A pilot trial using topical regular crystalline insulin vs. aqueous zinc solution for uncomplicated cutaneous wound healing: Impact on quality of life

Topical Insulin Eye Drops: Stability and Safety of Two Compounded Formulations for Treating Persistent Corneal Epithelial Defects

Compounded insulin eye drops were prepared at 1 IU/mL from commercially available subcutaneous insulin by dilution in saline solution or artificial tears. Physicochemical characterization and in vitro tolerance testing in human and conjunctival cells were followed by a 28-day short-term stability study under various conditions. The formulations were isotonic (280-300 mOsm/L), had a pH close to neutral (7-8), medium surface-tension values (<56 MN/m-1), and low (≈1 mPa·s) and medium (≈5 mPa·s) viscosities (compounded normal saline solution and artificial tear-based preparation, respectively). These values remained stable for 28 days under refrigeration. Microbiological stability was also excellent. Insulin potency remained in the 90-110% range in the compounded formulations containing normal saline solution when stored at 2-8 °C for 28 days, while it decreased in those based on artificial tears. Although both formulations were well tolerated in vitro, the compounded insulin diluted in a normal saline solution exhibited better cell tolerance. Preliminary data in humans showed that insulin in saline solution was an effective and safe treatment for persistent corneal epithelial defects. Compounded insulin eye drops diluted in normal saline solution could, therefore, constitute an emergent therapy for the treatment of persistent corneal epithelial defects.

Natural and Synthetic Drugs Approached for the Treatment of Recurrent Aphthous Stomatitis Over the Last Decade

Recurrent aphthous stomatitis (RAS) refers to a sore and frequently recurring inflammation of the oral tissues, distinguished by the presence of small ulcers that cause significant discomfort and cannot be attributed to any underlying disease. Different treatments have been used for RAS. This review aims to provide a comprehensive overview of the treatment options over the past decade for recurrent aphthous stomatitis (RAS), encompassing both natural and synthetic treatments. It will utilize clinical efficacy studies conducted in vivo and in vitro, along with a focus on the pharmaceutical approach through advancements in drug delivery development. We conducted a thorough literature search from 2013 to 2023 in prominent databases such as PubMed, Scopus, and Cochrane, utilizing appropriate keywords of recurrent aphthous stomatitis, and treatment. A total of 53 clinical trials with 3022 patients were included, with 35 using natural materials in their research and a total of 16 articles discussing RAS treatment using synthetic materials. All the clinical trials showed that natural and synthetic medicines seemed to benefit RAS patients by reducing pain score, ulcer size, and number of ulcers and shortening the healing duration.

Efficacy of the Novel Formulation of Topical Liothyronine and Liothyronine-insulin in Mild to Moderate Diabetic Foot Ulcer: A Randomized, Triple-blind Clinical Trial

BACKGROUND

Diabetic foot ulcer (DFU) is one of the challenging complications of chronic diabetes.

OBJECTIVE

The study aimed to investigate whether liothyronine (T3) and liothyronineinsulin (T3/Ins) topical preparations could significantly reduce the healing time of DFU.

METHODS

A prospective, randomized, placebo-controlled, patient-blinded clinical trial was conducted on patients with mild to moderate DFU, over a lesion area of no greater than 100 cm2. The patients were randomized to receive T3, T3/Ins, or honey cream 10% as the routine of care twice a day. Patients were examined for tissue healing weekly for 4 weeks, or until the total lesion clearance was observed, whichever was earlier.

RESULTS

Of 147 patients with DFUs, 78 patients (26 per group) completed the study and were included in the final evaluation. At the time of study termination, all participants in each of the T3 or T3/Ins groups were free of symptoms based on the REEDA score, while about 40% of participants in the control group were detected with each of grades 1, 2, or 3. A significant difference was observed on days 7, 14, and 21 of consumption of topical preparations (p-value < 0.001). The mean time to complete wound closure in the routine care group was about 60.6 days, while it was 15.9 and 16.4 days in T3 and T3/Ins groups, respectively. Within the T3 and T3/Ins groups, significant earlier wound closure was detected at day 28 (p-value < 0.001).

CONCLUSION

T3 or T3/Ins topical preparations are effective for wound healing and acceleration of wound closure in mild to moderate DFUs.

The Potential of Sheep or Camel Milk Constituents to Contribute to Novel Dressings for Diabetic Wounds

Impaired wound healing is a complication of diabetes, which constitutes a serious problem in clinical practice. Currently, there is a high demand on the market for local treatment options for difficult-to-heal wounds caused by diabetes. The development of dressings that accelerate wound healing has recently been the subject of much research. Sheep and camel milk is gaining importance due to the content of many bioactive substances with health-promoting effects, such as insulin, LF, proline, or CLA. Sheep and camel milk proteins are a promising source of insulin, antidiabetic, and antihypertensive peptides. Numerous studies show that local administration of insulin has a significant impact on the healing of diabetic wounds. Sheep and camel milk, due to the highest LF content among ruminants, reduces autoimmune inflammatory processes and protects against bacterial and viral infections in the wound environment. Sheep's milk has the highest content of proline and CLA, and their addition to a hydrogel dressing can help in the development of an effective dressing material. The production of hydrogel dressings containing sheep and camel milk, which are naturally rich in the bioactive substances presented in this review, may be a promising step in the market of specialized dressings for difficult-to-heal diabetic wounds.

Local Insulin Improves Wound Healing: A Systematic Review and Bayesian Network Meta-Analysis

BACKGROUND

Wounds are a significant health issue, and reliable and safe strategies to promote repair are needed. Clinical trials have demonstrated that local insulin promotes healing in acute and chronic wounds (ie, reductions of 7% to 40% versus placebo). However, the trials' sample sizes have prevented drawing solid conclusions. Furthermore, no analysis has focused on safety concerns (ie, hypoglycemia). Under the hypothesis that local insulin promotes healing through proangiogenic effects and cellular recruitment, the aim of this systematic review and network meta-analysis (NMA) was to assess its safety and relative effectiveness using a Bayesian approach.

METHODS

Medline, CENTRAL, Embase, Scopus, LILACS, and gray literature sources were searched for human studies assessing the local use of insulin versus any comparator since inception to October of 2020. Data on glucose changes and adverse events, wound and treatment characteristics, and healing outcomes were extracted, and an NMA was conducted.

RESULTS

A total of 949 reports were found, of which 23 ( n = 1240 patients) were included in the NMA. The studies evaluated six different therapies, and most comparisons were against placebo. NMA showed -1.8 mg/dL blood glucose level change with insulin and a lack of reported adverse events. Statistically significant clinical outcomes identified include reduction in wound size (-27%), increased healing rate (23 mm/day), reduction in Pressure Ulcer Scale for Healing scores (-2.7), -10 days to attain complete closure, and an odds ratio of 20 for complete wound closure with insulin use. Likewise, significantly increased neoangiogenesis (+30 vessels/mm 2 ) and granulation tissue (+25%) were also found.

CONCLUSION

Local insulin promotes wound healing without significant adverse events.

Localised insulin administration for wound healing in non-diabetic adults: A systematic review and meta-analysis of randomised controlled trials

Insulin has the potential to restore damaged skin and due to its affordability and global availability, it is an agent of interest when it comes to pioneering new remedies to accelerate wound healing. The aim of this study was to explore the efficacy and safety of localised insulin administration on wound healing in non-diabetic adults. Studies were systematically searched, using the electronic databases Embase, Ovid MEDLINE and PubMed, screened, and extracted by two independent reviewers. A total of seven randomised controlled trials that met the inclusion criteria were analysed. Risk of bias was assessed using the Revised Cochrane Risk-of-Bias Tool for Randomised Trials and a meta-analysis was performed. The primary outcome, which explored rate of wound healing (mm2 /day), concluded that there was an overall significant mean improvement in the insulin treated group (IV = 11.84; 95% CI: 0.64-23.04; p = 0.04; I2  = 97%) compared to the control group. Secondary outcomes concluded that there is no statistical difference between the healing time (days) of the wound (IV = -5.40; 95% CI: -11.28 to 0.48; p = 0.07; I2  = 89%); there is a significant reduction in wound area in the insulin group; no adverse events were noted with the administration of localised insulin; quality of life improves drastically as the wound heals, irrespective of insulin. We conclude that although the study showed an improved wound healing rate, other parameters were not statistically significant. Therefore, larger prospective studies are warranted to fully explore the effects of insulin on different wounds, where an appropriate insulin regime can be developed for clinical practice.

Bubble-Channeling Electrophoresis of Honeycomb-Like Chitosan Composites

A chitosan composite with a vertical array of pore channels is fabricated via an electrophoretic deposition (EPD) technique. The composite consists of chitosan and polyethylene glycol, as well as nanoparticles of silver oxide and silver. The formation of hydrogen bubbles during EPD renders a localized increase of hydroxyl ions that engenders the precipitation of chitosan. In addition, chemical interactions among the constituents facilitate the establishment of vertical channels occupied by hydrogen bubbles that leads to the unique honeycomb-like microstructure; a composite with a porosity of 84%, channel diameter of 488 µm, and channel length of 2 mm. The chitosan composite demonstrates an impressive water uptake of 2100% and a two-stage slow release of silver. In mass transport analysis, both Disperse Red 13 and ZnO powders show a much enhanced transport rate over that of commercial gauze. Due to its excellent structural integrity and channel independence, the chitosan composite is evaluated in a passive suction mode for an adhesive force of 9.8 N (0.56 N cm^-2 ). The chitosan composite is flexible and is able to maintain sufficient adhesive force toward objects with different surface curvatures.

Efficacy of Human Adipose Derived Mesenchymal Stem Cells in Promoting Skin Wound Healing

Background

The aim of this pilot clinical study is to evaluate the efficacy of human adipose derived mesenchymal stem cells (HAMSCs) treatment for the wound healing with patients.

Methods

This study was a clinical trial to investigate the efficacy of human adipose derived mesenchymal stem cells treatment for the wound healing with patients. 346 patients with skin wounds attending the central hospital of Yue Yang were enrolled in the study, setting in the period from January 2016 to January 2021. Patients were randomly allocated into two groups: experimental group received treatment with human adipose derived mesenchymal stem cells for each 10 cm2 of wound and control group received conventional dressing with normal saline for each 10 cm2 of wound.

Results

No adverse events were recorded during the period of treatment. The granulation tissue coverage rate and thickness of granulation tissue after 10 days of treatment in experimental group were significantly improved compared with control group. Furthermore, the occurrence of bleeding of wound and suppurative wounds between two groups had significant difference (P < 0.05).

Conclusion

The data in this pilot study indicated that human adipose derived mesenchymal stem cells may be a safe and effective alternative therapy for wound healing. Moreover, larger, placebo-controlled, perspective studies are necessity to evaluate the efficacy and safety of human adipose derived mesenchymal stem cells treatment for wound healing patients.

Insulin Topical Application for Wound Healing in Nondiabetic Patients

BACKGROUND

Low-cost and safe strategies to improve wound healing will be of great social and economic value. The goal of this pilot clinical trial is aimed at analyzing how effective insulin therapy is at healing wounds in nondiabetic people.

METHODS

In this protocol research, 346 individuals were included. Patients were divided as 2 groups at random: experimental patients were given a ten-unit answer. For each 10 cm2 of wound, insulin was injected in solution with 1 mL 0.9 percent saline, whereas the control group got a standard dressing with normal saline.

RESULTS

During the therapy period, no adverse effects were reported. After insulin therapy, no substantial insulin-related side effects were reduced. After 10 days of therapy, the experimental group's granulation tissue coverage rate and thickness were considerably improved as compared to control. Furthermore, a momentous difference in the occurrence of wound bleeding and suppurative wounds between the two groups (P = 0.05).

CONCLUSION

The results of this pilot research suggest that insulin injections could harmless and effective alternative therapy for wound healing in nondiabetic individuals and that larger, placebo-controlled trials are needed to evaluate effectiveness and safety of insulin treatment in wound healing patients.

Effects of topical insulin on wound healing: a meta-analysis of animal and clinical studies

Various researches have reported that the application of topical insulin improves wound healing. Considering the lack of a quantitative comprehensive research on this matter, we conducted a meta-analysis of clinical research and experimental animal studies. Prospective and randomized controlled trials of PubMed, Embase, and Cochrane Library were conducted using appropriate search strategies to compare the effectiveness of topical application of saline and insulin on wounds. The standardized mean difference was calculated as follows: wound healing time, wound healing rate, wound area, and the percentage of wound contraction. Each study used the Cochrane risk-of-bias tool and RevMan 5.3 software to create aggregated assessments and forest plots. The quality of evidence was evaluated in accordance with the methods of the Grading of Recommendations, Assessment, Development and Evaluation working group. Four clinical and nine animal studies eligible for inclusion were included in the meta-analysis. The assessments for clinical studies were as follows: wound healing time, -2.48 [-3.44, -1.51] and wound healing rate, 22.23 [18.17, 26.28]. Meanwhile, for animal studies, the following assessments were noted: wound healing time, -1.27 [-1.75, -0.79]; wound contraction rate, 15.91 [13.88, 17.95]; and wound area, -19.3 [-21.16, -17.44]. For the measurement of the following results, only one animal study was performed, pericyte recruitment of microvessels. Based on the analysis, it can be preliminarily judged that application of topical insulin can aid wound healing.

ROS-responsive capsules engineered from EGCG-Zinc networks improve therapeutic angiogenesis in mouse limb ischemia

The successful treatment of limb ischemia requires that promote angiogenesis along with microenvironment improvement. Zinc ions have been reported to stimulate angiogenesis, but application was limited to the toxicity concerns. We hypothesized that zinc based metal-EGCG capsule (EGCG/Zn Ps) can achieve sustained release Zn²⁺ resulting in reduced toxicity and improve angiogenesis as well as the improvement of microenvironment by ROS scavenging of EGCG. The surface morphology, zeta potential, infrared absorbance peaks and zinc ion release profile of the EGCG/Zn Ps were measured. In vitro, EGCG/Zn showed significantly antioxidant, anti-inflammatory and induced cell migration effect. In addition, EGCG/Zn Ps enabled the sustained release of zinc ions, which reduced cytotoxicity and enhanced the secretion of vascular endothelial growth factor (VEGF) in vitro and in vivo. In mouse models of limb ischemia, EGCG/Zn Ps promoted angiogenesis and cell proliferation in ischemic tissues. Moreover, EGCG/Zn Ps group exhibited the most significant recovery of limb ischemic score, limb temperature and blood flow than other groups. In conclusion, EGCG/Zn Ps is a safe and promising approach to combine the merit of Zn²⁺ and EGCG, thus enabling the direct application to limb ischemia.

•

Metal-polyphenol networks have been firstly applied in the Limb ischemic disease.

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EGCG improve the microenvironment of ischemic whereas Zinc exerts angiogenic property.

•The slowly release of zinc ions were achieved, resulting in better biocompatibility.

The Effect of Zinc on Post-neurosurgical Wound Healing: A Review

The aim of this article is to explore neurosurgeons' knowledge and understanding of the physiology of zinc and provide current information about the role zinc plays in post-neurological wound healing. We review several medical journals and bring together the most updated information related to lesion-healing after surgery.

Effects of Topical Insulin on Wound Healing: A Review of Animal and Human Evidences

Wound healing is a complex biological process that repairs damaged tissues and restores skin integrity. Insulin, a potent factor of wound healing, has been reported for nearly a century to induce rapid recovery of various wounds, as shown by numerous human and animal studies. Although many studies have addressed the healing effect of systemic insulin on burn wound, only few have investigated the efficacy of topical insulin. Thus, this study aimed to review evidence of the effects of topical insulin on wound healing, including on diabetic and non-diabetic wounds. The presented animal and clinical studies support that topical insulin improves wound healing through several mechanisms without causing side effects. Additionally, various wound dressings accelerate the wound healing with controlled and sustained delivery of bioactive insulin. Therefore, topical insulin has been appreciated in field of wound healing, and further studies are needed to improve our understanding of the role of insulin in the healing of various wounds.

Topical insulin-liposomal formulation in management of recurrent aphthous ulcers: A randomized placebo-controlled trial

AIM

To evaluate the effectiveness of topical insulin-liposomal gel in aphthous ulcer treatment.

METHODS

80 participants with minor aphthous ulcers were randomly divided to receive either topical insulin-liposomal gel or placebo gel (once daily) for 6 days. Assessment of outcomes included visual analog scale (VAS) for pain (primary outcome), and secondary outcomes included ulcer duration and impact of treatment on quality of life using the Oral Health Impact Profile 14 (OHIP-14). Testing of the outcomes was carried out at 1, 2, 3, 4 and 6 days after treatment for VAS and at 6 days for OHIP-14.

RESULTS

For pain scores, the test group showed a significant decrease by time, this was evident from day 1 (P < .001); at day 3, median and interquartile range (IQR) values were 0 (0-1). For the placebo group, a non-significant change by time was reported between baseline and day 1; at day 3, the median value was 7 (IQR, 7-9). The test group showed significantly lower mean duration than the placebo group (P < .001). OHIP-14 scores after 6 days showed that the test group had a significantly lower score than placebo (P < .001).

CONCLUSIONS

Topical insulin-liposomal formulation showed marked effectiveness in management of aphthous ulcers.

Ameliorative Effect Of Zinc Oxide Nanoparticles Against Dermal Toxicity Induced By Lead Oxide In Rats

Background

Recently, several studies demonstrate the possible role of zinc oxide (ZnO) in the protection of several skin diseases, but less is known about the role of ZnO nanoparticles in the inflammatory skin disease. So, this study was designed to confirm the pivotal role of the nano zinc oxide cream in the alleviation of lead oxide (PbO) induced-allergic dermatitis in rats.

Materials and methods

Two concentrations (1% and 6%) of ZnONPs creams were prepared and characterized prior to being used in the study. A total number of 30 male Wistar rats were randomly divided into six groups. Group 1 (negative control), groups 2&3 (either 1% or 6% ZnONPs control groups), group 4 (PbO), groups 5&6 (co-treatment of each ZnONPs concentration+PbO). All rats in different groups were observed daily to determine the severity of dermal gross lesions. Histopathological studies, mRNA analysis, and oxidative stress evaluations were performed on the affected skin tissue. Immunohistochemical studies were performed to evaluate the expression of cluster of differentiation CD4, CD8 and intercellular adhesion molecules ICAM-1 in different groups.

Results

PbO caused extensive skin oxidative damage manifested by a significant increase in MDA level with a decrease in GSH content and CAT activity. The results of histopathological and immunohistochemical examinations revealed that topical application of PbO for 14 days led to severe allergic dermatitis with remarkable elevations in the number of CD4+ T-helper, CD8+ T-cytotoxic lymphocytes, and ICAM-1 expression. On the other hand, noticeable improvements were recorded in all the previous toxicopathological parameters among the groups treated by either 1% or 6% ZnO-NPs cream. However, the best results were observed in the group treated with 1% ZnO-NPs cream.

Conclusion

Our findings suggest that 1% of ZnO-NPs cream is safe when applied topically on the inflamed skin. Moreover, it had anti-inflammatory and antioxidant effects so that, it is recommended to use the 1% ZnO-NPs cream to avert the dermal toxicity-induced by PbO.

Zinc in Wound Healing Modulation

Wound care is a major healthcare expenditure. Treatment of burns, surgical and trauma wounds, diabetic lower limb ulcers and skin wounds is a major medical challenge with current therapies largely focused on supportive care measures. Successful wound repair requires a series of tightly coordinated steps including coagulation, inflammation, angiogenesis, new tissue formation and extracellular matrix remodelling. Zinc is an essential trace element (micronutrient) which plays important roles in human physiology. Zinc is a cofactor for many metalloenzymes required for cell membrane repair, cell proliferation, growth and immune system function. The pathological effects of zinc deficiency include the occurrence of skin lesions, growth retardation, impaired immune function and compromised would healing. Here, we discuss investigations on the cellular and molecular mechanisms of zinc in modulating the wound healing process. Knowledge gained from this body of research will help to translate these findings into future clinical management of wound healing.

Effects of insulin on wound healing: A review of animal and human evidences

AIMS

Several studies have indicated that insulin that is used in reducing blood glucose is also affective on wound healing by various mechanisms. To understand the outcomes of insulin therapy on wound healing, a meta-analysis and systematic review was performed.

MAIN METHODS

The Cochrane library, PubMed, and Science Direct were searched for the literature published from January the 1st 1990 to September the 30th 2016. Twelve animals and nine clinical studies were included. A quantitative and qualitative review was performed on the clinical trials and the animal studies were comprehensively overviewed. Statistical analysis for development of granulation tissue, microvessel density, and time of healing was conducted in this systematic review.

KEY FINDINGS

The animal studies revealed that treatment with topical insulin lead to faster wound contraction and re-epithelialization. Meta-analysis of wound studies revealed that insulin therapy is significantly favored for growth of granulation tissue. Based on these findings, insulin enhanced development of granulation tissue on day 7 after treatment. The meta-analysis studies indicated significant reduction in time of healing in the patients treated with insulin. These studies also disclosed that the new vessels were observable from five days after injection in the treated group, compared to the control animals that developed significantly at later stage.

SIGNIFICANCE

Insulin is a low cost growth factor and can be considered as a therapeutic agent in wound healing. However, further studies are necessary to gain a better understanding of the role of insulin in wound healing.

Efficacy of topical insulin in wound healing: A preliminary systematic review and meta-analysis of randomized controlled trials

Topical insulin has been shown to promote wound healing in various studies. Considering the absence of a systematic review and quantitative synthesis on the same, the present study was carried out. Using an appropriate search strategy, electronic databases were searched for randomized controlled trials that have compared topical application of insulin in wounds with normal saline. Standardize mean differences were calculated for the following outcome measures: healing rate of ulcers/wound, percent granulation tissue growth, microvessel density, time to heal, wound area and ulcer severity score. Cochrane's risk of bias tool was used for each of the studies and RevMan 5.3 software was used to generate the pooled estimates and Forest plots. The quality of evidence was assessed by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) working group approach. A total of 8 studies were found eligible to be included in this review and 7 for the meta-analysis. The pooled estimates were as follows: healing rate-0.04 [-1.38, 1.46]; percent granulation tissue-10.99 [-10.07, 32.06], microvessel density-3.01 [-1.67, 7.69] and wound area--6.59 [-9.7, -3.48]. There was only one study for each of the following outcome measures: time to heal and ulcer severity score. Hence, pooling of the results was not attempted for these outcome measures. The studies conducted in this field were preliminary and it was difficult to draw any conclusion regarding the use of insulin topically for wound healing.

Clinical study on local application of low-dose insulin for promoting wound healing after operation for deep burns

Transplanted free skin flaps are often needed to treat deep burns; their survival, however, is less than optimal. This study examined whether local low-dose insulin injections can promote flap survival and wound healing after surgery. A total of 165 patients who underwent free skin flap transplantation for simple deep burns were enrolled in the study and divided into 5 groups of 33 patients each: Blank control group (no local subcutaneous drug injections), saline control group (saline injections), low-dose insulin group (0.5 units regular insulin injections), medium-dose group (1.0 units regular insulin injections) and high-dose group (2.0 units regular insulin injections). Wound healing and flap survival conditions were assessed and compared among groups. The best wound healing rate found was that of the low-dose insulin injection group where all the parameters measured improved significantly: The healing time was shorter; the blood flow volume, the flap survival, the number of fibroblasts and new vessels increased; the re-epithelialization occurred faster; the infiltration of inflammatory cells was reduced; the expression levels of heat shock protein-90, vascular endothelial growth factor, transforming growth factor-β and interleukin-1 were higher; and the plasma glucose levels only fluctuated slightly. The results clearly demonstrate that a local low-dose insulin regime after flap transplantation can accelerate the healing time and improve the surgical outcome without exerting detrimental secondary effects on the glucose plasma level of deep burn patients.

Diabetes medications: Impact on inflammation and wound healing

Chronic wounds are a common complication in patients with diabetes that often lead to amputation. These non-healing wounds are described as being stuck in a persistent inflammatory state characterized by accumulation of pro-inflammatory macrophages, cytokines and proteases. Some medications approved for management of type 2 diabetes have demonstrated anti-inflammatory properties independent of their marketed insulinotropic effects and thus have underappreciated potential to promote wound healing. In this review, the potential for insulin, metformin, specific sulfonylureas, thiazolidinediones, and dipeptidyl peptidase-4 inhibitors to promote healing is evaluated by reviewing human and animal studies on inflammation and wound healing. The available evidence indicates that diabetic medications have potential to prevent wounds from becoming arrested in the inflammatory stage of healing and to promote wound healing by downregulating pro-inflammatory cytokines, upregulating growth factors, lowering matrix metalloproteinases, stimulating angiogenesis, and increasing epithelization. However, no clinical recommendations currently exist on the potential for specific diabetic medications to impact healing of chronic wounds. Thus, we encourage further research that may guide physicians on providing personalized diabetes treatments that achieve glycemic goals while promoting healing in patients with chronic wounds.

Targeted localized use of therapeutic antibodies: a review of non-systemic, topical and oral applications

Therapeutic antibodies provide important tools in the "medicine chest" of today's clinician for the treatment of a range of disorders. Typically monoclonal or polyclonal antibodies are administered in large doses, either directly or indirectly into the circulation, via a systemic route which is well suited for disseminated ailments. Diseases confined within a specific localized tissue, however, may be treated more effectively and at reduced cost by a delivery system which targets directly the affected area. To explore the advantages of the local administration of antibodies, we reviewed current alternative, non-systemic delivery approaches which are in clinical use, being trialed or developed. These less conventional approaches comprise: (a) local injections, (b) topical and (c) peroral administration routes. Local delivery includes intra-ocular injections into the vitreal humor (i.e. Ranibizumab for age-related macular degeneration), subconjunctival injections (e.g. Bevacizumab for corneal neovascularization), intra-articular joint injections (i.e. anti-TNF alpha antibody for persistent inflammatory monoarthritis) and intratumoral or peritumoral injections (e.g. Ipilimumab for cancer). A range of other strategies, such as the local use of antibacterial antibodies, are also presented. Local injections of antibodies utilize doses which range from 1/10th to 1/100th of the required systemic dose therefore reducing both side-effects and treatment costs. In addition, any therapeutic antibody escaping from the local site of disease into the systemic circulation is immediately diluted within the large blood volume, further lowering the potential for unwanted effects. Needle-free topical application routes become an option when the condition is restricted locally to an external surface. The topical route may potentially be utilized in the form of eye drops for infections or corneal neovascularization or be applied to diseased skin for psoriasis, dermatitis, pyoderma gangrenosum, antibiotic resistant bacterial infections or ulcerated wounds. Diseases confined to the gastrointestinal tract can be targeted directly by applying antibody via the injection-free peroral route. The gastrointestinal tract is unusual in that its natural immuno-tolerant nature ensures the long-term safety of repeatedly ingesting heterologous antiserum or antibody materials. Without the stringent regulatory, purity and clean room requirements of manufacturing parenteral (injectable) antibodies, production costs are minimal, with the potential for more direct low-cost targeting of gastrointestinal diseases, especially with those caused by problematic antibiotic resistant or toxigenic bacteria (e.g. Clostridium difficile, Helicobacter pylori), viruses (e.g. rotavirus, norovirus) or inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease). Use of the oral route has previously been hindered by excessive antibody digestion within the gastrointestinal tract; however, this limitation may be overcome by intelligently applying one or more strategies (i.e. decoy proteins, masking therapeutic antibody cleavage sites, pH modulation, enzyme inhibition or encapsulation). These aspects are additionally discussed in this review and novel insights also provided. With the development of new applications via local injections, topical and peroral routes, it is envisaged that an extended range of ailments will increasingly fall within the clinical scope of therapeutic antibodies further expanding this market.