Biology Reference
In-Depth Information
of diabetes and also a treatment. Macleod initially rejected the idea, but
Banting persisted, and Macleod conceded to give him laboratory space,
experimental dogs, and a student assistant—Charles Best. Banting and
Best began their experiments in May, 1921, and within a few months
they had extracted a substance from the islets of Langerhans called
''insulin,'' (the name comes from the Latin insula, which means island).
When given to diabetic dogs, this substance lowered their high blood
sugar levels. Repeated experiments confirmed the blood sugar lowering
action of insulin, but the insulin preparation was not pure enough for
human testing. Macleod added the biochemist James Bertram Collip
(1892-1965) to the group to help with insulin purification. Within a few
weeks, the substance was sufficiently purified and deemed safe for
human application. The first patient who received insulin injections was
a 14-year-old boy dying of diabetes. The injected insulin reduced his
abnormally high blood sugar and alleviated other signs of the disease.
The scientific community quickly recognized the significance of these
findings, and, in 1923, the discovery of insulin action brought the Nobel
Prize in Medicine to Banting and Macleod, which they shared with the
other researchers on the team.
Although extremely important, the discovery of insulin did not solve all
of the problems associated with diabetes. We now know that diabetes is
a complex of disorders, characterized by the common element of high
blood sugar, or hyperglycemia, that arise from and are determined in
their progress by mechanisms acting at all levels of the biosystem—from
molecular through hormonal to behavioral. The treatment of diabetes
requires not only lowering extremely high blood sugar levels, but also
avoiding low blood sugar (hypoglycemia) and optimizing blood sugar
fluctuations within a certain target range.
II. CLINICAL BLOOD GLUCOSE OPTIMIZATION
PROBLEM OF DIABETES
In a healthy person, the BG level is internally regulated through insulin
released from the pancreas that counterbalances carbohydrate intake.
Because patients with diabetes are unable to produce insulin (T1DM) or
produce insufficient insulin combined with higher insulin resistance
(T2DM), this internal self-regulation is disrupted. The standard daily
control of T1DM involves multiple insulin injections or a continuous
insulin infusion (insulin pump) that lowers BG. The daily control of
T2DM also requires insulin or oral medications.
Large-scale research studies, including the 10-year Diabetes Control and
Complications Trial (DCCT; 1993) and a similar European trial (Reichard
and Phil 1994), have proved that intensive treatment with insulin and
with oral medication is indeed the best strategy for optimal glycemic
control. Such therapy has been proved effective in bringing BG to nearly
normal levels and markedly reducing the chronic complications of both
