Diabetes mellitus is a group of metabolic disorders characterized by high blood sugar levels over a prolonged period due to either insufficient insulin production or ineffective utilization of insulin. The etiologic classification of diabetes mellitus includes several types:

1、Type 1 Diabetes Mellitus (T1DM):

Etiology: Type 1 diabetes is considered an autoimmune disease where the body's immune system attacks and destroys the insulin-producing beta cells in the pancreas. As a result, people with T1DM produce little to no insulin.

Age of Onset: It often develops in childhood or adolescence but can occur at any age.

2、Type 2 Diabetes Mellitus (T2DM):

Etiology: Type 2 diabetes is primarily characterized by insulin resistance, where the body's cells do not respond effectively to insulin. Over time, the pancreas may become unable to produce enough insulin to compensate for the resistance.

Age of Onset: Historically, it was more common in adults, but due to lifestyle changes, it is now increasingly diagnosed in children and adolescents.

3、Gestational Diabetes Mellitus (GDM): 妊娠糖尿病

Etiology: Gestational diabetes occurs during pregnancy and is characterized by high blood glucose levels that develop due to insulin resistance. Hormonal changes during pregnancy can lead to insulin resistance, and some women may not produce enough insulin to overcome it.

Age of Onset: It occurs during pregnancy and typically resolves after childbirth. However, women who have had gestational diabetes are at an increased risk of developing type 2 diabetes later in life.

4、Other specific types of diabetes:

There are several other less common types of diabetes, which may have distinct causes. These include genetic defects in beta cells, genetic defects in insulin action, diseases of the pancreas (such as pancreatitis or cystic fibrosis), endocrinopathies (hormonal disorders), drug-induced diabetes (e.g., from certain medications like glucocorticoids), and other rare forms of diabetes.

The pathophysiology of type 2 diabetes mellitus (T2DM) is multifactorial and involves various biological processes that lead to the development and progression of the disease. The main elements that characterize the pathophysiology of type 2 diabetes include:

1、Insulin Resistance: Insulin resistance is a central feature of type 2 diabetes. It occurs when the body's cells, such as muscle, fat, and liver cells, become less responsive to insulin's action. As a result, these cells are less efficient at taking up glucose from the bloodstream, leading to elevated blood sugar levels (hyperglycemia). Insulin resistance is influenced by genetic factors and can be exacerbated by lifestyle factors such as obesity and physical inactivity.

2、Beta Cell Dysfunction: Beta cells in the pancreas are responsible for producing and releasing insulin. In individuals with type 2 diabetes, beta cells gradually lose their ability to secrete sufficient insulin in response to elevated blood glucose levels. This impairment in insulin secretion contributes to hyperglycemia and further exacerbates insulin resistance.

3、Abnormal Glucose Production by the Liver: In individuals with type 2 diabetes, the liver may produce excessive glucose, even when blood sugar levels are already high. Normally, the liver helps maintain blood glucose levels during fasting or between meals by releasing glucose into the bloodstream. However, in diabetes, this process becomes dysregulated, contributing to elevated glucose levels.

4、Incretin Hormone Dysfunction: Incretins 肠促胰岛素激素are hormones produced by the gastrointestinal tract that enhance insulin secretion and reduce glucagon胰高血糖素 production (a hormone that increases blood glucose levels). In type 2 diabetes, there may be a reduced response to incretin hormones, leading to impaired insulin release and increased glucagon secretion.

5、Adipokine Imbalance: Adipokines 脂肪因子are signaling molecules produced by adipose (fat) tissue. In individuals with obesity, there is often an imbalance of adipokines, which can contribute to insulin resistance and inflammation, both of which play a role in the pathophysiology of type 2 diabetes.

6、Chronic Low-Grade Inflammation: 慢性低度炎症Chronic low-grade inflammation is associated with insulin resistance and beta cell dysfunction. Obesity and excess fat tissue can trigger an inflammatory response, leading to impaired insulin signaling and function.

7、Genetic Predisposition: Genetics plays a significant role in the development of type 2 diabetes. Certain gene variants can increase an individual's susceptibility to insulin resistance and beta cell dysfunction, making them more prone to developing the disease.

8、Lifestyle Factors: Sedentary behavior, unhealthy eating habits, and obesity are major risk factors for type 2 diabetes. Lifestyle factors can exacerbate insulin resistance and contribute to the development of diabetes in genetically susceptible individuals.

The treatment of type 2 diabetes mellitus involves a combination of lifestyle modifications, medications, and sometimes insulin therapy. The primary goals of treatment are to control blood sugar levels, prevent complications, and improve overall health and quality of life. The specific treatment plan may vary depending on individual factors, such as age, overall health, duration of diabetes, and response to therapy. Here are the main elements of treatment and the types of medicine agents commonly used for type 2 diabetes:

1、Lifestyle Modifications:

a/Weight Management: Achieving and maintaining a healthy weight can improve insulin sensitivity and blood sugar control. It may involve a combination of dietary changes and regular physical activity.

b/Healthy Diet: A balanced diet that focuses on whole foods, including fruits, vegetables, whole grains, lean proteins, and healthy fats, can help control blood sugar levels and reduce the risk of complications.

c/Regular Exercise: Physical activity can improve insulin sensitivity and help with weight management. Engaging in regular aerobic and strength-training exercises is beneficial for people with type 2 diabetes.

2、Medications (Antidiabetic Drugs):

a/Metformin: 二甲双胍 It is usually the first-line medication for type 2 diabetes. Metformin works by reducing glucose production by the liver and improving insulin sensitivity in peripheral tissues.

b/Sulfonylureas: 磺脲类药物These drugs stimulate the pancreas to produce more insulin. Examples include glimepiride格列美脲, glipizide, 格列吡嗪 and gliclazide. 格列齐特。

c/Dipeptidyl Peptidase-4 (DPP-4) Inhibitors: 二肽基肽酶-4（DPP-4）抑制剂These medications enhance the body's natural incretin hormones, which help regulate blood sugar levels. Examples include sitagliptin西格列汀, saxagliptin, 沙格列汀 and linagliptin. 利格列汀

d/Sodium-Glucose Cotransporter-2 (SGLT-2) Inhibitors: 钠-葡萄糖共转运蛋白-2（SGLT-2）抑制剂：These drugs help the kidneys excrete glucose through urine, lowering blood sugar levels. Examples include canagliflozin, 卡格列净 dapagliflozin达格列净, and empagliflozin. 恩格列净

e/Thiazolidinediones (TZDs): 噻唑烷二酮类药物TZDs improve insulin sensitivity in peripheral tissues. Examples include pioglitazone吡格列酮 and rosiglitazone罗格列酮.

f/Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists: 胰高血糖素样肽-1（GLP-1）受体激动剂：These injectable medications mimic the action of incretin hormones and enhance insulin secretion. They also slow down gastric emptying, leading to reduced appetite and weight loss. Examples include exenatide艾塞那肽, liraglutide, 利拉鲁肽 and dulaglutide. 度拉糖肽。

g/Insulin: Some people with type 2 diabetes may require insulin therapy to achieve optimal blood sugar control. There are various types of insulin, such as rapid-acting, short-acting, intermediate-acting, and long-acting, which can be used alone or in combination.

Insulin is classified into several types based on its onset of action, peak time, and duration of effect. The different types of insulin are designed to mimic the body's natural insulin secretion and meet various insulin requirements throughout the day. The main types of insulin include:

1、Rapid-Acting Insulin:

Onset: It starts working within 15 minutes after injection.

Peak: Its peak effect occurs within 1 to 2 hours after injection.

Duration: It lasts for about 2 to 4 hours.

Examples: Insulin lispro, 赖脯胰岛素 insulin aspart, 门冬胰岛素and insulin glulisine谷赖胰岛素.

2、Short-Acting (Regular) Insulin:

Onset: It starts working within 30 minutes after injection.

Peak: Its peak effect occurs within 2 to 3 hours after injection.

Duration: It lasts for about 3 to 6 hours.

Example: Regular insulin (Humulin R, Novolin R).

3、Intermediate-Acting Insulin:

Onset: It starts working within 2 to 4 hours after injection.

Peak: Its peak effect occurs within 4 to 12 hours after injection.

Duration: It lasts for about 12 to 18 hours.

Examples: NPH insulin (Humulin N, Novolin N).

4、Long-Acting Insulin:

Onset: It starts working within 1 to 2 hours after injection (depending on the specific type).

Peak: Some long-acting insulins have a very minimal peak effect.

Duration: It can last for about 24 hours or even longer, providing basal insulin coverage.

Examples: Insulin glargine 甘精胰岛素(Lantus, Basaglar, Toujeo), insulin detemir 地特胰岛素(Levemir), insulin degludec (Tresiba).

5、Ultra-Long-Acting Insulin:

Onset: It starts working within 1 to 3 hours after injection (depending on the specific type).

Peak: These insulins have a very flat and steady action profile without a distinct peak.

Duration: They can last for more than 42 hours, providing a prolonged and consistent basal insulin effect.

Example: Insulin degludec (Tresiba).

It's essential to work closely with a healthcare professional to determine the appropriate type of insulin, dosage, and injection schedule based on individual needs, blood sugar levels, meal plans, and activity levels. Some people may use a combination of different insulin types to achieve optimal blood sugar control throughout the day, commonly using rapid-acting or short-acting insulin before meals and long-acting or ultra-long-acting insulin for basal coverage. Insulin therapy is an integral part of diabetes management, especially for individuals with type 1 diabetes and some people with type 2 diabetes who require insulin supplementation.

Diabetes is a complex and chronic condition that, if left uncontrolled, can lead to various complications affecting different organs and systems in the body. Proper management and control of blood sugar levels are crucial to prevent or delay the onset of these complications. Some of the common complications associated with diabetes include:

1、Cardiovascular Complications:

Coronary Artery Disease (CAD): Diabetes increases the risk of developing CAD, leading to heart attacks and other heart-related problems.

2、Stroke: Diabetes is a significant risk factor for stroke, which occurs when blood flow to the brain is disrupted.

3、Peripheral Arterial Disease (PAD): Diabetes can lead to reduced blood flow to the limbs, particularly the legs, which may cause pain, ulcers, and even gangrene坏痽 in severe cases.

4、Nephropathy (Kidney Disease):

Diabetes can damage the blood vessels in the kidneys, leading to diabetic nephropathy, a condition that can progress to kidney failure (end-stage renal disease, ESRD) if not managed properly.

5、Neuropathy (Nerve Damage):

Diabetes can damage the nerves, leading to peripheral neuropathy, causing pain, tingling, or loss of sensation in the extremities.

Autonomic neuropathy can affect the nerves that control internal organs, leading to digestive, urinary, and cardiovascular problems.

Retinopathy (Eye Disease):

6、Diabetes can damage the blood vessels in the retina, leading to diabetic retinopathy, a major cause of vision loss and blindness.

7、Diabetic Foot Complications:

Nerve damage and reduced blood flow to the feet can lead to foot ulcers, infections, and, in severe cases, amputation.

8、Skin Complications:

People with diabetes are more prone to skin infections and may experience slow wound healing.

9、Dental and Gum Problems: 牙齿和牙龈问题

Diabetes can increase the risk of gum disease and other dental issues.

Increased Susceptibility to Infections:

10、High blood sugar levels can weaken the immune system, making people with diabetes more susceptible to infections, including urinary tract infections and skin infections.