Comparative study on the efficacy of PRP gel and UC‐MSCs gel as adjuvant therapies in the treatment of DFU wounds

Abstract

Background

Diabetic foot ulcer (DFU) is a common and serious complication of diabetes, and its treatment is challenging. Platelet‐rich plasma (PRP) gel and umbilical cord mesenchymal stem cells (UC‐MSCs) gel have been concerned as new therapies for DFU in recent years, and comparative studies on the efficacy and mechanisms of these methods, however, are rarely reported.

Methods

Thirty patients with DFU were selected and divided into the PRP group and the UC‐MSCs group, and wound healing, foot blood vessels (ABI index), infection index (CRP), neuropathy symptoms (TCSS score), and foot skin temperature before and after treatment were compared between the two groups. SPSS 21.0 was used for statistical analysis.

Results

The results showed that the efficacy of the UC‐MSCs gel group was significantly better than that of the PRP group in terms of wound healing rate, time to complete wound closure, ABI index, CRP level and TCSS score. No statistically significant difference in foot skin temperature was observed between the two groups.

Conclusion

The efficacy of UC‐MSCs gel is significantly superior to that of PRP gel in the treatment of DFU, with shortened time to complete wound closure, increased wound healing rate, better pain and infection control, and improved vascular and neurological symptoms.

1. INTRODUCTION

The prevalence of chronical diseases is increasing due to the increased aging population worldwide. According to the data of the International Diabetes Federation, the number of diabetic patients in the world has increased dramatically, ¹ and 463 million people suffered from diabetes worldwide in 2019. ² It is estimated that the number of diabetic patients in China will reach 164 million in 2030, ranking first in the world. ³

Diabetic foot ulcer (DFU) is a common complication of diabetes, with an incidence of 15–25% in the diabetic population. ⁴ DFU is associated with various symptoms, such as rest pain, intermittent claudication, and ulcerative infections, seriously affecting quality of life of patients. DFU is also one of the leading causes for amputation and death in individuals with diabetes. The treatment of DFU is challenged by the insufficiency of growth factors in the wound, and the hyperglycemia and hypercoagulability in diabetic patients also delay the wound healing. Therefore, it is essential to find effective methods to promote DFU healing.

Studies in recent years begun to focus on growth factors, cytokines, inflammatory factors, and internal environment metabolic disorders during DFU wound healing process, ⁵ , ⁶ leading to the development of various new treatment methods, including stem cell therapies and recombinant human growth factor‐based therapies. ⁷ Stem cell therapies can promote neovascularization via paracrine mechanisms to improve blood supply in DFU patients. ⁸ For instance, gel prepared with umbilical cord mesenchymal stem cells (UC‐MSCs) can promote the healing, improve the blood supply and reduce inflammatory responses of the wound. In recombinant human growth factor‐based therapies, platelet‐rich plasma (PRP) is effective in promoting wound healing by increasing the level of growth factors in the wound of DFU patients. ⁹ , ¹⁰

Although PRP and stem cells act similarly in DFU treatment, their efficacies and underlying mechanisms are possibly different. Publications exploring the therapeutic effects of each method are often found in literature review, ¹¹ , ¹² and those comparing the therapeutic effects of the two treatments, however, have been rarely reported. The present study was designed to compare the efficacy of PRP gel and UC‐MSCs gel in the treatment of DFU, providing more evidence‐based medical evidence for the two treatments.

2. METHODS

2.1. Patient selection

A total of 30 patients admitted to the Department of Orthopedics, Yan'an Hospital, Kunming, China, for DFU wound debridement and treatment between November 2021 and November 2022 were selected. The sample size was calculated using the formula for the comparison of rates between two samples, and at least 30 patients were finally determined after preliminary testing and taking into account the dropout rate, with 15 in each of the PRP and UC‐MSCs groups. Inclusion criteria included patients who were diagnosed with type 1 or 2 diabetes, aged 18–65 years, with wounds occurred 4 weeks ago that located below the ankle on the plantar or dorsal surface of the foot with an ulcer area of 1—15 cm²; needed wound treatment; without consciousness disorders and mental illness; with certain reading, writing, and understanding abilities and no speech disorder; could take hypoglycemic drugs according to medical advice, with a stable level of blood glucose; and volunteered to participate in this study and signed informed consent. Exclusion criteria included patients with hemoglobin A1c level > 12%; evidence of active infection, including osteomyelitis or cellulitis; inadequate circulation in the affected foot as defined by an ankle‐brachial index(ABI) < 0.70 or > 1.30, or a toe‐brachial index ≤0.50 or a Doppler study showing insufficient arteriopalmus; exposed muscle, tendon, bone or joint capsule; consciousness disorders and mental illness; severe dysfunction of organs such as heart, liver, and kidney; and serious diseases, including malignant tumors and AIDS. Criteria for elimination and dropout included patients who did not cooperate with blood glucose management; voluntarily withdrew from the study; and died during treatment.

This study has been approved by the Ethics Committee of Yan'an Hospital in Kunming. UC‐MSCs were collected in accordance with ethical principles and laws and regulations. Prior to the start of the study, all patients were informed of the purpose, process, risks and benefits of the study, as well as their rights. After fully understanding the study, patients confirmed their voluntary participation in the study by signing informed consent forms.

2.2. Grouping and treatment

2.2.1. The PRP group

Preparation of PRP: 45 mL of blood was collected from the peripheral veins of patients, add 5 mL anticoagulant was added and mixed. The mixture (50 mL) was injected into a centrifuge tube and centrifuged for the first time. Platelets were collected from the tube to the lower one‐third of the cone. The platelets obtained were centrifuged gain. The centrifuge tube was removed after the second centrifugation, and the knob on the side of the PRP tube was open to collect the upper layer of PPP, with 10 mL of PRP left in the tube.

Treatment: After debridement, 10 mL PRP gel was applied to the wound surface and then covered with foam dressing. Wound healing was checked every 10 days until it was completely healed.

2.2.2. The UC‐MSCs group

Preparation of UC‐MSCs: Umbilical cord (UC) was aseptically collected from healthy normal pregnant women at birth giving. After rinsed with normal saline, the UC was cut into 1.0–2.0 cm segments and blood vessels were removed to avoid contamination from endothelial cells. The UC segments were further cut into 1 mm³ blocks and serum‐free medium was added. These tissue blocks were inoculated into a 75 cm² culture flask at a density of 1 × 10³/cm². The flask was incubated in a 37°C, 5% CO₂ incubator. The culture medium was replaced after 7 days and then once every 3–4 days. Fibroblast growth was observed after 2 weeks. The cells were digested by 0.05% trypsin and harvested, followed by subculture at a density of about 3 × 10⁴/cm². The Cells were serially subcultured for —three to five passages, and the morphology, cell surface biomarkers, differentiation ability, and pathogenic microorganisms of the cells were detected under sterile conditions.

Treatment: After debridement, UC‐MSCs gel was applied to the wound surface and then covered with foam dressing. Wound healing was checked every 10 days until it was completely healed.

2.3. Outcome measures

Wound areas of the two groups were measured and recorded on the day of wound treatment and every 10 days after treatment. Wound healing rate was calculated as (wound area before treatment‐wound area after treatment/wound area before treatment x100.00%), in which wound area was calculated by photographing and graphics software. The healing rate of scab was recorded as 100%.

Serum inflammatory factor C‐reactive protein (CRP) was determined for the two groups of patients on the day of wound treatment and after the wound was completely healed.

Peripheral neuropathy assessment was conducted for the two groups of patients on the day of treatment and every 3 days thereafter, using the Toronto Clinical Scoring System (TCSS), which included three parts, that is, neurological symptoms, neurological reflex, and sensory function test. ¹³

ABI ¹⁴ was measured for the two groups of patients on the day of wound treatment and every 3 days thereafter to assess the condition of foot blood vessels and rest pain.

Foot skin temperature was measured using a multifunctional infrared thermometer for the two groups of patients on the day of wound treatment and every day after treatment. The measurement frequency was twice a day at 8:00 and 20:00.

Time to complete wound closure (scab fell off) was recorded for the two groups.

2.4. Statistic analysis

Statistical analysis was conducted using SPSS 21.0, and the reliability of entry and quality of data were ensured by double entry using EpiDate 3.1. General data and disease‐related data were presented as frequency, percentage, proportion, and mean and standard deviation; enumeration data were presented as frequency and percentage and compared using Chi‐square test; measurement data with normal distribution and homogeneity of variance were presented as mean ± standard deviation and those with nonnormal distribution were compared using Wilcoxon rank sum test or t test; and the rank data were compared using non parametric rank sum test. Differences with a p value of < 0.05 were considered statistically significant.

3. RESULTS

3.1. Baseline data

Thirty patients were finally included in this study, with 15 in each of the PRP and UC MSCs groups. Statistical analysis of the general data found that there were no statistically significant differences in demographic and clinical data between the two groups. The baseline data were consistent and comparable (Table 1).

TABLE 1.

Comparison of general data between the two groups ($\overline{x}\pm s$, n = 30).

		the PRP group	the UC‐MSCs group	Statistics	p
Age (years)		53.60 ± 15.08	57.07 ± 10.74	−0.725 a	0.474
BMI (kg/m2)		25.86 ± 2.78	25.17 ± 2.35	0.732 a	0.470
Duration of diabetes (years)		11.2 ± 5.85	11.9 ± 9.36	−0.246 a	0.808
Sex	M	8	11	1.292 b	0.256
	F	7	4
Wagner grade	II	10	12	0.682 b	0.409
	III	5	3
Smoking history	Yes	5	3	0.682 b	0.409
	No	10	12
Drinking history	Yes	4	3	0.186 b	0.666
	No	11	12
Family history	Yes	2	3	0.240 b	0.624
	No	13	12
Regular medication	Yes	10	11	0.159 b	0.690
	No	5	4

^a t value.

^b χ^2.

3.2. Wound healing

Efficacies of wound healing of the two treatments in DFU patients were analyzed (Table 2), and it was found that both PRP and UC‐MSCs were effective in wound healing. Statistical analysis showed that the efficacy of wound healing in the UC‐MSCs group was significantly superior to that in the PRP group. Specifically, the wound healing rate of the UC‐MSCs group (93.93%) was significantly higher than that of the PRP group (77.20%), with a statistically significant difference (p < 0.001). In addition, the mean time to complete wound closure in the UC‐MSCs group (26.67 days) was significantly shorter than that in the PRP group (37.73 days), and the difference was statistically significant (p = 0.046).

TABLE 2.

Wound healing of the two groups ($\overline{x}\pm s$).

	the PRP group	the UC‐MSCs group	P25	M	P75	z a	p a
Area before treatment (cm2)	9.04 ± 4.50	8.75 ± 6.95	4.69	8.56	12.5	−0.602	0.547
Area 10 days after treatment (cm2)	1.73 ± 1.04	0.89 ± 2.58	0	0.63	2.06	−3.580	<0.001
Wound healing rate (%)	77.20 ± 16.09	93.93 ± 11.86	79.75	87.5	100	−3.323	0.001
Time to complete wound closure (days)	37.73 ± 10.58	26.67 ± 15.23	21.25	33	43.25	−1.993	0.046
z b	−3.408	−3.411
p b	0.001	0.001

^a Rank sum test for two random samples.

^b Paired rank sum test before and after treatment.

3.3. ABI index of the two groups of patients

The ABI indexes of the two groups of patients before treatment were in the normal low range, and returned to the normal level after treatment. However, there was no statistically significant difference in ABI index in the PRP group before and after treatment, and no significant difference in this index after treatment between the two groups (Table 3).

TABLE 3.

ABI of the two groups ($\overline{x}\pm s$).

Groups	Before treatment	After treatment	t	p
PRP group	0.99 ± 0.09	1.06 ± 0.13	−1.495	0.157
UC‐MSCs group	0.98 ± 0.10	1.07 ± 0.09	−2.894	0.012
t	0.115	−0.285
p	0.909	0.778

3.4. Serological examination of the two groups of patients

The CRP levels of the two groups decreased after treatment, and the difference before and after treatment was statistically significant in both groups. However, UC‐MSCs was more effective in reducing the CRP value. Specifically, no difference was observed between the two groups before treatment, and the post‐treatment CRP value of the UC‐MSCs group was significantly decreased compared with that of the PRP group, and the difference was statistically significant (p = 0.013) (Table 4).

TABLE 4.

CRP of the two groups (mg/L, $\overline{x}\pm s$).

Groups	Before treatment	After treatment	t	p
PRP group	33.71 ± 5.02	10.03 ± 1.90	19.979	<0.001
UC‐MSCs group	33.18 ± 4.84	8.06 ± 1.76	18.630	<0.001
t	0.279	2.695
P	0.783	0.013

3.5. TCSS score of the two groups of patients

The TCSS scores of the two groups of patients were improved by both treatment methods, especially in the symptom scores with a significant difference. Moreover, comparison between groups found that the post‐treatment TCSS score of the UC‐MSCs group was improved compared with that of the PRP groups (Tables 5 and 6).

TABLE 5.

Total TCSS scores of the two groups ($\overline{x}\pm s$).

Groups	Before treatment	After treatment	t	p
PRP group	8.40 ± 0.83	2.67 ± 1.05	15.446	<0.001
UC‐MSCs group	8.73 ± 0.70	1.60 ± 0.74	26.061	<0.001
t	−1.188	3.228
p	0.245	0.003

TABLE 6.

TCSS scores of the two groups before and after treatment($\overline{x}\pm s$).

	Symptoms		Reflex		Sensory test
Groups	Before treatment	After treatment	Before treatment	After treatment	Before treatment	After treatment
PRP group	3.20 ± 0.56	1.47 ± 0.92	2.60 ± 0.51	0.40 ± 0.51	2.60 ± 0.51	0.80 ± 0.41
UC‐MSCs group	3.40 ± 0.63	0.87 ± 0.52	2.87 ± 0.35	0.20 ± 0.41	2.47 ± 0.52	0.53 ± 0.52
t	−0.917	2.211	−1.673	1.183	0.714	1.560
p	0.367	0.035	0.105	0.247	0.481	0.130

3.6. Skin temperature tracking in the two groups of patients

Repeated measures analysis of variance revealed that there was no interaction between time factor and grouping in terms of skin temperature in the two groups (F = 1.411, p = 0.175), and the analysis of variance of intersubject effects showed no statistical significance (F = 0.018, p = 0.894). Therefore, it was not concluded that the two treatment methods had any effect on foot skin temperature in patients.

4. DISCUSSION

Wound repair is a dynamic, complex, and orderly process, in which the destruction of any step will affect wound healing. ¹⁵ , ¹⁶ Both PRP gel and UC‐MSCs gel have been widely studied in recent years. In the present study, PRP gel and UC‐MSCs gel in the treatment of DFU was compared, and it was found that both treatments were effective in treatment, with more advantages found in UC‐MSCs gel.

PRP, as an adjuvant therapy, has been often reported in evidence‐based publications, including meta‐analysis ¹⁷ and evidence summary. ¹⁸ PRP has natural advantages in wound repair by inhibiting the growth of microorganisms and inflammatory response and releasing growth factors in wound to promote the formation of blood vessels and peripheral nerves. However, stem cell adjuvant therapy has developed rapidly in recent years and become the research focus due to its ability to promote cytokine secretion, enhance extracellular matrix remodeling and angiogenesis, and differentiate into functional cells directly or through paracrine mechanism ¹⁹ to participate in wound healing. ²⁰ Stem cells currently used in wound healing mainly include mesenchymal stem cells (MSCs), ²¹ which can be subdivided into bone marrow MSCs, UC‐MSCs, and placenta‐derived MSCs. Different MSCs share similar features with subtle differences. However, due to their immune privileges, MSCs may not induce immune conflict between host cells and transplanted cells. ²² Compared with BM‐MSCs, the proliferation ability is increased and the expression of HLA‐ABC and HLA‐DR is decreased in UC‐MSCs. ²³ In addition, source stability and consistency of PD‐MSCs, which are isolated from different parts of placenta with slightly different features, are decreased compared with those of UC‐MSCs. ²⁴ Therefore, UC‐MSCs were selected and used in present study.

Comparison of previous studies found that time to complete wound closure is 40–60 days in DFU patients receiving conventional treatment, and 30 to 40 days in those receiving PRP treatment. ²⁵ Most of studies on stem cell therapy for DFU currently available are animal experiments and in vitro assays, and few clinical trials have been reported. In a phase I/II safety study, the average time to complete wound closure was 31.0 ± 10.7 days, ²⁶ and in a case report, the wound fully healed after 3 weeks of stem cell therapy. ²⁷ In the present study, wound healing was observed for the two groups of patients, and found that the average time to complete wound closure was 37.73 ± 10.58 days when the PRP dressing was used and 26.67 ± 15.23 days when the UC‐MSCs dressing was used. The time to complete wound closure of the PRP and UC MSCs groups in the present study was similar to the results of previous studies, which indirectly demonstrated the rationality and validity of our results. Further analysis of the wound healing of the two groups revealed that wound was fully healed as early as 10 days after treatment in the UC‐MSCs group, with a wound healing rate of 93.93 ± 11.86% on the 10th day after treatment. The UC MSCs group was better than the PRP group in both efficiency and time of wound healing (p < 0.05).

Rest pain and wound infection caused by DFU continuously impact the quality of life and normal function of these patients. Therefore, it is necessary to repair the wound and pay close attention to various DFU‐induced diseases and symptoms as well when treating and caring for DFU patients. ABI is a diagnostic method for determining the ratio of ankle arterial pressure to brachial arterial pressure, ²⁸ and commonly used as an auxiliary diagnostic tool for peripheral arterial diseases in the lower limbs. In the present study, the difference in ABI index before and after treatment was not statistically significant in the PRP group, while it was significantly improved in the UC‐MSCs group after treatment compared with that before treatment (p < 0.05). In addition to ABI, there are also many screening and evaluation scales for the degree of lesions in DFU patients in clinical practice, among which the TCSS scale is more commonly used. ²⁹ In the present study, a statistically significant difference in the total TCSS scores of the PRP group and the UC MSCs group was noted before and after treatment. Moreover, comparison of individual items revealed that the symptom score of TSCC in the UC MSCs group was better than that in the PRP group (p < 0.05). DFU patients are often complicated with pain and infection. According to clinical guidelines, 40–70% of DFU patients have already been infected when seeking medical treatment. ³⁰ Studies have shown that CRP is a very important sensitive indicator to evaluate the presence of infection in patients with diabetes. ³¹ In the present study, the CRP value of the two groups of patients before treatment confirmed that both groups of patients were infected. Posttreatment comparison of CRP showed that the UC‐MSCs gel dressing was better than PRP gel dressing in inhibiting inflammatory responses.

In summary, effects of the two treatment methods on the related symptoms of DFU were evaluated in several dimensions. TCSS scale is highly sensitive and less specific to diabetic peripheral neuropathy (DPN) in terms of symptoms of neuropathic pain and vascular lesions. Therefore, TSCC scale was combined with another objective index, namely, ABI index, to support each other. It was found that both PRP and UC‐MSCs gel dressings could improve the symptoms of vascular and peripheral neuropathy in DFU patients. On the other hand, observation of CRP value revealed that the two dressings also effectively inhibited the inflammatory response in these patients. UC‐MSCs gel tended to be superior to PRP gel in all these comparisons.

There were limitations in this study that need to be considered. First, the preparation of UC‐MSCs gel was relatively complex, and stem cell harvest from the umbilical cord and periodic cell culture were required, which may increase the treatment time and cost. Second, the sample size was small and patients were enrolled from the same hospital, which limited the external generalization of these findings. Future studies with larger sample sizes from multiple centers are needed. Third, the follow‐up time was short in this study, and studies with a longer follow‐up time can be conducted in the future to assess the long‐term effects and recurrence rates. Finally, factors such as cost‐effectiveness and quality of life were not considered in this study, and more comprehensive evaluation are necessary in future studies. Despite the potential of UC‐MSCs gel in the treatment of DFU, the findings of the present study need to be validated in studies with larger samples, longer follow‐up, and multi‐dimensional evaluation to fully understand its application in clinical practice.

5. CONCLUSION

In the present study, PRP gel and UC‐MSCs gel are used in the treatment of DFU after debridement, and it was found that both dressings are effective for DFU, with a higher wound healing rate, shorter time to complete wound closure, better symptomatic treatment effect, and more effective inhibition on inflammatory response in UC‐MSCs gel. However, this study also has limitations, including small sample size and lack of conventional treatment control group. The efficacy and relative advantages and disadvantages of the two dressings are established in this study, and future studies with larger sample sizes and multidimensional comparison are needed to explore the combination of these dressings in order to promote the development of DFU treatment and alleviate the pain of DFU patients.

CONFLICT OF INTEREST STATEMENT

All of the authors had no personal, financial, commercial, or academic conflicts of interest separately.

ETHICS STATEMENT

This study was conducted in accordance with the Declaration of Helsinki and approved by the ethics committee of Yan'an Hospital Affiliated to Kunming Medical University. We obtained signed informed consent from the participants / legal guardians in this study.

Jin Y, Meng MY, Zhang YF, et al. Comparative study on the efficacy of PRP gel and UC‐MSCs gel as adjuvant therapies in the treatment of DFU wounds. Skin Res Technol. 2024;30:e13549. 10.1111/srt.13549

DATA AVAILABILITY STATEMENT

All data generated or analyzed during this study are included in this published article.