Chronic wounds represent a significant global healthcare challenge affecting millions of patients and costing billions of dollars annually. These non-healing wounds are characterized by persistent inflammation, aberrant microenvironments, and defective tissue repair responses.
Recent advances in wound healing biology have illuminated crucial roles for interleukins in inflammatory regulation and demonstrated promising outcomes with dehydrated human amnion/chorion membrane (dHACM) for managing recalcitrant wounds.
This white paper examines the interplay between interleukins, particularly IL-1β, and the therapeutic potential of dHACM in addressing the complex pathophysiology of chronic wounds, with a focus on diabetic foot ulcers and venous leg ulcers.
Understanding Chronic Wound Pathophysiology
Normal wound healing progresses through precisely orchestrated phases: hemostasis, inflammation, proliferation, and remodeling. Each phase requires specific cellular and molecular events to advance healing. In chronic wounds, however, this progression stalls, often becoming trapped in a persistent inflammatory state that prevents advancement to subsequent healing phases. This stalled healing process is particularly evident in wounds associated with underlying conditions such as diabetes, venous insufficiency, or pressure injuries.
Chronic, or delayed healing, wounds are characterized by an aberrant and hostile wound microenvironment, including persistent inflammation, cellular dysfunction, and biochemical imbalances 2. This inhospitable environment prevents the normal cascade of cellular activities necessary for tissue repair and regeneration. The persistence of inflammation represents a critical barrier to healing, creating a self-perpetuating cycle of tissue damage and impaired repair. Extended inflammatory phases lead to continued recruitment of proinflammatory cells, production of inflammatory mediators, and elevated levels of destructive enzymes that degrade extracellular matrix components and growth factors needed for healing.
In diabetic wounds, this pathophysiological state is exemplified by persistent inflammation and demonstrably defective tissue repair responses 1. The inflammatory microenvironment of diabetic wounds features prolonged accumulation of proinflammatory macrophages and elevated levels of proinflammatory cytokines, particularly interleukins. These conditions establish a hostile wound environment that actively impedes the normal healing cascade rather than merely failing to support it. This understanding of chronic wound pathophysiology has led to increased interest in therapeutic approaches that directly address the underlying inflammatory dysregulation.
The Critical Role of Interleukins in Chronic Wound Inflammation
Interleukins constitute a large family of cytokines that regulate various aspects of inflammation and immunity. In wound healing contexts, specific interleukins critically influence the initiation, maintenance, and resolution of inflammation. Research has particularly identified interleukin-1β (IL-1β) as a key mediator in chronic wound inflammation, especially in diabetic wounds. Studies demonstrate that macrophages isolated from wounds in both diabetic humans and mice exhibit proinflammatory phenotypes with elevated expression and secretion of IL-1β1. This suggests IL-1β serves not merely as a byproduct of inflammation but actively contributes to perpetuating the inflammatory state.
The diabetic wound environment appears remarkably self-sustaining in its inflammatory characteristics. In vitro studies have shown that conditioned medium from both mouse and human diabetic wounds upregulates expression of proinflammatory genes while simultaneously downregulating expression of prohealing factors in cultured macrophages 1. This creates a feed-forward loop where inflammation generates additional inflammation, preventing transition to later healing phases. This finding illuminates why chronic wounds remain resistant to standard interventions that do not address this fundamental inflammatory dysregulation.
The hypothesis that IL-1β participates in a proinflammatory positive feedback loop sustaining persistent proinflammatory wound macrophage phenotypes has significant therapeutic implications. Research demonstrates that inhibiting the IL-1β pathway using neutralizing antibodies blocks the conditioned medium-induced upregulation of proinflammatory genes and downregulation of prohealing factors1. Furthermore, studies using macrophages from IL-1 receptor knockout mice showed similar protective effects against the proinflammatory influence of diabetic wound environments. These findings suggest that interrupting IL-1β signaling could potentially disrupt the persistent inflammatory cycle characteristic of chronic wounds.
Importantly, in vivo research has provided compelling evidence for IL-1β inhibition’s therapeutic potential. When researchers inhibited the IL-1β pathway in wounds of diabetic mice using neutralizing antibodies, they observed a remarkable phenotypic switch in wound macrophages from proinflammatory to healing-associated states1. This immunological shift was accompanied by increased levels of wound growth factors and significantly improved healing outcomes, supporting the concept that targeting the IL-1β pathway represents a promising therapeutic approach for improving diabetic wound healing.
Dehydrated Human Amnion/Chorion Membrane: Composition and Biological Properties
Dehydrated human amnion/chorion membrane (dHACM) represents an advanced wound care product derived from donated human placental tissues. Through proprietary processing methods such as the PURION® process, dHACM preserves the structural integrity and biological activity of these tissues while allowing for practical clinical application with extended shelf life. The composition of dHACM includes both structural components that provide scaffolding for cellular activities and an array of bioactive molecules that actively influence the wound healing environment.
The structural elements of dHACM comprise a collagen-rich extracellular matrix that provides a scaffold for cell migration and attachment. This matrix contains various types of collagen, fibronectin, laminin, and proteoglycans, collectively creating an environment conducive to cellular processes involved in wound healing. Beyond these structural components, dHACM contains a rich array of biologically active molecules that regulate various aspects of the wound healing process, including growth factors such as epidermal growth factor (EGF), transforming growth factor beta (TGF-β), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF) 23.
Research has demonstrated that PURION® processed dHACM retains biologically active components despite processing. Studies have shown that dHACM contains one or more soluble factors capable of stimulating mesenchymal stem cell migration and recruitment 3. Additionally, dHACM has been shown to retain soluble biological molecules that promote human dermal fibroblast proliferation and migration of human mesenchymal stem cells3. These findings establish that properly processed dHACM preserves its biological activities relevant to wound healing.
Specifically, dHACM has been shown to positively affect four distinct and pivotal physiological processes intimately involved in wound healing: cell proliferation, inflammation modulation, metalloproteinase activity regulation, and recruitment of progenitor cells 3. The preservation of these biological properties distinguishes dHACM from conventional wound dressings, positioning it as a “biological dressing” with the potential to actively influence the wound environment rather than merely providing passive coverage. This bioactivity forms the basis for dHACM’s therapeutic applications in managing challenging chronic wounds that have proven resistant to standard care approaches.
Mechanisms of Action of dHACM in Wound Healing
The therapeutic effects of dHACM in chronic wound management derive from multiple mechanisms of action that collectively address various aspects of impaired healing. Understanding these mechanisms provides insights into the biological basis for the clinical efficacy observed with dHACM application in challenging wounds.
Research has elucidated several key mechanisms through which dHACM promotes healing of chronic wounds.
One of the most significant mechanisms is dHACM’s ability to recruit stem cells to the wound site. Studies have demonstrated that dHACM contains stromal cell-derived factor 1 (SDF-1) and chemokine receptor type 4 (CXCR4), which function as stem cell recruitment and homing factors 2.
In vitro studies have confirmed that dHACM can attract stem cells and stimulate the migration of mesenchymal stem cells 2.
Furthermore, in vivo research has shown that stem cells home to sites of neovascularization when dHACM is applied, reflecting their role as endothelial progenitor cells 2.
This recruitment of endogenous stem cells distinguishes dHACM from cellular therapies that directly deliver cells to the wound, suggesting a potentially more sustainable regenerative approach that leverages the body’s own reparative capacity.
Angiogenesis, the formation of new blood vessels, represents another crucial process facilitated by dHACM. Studies have clearly demonstrated dHACM grafts’ ability to induce angiogenesis, associated with multiple proangiogenic factors present in and released by the dehydrated tissue with retained biological activity 2.
Moreover, research using conditioned media of dHACM has shown that it can stimulate the upregulated production of endogenous angiogenic factors by endothelial cells, supporting a paracrine amplifying effect that stimulates wound angiogenesis 2.
This promotion of vascularity addresses a fundamental requirement for wound healing, as adequate blood supply provides oxygen and nutrients essential for cellular activities and tissue regeneration.
dHACM also influences cellular proliferation and migration, essential processes in wound healing. The growth factors contained in dHACM, including EGF, TGF-β, and FGF, are known to stimulate epithelial cell migration and proliferation2. Factors such as PDGF-A and PDGF-B stimulate various metabolic processes, including protein and collagen synthesis, collagenase activity, and chemotaxis of fibroblasts and smooth muscle cells2. TGF-β has been shown to significantly increase type I collagen production by tendon sheath fibroblasts, which has implications for extracellular matrix remodeling during healing2. These effects collectively contribute to the formation of granulation tissue and eventual re-epithelialization of the wound.
The research findings suggest that dHACM functions through a paracrine model, releasing soluble factors that influence surrounding cells to create an environment favorable for healing3. This multifaceted approach addresses several key aspects of impaired healing in chronic wounds, potentially explaining the positive clinical outcomes observed with dHACM application. The combined effects on stem cell recruitment, angiogenesis, cell proliferation, and potentially inflammation modulation provide a comprehensive approach to overcoming the multiple barriers to healing present in chronic wounds.
Clinical Evidence for dHACM in Chronic Wound Management
The therapeutic potential of dHACM for chronic wound management is supported by a growing body of clinical evidence, particularly for diabetic foot ulcers and venous leg ulcers. These studies provide insights into the efficacy, optimal application protocols, and long-term outcomes associated with dHACM treatment in clinical settings. The consistent positive outcomes across multiple studies have established dHACM as an evidence-based approach for challenging wounds that have failed to respond to standard care.
Several randomized controlled trials have evaluated dHACM for diabetic foot ulcer management. In one prospective, randomized, single-center clinical trial, patients were randomized to receive either standard of care alone or standard of care with dHACM. The results demonstrated remarkable differences in healing outcomes between the groups. At 4 weeks, wounds in the standard of care group reduced in size by a mean of 32.0% ±43.7% compared to 97.1% ±7.0% in the dHACM group (P≤0.001)2. By 6 weeks, the disparities were even more pronounced, with wounds in the standard of care group actually increasing in size by 1.8% ±0.3%, while the dHACM group showed a mean wound size reduction of 98.4% ±5.8% (P≤0.001)2. The overall healing rates at 6 weeks were 92% for dHACM compared to just 8% for standard of care. The magnitude of the treatment effect was so substantial that the study was terminated early for ethical reasons, despite the relatively small sample size.
In a subsequent analysis, patients from the standard of care group who remained unhealed after 6 weeks were transitioned to dHACM treatment. This retrospective evaluation showed that these previously non-responsive wounds also exhibited accelerated healing with dHACM application, with 91% achieving complete healing by 12 weeks with biweekly applications2. This finding further supports dHACM’s efficacy even for recalcitrant wounds that have explicitly demonstrated resistance to standard care approaches. The mean wound chronicity was 21.1 ±12.4 weeks before dHACM treatment, indicating these were truly challenging, long-standing wounds unresponsive to conventional therapies.
The durability of healing represents a critical consideration for any wound therapy since recurrence frequently complicates chronic wound management. A follow-up study evaluated patients who had achieved complete healing with dHACM at 9 to 12 months after primary healing. Remarkably, 94.4% of ulcers (17 of 18) remained fully healed at this later time point2, suggesting that dHACM treatment may lead to durable wound closure, potentially by addressing underlying pathophysiological factors rather than merely providing temporary coverage. This finding has significant implications for the long-term efficacy and cost-effectiveness of dHACM therapy.
Optimization of application frequency is important for maximizing clinical outcomes while managing healthcare resources effectively. A randomized comparative study evaluated weekly versus biweekly application of dHACM in diabetic foot ulcers. Both regimens achieved high healing rates (92.5% overall), but the weekly application group demonstrated significantly faster healing (2.4 ±1.8 weeks) compared to the biweekly group (4.1 ±2.9 weeks) (P=0.039)2. This finding suggests a clinical preference for weekly application, as it resulted in more than 40% faster healing without requiring more grafts overall. The economic advantages of weekly application include fewer overall treatment visits and dressing changes at wound healing centers, despite the more frequent applications within a shorter timeframe.
Beyond diabetic foot ulcers, dHACM has shown efficacy in venous leg ulcers, which represent the largest category of ambulatory wounds in the United States. A multicenter randomized controlled trial evaluated dHACM combined with multilayered compression therapy versus compression therapy alone. At 4 weeks, 62% of patients in the dHACM group achieved greater than 40% wound closure, compared to 32% in the control group (P=0.005)2. The mean wound size reduction was 48.1% in the dHACM group versus 19.0% in the control group, demonstrating a significant advantage with dHACM treatment for this challenging wound type as well.
Synergistic Potential: Interleukin Modulation and dHACM
The pathophysiology of chronic wounds involves complex and interrelated factors, including persistent inflammation, impaired angiogenesis, deficient stem cell recruitment, and proteolytic imbalance. Given this complexity, therapeutic approaches that target multiple aspects of impaired healing may offer synergistic benefits. The potential combination of interleukin modulation strategies with dHACM application represents a particularly promising avenue for investigation that could address both inflammatory dysregulation and regenerative deficiencies simultaneously.
Interleukin-1β has been identified as a key mediator of persistent inflammation in diabetic wounds, contributing to a proinflammatory feedback loop that impedes healing1. Research has demonstrated that inhibiting the IL-1β pathway induces a phenotypic switch in wound macrophages from proinflammatory to healing-associated phenotypes, leading to improved healing outcomes1. This approach directly addresses the inflammatory component of chronic wounds that otherwise prevents progression through normal healing phases.
Meanwhile, dHACM has demonstrated multifaceted effects on wound healing, including stem cell recruitment, angiogenesis stimulation, cell proliferation enhancement, and potential modulation of inflammation23. While the specific effects of dHACM on interleukin pathways have not been fully elucidated, its overall impact on the wound environment may complement targeted anti-inflammatory effects of IL-1β inhibition or other interleukin-modulating approaches.
The potential synergy between these approaches lies in their complementary mechanisms of action. IL-1β inhibition may disrupt the proinflammatory feedback loop, creating an environment more conducive to healing, while dHACM provides the biological signals and structural elements necessary for tissue regeneration. By simultaneously addressing both the inflammatory obstacles to healing and providing the stimuli for regenerative processes, this combined approach could potentially accelerate healing rates and improve outcomes for patients with chronic wounds.
The biological properties of dHACM include retention of soluble factors that can positively affect cell proliferation, inflammation, metalloproteinase activity, and recruitment of progenitor cells—all physiological processes intimately involved in wound healing3. These properties suggest potential mechanisms through which dHACM might complement interleukin-targeted therapies. For instance, while IL-1β inhibition might reduce destructive inflammation, dHACM could simultaneously promote constructive cellular activities through its growth factors and structural components.
This concept of combinatorial approaches aligns with the emerging paradigm of personalized wound care, where therapeutic interventions are tailored to the specific pathophysiological characteristics of individual wounds. Such an approach recognizes that chronic wounds are heterogeneous in their underlying causes and manifestations, requiring customized treatment strategies for optimal outcomes. Future research should explore various combinations of inflammatory modulators and regenerative therapies to identify the most effective approaches for different wound types and patient populations.
Clinical Applications and Best Practices
Implementing advanced therapeutic approaches such as interleukin modulation and dHACM application in clinical practice requires careful consideration of patient selection, application protocols, monitoring strategies, and integration with standard care practices. Current evidence supports specific approaches that optimize outcomes while managing healthcare resources efficiently.
Patient selection is crucial for maximizing therapeutic benefits. Candidates for dHACM treatment typically include patients with chronic wounds that have failed to respond adequately to standard care. Clinical studies have focused primarily on diabetic foot ulcers of at least 4 weeks’ duration and venous leg ulcers that have demonstrated insufficient progress with conventional approaches2. Thorough assessment of underlying factors contributing to impaired healing—such as inadequate offloading, poor glycemic control in diabetic patients, or insufficient compression in venous ulcers—remains essential, as these issues must be addressed concurrently with advanced therapies to achieve optimal outcomes.
Application protocols for dHACM have been refined through clinical research. Evidence suggests that weekly application of dHACM yields faster healing compared to biweekly application for diabetic foot ulcers2. This finding has important clinical and economic implications, as faster healing reduces the total number of clinic visits and dressing changes required despite more frequent applications within a shorter timeframe. The typical application procedure involves standard wound bed preparation, placement of the dHACM graft directly on the wound surface, and coverage with appropriate secondary dressings based on wound characteristics and exudate levels.
Wound monitoring should include regular assessment of size, depth, and wound bed characteristics. Documentation with clinical photography helps track visual changes over time. Based on clinical trial data, significant reduction in wound size should typically be observed within the first 4 weeks of dHACM treatment2. If adequate progress is not observed within this timeframe, reassessment of the treatment approach may be warranted, including evaluation of patient compliance with adjunctive measures such as offloading or compression.
The durability of healing represents an important consideration in chronic wound management. Follow-up studies of dHACM-treated wounds have demonstrated impressive long-term results, with 94.4% of diabetic foot ulcers remaining healed at 9-12 months after initial closure2. This finding suggests that dHACM treatment may provide sustained benefits rather than merely temporary improvement. Continued monitoring after wound closure remains important, however, particularly for patients with ongoing risk factors for recurrence.
For interleukin-targeted therapies, which remain largely investigational for wound healing applications, clinical implementation would require additional considerations. These might include monitoring for systemic effects of cytokine modulation, potential interactions with other medications, and specialized assessment of inflammatory markers in the wound environment. As research advances in this area, specific protocols will need development based on emerging evidence.
The successful implementation of advanced wound care approaches requires a multidisciplinary team approach, including various specialists depending on wound etiology. This collaborative model ensures that all aspects of wound healing are addressed, from local wound care to management of systemic conditions that impact healing potential. Advanced wound care products like dHACM should be viewed as components of a comprehensive treatment strategy rather than standalone solutions, underscoring the continued importance of addressing fundamental aspects of wound care regardless of which advanced therapies are employed.
Conclusion
Chronic wounds represent a significant healthcare challenge characterized by persistent inflammation, aberrant cellular responses, and defective tissue repair mechanisms. The pathophysiological complexity of these wounds necessitates therapeutic approaches that address multiple aspects of impaired healing. Recent advances in understanding the role of interleukins in sustaining inflammation and the development of advanced biological therapies such as dHACM have opened new avenues for intervention that target fundamental aspects of chronic wound pathology.
Interleukin-1β has emerged as a key mediator in the persistent inflammatory state characteristic of chronic wounds, particularly in diabetic patients. Research has demonstrated that IL-1β participates in a proinflammatory positive feedback loop that sustains macrophage activation in a proinflammatory phenotype, preventing the transition to healing-associated states1. Experimental evidence shows that inhibiting the IL-1β pathway induces a phenotypic switch in wound macrophages, increases levels of growth factors, and improves healing outcomes, suggesting significant therapeutic potential for interleukin-targeted approaches.
Concurrently, dehydrated human amnion/chorion membrane has demonstrated remarkable efficacy in promoting healing of chronic wounds through multiple mechanisms. These include stem cell recruitment, angiogenesis stimulation, cell proliferation enhancement, and potential modulation of inflammatory processes23. Clinical evidence supporting dHACM’s use for diabetic foot ulcers and venous leg ulcers is substantial and growing, with randomized controlled trials consistently demonstrating accelerated healing compared to standard care alone. The durability of healing observed with dHACM treatment further supports its value as an advanced wound care option.
The convergence of these two approaches—interleukin modulation and dHACM application—represents a promising frontier in chronic wound management. By addressing both the inflammatory obstacles to healing and providing the biological signals necessary for tissue regeneration, this combined approach could potentially offer synergistic benefits for patients with recalcitrant wounds. Future research should explore this combination through well-designed studies to assess optimal implementation strategies and comparative efficacy against each treatment alone.
From a broader perspective, advances in understanding and treating chronic wounds reflect a shift toward biologically informed therapies that address underlying pathophysiology rather than merely providing passive coverage or debridement. This paradigm shift holds promise for improving outcomes for millions of patients affected by chronic wounds worldwide, reducing associated morbidity, and alleviating the substantial economic burden on healthcare systems. As our understanding of wound healing biology continues to evolve, so too will our therapeutic approaches, with increasing precision and efficacy in addressing this challenging clinical problem.
References
- https://diabetesjournals.org/diabetes/article/62/7/2579/33799/Blocking-Interleukin-1-Induces-a-Healing
- https://woundresearch.org/wp-content/uploads/2019/11/Use-of-Human-Amnion-for-Lower-Extremity-Repair.pdf
- https://pmc.ncbi.nlm.nih.gov/articles/PMC4228928/