TYPE I DIABETES MELLITES

TYPE I DIABETES MELLITES : 

TYPE I DIABETES MELLITES BY G.MUTHULAKSHMI M.Tech Biopharmaceutical technology

INTRODUCTION : 

INTRODUCTION Type 1 diabetes mellites is a chronic disease results from severe or absolute insulin deficiency that is pancreatic cells fails to produce insulin. Two main causes: 1. Immune mediated- most prevalent Destruction of -cells of pancreas by T-cells. 2. Idiopathic No known cause and autoimmunity but patients cannot produce insulin

FACTORS CONTRIBUTE TO TYPE I DIABETES MELLITUS : 

FACTORS CONTRIBUTE TO TYPE I DIABETES MELLITUS Genetic factors: specific HLA allele type (HLA- DR3/4, DQ2/8) Viral infection: congenital rubella infection increase the risk of type I diabetes mellitus Environmental factors: Increased free radicals and toxic doses of nitrosamines From mother to young: Onset of type I diabetes mellitus is seen in young before 5yrs of age due to transfer of auto insulin antibodies.

PANCREAS : 

PANCREAS Three types of cells  cell - Glucagon, Proglucagon  cell – Insulin, C-peptide, Proinsulin, amylin δ cell – Somatostatin F cell – Pancreatic polypeptide

INSULIN : 

INSULIN Insulin is a polypeptide hormone formed, after elimination of C peptide by hydrolysis. Its molecular weight is 58KDa consist of two chains of 21 and 30 amino acids, connected by two disulfide bridges. Belongs to the group of peptides called IGF (insulin like growth factors) or somatomedins. Insulin concentration in blood is 10-8 to 10-11 M Exist as a monomer during biological action Exist as dimer in aqueous and neutral solution and in the presence of zinc

INSULIN SECRETION : 

INSULIN SECRETION Secretion is biphasic immediate effect of short duration and sustained effect Pancreatic cells releases insulin into portal venous system Basal insulin alues of 5-15μU/ml (30-90 pmol/L) are found in normal humans, with a peak rise to 60-90 μU/ml (360-540 pmol/L) during meals

REGULATION OF INSULIN RELEASE : 

REGULATION OF INSULIN RELEASE Nutrient secretagogues: Increase level of glucose in blood Non-nutrient secretagogues: Neural stimuli - ‘cephalic phase’ of secretion. Stimulated by vagus nerve, cholinergic and muscarinic receptors in  cells activate phospholipase C with subsequent intracellular events activating protein kinase A ,triggering calcium release and insulin secretion. Adrenergic pathway - Catecholamines inhibit insulin release through 2-adreno receptors and stimulate insulin synthesis by - adrenoreceptors.

Contd.. : 

Contd.. Peptide hormones Somatostatin – inhibit insulin secretion GLP-1 –combined with glucose it enhances proinsulin biosynthesis. The mechanism of action is mediated by C-AMP pathway. Amino acids Arginine – cationic amino acid activates insulin secretion by depolarizing the cell. Leucine + glutamine- enhances insulin secretion.

Regulation of insulin release : 

Regulation of insulin release

Long term influences on insulin secretion : 

Long term influences on insulin secretion Insulin secretion decreases during Neonatal maturation Exercise Starvation Aging ` Growth hormone deficiency Excess thyroid hormone Insulin secretion increases during pregnancy

INSULIN RECEPTOR : 

INSULIN RECEPTOR Insulin exerts its action on various tissues by binding with the receptor present on the membrane surface Insulin receptor consists of two covalently linked heterodimers. α subunit – extracellular and consitutes recognition site β subunit – spans the membrane, contains tyrosine kinase

ACTION OF INSULIN : 

ACTION OF INSULIN Insulin action at cellular level encompasses carbohydrate, lipids, aminoacid metabolism and mRNA transcription and translation.

GLUCOSE TRANSPORTERS : 

GLUCOSE TRANSPORTERS

PHYSIOLOGICAL ACTION OF INSULIN : 

PHYSIOLOGICAL ACTION OF INSULIN MUSCLE: Insulin uptake is through GLUT-4 and muscle accounts for 60%- 70% whole body insulin mediated uptake. Effects: Increases glucose transport Increased glycogen synthesis Increased protein synthesis Increased aminoacid synthesis Supression of proteolysis

Slide 16: 

In case of insulin deficiency , there is an increase in protein break down leads to increase level of nitrogen in the urine (honey- urine-disease). imbalance in protein turnover and protein balance leads to muscle wastage. decreased synthesis of intestinal mucosal proteins results in gastrointestinal complications.

ACTION ON LIVER : 

ACTION ON LIVER While glucose uptake in liver is not insulin- dependent, it accounts for about 30% of total body insuin mediated glucose disposal. EFFECTS: Promotes glucose storage as glycogen Increases triglyceride synthesis and VLDL formation Inhibits conversion of fatty acids and amino acids to keto acids inhibits glycogenolysis and gluconeogenesis inhibits conversion of amino acids to glucose

ACTION ON ADIPOSE TISSUE : 

ACTION ON ADIPOSE TISSUE Insulin uptake is through GLUT-4 and constitutes 10% of total body insulin mediated glucose uptake Effects: Increased triglyceride synthesis Lipoprotein lipase is induced and activated by insulin to hydrolyze triglycerides from lipoproteins Glucose transport into cell provides glycerol phosphate to esterification of fattyacids

ACTION ON BRAIN : 

ACTION ON BRAIN While the brain is not insulin-dependent, insulin receptors are concentrated in the olfactory bulb, hypothalamus, hippocampus,40 retina and vessels of the choroid plexus, as well as in regions of the striatum and cerebral cortex. Insulin is believed to act as a neuropeptide, involved in satiety, appetite regulation, olfaction, memory and cognition. There is suggestion of a potential link to Alzheimer’s disease.

CONTD.. : 

CONTD.. PITUITARY: Insulin receptors present in anterior pituitary gland stimulates production of growth hormone and in turn stimulates IGF-1 production by liver KIDNEY: The kidney does not require insulin for glucose transport.Insulin receptors are found in the proximal tubules; insulin regulates mineral transport and gluconeogenesis in the kidney.Insulin is degraded in the kidney.

TYPE I DIABETES MELLITUS : 

TYPE I DIABETES MELLITUS In Normal individuals: Glucose concentration is in the range of 3.5-7mM throughout the day. Fasting or pre-prandial insulin concentration is 6.1mM 2-hr Postprandial glucose level peaks within 30-60 min after meal and does not exceed 7.8mM. HbA1c level in the range of 4%-6% In treatment regimens for type I diabetes patients, Blood glucose concentration of 5.0-7.2 mM, and 6.1-8.3 mM at bedtime is maintained. HbA1c level in the range less than 6.5% is maintained In treatment regimens for type I diabetes patients,

TREATMENT OF DIABETES MELLITUS : 

TREATMENT OF DIABETES MELLITUS The goal of therapy is (a) elimination of ketosis; (b) elimination of symptoms of hyperglycemia such as polydipsia, polyuria, vaginitis, fatigue, and visual blurring; (c) restoration of normal blood chemistry values; (d) regaining of lost weight; and (e) restoration of sense of well-being.

COMPLICATIONS IN HYPERGLYCEMIA : 

COMPLICATIONS IN HYPERGLYCEMIA Acute complications: Thirst, polyuria, glucosuria, hunger, hyperosmolar hyperglycemic nonketotic coma, an often fatal result of osmotic diuresis and dehydration. Ketoacidosis due to excessive lipolysis Late complications: microvascular-retinopathy, nephropathy and neuropathy, and macrovascular-ischemic heart disease ,peripheral vascular disease, and stroke.

INSULIN THERAPY : 

INSULIN THERAPY Insulin therapy is the only efficacious treatment for type I diabetes mellites. Ideally, insulin therapy should imitate the normal level of insulin secretion. In people who do not have diabetes, the release of insulin follows 2 patterns: A baseline secretion of insulin and intermittent pulses of insulin release following each meal .Administration of exogenous insulin in a basal-bolus regimen attempts to mimic the natural release of insulin through multiple daily injections.

Contd.. : 

Contd.. Earlier, bovine and porcine insulin was used for treatment of type I diabetes mellites Production of human insulin À Semisynthetic method: Porcine insulin is changed enzymatically Ex: Velosulin, Hoechst insulin Á Biosynthetical DNA-technology method Production from baker’s yeast Novo-Nordisk insulin Production from Ecoli-bacteria Eli-Lilly insulin

STRUCTURE ACTIVITY RELATIONSHIP : 

STRUCTURE ACTIVITY RELATIONSHIP High binding affinity to insulin receptor is accomplished by amino acids at positions A chain: A1, A2, A3, A16, A19, A21, A13 B chain: B6, B12, B15, B23, B24, B25, B17 B8, B9, B12, B13, B16, and B23- B28 are amino acid positions required for dimer formation Hexamer formation is stabilised through association of six His B10 with two zinc atoms Subsitutions at B26- B30 maintains high binding affinity. This region is not critical for binding of insulin receptor but binding affinity in IGF-1 receptor is altered.

Contd.. : 

Contd.. Aspartic acid subsituted at His B10 which is essential for hexamer formation, is absorbed twice as rapidly as regular insulin 3.5 fold increasing affinity for insulin receptor compare to regular insulin About twice as potent than regular insulin in metabolic assays.

TYPES OF INSULIN : 

TYPES OF INSULIN Insulin, classified based on the action profile as Rapid/Short-acting insulin Used for bolus (meal time) needs Used for elevated BG Intermediate/Long-acting insulin Used for basal (between meal) needs Not intended to cover meals

Dosage unit : 

Dosage unit One international unit of insulin (1 IU) is defined as the biological equivalent of about 45.5 μg pure crystalline insulin (1/22 mg exactly). This corresponds to the old USP insulin unit, where one unit (U) of insulin was (arbitrarily) set equal to the amount required to reduce the concentration of blood glucose in a fasting rabbit to 45 mg/dl (2.5 mmol/L).

REGULAR INSULIN : 

REGULAR INSULIN It is a man made human insulin structurally identical to that of human insulin secreted by pancreas. Normal insulin concentration peaks at 30-45 min and returns to basal level after 2-3 hr. Does not mimic endogenous insulin level due to delayed absorption from subcutaneous injection site Disparity in plasma glucose levels create brief hyperglycemic period immediately after meal and post hypoglycemic period 3-4 hr after a meal. Ex:Novolin®

RAPID ACTING INSULIN : 

RAPID ACTING INSULIN These are insulin analogs of human insulin Types: Insulin lispro (Humalog ®), Insulin aspart (Novolog ®), Insulin glulisine (Apidra ®) Best mimics normal insulin secretion during meals.

INSULIN LISPRO(HUMALOG®) : 

INSULIN LISPRO(HUMALOG®) First rapid acting analogue produced by Eli lilly company. Its M.W is 5808. Lysine in B29 and proline in B28 position is reversed in insuline lispro . It does not alter insulin receptor binding affinity. Does not self associate because of changes in terminal portion of B chain. Thus it dissociates rapidly from SC injection site It has high affinity towards IGF-1 receptor compared with human insulin

INSULIN LISPRO : 

INSULIN LISPRO

Pharmacokinetic properties : 

Pharmacokinetic properties Absorption: Rapid absorption from injection site. Absorption is more quickly from intenstinal site than from deltoid or femoral sites. Heat increases absorption. Distribution: volume of distribution is 0.26-0.36L/Kg Bioavailablity: 55%-77% Elimination: dose dependent half life is 26-52 min.

Pharmacodynamic properties : 

Pharmacodynamic properties Insulin lispro reach the maximum concentration within 38 min compared to 101 min for human insulin Mean residence time that is average time a drug remains in the body for insulin lispro is half the time of regular insulin. Lower post prandial rise in serum glucose level and lower occurrence of hypoglycemia due to its short duration of action.

INSULIN ASPART ( NOVOLOG®) : 

INSULIN ASPART ( NOVOLOG®) Proline at B28 position is replaced by aspartic acid Introduction of charged group prevents the formation of dimers and hexamers. Affinity towards insulin receptors and IGF-1 receptor is similar to that of human insulin

Pharmacokinetic properties : 

Pharmacokinetic properties Absorption: choice of injection affects action profile. Abdominal administration decreases plasma glucose level in short duration compared to deltoid or thigh muscle . Faster rate of absorption and narrow peak Distribution: Low plasma protein binding <10% Elimination: apparent half life is 81 min

Pharmacodynamic properties : 

Pharmacodynamic properties Peak serum concentration reaches approximately twice as that of human insulin Mean residence time is 40-50 min Occurrence of post prandial rise in glucose level after 4 hr of administration Increase occurrence of hypoglycemia in night time.

INSULIN GLULISINE(APIDRA®) : 

INSULIN GLULISINE(APIDRA®) Substitution of asparagine by lysine in B3 and Lysine at position B29 by glutamine. Isoelectric point shifted from 5.1 to 5.5 increases solublity . Increased affinity towards IGF-1 receptor thus there is a risk of tumorogenecity.

Pharmacokinetic properties : 

Pharmacokinetic properties Absorption: Faster absorption due to its high solublity Bioavailablity: 70% Elimination: 13-17min Pharmacodynamic properties Peak concentration occur within 6omin Lower occurrence of hypoglycemia, nocturnal hypoglycemia.

INTERMEDIATE ACTING INSULIN : 

INTERMEDIATE ACTING INSULIN NPH insulin is an intermediate acting insulin wherein absorption and onset of action is delayed by appropriate amount insulin and protomine so that neither is present is uncomplexed form Protamine is a mixture of six major and some minor compounds isolated from the sperm of rainbow trout

Pharmacokinetic properties : 

Pharmacokinetic properties Absoption: After subcutaneous injection, proteolytic tissue enzymes degrade the protamine to permit absorption of insulin. It has onset of action 2-5 hr and duration of 4-12 hr It cannot be injected intravenously and intravenously It can be mixed with regular insulin.

LONG ACTING INSULIN : 

LONG ACTING INSULIN Mimics the basal insulin secretion level Given once in a day or twice

INSULIN DETEMIR (LEVEMIR®) : 

INSULIN DETEMIR (LEVEMIR®) It is an acylated derivative of human insulin It binds to albumin through fatty acid chain attached to lysine at residue at B29 Lower affinity for insulin receptor necessiates higher doses. Given twice daily for smooth basal insulin level

Pharmacokinetic properties : 

Pharmacokinetic properties Absorption: Less variablity in absorption than NPH. Maximum serum concentration reached between 6-8 hr after administration. Slower and prolonged absorption is seen Distribution: 98% bound to albumin Elimination: terminal half life is 5-7hr depend on dose. renal impairment decreases elimination. Pharmacodynamic properties Flat action profile with duration 23hr at the highest dose and 5.7hr at the lowest dose.

INSULINE GLARGINE(LANTUS®) : 

INSULINE GLARGINE(LANTUS®) Subsitution of glycine for asparagine at position A21 and addition of 2 arginine rings at B30. Isoelectric pH shifts from 5.4 to 6.7 makes it more soluble at acidic solution and less soluble at physiological pH. Increase in affinity towards IGF-1 receptor

Pharmacokinetic properties : 

Pharmacokinetic properties Absorption and Bioavailability: After subcutaneous injection of insulin glargine , the insulin serum concentrations indicated a slower, more prolonged absorption and a relatively constant concentration/time profile over 24 hours with no pronounced peak in comparison to NPH insulin. Metabolism: Insulin glargine is partly metabolized at the carboxyl terminus of the B chain in the subcutaneous depot to form two active metabolites with in vitro activity similar to that of insulin, M1 (21A-Gly-insulin) and M2 (21A-Gly-des-30B-Thr-insulin). Unchanged drug and these degradation products are also present in the circulation

Mixed insulin(Humulin®70/30) : 

Mixed insulin(Humulin®70/30) Humulin 70/30 is a mixture of 70% Human Insulin Isophane Suspension and 30% Human Insulin Injection (rDNA origin). Itis an intermediate-acting insulin combined with the more rapid onset of action of Regular human insulin. The duration of activity may last up to 24 hours following injection. As with all insulin preparations, the duration of action of Humulin 70/30 is dependent on dose, site of injection, blood supply, temperature, and physical activity

Insulin preparations : 

Insulin preparations

Modes of Administration : 

Modes of Administration Subcutaneous administration: Insulin is usually taken as subcutaneous injections by single-use syringes with needles, an insulin pump, or by repeated-use insulin pens with needles. Administration schedules often attempt to mimic the physiologic secretion of insulin by the pancreas. Hence, both a long-acting insulin and a short-acting insulin are typically used Standard mode of subcutaneous injection is by using disposable needles and syringes.

Insulin pens : 

Insulin pens To facilitate multiple sub cutaneous injections of insulin. Contain cartridges of insulin and replaceable needles. Pen-like device with cartridges holding 150-300 units of insulin Reusable or Disposable Dial insulin dosage and inject (like a syringe)

INSULIN PUMPS : 

INSULIN PUMPS Insulin pumps are used to create an artificial insulin secretion subcutaneously that can suppress excessive blood glucose. In general, it continuously delivers a basal rate of exogenous insulin automatically and also has capability of manually adding extra insulin to the basal rate for the intensive insulin secretion by a continuous subcutaneous insulin infusion (CSII) technique.

Contd.. : 

Contd.. Most of the insulin pumps consist of a small processing module with a display, a disposable insulin reservoir, and an insulin syringe, and are powered by batteries. Advantages : Better control over background or 'basal' insulin dosage. Limitations: Cost, catheter problems, and no "closed loop" means of controlling insulin delivery based on current blood glucose levels.

Inhaled insulin : 

Inhaled insulin FDA has approved an inhaled insulin preparation of finely powdered form and aerosolized human insulin Insulin has been readily absorbed through alveolar walls but the molecule should be small. It has a rapid onset of action and peak action similar to rapid acting insulins and duration of action similar to regular insulin

Slide 55: 

Exubera , powder form of inhaled insulin was introduced in Jan-06 by Pfizer and Nektar therapeutics Bio availablity is only 10% to 40% It is discontinued due to patients uncompliance. AIR insulin system introduced by Eli lilly in a dry powder form was also discontinued due to its high particle size of 5 to 50μm.

Buccal insulin : 

Buccal insulin Drug delivery through the buccal mucosa has following advantages, Direct contact with mucosa relatively large surface for absorption (100–200 cm²); level of vascularization is very high in some areas; weak variations of pH (≠GI); buccal enzymatic activity is mainly intracellular and less developed than in other mucosae.

Drawbacks : 

Drawbacks The buccal mucosa is not an absorptive organ. Sublingual area is thin and nonkeratinized, highly permeable (high drug input); Cheek mucosa is thicker and nonkeratinized, fairly permeable (low but sustained drug input); and In summary, the continuous, but variable, saliva flow and the robust multilayered structure of the oral epithelium constitute an effective barrier to penetration of drugs.

oral-lyn : 

oral-lyn Generex US-based company develop oral-lyn Oral-lyn is a liquid formulation of human regular insulin with a spray propellant for prandial insulin therapy. The formulation results in an aerosol with relatively large micelles (85% of that having a mean size >10 μm) and therefore cannot go into the lungs.

Slide 59: 

On administration with Rapid Mist device insulin passes through superficial layers of mucosa into the blood stream Each 28 mlcanister contains 400 U of regular human insulin. The drug is under clinical trials

Oral insulin : 

Oral insulin Advantages: Increased patients compliance Direct absorption from the gut. Transfer of insulin directly to liver Control hepatic glucose production to the same extent of natural insulin. This more “physiological insulin delivery” would be associated with reduced peripheral hyperinsulinemia

obstacles: : 

obstacles: Enzymatic degradation in the gut. Insulin has to pass through the high viscous mucous layer of the gut Disadvantages: 50% of insulin is degraded by liver thus peripheral insulin concentration is low.

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Biocon has taken over the oral insulin technology developed by Nobex. IN-105 is a human insulin molecule conjugated on position B29 with polyethylene glycol via an acyl chain IN-105 is declared to have the following characteristics: improved half-life in the digestive tract and improved absorption, lower immunogenicity as compared to insulin, lower mitogenicity as compared to insulin, retains a similar pharmacological activity as insulin, and conserves safety profile and good clearance profile as compared to insulin. It is under phase III clinical trials

Adverse reactions : 

Adverse reactions Hypoglycemia: Most common complication of insulin therapy. They may result from delay in taking a meal, inadequate carbohydrate intake, unusual physical exertion or dose of insulin is too large. Symptoms are palpitations, sweating, nausea, hunger. In persons with persistent hypoglycemia manifestations of insulin excess may develop. Includes confusion, weakness, bizarre behavior, coma. Mainfestations of hypoglycemia are relieved by glucose administration.

Contd.. : 

Contd.. Lipodystrophy: It occurs in the subcutaneous fatty tissue if injected repeatedly at the same site Weight gain Immune allergy: immediate type hypersensitivity results from histamine release from mast cells sensitized by anti-insulin IgE antibodies. Immune insulin resistance: IgG anti-insulin antibodies neutralizes the action of insulin

Drug interactions : 

Drug interactions Drug increases glucose lowering effects of insulin pramlintide, ACE inhibitors, disopyramide, fibrates, fluoxetime, propoxyphene, pentoxyfyline, salicylates, Drug decreases glucose lowering effects corticosteroids, niacin, danazol, diuretics, isoniazid, phenothiazin, somatropin, thyroid h0rmone, estrogen, protease inhibitors, atypical antipsycotics.

DIABETES EXPOSURE : 

DIABETES EXPOSURE Although conventional hypoglycemic therapies prevent acute metabolic complications in patients with diabetes, they do not restore metabolic homeostasis. The result of this imperfect treatment is a novel milieu that includes various combinations of metabolic, hormonal, and physiologic alterations. These include hyperinsulinemia, hyperglycemia, hyperlipidemia, abnormalities in blood flow, and the formation of glycation products all of which constitute diabetes exposure. As a consequence of this exposure, diverse functional and morphologic alterations develop that lead to severe complications affecting the eyes, kidneys, and heart.

DIABETIC RETINOPATHY : 

DIABETIC RETINOPATHY Structural changes: thickening of the capillary basement membrane, loss of retinal pericytes, increased vessel permeability and formation of capillary microaneurysms. These structural changes are accompanied by decreased retinal blood flow, capillary occlusion, angiogenesis, hemorrhage, fibrotic tissue formation, and tractional retinal detachment. Some of these events, or all of them in combination, can ultimately result in impairment or complete loss of vision

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Incidence, progression and development of proliferative diabetic retinopathy is highest in type I diabetes patients compared to type II diabetes patients High glycemic control reduces the onset of disease Hypertension, Higher ocular perfusion pressure and myopia increases the risk of progression

DIABETIC NEUROPATHY : 

DIABETIC NEUROPATHY Diabetic neuropathy is common in diabetic patients, with a prevalence of more than 50% The pathogenesis is multifactorial and considered to be both hyperglycemia-induced pathologic changes intrinsic to neurons and ischemia-induced neuronal damage by decreased neurovascular blood flow . Histologically, increases in endothelial cell area and luminar narrowing of capillaries are present in the endoneurium of patients with diabetes.

DIABETIC NEPHROPATHY : 

DIABETIC NEPHROPATHY Diabetic nephropathy is characterized by thickening of the glomerular basement membrane, increased fractional mesangial volume, Expansion of the glomerular mesangium, which occurs at the expense of the glomerular capillary lumen and filtration surface area, correlates most closely with the decline in renal function and the development of proteinuria

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Thank you