese researchers have revealed the mechanism of how chronic stress promotes breast cancer development, shedding light on future clinical treatment for cancer.
Cancer patients often suffer negative emotions such as anxiety, despair and fear, which are risk factors facilitating tumour growth as well as promoting cancer progression. However, the specific mechanisms of how chronic stress affects cancer development remains unknown yet.
Researchers from the Dalian Medical University in China found that chronic stress might increase epinephrine levels, which enhances lactate dehydrogenase A (LDHA) and promotes breast cancer stem-like cells, Xinhua reported.
Using a drug screen that targeted LDHA, they found that Vitamin C reversed the chronic stress-induced cancer stem-like phenotype.
The study demonstrates the critical importance of psychological factors in promoting stem-like properties in breast cancer cells and provides a promising therapeutic approach for breast cancer, according to Liu Qiang, lead researcher at the varsity.
“The LDHA-lowering agent Vitamin C can be a potential approach for combating stress-associated breast cancer,” Qiang said, in the paper published in the Journal of Clinical Investigation.
His team has been engaged in the dynamic regulation of cancer stem cells research as well as the mechanism of psychosocial behaviour affecting tumour development.
Qiang noted that patients with breast cancer, ovarian cancer and stomach cancer often have negative emotions, which in turn accelerates the development of their own tumours.
“It is necessary to monitor their chronic stress comprehensively by taking psychological assessments as well as conducting blood tests which include epinephrine levels,” Qiang said.
Moderate cholesterol intake not associated with risk of stroke
Consuming up to one egg per day or moderately high intake of dietary cholesterol does not increase the risk of stroke, according to a study from the University of Eastern Finland. Furthermore, no association was found in carriers of the APOE4 phenotype, which affects cholesterol metabolism. The study was published in the ‘American Journal of Clinical Nutrition’.
Findings from earlier studies addressing the association of dietary cholesterol or egg intake with the risk of stroke have been contradictory. Some studies have found an association between high dietary cholesterol intake and an increased risk of stroke, while others have associated the consumption of eggs, which are high in cholesterol, with a reduced risk of stroke.
The dietary habits of 1,950 men aged between 42 and 60 years with no baseline diagnosis of cardiovascular disease were assessed at the onset the Kuopio Ischaemic Heart Disease Risk Factor Study, KIHD, in 1984-1989 at the University of Eastern Finland. APOE phenotype data were available for 1,015 of the men participating in the study. Of those, 32 per cent were known carriers of APOE4.
During a follow-up of 21 years, 217 men were diagnosed with a stroke. The study found that neither dietary cholesterol nor egg consumption was associated with the risk of stroke – not even in carriers of APOE4.
The findings suggested that moderate cholesterol intake or daily egg consumption are not associated with the risk of stroke, even in persons who are genetically predisposed to a greater effect of dietary cholesterol on serum cholesterol levels.
In the highest control group, the study participants had an average daily dietary cholesterol intake of 520 mg and they consumed an average of one egg per day, which means that the findings cannot be generalised beyond these levels. One egg contains approximately 200 mg of cholesterol. In this study, about a fourth of the total dietary cholesterol consumed came from eggs.