Diabetes Insulin: Action, Effects, and Administration || pharmacyteach

  Diabetes Insulin: Action, Effects, and Administration

 1. Introduction

1.1 Overview of Diabetes and Insulin 

Diabetes is a chronic condition characterized by elevated blood sugar levels due to the body’s inability to produce or effectively use insulin. Insulin, a hormone produced by the pancreas, plays a vital role in glucose metabolism. Without it, glucose remains in the bloodstream, leading to hyperglycemia, which can cause long-term complications.

One of the most prominent medical issues of the twenty-first century is type 2 diabetes mellitus (T2D). In industrialized nations, the overindulgence in relatively cheap, calorie-dense, highly appealing, and insufficiently satiating food has resulted in unparalleled rises in obesity rates. The combined prevalence of prediabetes and diabetes in the US is more than 50%. Obesity is a key risk factor for T2D, even though only a small percentage of obese individuals go on to acquire the disease, and rates of T2D prevalence have mirrored those of obesity. The primary hormone that lowers blood sugar levels, insulin, is not acting well enough to cause the fasting hyperglycemia that characterizes type 2 diabetes. Thus, a thorough understanding of the processes underlying insulin action is crucial to the ongoing creation of potent treatment approaches to address T2D [1].

 

Blood sugar levels that are higher than the normal range can cause damage to the eyes, kidneys, and nerves over time, as well as heart disease and stroke. Every day, about 300 Australians get diabetes. Diabetes is Australia's quickest-developing ongoing illness. The major kinds of diabetes are type 1 diabetes, type 2 diabetes, and gestational diabetes.

The predominance of cardiovascular breakdown in patients with type 2 diabetes mellitus (T2DM) is assessed to be 22%. The Framingham Heart Study detailed that 19% of patients with cardiovascular failure have T2DM and that the presence of T2DM expands the gamble of cardiovascular failure by 2-8 times. In addition, an 8% increased risk of heart failure is associated with a 1% increase in HbA1c levels, regardless of blood pressure, body mass index (BMI), age, or the presence of coronary artery disease. This suggests that the risk of heart failure is solely influenced by T2DM-related factors like insulin resistance and hyperglycemia. On the other hand, a 1 percent drop in HbA1c levels is linked to a 16 percent lower risk of heart failure and worse outcomes. As a result, this two-way interaction demonstrates the existence of diabetic cardiomyopathy as a distinct clinical entity and suggests that diabetes may increase the risk of heart failure on its own.

 

1.2 Importance of Insulin in Diabetes Management 

Insulin therapy is central to managing diabetes, particularly for those with Type 1 diabetes, where the body produces little to no insulin. For Type 2 diabetes, insulin may be required when other medications and lifestyle changes are insufficient. Proper insulin management is crucial to maintaining blood glucose levels within a target range.

Insulin's direct actions on skeletal muscle, liver, and white adipocytes typify its involvement in glucose homeostasis, although numerous somatic cell types express insulin receptors [2]. Tissue-specific insulin signal transduction pathways are required because of the different roles that these tissues play in maintaining metabolic balance. For instance, insulin increases net glycogen synthesis and glucose transit in skeletal muscle, which facilitates glucose storage and utilization. Insulin stimulates hepatic glycogen synthesis, elevates the expression of lipogenic genes, and diminishes the expression of gluconeogenic genes. Insulin enhances glucose transport and lipogenesis while suppressing lipolysis in white adipocyte tissue (WAT). The proximal elements of insulin signal transduction are very similar in all insulin-responsive cells, despite these disparate consequences. The variety in physiological insulin responses found in various cell types can be attributed in large part to varied distal effectors. In section II, we will examine the cell-autonomous effects of insulin in skeletal muscle, liver, and WAT, with a focus on signal transduction processes related to the physiological regulation of metabolic fluxes [3].

 

1.3 Purpose of the Article 

This article aims to provide a comprehensive overview of insulin, its mechanisms, types, and administration methods. It will also explore the effects of insulin, challenges in its use, and future advancements in insulin therapy.

 2. What is Insulin?

2.1 Definition and Function 

Insulin is a peptide hormone that regulates blood glucose levels by facilitating the uptake of glucose into cells, where it can be used for energy or stored as glycogen.

In type 1 diabetes, your body doesn't produce insulin, so you need to continually inject it to stay alive. But in type 2 diabetes, your body doesn't produce enough insulin, or the insulin that is produced doesn't work properly. In some cases, you need insulin injections to control your blood sugar levels.

2.2 Types of Insulin 

There are various types of insulin, each designed to act at different speeds and durations to mimic the natural pattern of insulin release in the body.

2.3 Historical Background of Insulin Discovery 

Insulin was first discovered in 1921 by Frederick Banting and Charles Best, marking a significant breakthrough in the treatment of diabetes.

 3. How Insulin Works in the Body

3.1 Insulin and Blood Glucose Regulation 

Insulin lowers blood glucose levels by promoting the absorption of glucose into liver, fat, and muscle cells. It inhibits the production of glucose by the liver, thereby controlling blood sugar levels.

 

3.2 Insulin's Role in Metabolism 

In addition to regulating glucose, insulin plays a role in fat storage and protein synthesis, influencing overall metabolic processes.

3.3 Mechanisms of Insulin Action 

Insulin binds to insulin receptors on the surface of cells, triggering a series of reactions that allow glucose to enter the cells.

Figure: [4] Insulin signaling at close range. The insulin receptor (INSR) binds many substrates and undergoes autophosphorylation upon interaction with insulin. Mitogenic (started by GRB2 and SHC) and metabolic (started by insulin receptor substrate (IRS) proteins and SH2B2/APS) signaling are the two main branches of insulin signaling. Additionally, GIV potentiates phosphoinositide-3-kinase (PI3K)-AKT signaling, and NAD(P)H oxidase 4 (NOX4)-derived H2O2 inhibits phosphatase. Positive feedback mechanisms associated with insulin signaling include stabilizing and recruiting GRB10 to the INSR, as well as activating S6 kinase 1 (S6K1) to phosphorylate and inhibit IRS proteins. Red circles and arrows indicate inhibitory events, whereas green circles and arrows indicate activating events.

 

 

 4. Types of Insulin and Their Characteristics

4.1 Rapid-Acting Insulin 

Rapid-acting insulin begins to work within 15 minutes and is typically used before meals.

4.2 Short-Acting Insulin 

Short-acting insulin starts to work within 30 minutes and covers insulin needs for meals eaten within 30-60 minutes.

4.3 Intermediate-Acting Insulin 

Intermediate-acting insulin covers insulin needs for about half a day or overnight.

4.4 Long-Acting Insulin 

Long-acting insulin provides a consistent level of insulin throughout the day and night.

4.5 Ultra-Long-Acting Insulin 

Ultra-long-acting insulin lasts for more than 24 hours, reducing the need for multiple daily injections.

 

 5. Insulin Administration Methods

5.1 Syringes and Vials 

Traditional methods include the use of syringes and vials, where insulin is drawn into the syringe and injected subcutaneously.

 

5.2 Insulin Pens 

Insulin pens are convenient devices that prefill insulin, making it easier and more accurate to administer.

5.3 Insulin Pumps 

Insulin pumps deliver continuous insulin infusion, closely mimicking the body’s natural insulin release.

5.4 Inhalable Insulin 

Inhalable insulin offers an alternative for those who prefer not to inject, though it’s not suitable for everyone.

5.5 Continuous Glucose Monitoring Systems (CGMS) 

CGMS provides real-time blood glucose readings, helping users adjust insulin doses more accurately.

 

 6. Effects of Insulin on the Body

6.1 Immediate Effects 

Insulin quickly reduces blood glucose levels, preventing hyperglycemia and its associated symptoms.

6.2 Long-Term Effects 

Long-term insulin use helps manage diabetes and prevent complications such as neuropathy, retinopathy, and cardiovascular disease.

6.3 Side Effects and Risks

Possible side effects of insulin include hypoglycemia, weight gain, and injection site reactions.

 

 7. Insulin Therapy in Different Types of Diabetes

7.1 Type 1 Diabetes 

In Type 1 diabetes, insulin therapy is essential as the body produces little to no insulin.

7.2 Type 2 Diabetes 

Type 2 diabetes may require insulin therapy when other treatments are insufficient.

7.3 Gestational Diabetes 

Some pregnant women with gestational diabetes may need insulin to manage their blood sugar levels.

 

 8. Insulin Dosing and Timing

8.1 Factors Influencing Insulin Dosage 

The dosage depends on factors such as age, weight, diet, activity level, and blood glucose patterns.

8.2 Timing of Insulin Administration 

Timing is critical to ensure insulin effectiveness, with some types needing administration before meals and others providing basal coverage.

8.3 Adjusting Dosages Based on Blood Glucose Levels 

Regular monitoring allows for dosage adjustments to maintain optimal blood glucose control.

 9. Common Challenges in Insulin Therapy

9.1 Hypoglycemia 

Hypoglycemia, or low blood sugar, is a common challenge in insulin therapy. It can occur if too much insulin is taken or if meals are missed. Symptoms include dizziness, sweating, confusion, and, in severe cases, unconsciousness. Managing hypoglycemia involves careful monitoring of blood sugar levels and having quick sources of glucose available, such as juice or glucose tablets.

9.2 Hyperglycemia 

Hyperglycemia, or high blood sugar, can happen if insulin doses are too low or if the body becomes resistant to insulin. Symptoms include frequent urination, excessive thirst, and fatigue. Persistent hyperglycemia can lead to long-term complications such as kidney damage and cardiovascular disease. Managing hyperglycemia requires adjusting insulin doses, dietary changes, and regular monitoring.

9.3 Insulin Resistance 

Insulin resistance occurs when cells in the body become less responsive to insulin, leading to higher blood sugar levels. This is particularly common in Type 2 diabetes. Overcoming insulin resistance often requires higher doses of insulin or the addition of other medications that improve insulin sensitivity.

9.4 Fear of Needles and Injection Anxiety 

Many patients experience anxiety related to insulin injections, which can be a barrier to effective treatment. Education, counseling, and the use of alternative administration methods, such as insulin pens or inhalable insulin, can help alleviate this fear.

 

 10. Advancements in Insulin Therapy

10.1 Modern Insulin Formulations 

Advancements in insulin formulations have led to the development of more stable and predictable insulins, such as insulin analogs. These modern insulins offer more consistent glucose control and fewer side effects.

 

10.2 Artificial Pancreas 

The artificial pancreas, an integrated system combining an insulin pump and a continuous glucose monitor, automatically adjusts insulin delivery based on real-time glucose readings. This technology mimics the function of a healthy pancreas and reduces the burden of diabetes management.

10.3 Future Innovations in Insulin Delivery 

Research is ongoing to develop new insulin delivery methods, such as oral insulin, which could eliminate the need for injections. Additionally, smart insulins that activate only when blood glucose levels rise are being explored.

 

 11. Expert Insights on Insulin Use

11.1 Best Practices for Insulin Management 

Experts recommend regular blood glucose monitoring, consistent meal timing, and adherence to prescribed insulin regimens to optimize diabetes management. Patient education and support are crucial for successful insulin therapy.

11.2 Expert Opinions on Emerging Trends 

Emerging trends in insulin therapy include personalized treatment plans based on genetic profiles and the increasing use of technology, such as smartphone apps, to track and manage insulin usage. Experts emphasize the importance of ongoing research to improve insulin accessibility and affordability worldwide.

 12. Future Outlook for Insulin Therapy

12.1 Personalized Medicine 

Personalized medicine, where treatments are tailored to an individual’s genetic makeup, is expected to play a significant role in the future of insulin therapy. This approach could lead to more effective and targeted treatments for diabetes.

12.2 Biotechnological Advances 

Biotechnological advancements are driving the development of novel insulin therapies, including bioengineered insulin that more closely mimics natural human insulin. These innovations aim to improve the effectiveness and convenience of insulin therapy.

12.3 Global Accessibility of Insulin 

Efforts are being made to improve global access to insulin, particularly in low- and middle-income countries where insulin is often unaffordable or unavailable. International initiatives are focused on reducing costs and increasing the availability of life-saving insulin.

 

 13. Practical Tips for Insulin Users

13.1 Lifestyle Adjustments 

Making lifestyle adjustments, such as maintaining a balanced diet, regular physical activity, and stress management, can enhance the effectiveness of insulin therapy. These adjustments help maintain stable blood sugar levels and improve overall health.

13.2 Monitoring and Adjusting Dosage 

Regular blood glucose monitoring is essential for adjusting insulin dosages. Keeping a log of blood sugar levels, insulin doses, and food intake can help identify patterns and make necessary adjustments to avoid hypo- or hyperglycemia.

13.3 Coping with Side Effects 

Managing side effects, such as weight gain or injection site reactions, involves working closely with healthcare providers to adjust treatment plans. Exploring different insulin types or administration methods can also help minimize side effects.

 

 14. Frequently Asked Questions (FAQs)

 

14.1 What is the Best Time to Take Insulin? 

The best time to take insulin depends on the type of insulin and your meal schedule. Rapid-acting insulins are usually taken before meals, while long-acting insulins are taken once or twice daily, typically in the morning or evening. Always follow your healthcare provider's instructions.

14.2 Can Insulin Cure Diabetes? 

Insulin does not cure diabetes, but it is essential for managing blood sugar levels in people with diabetes. Proper insulin therapy can help prevent complications and improve quality of life.

14.3 How Can I Overcome the Fear of Injections? 

Overcoming the fear of injections can be achieved through education, practice, and the use of more comfortable administration methods, such as insulin pens or needle-free devices. Counseling and support from healthcare providers can also help reduce anxiety.

 

 15. Conclusion

15.1 Summary of Key Points 

Insulin is a vital hormone for the management of diabetes, with various types and administration methods available to meet individual needs. Understanding how insulin works, its effects and the challenges associated with its use is crucial for effective diabetes management.

15.2 Final Thoughts 

Advancements in insulin therapy and ongoing research promise to improve the lives of those with diabetes. By staying informed and working closely with healthcare providers, patients can optimize their insulin therapy and achieve better health outcomes.

15.3 Call-to-Action 

If you or a loved one is managing diabetes, consult with your healthcare provider to learn more about the best insulin therapy options for your situation. Stay updated on the latest advancements in diabetes care to make informed decisions about your health.

 

References 

1. Garvey, W. Timothy, et al. "The effect of insulin treatment on insulin secretion and insulin action in type II diabetes mellitus." Diabetes 34.3 (1985): 222-234.

2. Petersen, Max C., and Gerald I. Shulman. "Mechanisms of insulin action and insulin resistance." Physiological reviews (2018).

3. Firth, Richard G., Patrick M. Bell, and Robert A. Rizza. "Effects of tolazamide and exogenous insulin on insulin action in patients with non-insulin-dependent diabetes mellitus." New England Journal of Medicine 314.20 (1986): 1280-1286.

4. Mechanisms of Insulin Action and Insulin Resistance Max C. Petersen and Gerald I. Shulman Physiological Reviews 2018 98:4, 2133-2223