Understanding Peptides and Their Function in Medicine and Biology

What Are Peptides?

Peptides are small chains of amino acids—the building blocks that make up proteins in your body. While proteins can contain hundreds or thousands of amino acids, peptides are typically much shorter, containing anywhere from 2 to 50 amino acids linked together. Think of them as short amino acid chains ACS Publications that can communicate specific instructions to your cells.

Your body naturally produces many different peptides that serve as hormones, signaling molecules, and part of your immune system. For example, insulin—a hormone that helps regulate blood sugar—is a peptide. Scientists have learned to create synthetic versions of these natural peptides, as well as design entirely new ones, to treat various medical conditions.

Why Peptides Matter in Modern Medicine

Peptide therapies are currently employed in managing and diagnosing diverse medical conditions, including diabetes mellitus, weight loss, oncology, and rare diseases Nature. What makes peptides particularly valuable as medications is their ability to demonstrate high receptor specificity, which minimizes off-target effects, along with enhanced therapeutic efficacy, biodegradability, low toxicity, and minimal immunogenicity ACS Publications.

In simpler terms, peptide medications can target specific cells or processes in your body with remarkable precision, much like a key fitting into a specific lock. This targeting ability often results in fewer side effects compared to traditional medications that may affect multiple body systems.

The peptide drug market has grown substantially. Sales statistics for the first half of 2023 showed semaglutide led global sales of peptide drugs at $90.217 billion Nature, demonstrating both their effectiveness and widespread adoption in clinical practice.

Current Medical Uses of Peptides

Diabetes and Weight Management

The most well-known peptide medications today are the GLP-1 (glucagon-like peptide-1) receptor agonists used for type 2 diabetes and obesity. The FDA approved the first GLP-1 agonist (exenatide) in 2005 Cleveland Clinic, and this class of medications has since transformed diabetes care.

These medications work by mimicking a natural hormone your intestine produces. Upon activation of the GLP-1 receptor, semaglutide enhances glucose-dependent insulin secretion, slows gastric emptying, increases pancreatic β-cell proliferation, and reduces glucagon release, contributing to an overall reduction in appetite NCBI.

Clinical trials demonstrate the superiority of GLP-1 receptor agonists to other antihyperglycemic drugs in improving glycemic efficacy, reducing weight and blood pressure, and having a cardioprotective effect, all without the risk of hypoglycemia NCBI. Currently available GLP-1 medications include liraglutide (Victoza®), semaglutide (Ozempic®, Wegovy®, Rybelsus®), dulaglutide (Trulicity®), and tirzepatide (Mounjaro®, Zepbound®).

An important milestone came when the approval of oral semaglutide (Rybelsus®) in 2019 for treating type 2 diabetes marked a significant milestone in the advancement of peptide therapeutics PubMed Central, as most peptides previously required injection.

Fighting Antibiotic-Resistant Infections

One of the most promising frontier applications of peptides is in combating bacteria that have become resistant to traditional antibiotics. Antimicrobial peptides (AMPs) are produced from synthetic and natural sources and demonstrate broad-spectrum antimicrobial activity with high specificity and low toxicity Springer.

These peptides work differently than traditional antibiotics. Rather than targeting specific bacterial processes that can mutate, many AMPs disrupt bacterial cell membranes directly, making it harder for bacteria to develop resistance. hLF1-11, a short synthetic peptide derived from the N-terminal region of human lactoferrin, shows highly effective in vivo activity against bacteria (Gram positive and negative) and fungi, including infections caused by methicillin-resistant S. aureus (MRSA), Klebsiella pneumoniae and Listeria monocytogenes PubMed Central.

Several polymyxin derivatives including SPR 206, QPX 9003, and MRX 8, along with the synthetic cyclic peptide murepavadin, are currently in clinical trials PubMed Central for treating multidrug-resistant bacterial infections.

Cancer Treatment

Peptides are being investigated extensively in cancer therapy. Clinical trials have been conducted on major peptide-based vaccines such as E75, GP2, AE37, P3, P4, P5, P7, P13, P14, and P15 ACS Publications for various types of cancer. These peptide vaccines work by training your immune system to recognize and attack cancer cells.

Additionally, CIGB-300, a peptide-based inhibitor of casein kinase 2 combined with cell-penetrating peptide, can stop phosphorylation which results in the death of cervical and non-small cell lung cancer cells ACS Publications. Other peptides are being designed to disrupt proteins that help cancer cells survive or to deliver chemotherapy drugs directly to tumor cells.

Other Medical Applications

Beyond these major areas, peptides are being developed and used for:

• Rare diseases: Many peptide therapies target specific protein deficiencies

• Cardiovascular protection: GLP-1 receptor agonists can improve left ventricular ejection fraction, myocardial contractility, coronary blood flow, cardiac output, and endothelial function while reducing infarction size Nature

• Inflammatory conditions: Certain peptides can modulate immune responses

• Wound healing: Some peptides promote tissue repair

• Bone health: Peptides like teriparatide treat osteoporosis
  

How Peptide Medications Are Given

Most peptide medications are given by injection under the skin (subcutaneous injection), similar to insulin. This is because peptides are broken down by digestive enzymes if taken by mouth. GLP-1 agonists are most often injectable medications delivered in the fatty tissue just under your skin in areas like your belly, outer thighs, upper buttocks, and backs of your arms Cleveland Clinic.

However, researchers have made significant progress in developing oral formulations. The development of oral semaglutide represents a breakthrough—it's formulated with a special compound that protects it in the stomach and helps it absorb through the intestinal wall.

Depending on the medication, peptides may be given:

• Daily (like some GLP-1 medications)

• Weekly (like semaglutide and dulaglutide)

• Monthly or less frequently (for some other peptide therapies)
  

What to Expect: Benefits and Side Effects

Common Benefits

The advantages of peptide medications include:

• High specificity: They target specific receptors or cells, reducing unwanted effects on other body systems

• Effectiveness: Many show superior results compared to older medications

• Generally lower risk of drug interactions: Their specific targeting means less interference with other medications
  

Potential Side Effects

Side effects vary depending on the specific peptide medication. For GLP-1 receptor agonists, the most commonly reported include:

Nausea, diarrhea, vomiting, decreased appetite, dyspepsia, and constipation were the most commonly reported adverse events in clinical trials for liraglutide injection AJMC. These gastrointestinal effects typically improve over time as your body adjusts to the medication.

For antimicrobial peptides in development, researchers are working to minimize potential issues with stability and ensuring the peptides remain active at the site of infection.

It's important to discuss any side effects you experience with your healthcare provider, as they can often adjust dosing or provide strategies to manage symptoms.

The Future of Peptide Medicine

The field of peptide therapeutics is expanding rapidly. More than 80 peptides have reached the market, more than 150 peptides are in clinical development, and another 400-600 are in preclinical evaluation Taylor & Francis.

Researchers are working on several exciting advances:

1. Improved delivery methods: Scientists are developing better ways to give peptides orally and through other routes

2. Longer-lasting formulations: New technologies allow peptides to remain active in the body for longer periods, reducing injection frequency

3. Personalized peptide vaccines: Cancer treatments tailored to individual patients' specific tumor characteristics

4. Combination therapies: Pairing peptides with other medications for enhanced effectiveness

The integration of novel drug design and synthesis techniques, display library technology, delivery systems, bioengineering advancements, and artificial intelligence have significantly expedited the development of peptide-based drugs ACS Publications, addressing earlier limitations like rapid breakdown in the body.

Important Considerations

If your healthcare provider recommends a peptide medication:

1. Ask questions: Understand why this medication is recommended for your specific condition

2. Learn proper administration: If it's injectable, ensure you're comfortable with the technique or have support

3. Be aware of storage requirements: Many peptide medications require refrigeration

4. Report side effects: Keep your healthcare team informed about how you're responding to treatment

5. Don't stop suddenly: Always consult your provider before discontinuing peptide therapy

6. Obtain from legitimate sources: Only obtain drugs containing peptides with a prescription from a licensed healthcare provider, and obtain medicines only from state-licensed pharmacies NCBI

Conclusion

Peptide-based medications represent a significant advancement in modern medicine, offering targeted, effective treatments for conditions ranging from diabetes to infections to cancer. As research continues and new peptides enter clinical practice, these therapies will likely play an increasingly important role in personalized medicine—treatments tailored specifically to individual patients' needs.

While peptide medications may require different administration methods than traditional pills, their precision and effectiveness make them valuable tools in managing many health conditions. If you have questions about whether peptide therapy might be appropriate for your situation, discuss this with your healthcare provider, who can evaluate your specific medical needs and explain the potential benefits and risks.

Note: This information is for educational purposes and should not replace consultation with your healthcare provider. Always discuss treatment options, including risks and benefits, with qualified medical professionals before making healthcare decisions.

Evolution in the Treatment and Management of Plantar Fasciitis

Dr. J. Adrian Wright Sports Medicine,

We receive many people in our office with the presenting concern that they have heel pain. As with all medical problems, it is important to determine the key details of the issues. If you have been experiencing heel pain, pay close attention to what the pain feels like, when does it start, how long does it last, and what makes it better or worse. These key details will help your doctor determine an accurate diagnosis and proper treatment plan. Let's review some of the basics.

Does your heel pain start in the morning with the first few steps out of bed or after long periods of driving or sitting? This may sound strange to you as resting is supposed to make the problem better, but one of the most common causes of heel pain after rest is plantar fasciitis. At night, the foot rests in a plantarflexed position (toes pointing downward) with the calf muscle in a shortened position as well as the plantar fascia in a contracted position. The first steps out of bed can cause tension on the plantar fascia resulting in microtears that can be quite painful. More recently we also understand that a key component in the development of this pain is the immune system (the system in the body that fights infection, as well as works to repair daily stress and damage to the body). In the evening, the body's cortisol levels tend to taper resulting in an increased activity level of the immune system. Ever wonder why when you have a cold the symptoms are worse at night? This is also the culprit for why your hands and feet will feel more stiff in the morning if you have a seropositive condition like rheumatoid arthritis. Historically, we used to treat plantar fasciitis with steroid injections to attenuate this immune response but recent studies suggest that the employment of steroids is only effective if done within a certain window of symptom onset. If this condition has been present for months, the likelihood of success for steroid use is minimal.

Understanding what causes a condition, and how the body responds to it, is one of the most challenging aspects in medicine. Sadly, many times a scientific breakthrough leads to more questions than answers, leaving us humbled by how little we really know. Fortunately, we always gain insight from each discovery that allows us to at least improve somewhat our treatment modalities. With that in mind, what are some of the advancements in medicine for the treatment of plantar fasciitis?

Extracorporeal Shockwave Therapy (ECSWT): for the past couple of decades ECSWT has gained traction as an excellent tool for the management of chronic inflammatory conditions not limited to plantar fasciosis but also tendonosis, and bursitis. ESWT delivers focused sound waves that create controlled microtrauma in the targeted tissue. These acoustic pulses penetrate deep into the plantar fascia and surrounding areas, triggering the body's natural healing response without requiring surgery. The key components of this are:

Neovascularization: Stimulates the formation of new blood vessels, improving blood flow to the chronically injured area

Cellular regeneration: Activates stem cells and promotes the production of growth factors that help repair damaged tissue

Pain reduction: Disrupts pain signals by affecting nerve endings and can desensitize pain receptors

Tissue remodeling: Breaks down scar tissue and calcifications while promoting the formation of healthy collagen

Treatment process: Sessions typically last 15-20 minutes, with treatments spaced about a week apart. Most protocols involve 3-5 sessions total. You might experience some discomfort during treatment and temporary soreness afterward.

Effectiveness timeline: Results aren't immediate - healing typically occurs over 8-12 weeks after treatment as new tissue forms and blood supply improves. Success rates for plantar fasciosis range from 60-90% in various studies.

ESWT is particularly effective for chronic cases (fasciosis) that haven't responded to conservative treatments, since it addresses the underlying tissue degeneration rather than just inflammation.

Regenerative Medicine / Regenerative Matrix Injections: are another rapidly evolving area in the management and treatment of plantar fasciitis. Injectable human umbilical cord and amniotic membrane matrix serums are a flowable amniotic membrane injection derived from human amniotic tissues that contains naturally occurring growth factors, cytokines, and anti-inflammatory agents. It is important to understand that although stem cells are responsible for producing many of these protein cascades, the actual stem cells are not present in the injections.

How it works: The treatment harnesses the unique regenerative properties of placental tissue. The growth factors present in these injections help modulate inflammation and promote cellular proliferation, leading to accelerated healing processes. Specifically, it works through several mechanisms:

• Growth factors: Promote cellular growth and repair of damaged tissues by carefully modulating cellular behavior.

• Cytokines: Control inflammation, reducing pain and swelling while facilitating, to a certain degree, phagocytosis (cellular ingestion of diseased tissue).

• Anti-inflammatory agents: Decrease inflammation and expedite recovery

• Tissue regeneration: controls discomfort and inflammation from plantar fasciitis and helps long-term tissue regeneration

Treatment process: The area may require a small amount of anesthesia prior to delivery of the regenerative matrix. Some mild pain / swelling may occur after the first few days, and improvement in function is usually reported gradually over the course of 4-8 weeks. The effects of the regenerative matrix may even last up to 90 days.

Clinical results: A study by Midwest Orthopedic Consultants, revealed that almost 100 percent of the 43 patients in the clinical trial saw some level of improvement with pain dropping on average from 7/10 to 1/10 on a VAS scale. Most cases saw improvement in about three to four weeks.

Key advantages: Unlike corticosteroid injections that can degrade tissue, or PRP therapy that uses your own potentially compromised healing factors, regenerative matrix injections can offer regeneration and healing, helping to modulate inflammation and bring new cells into the area for healing.

So you've been diagnosed with arthritis . . . now what?

You have started to notice pain in your hands and feet. A trip to your doctor leads to the diagnosis of "arthritis". Like many others, you have probably asked your doctor, what you should do about it and get a vague response to the effect of "take ibuprofen" or "you should see a specialist". Many times these referrals lead to a reiteration of the same information, leaving you frustrated and not knowing where to go next. If any part of this scenario resonates with your story, read on.

The most important first step is to get a concrete diagnosis. There are many types of arthritis. Some are the result of daily wear and tear (osteoarthritis) whereas others are the effect of an irregular immune response (such as rheumatoid arthritis, psoriatic arthritis, etc). To determine what type of arthritis is present, your doctor will likely need imaging and / or blood work. An X-ray will give information of the wear pattern, or any key findings to suggest one type of arthritis over the other. Sometimes an ultrasound or MRI can provide more information, however many insurance plans make it extremely difficult to get a MRI relegating you to imaging that is not considered "high tech". Certain forms of arthritis, like rheumatoid arthritis will have key findings such as erosion of the bone around the margin of the joint. This is usually present in 30% of individuals with early stage rheumatoid arthritis, and approximately 60% of individuals with a later stage of the disease. Blood work is very important for determining the type of arthritis. Certain tests such as Anti-CCP can determine the type of arthritis you have as well as the possible severity of the disease long term. This test is important as many pharmaceuticals are available to combat certain types of arthritis to limit and even prevent their progression in certain cases. There are many other types of lab tests that can be performed that we will go into in a later article for those individuals that are newly diagnosed.

If you have already been diagnosed with a form of arthritis, quickly determining the right treatment option is very important as early intervention can delay, and sometimes halt, the progression of disease. The best treatment is not the same for everyone. Large institutions are constantly attempting to "standardize" medicine, but unfortunately there is only so much standardization that can be done. As physicians, we go to school for many years because medicine is anything but simple. Our treatment options must be flexible to address the individual needs of our patients. Some patient's do well with immunomodulating drugs, others have side effects that are more severe than the condition being treated. Some patients do well with non-steroidal anti-inflammatory drugs (NSAIDS) whereas others cannot take them as a consequent of a gastrointestinal bleed (ulcer). We will not belabor the issue, but you get the point. Let's discuss some treatment options and suggestions for each type of arthritis. For sake of brevity, we have limited this review to the most common forms of arthritis. Should you possess a more rare variant, it is crucial you see a rheumatologist for specific management of your condition.

OSTEOARTHRITIS (OA)

Osteoarthritis, or OA, is the "wear and tear" arthritis. It is usually the consequent of aberrant anatomic alignment as well as environmental factors such as type of stress and strain that has been placed on the joints over the years. This is typically seen later in life. Like discussed above, if OA is diagnosed early, certain measures can be taken to prevent further progress. Forms of durable medical equipment (DME) such as custom or prefabricated orthotics can be used to limit the strain on certain joints. If you have already developed chronic symptoms of pain in the joint, conservative measures should be attempted prior to any form of surgical intervention such as steroid injections or physical therapy. A more recent, cutting edge technology for the management of arthritis pain, Class IV laser therapy, is available for patients wishing to pursue conservative measures only.

RHEUMATOID ARTHRITIS (RA)

Rheumatoid, or RA is very different from OA in that younger individuals can develop the disease as a consequent of the body's immune system (the system that protects you from bacteria, viruses, parasites and fungus) attacking your cartilage. In this particular condition, as well as other immune based arthritic conditions, the body's immune system gets confused, attacking your own body as though it is a pathogen (bacteria, fungus, virus, etc). Although some of the treatment methods for OA such as cortisone injections and Class IV laser therapy has been shown to improve and sometimes resolve the symptoms of RA, it is recommended that you see a rheumatologist to discuss medications that could control the progression of the disease.

PSORIATIC ARTHRITIS Psoriatic arthritis is a seronegative arthritis that affects approximately 329,000 Americans. It is recommended that individuals with psoriatic arthritis seek the counsel of a rheumatologist in the management of the condition. Numerous medications are available to manage psoriatic arthritis. Your rheumatologist will determine which medication is right for you, but a summary of the different classes of drugs are NSAIDs, corticosteroids, and disease modifying anti-rheumatic drugs (DMARDs). There are two arms of DMARDs, biologic and non-biologic. It is important to monitor how your body tolerates certain drugs. DMARDs are known for their side effects and they do not affect all individuals the same. Pay close attention to changes in your body when starting these drugs. Your rheumatologist will review the warnings as well as precautions prior to taking the medication.