ANTI-INSULIN ANTIBODIES, HBA1C AND DIABETIC COMPLICATIONS IN T2DM
Shashikala K.T * Srinivasulu Naidu.S* Jaisri. G **
* Assistant professor of Physiology, Bangalore Medical College & Research Institute, Banga
**Prof & HOD, Dept of Physiologym M.S.Ramaiah Medical College, Bangalore.
Background: Normal insulin secretary function is essential for the maintenance of normal glucose tolerance and abnormal insulin secretion is invariably present in type II diabetes mellitus patients. Autoantibodies against insulin could also be one of the causes for decreased insulin function and increased frequency of complications in T2DM.
Materials and Method: we evaluated for AIA in 80 T2DM patients on oral hypoglycemic drugs and or diet from Bangalore. We compared AIA titres (RIA method) with HbA1c (ELISA) and diabetic complications (neuropathy, nephropathy, and retinopathy) in T2DM. Results were analyzed using student T-test. All the values are expressed as Mean ± standard deviation.
Results: we observed a positive association between AIA and HbA1c. In T2DM with HbA1c ≤ 7.0 AIA titres were 4.44 ± 0.23 and with HbA1c > 7.0, 6.76 ±0.95, with a p value of 0.214. We observed no association of AIA titers with diabetic associated complications, Mean ±SD of 5.91± 0.89 in T2DM without complications and 6.60±1.24 with complications, P>0.05. We observed a significant association between diabetic complications and glycemic status (HbA1c). Among T2DM with complications, AIA titers were 8.91 ± 2.06, without complications 8.0745 ± 1.73, with a p value of 0.039.
Conclusion: Prevalence of chronic diabetic complications neuropathy, nephropathy and retinopathy in AIA positive and AIA negative type-II diabetics did not differ. We found that glycemic control (HbA1c) was associated with diabetic complications in AIA positive T2DM compared to AIA negative type-II diabetics. We also found T2DM with bad glycemic status (HbA1c >7) had increased AIA levels. So there is only a secondary connection of the complications with AIA in T2DM
Keywords: AIA (Anti-insulin antibodies); T2DM (type II diabetes mellitus); HbA1c (glycosylated Hemoglobin); Diabetic complications.
Diabetes mellitus is a chronic condition that can lead to complications over a period of time. These complications include: Coronary heart disease, which can lead to a heart attack, Cerebrovascular disease, which can lead to stroke, retinopathy (disease of the eye), which can lead to blindness, nephropathy (disease of the kidney), which can lead to kidney failure, neuropathy (disease of the nerves), which can lead to ulceration of the foot requiring amputation.Many of these complications produce no symptoms in the early stages, and most can be prevented or minimized with a combination of regular medical care and blood glucose monitoring. Diabetes remains the greatest cause of blindness, kidney failure, and amputations in the United States and in much of the world. 1
In 30-40% of type-I diabetes mellitus and type-II diabetes mellitus AIA positive patients had micro-angiopathies of different sites. The levels of circulating AIA and other diabetic related antibodies reflect the gravity of diabetic complications (micro and microangiopathy).2
Antibody positive type-II diabetes mellitus that is autoimmune diabetes of adults affects 10% of recently diagnosed NIDDM in European adults, implying that it is more prevalent than childhood type-I diabetes mellitus. The incidence of autoimmune diseases has increased notably over the last 3 decades.3
Understanding the pathogenesis and physiologic mechanisms that lead to complications in the patients with type 2 diabetes mellitus is imperative to prevent their progression and improve their quality of life. Diabetic related antibodies could be one of the causes for increased frequency of complications in type-II diabetes mellitus.4
Nephropathy and retinopathy were more frequent in GADA positive type-II diabetes mellitus than GADA negative T2DM. The prevalence of neuropathy was comparable between the 2 groups. GADA was positively associated with retinopathy, nephropathy and insulin treated T2DM. High prevalence of nephropathy and retinopathy in GADA positive T2DM suggests the importance of early diagnosis and strict metabolic control in these patients.5, 6
To evaluate the relationship between anti-insulin antibodies (AIA) and diabetic complications and glycemic status (HbAIc) in T2DM patients.
- 80 T2DM patients on Diet/Oral hypoglycemic agents and never on insulin
- The subjects age was between 35 – 60 years
- Subjects with preexisting endocrinal and other autoimmune diseases
- Fever and other infections
Ethical clearance was obtained from the M. S. Ramaiah Medical College ethical committee for human research to conduct the study. Diabetic patients were recruited from the outpatient diabetic clinic at the Division of Endocrinology M.S Ramaiah Memorial Hospital. A detailed physical examination was done. History of diabetic complications(retinopathy, nephropathy, neuropathy) was taken and blood samples were evalyated for AIA, FBS, PPBS, HbA1C.
Fasting and postprandial venous plasma glucose was determined by glucose-oxidase method using glucose autoanalyser. Glycosylated hemoglobin (HbA1c) was determined using ELISA method. AIA titres were determined using RIA (Radio immuno assay).
The levels of AIA were expressed as BT titre and BT %.
The bound radioactivity was calculated using formula
B/T titre = Count (sample or control)/Total count
B/T % = B/T titre × 100
(B = bound radioactivity, T = total radioactivity)
Student t test (two tailed, Independent)/, has been used to find the significance of BT count and BT% in diabetics
Statistical software: The Statistical software namely SPSS 11.0, Stata 8.0 and Systat 11.0 were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc.
Association of AIA titre with Glycemic status (HbA1c) of T2DM:
As shown in table 1; HbA1c (%) is positively associated with AIA titers
T2DM with HbA1c ≤ 7.0 mean of AIA is 4.44 with a S.D of 0.23 and in T2DM with HbA1c > 7.0 mean of AIA is 6.76 with a S.D of 0.95.with a p value of 0.214
So of type-II diabetes mellitus patients with poor glycemic status (HbA1c>7) have high AIA titers compared to T2DM with good glycemic status (HbA1c ≤ 7)
|Mean ± SE||4.44±0.23||6.76±0.95|
|Inference||Increased AIA is positively associated increased HbA1c (%) with P=0.214|
We observed no association of AIA titers with diabetic associated complications in type-II diabetes mellitus (Table 2)
(Mean ± SE)
|BT (AIA) %||5.91 ± 0.89||6.60 ± 1.24|
|Inference||Presence of complications is not statistically associated with the (AIA) BT count and BT% (P>0.05)|
We have observed a significant association between diabetic complications and glycemic status (HbA1c).
(Mean ± SE)
|HbA1C||8.91 ± 2.063831||8.0745 ± 1.736882|
|Inference||Increased HbA1C is significantly associated with complications
(p = 0.039 ) *
* Moderately significant
There is a wide spectrum within diabetes syndrome. Type-I diabetes mellitus may have a slow progression with good residual insulin secretion and without autoantibodies, while phenotypic type-II diabetes mellitus may have autoantibodies. A single patient may have traits of both TIDM and T2DM. The etiology is mainly unknown, but environmental factors play an important role in genetically predisposed individuals. The search for just one single cause for the manifestation of diabetes mellitus is confusing. Different mechanisms may be important in different parts of the world. Several hypothesis of etiology may fit different parts of the disease process. Increased insulin demand because of rapid growth of insulin resistance caused by stress, infections, puberty etc. lead to β cell stress, antigen presentation and may cause both an autoimmune reaction in genetically predisposed individuals and insulin deficiency leading to manifest diabetes mellitus in individuals who have lost beta cell function.6
In light of the occurring growth of type-II diabetes mellitus and recent observations indicating that type-II diabetes mellitus may be a disease of the innate immune system, we evaluated whether signs of islet cell autoimmunity are associated with an abnormal glucose control, the presence of insulin requirement.
Our study clearly showed that the level of AIA was more in type-II diabetics with poor glycemic status that is with HbA1c > 7 had high AIA titres (6.76±0.95) compared to T2DM with good glycemic control HbA1c < 7 AIA titres were low (4.44±0.23) (Table 1), thus showing that the presence of circulating AIA could in some way contribute to the poor action of insulin in a percentage of patients with type II diabetes mellitus. Thus AIA could be associated with increased insulin resistance.
A follow up study was done for 5 years and was found that antibody positive type-II diabetes mellitus patients who were on diet/or OHA, serum C-peptide level decreased gradually necessitating insulin treatment and suggested that GAD-65 and AIA are good markers for predicting insulin dependency in T2DM patients.7
Studies done previously found that 80% of type II diabetes mellitus on OHA requiring insulin in future were GAD -65 positive. They concluded that GAD either with AIA or IA-2 had 100% positive prediction for insulin dependency and AIA and IA-2 are useful 2nd line tests.9It has also been concluded that multiple diabetic associated antibodies or GAD alone in high concentration at diagnosis predicted future beta cell failure.8
Micro vascular and Macro vascular complications occur earlier in individuals with diabetes mellitus than others. The underlying pathologies are often more diffuse and diabetic related antibodies could be one of the causes. It is a well-known fact that 50% of newly diagnosed type II diabetes mellitus patients present with late complication. One of the studies done previously evaluated for the presence of late complications in group of 41 T2DM, measured GAD-55, IA-2 and AIA titers by RIA and found that 25 were antibody positive and also observed high frequency of Micro-angiopathy in antibody positive type II diabetics and Macro-angiopathy in antibody negative T2DM.9
In the present study we compared AIA titers in 40 type II diabetics with diabetic associated complications like neuropathy, nephropathy and retinopathy and 40 type II diabetics without these complications. We did not observe any association of AIA in either of the 2 groups (Table 2). We also observed that diabetic complications were associated with glycemic control (HbA1c) not the AIA titers.
Our results are similar to the study done by Isoma B et al in their study. Prevalence of chronic diabetic complications neuropathy, nephropathy and retinopathy in 59 GAD positive and 59 GAD-65 negative, type-II diabetics did not differ. They also found that glycemic control (fasting C-peptide) was associated with diabetic complications in GAD-65 positive T2DM compared to GAD-65 negative type-II diabetics and type-I diabetes mellitus patients.10
Prevalence of chronic diabetic complications neuropathy, nephropathy and retinopathy in AIA positive and AIA negative type-II diabetics did not differ. We found that glycemic control (HbA1c) was associated with diabetic complications in AIA positive T2DM compared to AIA negative type-II diabetics. We also found T2DM with bad glycemic status (HbA1c >7) had increased AIA levels. So there is only a secondary connection of the complications with AIA in T2DM
The authors would like to thank and acknowledge the immense support of Dr.S.Kumar, Principal and Dean M.S.Ramaiah Medical College and Research Hospital.
The authors also acknowledge Dr. K. P. Suresh, Statistician, Animal Nutrition and Physiology for his contribution to work.
Conflict of Interest-NIL
- Maciej T et al “Type 2 Diabetes Mellitus and its Complications: From the Molecular Biology to the Clinical Practice” Department of Metabolic Diseases, Medical College, Jagiellonian University. Diabetology Rev Diabet Stud. Spring 2004: 1(1): 5-8
- Alok kanungo and C. B. Sanjeevi “ IA-2 Autoantibodies Are Predominant in Latent Autoimmune Diabetes in Adults Patients from Eastern India” New York Academy of Sciences Ann. N.Y. Acad. Sci. 1005: 390–394 (2003)
- R. David G Leslie, and Michela Delli Castelli et al “Age dependent influence on the Origins of Autoimmune Diabetes” Institute of Cell and Molecular Science, Queen Mary College, University of London, U.K. DIABETES 53; 3033-40,2004, The American diabetes association
- David K, Leslie, Rhys Williams and Paolo Pozzilli et al “Complications of type 2 diabetes mellitus: a brief overview” Journal of the American Osteopathic Association, Vol 99, Issue 90120. August 31, 2006
- Arikan E, Sabuncu T, Ozer EM, Hatemi H “ The clinical characteristics of latent autoimmune diabetes in adults and its relation with chronic complications in metabolically poor controlled Turkish patients with type 2 diabetes mellitus.” ” Department of Endocrinology and metabolism. Medical Faculty, Trakya, University, Edrine,Turkey: J Diabetes Complications. 2005 Sep-oct;19(5):254-8
- Panczel P Hosszufalusi N, Bornemisza B Horvath L et al “Detection of antibodies against pancreatic islet cells in clinical practice.” III. Belgyogyaszati, Klinika, Semmelweis Orvostudomanyi Egyetem, Budapest. Orv Hetil.1999 Nov 28; 140(48):2695-701.
- Maruyama T, Kasuga A, Ozawa Y, Nagata A et al “Glutamic acid decorboxylase65(GAD65)antibodies and insulin auto-antibodies in Japanese patients with non-insulin-dependent Diabetes mellitus” Endocr J.1997 Feb:44(1):43-51
- Akira Kasuga b, a ,fl,Taro Maruyamac, Shinya Nakamotob, Yukako Ozawac et al “High-Titer Autoantibodies against Glutamic acid decorboxylase Plus Autoantibodies against Insulin and IA-2 Predicts Insulin Requirement in Adult Diabetic Patient” Department of Internal medicine Tokyo, Japan: 12th April 2002.
- Henrik Borg, Anders Gottsater, Per Fernlund, and Goran Sundkvist “A 12 Year Prospective study of the Relationship Between Islet Antibodies and β-Cell Function At and After the Diagnosis in Patients With Adult- Onset Diabetes” Department of Endocrinology, Malmo University Hospital, Sweden, Diabetes 51:1754-1762,2002
- Isomaa B, Almgren P, Henricsson M, Taskinen MR et al “Chronic complications in patients with slowly progressing autoimmune type 1 diabetes (LADA)” diabetes Care. 1999 Aug; 22 (8); 1347-53
- Szepietowska B, Szelachowska M, Gorska M et al “Chronic complications in adult patients with newly diagnosed diabetes mellitus in relation to the presence of humoral autoimmune markers against pancreatic islet cells” Clinical endocrinology, Diabetology,Pol Arch Med Wewn. 2004 May;111(5):563-9