Type 2 diabetes is characterized by a combination of peripheral insulin resistance and inadequate insulin secretion by pancreatic beta cells. Insulin resistance, which has been attributed to elevated levels of free fatty acids and proinflammatory cytokines in plasma, leads to decreased glucose transport into muscle cells, elevated hepatic glucose production, and increased breakdown of fat.
Cardiac anatomy today… I had a quick formative and found it straight forward which was great - just need to review cardio, joints and neuroanatomy. Happy studying!
“There are two main endocrine cell lines of the pancreas. The most prolific - the beta cells - are responsible for the secretion of insulin. Alpha cells secrete glucagon and these cell types are collectively known as islet cells. Acinar cells are exocrine in nature and synthesise and secrete digestive enzymes.”
Traditionally, the two main types of diabetes have been known as the:
- Type 1 - the “genetic” diabetes which relates to the immune system killing the insulin-producing cells of the pancreas, otherwise known as the beta-cells.
Without insulin, the glucose (sugar) has no way to move from the blood into the cell.
It occurs more often in younger people.
- Type 2 - the environmental/diet-related diabetes where the body becomes resistant to insulin. This means the cell does not open to let glucose in despite insulin being present. This type is more likely to occur in overweight people.
However the genetic influence is not as previously thought. Studies of identical twins have found a concordance rate of 90% for Type 2 and only 50% for Type 1. That means that if one twin develops Type 2 there is a 90% chance the other twin will also develop it whilst there is only a 50% chance for Type 1. This indicates a much higher genetic influence in Type 2 than previously thought.
Source: Monash University PHY2032 - Endocrine Control Systems - 2015 Lecture Series
Genetically Engineered Mice Suggest New Model for How Alzheimer’s Disease Causes Dementia
Using a novel, newly developed mouse model that mimics the development
of Alzheimer’s disease in humans, Johns Hopkins researchers say they
have been able to determine that a one-two punch of major biological
“insults” must occur in the brain to cause the dementia that is the
hallmark of the disease. A description of their experiments is published
online in the journal Nature Communications.
For decades, Alzheimer’s disease, the most common cause of dementia,
has been known to be associated with the accumulation of so-called
neurofibrillary tangles, consisting of abnormal clumps of a protein
called tau inside brain nerve cells, and by neuritic plaques, or
deposits of a protein called beta-amyloid outside these cells along with
dying nerve cells, in brain tissue.
In Alzheimer’s disease, tau bunches up inside the nerve cells and
beta-amyloid clumps up outside these cells, mucking up the nerve cells
controlling memory, notes Philip C. Wong, Ph.D., professor of pathology at the Johns Hopkins University School of Medicine.
What hasn’t been clear is the relationship and timing between those two
clumping processes, since one is inside cells and one is outside cells,
says lead and corresponding study author Tong Li, Ph.D.,
an assistant professor of pathology at Johns Hopkins. Prior studies of
early-onset Alzheimer’s disease have suggested that the abnormal
accumulation of beta-amyloid in the brain somehow triggers the
aggregation of tau leading directly to dementia and brain cell
degeneration. But the new research from Li, Wong and colleagues suggests
that the accumulation of beta-amyloid in and of itself is insufficient
to trigger the conversion of tau from a normal to abnormal state.
Instead, their studies show, it may set off a chain of chemical
signaling events that lead to the “conversion” of tau to a clumping
state and subsequent development of symptoms.
“For the first time, we think we understand that the accumulation of
amyloid plaque alone can damage the brain, but that’s actually not
sufficient to drive the loss of nerve cells or behavioral and cognitive
changes,” Wong says. “What appears to be needed is a second insult — the
conversion of tau — as well.”
In humans, the lag between development of the beta-amyloid plaques and
the tau tangles inside brain nerve cells can be 10 to 15 years or more,
Li says, but because the lifetime of a mouse is only two to three years,
current animal models that successfully mimic the appearance of
beta-amyloid plaques did not offer enough time to observe the changes in
To address that problem, the Johns Hopkins researchers genetically
engineered a mouse model that used a tau fragment to promote the
clumping of normal tau protein. They then cross-bred these mice with
mice engineered to accumulate beta-amyloid. The result was a mouse model
that developed dementia in a manner more similar to what happens in
humans, Li says.
The researchers found during brain dissections of the animals that the
presence of beta-amyloid plaque alone was not sufficient to cause the
biochemical conversion of tau, the repeat domain of tau — the part of
tau protein that is responsible for the conversion of normal tau to an
abnormal state — alone was insufficient for the conversion of tau,
beta-amyloid plaques must be present in the brain for the conversion of
tau and the tau fragments could “seed” the plaque-dependent pathological
conversion of tau.
One implication of the new research, Wong says, is to possibly explain
why some drugs designed to attack the disease after the conversion of
tau haven’t worked. “The timing may be off,” he says. “If you were to
intervene in the time period before the conversion of tau, you might
have a good chance of ameliorating the deficits, brain cell loss and
ensuing consequence of the disease.”
The work also suggests that combination therapy designed to prevent
both the beta-amyloid plaque formation as well as pathological
conversion of tau may provide optimal benefit for Alzheimer’s disease,
the researchers say. Their mouse model could be used to test new
An estimated 5.4 million Americans are living with Alzheimer’s disease,
according to 2016 statistics from the Alzheimer’s Association. There is
no cure, but there are some medications that may help stabilize
cognition for a limited time or help with related depression, anxiety or
My pancreas is the innocent victim of a tragic accident.
My immune system isn’t murdering my beta cells. If anything it’s accidental manslaughter. It thinks it’s doing its job, it just misunderstood the directions. Somewhere in the network there’s a communication error.
I don’t blame my pancreas, and I try not to hold a grudge against my immune system either. They’re doing their best.
Designer protein gives new hope to scientists studying Alzheimer’s disease
A new protein which will help scientists to understand why nerve
cells die in people with Alzheimer’s disease has been designed in a
University of Sussex laboratory.
In people with Alzheimer’s, Amyloid-beta (Abeta) proteins stick
together to make amyloid fibrils which form clumps between neurons in
the brain. It’s believed the build-up of these clumps causes brain cells
to die, leading to the cognitive decline in patients suffering from the
It is not known why this particular protein’s “stickiness" causes
cells to die and scientists have been unable to properly test whether
the sticky clumps of Abeta proteins have different effects, compared
with individual proteins that are not stuck together.
Now University of Sussex scientists have created a new protein which
closely resembles the Abeta protein in size and shape, but contains two
different amino acids (the building blocks that proteins are made up
of). These changes mean that the new protein does not form amyloid
fibres or sticky clumps, and, unlike Abeta, is not toxic to nerve
cells, according to a study in the open access Nature Publishing Group
journal Scientific Reports.
The new protein will be an essential laboratory tool for researchers
working to understand the causes and role Abeta plays in Alzheimer’s
disease. The scientists who designed it are now working closely with the
Sussex Innovation Centre, the University’s business-incubation hub, to
research commercial opportunities for the protein.
Dr Karen Marshall, who led on the study, said: “Understanding
how the brain protein Abeta causes nerve cell death in Alzheimer’s
patients is key if we are to find a cure for this disease.
“Our study clearly shows that the aggregation of Abeta into bigger
species is critical in its ability to kill cells. Stopping the protein
aggregating in people with Alzheimer’s could slow down the progression
symptoms of the disease. We hope to work towards finding a strategy to
do this in the lab and reverse the damaging effects of toxic Abeta.“
Professor Louise Serpell, a senior author on the study and
co-director of the University of Sussex’s Dementia Research Group, said:
“This is a really exciting new tool that will contribute to
research to uncover the causes for Alzheimer’s disease and enable
tangible progress to be made towards finding targets for therapy.”
Peter Lane, Innovation Support Manager at the Sussex Innovation Centre, said: “This
is a really exciting development. The Centre is thrilled to be working
alongside Professor Serpell to make sure the benefits offered by this
new laboratory tool are made widely available to the Alzheimer’s
research community in the very near future.”
Type 1 diabetes (T1D) is an autoimmune disease in which a person’s pancreas stops producing insulin, a hormone that enables people to get energy from food.
What are symptoms of Type One Diabetes?
Drowsiness or lethargy
Sudden weight loss
Sudden vision changes
Sugar in the urine
Fruity odor on the breath
Heavy or labored breathing
Stupor or unconsciousness
How/Why does it happen?
It occurs when the body’s immune system attacks and destroys the insulin-producing cells in the pancreas, called beta cells. While its causes are not yet entirely understood, scientists believe that both genetic factors and environmental triggers are involved. It has nothing to do with diet or lifestyle. There is nothing you can do to prevent T1D, and right now there is nothing you can do to get rid of it.
Who does it effect?
Type 1 diabetes strikes both children and adults at any age. It comes on suddenly, causes dependence on injected or pumped insulin for life, and carries the constant threat of devastating complications.
How is Type One Diabetes managed?
Living with T1D is a constant challenge. People with the disease must carefully balance insulin doses (either by injections multiple times a day or continuous infusion through a pump) with eating and other activities throughout the day and night. They must also measure their blood-glucose level by pricking their fingers for blood six or more times a day. Despite this constant attention, people with T1D still run the risk of dangerous high or low blood-glucose levels, both of which can be life threatening. People with T1D overcome these challenges on a daily basis.