Stem cell transplantation helps diabetics become
insulin free
8 May 2009
The majority of patients with type 1 diabetes who underwent a certain
type of stem cell transplantation became insulin free, several for more
than three years, according to a study published in the April 15 issue
of JAMA. The patients also showed good glycemic control, and increased
C-peptide levels, an indirect measure of beta-cell function.
Clinical evidence indicates that there is an inverse association
between beta-cell (a type of cell in the pancreas that secretes insulin)
preservation and function and chronic complications of type 1 diabetes
mellitus (DM), and the higher the C-peptide levels (a byproduct of
insulin production, made up of amino acids), the lower the incidence of
some types of complications of type 1 DM.
A previous study found that autologous nonmyeloablative hematopoietic
stem cell transplantation (HSCT) in 15 patients with newly diagnosed
type 1 DM resulted in the majority of patients becoming insulin free
during the follow-up, which averaged about 19 months.
“However, it was suggested that subsequent insulin independence was a
prolonged honeymoon period due to dietary and exercise changes
associated with close posttransplant medical observation,” the authors
write, and it was not known if this change was because of an improvement
in beta-cell preservation.
HSCT, which uses a patient’s own blood stem cells, involves the
removal and treatment of the stem cells, and their return to the patient
by intravenous injection.
Dr. Burt and colleagues conducted a study to determine if
posttransplant insulin independence was due to improved beta-cell
function by monitoring the C-peptide levels of 23 patients who underwent
stem cell transplantation. The patients, with type 1 DM, were ages 13-31
years.
Of the 23 patients, 20 experienced time free from insulin (12
continuously and 8 transiently). Patients remained continuously insulin
free for an average time of 31 months (range, 14-52 months). One patient
had more than 4 years with no exogenous (produced outside the body)
insulin use, 4 patients for at least 3 years, 3 patients for at least 2
years, and 4 patients for at least 1 year. Eight patients relapsed and
resumed insulin use at low doses. The majority of patients achieved good
glycemic control.
In the continuously insulin-free group, average area under the curve
(AUC; a type of measurement) of C-peptide levels before transplantation
(225.0 ng/mL per 2 hours) showed a significant increase at 24 months
after transplantation (785.4 ng/mL per 2 hours) and at 36 months after
transplantation (728.1 ng/mL per 2 hours).
In the transient insulin–independent group, average AUC of C-peptide
levels also increased from 148.9 ng/mL per 2 hours pretransplantation to
546.8 ng/mL per 2 hours at 36 months, which was sustained at 48 months.
In this group, 2 patients regained insulin independence after treatment
with the antihyperglycemic drug sitagliptin, which was associated with
an increase in C-peptide levels.
Two patients developed pneumonia in the hospital, 3 patients
developed late endocrine dysfunction, and 9 patients developed
oligospermia (sperm deficiency). There were no deaths.
“In conclusion, autologous nonmyeloablative HSCT was able to induce
prolonged and significant increases of C-peptide levels associated with
absence of or reduction of daily insulin doses in a small group of
patients with type 1 DM,” the researchers write.
“At the present time, autologous nonmyeloablative HSCT remains the
only treatment capable of reversing type 1 DM in humans. Randomized
controlled trials and further biological studies are necessary to
confirm the role of this treatment in changing the natural history of
type 1 DM.”
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