Effects of nicotinamide and intravenous insulin therapy in newly diagnosed type 1 diabetes.
OBJECTIVE
To investigate the effect of intravenous insulin therapy combined with nicotinamide in the metabolic control and beta-cell function of newly diagnosed type 1 diabetic subjects in comparison with intensive insulin therapy and nicotinamide alone.


METHODS
A total of 34 newly diagnosed type 1 diabetic patients were included. After the correction of initial metabolic disturbances, subjects were randomly assigned to the following three groups within 72 h after admission: 1) intensive insulin therapy + placebo (C) (n = 12); 2) intensive insulin therapy + nicotinamide, 700 mg three times a day (NIC) (n = 11); and 3) 72-h intravenous insulin followed by intensive insulin therapy + nicotinamide, 700 mg three times a day (NIV) (n = 11). The subjects were monitored for 12 months. GAD, tyrosine phosphatase antibodies, and insulin autoantibodies were measured. C-peptide was measured basally and after 2, 4, 6, 8, and 10 min of 1 mg intravenous glucagon. HbA1c, glucagon, and antibody measurements were determined initially and at 1, 3, 6, 9, and 12 months.


RESULTS
HbA1c values declined to normal after treatment was initiated in all groups and remained not significantly different during the follow-up period. We did not find differences between experimental (NIC and NIV) and placebo (C) groups in terms of beta-cell function, considering basal or glucagon-stimulated C-peptide (maximal stimulated C-peptide and area under the curve [AUC] of C-peptide) values during the follow-up period. After pooling data from the NIC and NIV groups (both including nicotinamide) and comparing it with data from the C group, the results remained unchanged. At diagnosis, GAD positivity was observed in 10 of 12, 8 of 11, and 10 of 11 subjects (NS) in the C, NIC, and NIV groups, respectively, and IA2 positivity was observed in 3 of 12, 4 of 11, and 4 of 11 subjects (NS) in the C, NIC, and NIV groups, respectively. Antibody titers displayed a similar behavior in all groups during the follow-up period.


CONCLUSIONS
Our pilot study failed to demonstrate that the addition of 72-h intravenous insulin and nicotinamide to conventional intensive insulin therapy produces any beneficial effect in newly diagnosed type 1 diabetic subjects in terms of beta-cell function and metabolic control.
Vidal
J
J
Endocrinology and Diabetes Unit, Institut d'Investigacions Biomèdicas August Pi i Sunyer, Hospital Clínic i Universitari, Barcelona, Spain.
Fernández-Balsells
M
M
Sesmilo
G
G
Aguilera
E
E
Casamitjana
R
R
Gomis
R
R
Conget
I
I
D000328:Adult; D001323:Autoantibodies / Q000097:blood; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007275:Injections, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use*; D007332:Insulin Infusion Systems; D007515:Islets of Langerhans / Q000503:physiopathology; D008297:Male; D009536:Niacinamide / Q000627:therapeutic use*; D010865:Pilot Projects; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000276:immunology; D013997:Time Factors
D001323:Autoantibodies; D002096:C-Peptide; C096322:ICA512 autoantibody; D007328:Insulin; D009536:Niacinamide; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D005968:Glutamate Decarboxylase