Remission of Type 1 Diabetes with Sitagliptin and Vitamin D

Original Case by Marcelo Maia Pinheiro1, Felipe Moura Maia Pinheiro2 and Margareth Afonso Torres3[1] Pharmaceutical Assistance Center of the State of Mato Grosso, Cuiaba, Brazil[2] Faculdade de Medicina da Universidade de Cuiabá-UNIC, Cuiaba, Brazil [3] Laboratório Clinico do Hospital Israelita Albert Eistein, São Paulo, SP, Brazil

Patient #1 was a 20-year-old woman with a history of hypothyroidism due to Hashimoto’s thyroiditis treated since the age of 6 years with levothyroxine. In April 2012, she presented with weight loss, polyuria, polydipsia and leg cramps. Her physical examination was normal; she weighed 62 kg, had a body mass index (BMI) of 21.7 kg/m2 and blood pressure of 100/60 mmHg. She had a grandmother with Hashimoto’s thyroiditis and type 2 diabetes mellitus.

Q What percentage of type 1 diabetic have autoimmune thyroid disorder ?

  • 2-5% have overt hypothyroidism
  • 20% have Anti TPO positive

Q What is the effect of subclinical hypothyroidism in type 1 diabetes ?

  • Reduced linear growth
  • Increased risk of Hypoglycemia

Q How and when if TFT monitoring done in children with type 1 diabetes ?

  • At the time of diagnosis
  • If normal repeat every 1-2 years

Q What percentage of type 1 diabetics have celiac disease ?

  • 5%

Q What are concerns with celiac disease in type 1  ?

  • Risk of hypoglycemia
  • Poor linear growth
  • Poor bone accural

Q How is screening for celiac done in type 1 diabetics ?

  • At the time of diagnosis
  • Every 1-2 years after diagnosis
  • Use Anti TTG antibody – if positive then do Duodenal biopsy

Q Which HLA in type 1 has higher risk of autoimmune disease ?

  • HLA DR3 > HLA DR4

Q Enlist some other autoimmune disorder in type 1 diabetes ?

  • Autoimmune adrenalitis
  • APS type 2
  • IPEX syndrome

Patient #2 was a 21-year-old woman who presented in May 2011 with weight loss, polyuria, polydipsia and leg cramps. Her physical examination was normal; she weighed 62.5 kg, had a BMI of 19.5 kg/m2 and blood pressure of 115/70 mmHg. Her mother had Hashimoto’s thyroiditis, and her brother had Crohn’s disease

The diagnosis of diabetes mellitus was confirmed in patient #1 based on her serum glucose and HbA1c levels (Fig. 1 and Table 1). The patient’s anti-GAD antibody was positive (Fig. 2)

Q Enlist the antibodies associated with type 1 diabetes ?

  • GAD 65
  • Insulinoma associated antibody – IA-2 (also called ICA5-12)
  • Insulin autoantibody – IAA
  • Zinc transporter 8 antibody- Znt8

Q Antibodies are formed against which part of GAD65 ?

  • Carboxy terminal of GAD65 antibody

Q What is the other name of Insulinoma associated antibody 2  ?

  • ICA512

Q Tell me something about GAD65 antibody ?

  • Present in 70% of type 1 diabetics
  • Does not reduce with age- most common antibody to check in adults
  • Slowly developing diabetes
  • HLA-DR3 associated

Q Which is the antigenic main target in type 1 diabetes ?

  • The main target seems to be Beta chain of Insulin

Q Which is the first antibody to appear in type 1 diabetes  ?

  • IAA- insulin autoantibody is the first to appear

Q  If IAA is the first to appear, why does it not have more importance compared to GAD65 etc  ?

  • Any person given insulin can develop IAA antibody
  • Hence measurement of antibody anytime after 2 weeks after insulin injection will give a positive result

Q Which is often the last antibody to appear ?

  • Znt8
  • It disappears also first
  • IAA first à then GAD à then IA2 à Last ZnT8

Q Summarize the prevelance of various antibodies in type 1 diabetes ?

  • IAA – almost 100% – but not reliable marker
  • GAD65- 70%
  • IA-2 – 68%
  • Znt8 – 60-80%

Q What do Indian studies say about Antibodies in type 1 ?

  • South Indian study – GAD65 was present in 70% – just like west
  • Cuttuck Study- ICA512 was more common – in 43% , GAD65 only in 7%
  • Her HLA typing was DQA1*01:01, 03:01, DQB1*03:02, 05:01, DRB1*04:01, 10:01. Of note, the occurrence of the haplotype HLA-DQA1*03:01, −DQB1*03:02, −DRB1*04:01 is associated with an increased risk of T1DM.

Q What is the role of MHC ?

  • MHC carry the antigen on the surface of antigen presenting cells and activate the T cells

Q Which 2 haplotypes of HLA  confer the highest risk of type 1 diabetes ?

  • HLA DR3,DQB1*0201 – Also called HLA DR3- DQ2
  • HLA DR4,DQB1*0302 – also called HLA DR4-DQ8
  • 90% of type 1 have either of these two haplotypes
  • 30% have both !
  • The risk of type 1 diabetes is you carry either of these two haplotypes is 5% compared to 0.4 % in controls

Q Which HLA haplotypes protect from type 1 ?

  • HLADRB1*0403
  • HLADPB1*0402
  • Additionally HLA DQB1*0602 – also protective

In patient #2, the diagnosis of diabetes mellitus was also confirmed by serum glucose and HbA1c levels (Fig. 1 and Table 1). The patient’s anti-GAD antibody was positive (Fig. 2), her urinalysis revealed glycosuria without ketonuria, and her serum levels of lipids, BUN and creatinine were normal. Antithyroid antibodies measurement (Table 1) and thyroid ultrasound evaluation confirmed the diagnosis of Hashimoto’s thyroiditis with a normal TSH level (1.83 µIU/mL). Her HLA typing was DQA1*01:01, 01:01, DQB1*05:01, 05:01, DRB1*01:01, 01:01, which is not associated with an increased risk of T1DM.

Q How will you treat these patients ?

  • I would start both the patients on Basal-bolus insulin regimen.
  • I would start with 0.5 unit/kg of total insulin dose with 50% basal and 50% bolus.
  • I would also screen these patients for Celiac disease at baseline.

Patient #1 started treatment with insulin glargine 35 IU once a day and insulin lispro 2 IU before breakfast and 6 IU before lunch and dinner.

On May 2012, she started treatment with sitagliptin 100 mg/day and vitamin D3 5000 IU/day, and on June 6, 2012, she interrupted the administration of insulin.

Patient #2 started treatment with insulin glargine 20 IU once a day, and insulin glulisine 6 IU before breakfast, lunch and dinner. In July 2011, she experienced a honeymoon phase in which she used only insulin glargine 6–10 IU/day. Two months later, she resumed a basal-bolus regimen with the same initial doses. In March 2012, she was started on sitagliptin 100 mg/day and vitamin D3 5000 IU/day.

Both patients were duly informed that treatment of T1DM with sitagliptin and vitamin D3 was off-label and signed an informed consent form, accepting this treatment.

Q What is the objective definition of Honeymoon phase of Type 1 diabetes ?

  • Partial remission of honeymoon phase of type 1 diabetes is defined as follows:
  • HbA1c <6.0%
  • Insulin requirement
  • Stimulated C peptide >0.9 ng/ml

Q How long does the honeymoon phase last ?

  • It lasts for several weeks to months. It rarely lasts beyond 1 year.

Q What is the recommended dose of Vitamin D daily in adults ?

  • Recommended Daily allowance of Vitamin D is 600 IU /day
  • For those having Vitamin D deficiency, it is recommended to give 60,000 IU once a week for 8 weeks followed by 2000 IU once a day.

Patient #1 continues treatment with sitagliptin and vitamin D3. Since June 6, 2012, she has not used insulin and her levels of capillary glucose and serum fasting glucose, HbA1c and C-peptide remain normal (Fig. 1). In May 2014, her glucose levels, determined with a continuous glucose monitoring system (CGMS-72 h), confirmed the persistence of normal glucose values (Fig. 2).

Q Patient #1 has vitamin D levels of 22 ng/ml. According to Endocrine society guidelines, how will you classify her Vitamin D status ?

  • Vitamin D values between 20-29 ng/ml are classified as Vitamin D insufficiency.

Q How will you convert Vitamin D ng/ml to nmol/l ?

  • Vitamin D value of 1 ng/ml is 0.4 nmol/l

After 1 month of treatment with sitagliptin and vitamin D3, patient #2 started decreasing her insulin dose, and in March 2015, she interrupted the administration of insulin glargine. At the time of this report, she was only administering insulin glulisine 2–4 IU before breakfast, lunch and dinner when eating carbohydrates and she maintains use of sitagliptin and vitamin D3. She chose not to interrupt the use of insulin glulisine to maintain flexibility in her diet. She has been maintaining normal levels of capillary glucose, fasting blood glucose, HbA1c and C-peptide (Fig. 1). Results from her CGMS-72 h in May 2014 were normal (Fig. 2).

Both patients maintained normal serum levels of calcium and 25(OH) vitamin D. No side effects related to sitagliptin use have been reported by the patients.

Q Where does the evidence of vitamin D action in type 1 diabetes come from ?

  • Mainly from observation studies which have shown that vitamin D deficiency is associated with increased risk of diabetes

Case control studies have shown that vitamin D reduces risk of type 1 diabetes by 30%

  • However there are no RCT for use of vitamin D in type 1 diabetes
  • Genetic polymorphism in vitamin D has been associated with diabetes

Q How does vitamin D reduce risk of type 1 diabetes ?

  • Immune modulation
  • Increase insulin secretion (see later)
  • Reduce beta cell apoptosis

Q How does vitamin D reduce beta cell apoptosis ?

  • Vitamin D activates- Nf- kb pathway which increase beta cell survival

Q What kind of immune modulation is seen with vitamin D which is beneficial for type 1 diabetes ?

  • Its actions mainly via 1,25 Dihydroxyvitamin D produced by the macrophages
  • Reduces Th1
  • Increases Th2
  • Reduces production of IgG by B cells
  • Increases Treg (Regulatory T cells) cell function
  • Reduce damaging cytokine production

Q What are the potential benefits of Sitagliptin in Type 1 diabetes ?

  • By its incretin effect Sitagliptin can increase the GLP1, which can potentially enhance beta cell survival and function
  • Sitagliptin may potentially have immunomodulatory effects in Type 1 diabetes.

Q What is the effect of Sitagliptin on Immune system relevant to type 1 diabetes ?

  • Sitagliptin is shown to reduce Th1 cytokine (IFN –gamma) and increase Th2 Cytokine (IL-4)

Q What is the effect of DPP IV inhibitors in type 1 diabetes ?

  • Meta-analysis by Guo et al shows that DPP IV use in type 1 diabetes reduces the insulin dose requirement without change in HbA1c.
  • It does not increase or reduce the risk of hypoglycemia.

Q Apart from this case, has it been shown before that DPP IV inhibitors can potentially reverse type 1 diabetes ?

  • In several studies in NOD mice which are models for type 1 diabetes it has been shown that DPP IV can delay the onset of type 1 diabetes or bring an early onset type 1 diabetes in remission.

Learning Objectives

  1. DPP IV inhibitors and Vitamin D have immunomodulatory effects which can potentially reverse and early onset type 1 diabetes and bring it to remission.
  2. Partial remission of type 1 diabetes (Honeymoon phase) is defined as Insulin requirement 0.9 ng/ml.