Diabetes Mellitus Overview and Treatments Andrew P Vogt

Diabetes Mellitus Overview and Treatments Andrew P. Vogt Chemistry 6116

Diabetes Mellitus : a group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both ¨ 20. 8 million in US ( 7% of population) ¨ estimated 14. 6 million diagnosed (only 2/3) ¨ Consists of 3 types: 1) Type 1 diabetes 2) Type 2 diabetes 3) Gestational diabetes ¨ Complications : - Stroke - Heart attack - Kidney disease - Eye Disease - Nerve Damage

Diabetes Mellitus ¨ Type 1 Diabetes - cells that produce insulin are destroyed - results in insulin dependence - commonly detected before 30 ¨ Type 2 Diabetes - blood glucose levels rise due to 1) Lack of insulin production 2) Insufficient insulin action (resistant cells) - commonly detected after 40 - effects > 90% - eventually leads to β-cell failure (resulting in insulin dependence) Gestational Diabetes 3 -5% of pregnant women in the US develop gestational diabetes

Testing : Fasting Plasma Glucose Test (FPG) - (cheap, fast) *fasting B. G. L. 100 -125 mg/dl signals pre-diabetes *>126 mg/dl signals diabetes Oral Glucose Tolerance Test (OGTT) *tested for 2 hrs after glucoserich drink *140 -199 mg/dl signals prediabetes *>200 mg/dl signals diabetes A. K. A. : Glycated Hemoglobin tests A 1 C ¨ 80 to 90 mg per 100 ml, is the normal fasting blood glucose concentration in humans and most mammals which is associated with very low levels of insulin secretion.

Diabetes - Insulin ¨ Discovered in 1921 by Banting ~ and Best ¨ Consist of A & B chains linked by 2 disulfide bonds (plus additional disulfide in A) ¨A = 21 amino acids B = 30 amino acids

Diabetes – Insulin (synthesis, storage, secretion) ¨ Produced within the pancreas by β cells islets of Langerhans ¨ insulin m. RNA is translated as a single chain precursor called preproinsulin ¨ removal of signal peptide during insertion into the endoplasmic reticulum generates proinsulin ¨ Within the endoplasmic reticulum, proinsulin is exposed to several specific endopeptidases which excise the C peptide, thereby generating the mature form of insulin ¨ Stored as β granules This light micrograph of a section of the human pancreas shows one of the islets of Langerhans, center, a group of modified glandular cells. These cells secrete insulin, a hormone that helps the body metabolize sugars, fats, and starches. The blue and white lines in the islets of Langerhans are blood vessels that carry the insulin to the rest of the body. Zn

Diabetes – Insulin (Biochemical Role) -Tyrosine Kinase receptors are the locks in which the insulin key fits - Involved in signal transduction (insulin hormone being 1 st messenger)

Diabetes – Oral Medications 6 Classes : ¨ Sulfonylureas ¨ Biguanides ¨ Sulfonylureas and biguanide combination drugs ¨ Thiazolidinediones ¨ Alpha-glycosidase inhibitors ¨ Meglitinides

Sulfonylureas : stimulate β cells to produce more insulin ¨ 1 st generation – (1)Orinase (tolbutamide) 2 -(p-aminobenzenesulfonamido)-5 -isopropyl -thiadiazole (IPTD) was used in treatment of typhoid fever in 1940’s hypoglycemia – (3)Tolinase (tolazamide) Currently > 12, 000 – (6)Diabinese (chlorpropamide) may become dislodged delayed activity ¨ 2 nd generation – (75)Glucotrol (glipizide) – (150)Glucotrol XL (ex. rel. glipizide) – (150)Micronase, Diabeta (glyburide) – (250)Glynase (micronized glyburide) ¨ 3 rd generation – (350)Amaryl (glimepiride) *Hydroxylation of the aromatic ring appears to be the most favored metabolic pathway *Hydroxylated derivatives have much lower hypoglycemic activity

Biguanides : improves insulin’s ability to move glucose into cells (esp. muscle) ¨ Metformin - Glucophage®, Fortamet®, Riomet® - mechanism improves insulin sensitivity by increasing peripheral glucose uptake and utilization. - Zhou et al (2001) showed that metformin stimulates the hepatic enzyme AMP-activated protein kinase - Metformin was first described in the scientific literature in 1957 (Unger et al). - It was first marketed in France in 1979 but did not receive FDA approval for Type 2 diabetes until 1994. *only anti-diabetic drug that has been proven to reduce the complications of diabetes, as evidenced in a large study of overweight patients with diabetes (UKPDS 1998).

Sulfonylurea & Biguanide Combo drugs/ Cocktails ¨ Glucovance® (Glyburide & Metformine HCl) & &

Thiazolidinediones (TZD’s) : make cells more sensitive to insulin (esp. fatty cells) ¨ Pioglitazone - Actos®, Avandia® - binds to and activates the gamma isoform of the peroxisome proliferator-activated receptor (PPARγ). - PPARγ is a member of the steroid hormone nuclear receptor superfamily, and is found in adipose tissue, cardiac and skeletal muscle, liver and placenta - upon activation of this nuclear receptor by a ligand such as a TZD, PPARγ–ligand complex binds to a specific region of DNA and thereby regulates the transcription of many genes involved in glucose and fatty acid metabolism. - Marketed in USA in August of 1999 PPAR - γ

Αlpha – glycosidase inhibitors : Block enzymes that help digest starches slowing the rise in B. G. L. ¨ AGI’s - Precose ® (acarbose), - Glyset ® (miglitol)

Meglitinides : Stimulate more insulin production ; dependant upon level of glucose present ¨ Meglitinides - Prandin ® (repaglinide) - Starlix ® (nateglinide)

Diabetes – Oral Medications Summary 6 Classes : ¨ Sulfonylureas ¨ Biguanides stimulate β cells improves insulin’s ability to move glucose ¨ Sulfonylureas and biguanide combination drugs BOTH ¨ Thiazolidinediones cells more sensitive to insulin ¨ Alpha-glycosidase inhibitors Block enzymes that help digest starches ¨ Meglitinides stimulate β cells (dependant upon glucose conc. )

In Conclusion : ¨ 2 major types of diabetes (3 with Gestational) ¨ Type 1 => insulin dependant (5 -10%) ¨ Type 2 => may treat with oral medication which may alter insulin production &/or sensitivity ; disease often succumbs to insulin dependence (>90%)

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