Prolotherapy Induces an Inflammatory Response in Human Tenocytes In Vitro

Rapid Decrease in Dextrose Concentration After Intra-Articular Knee Injection: Implications for Mechanism of Action of Dextrose Prolotherapy

BACKGROUND

D-glucose (dextrose) is used as a 5000-25,000 mg% solution in the injection-based pain therapy known as dextrose prolotherapy (DPT). The number of peer-reviewed clinical trials supporting its use is growing. However, the mechanism of action is unknown, limiting further research. A commonly expressed theory is that hyperosmotic dextrose injection induces inflammation, initiating a healing-specific inflammatory cascade. In vitro study models have used continuous exposure to high concentration dextrose. But the rate of dextrose clearance after intra-articular injection, and, therefore, the duration of exposure of tissues to any particular dextrose concentration, remains unknown. We therefore determined the rate of dextrose concentration diminution in one human participant's knees after intra-articular dextrose knee injection.

METHOD

In this pre-post N-of-1 study, the first author (KDR), a well 70-year-old male without knee-related pathology, injected his own knees with 30 mL of 12,500 mg% dextrose on three occasions; performed serial aspirations of 1.2 mL of intra-articular fluid from 7 to 360 min post-injection; and assessed synovial dextrose concentration. Dextrose clearance kinetics were determined using Minitab and GraphPad Prism software.

RESULTS

Dextrose concentration dropped rapidly in all three trials, approximating an exponential or steep S curve. A third order chemical reaction pattern was found, suggesting factors other than dilution or glucose transporter activity, such as rapid diffusion of dextrose across the synovial membrane, may have contributed to the rapid drop in dextrose concentration.

CONCLUSION

This pre-post N-of-1 study shows that, after intraarticular injection of 30 mL of 12,500 mg% dextrose injection into a well knee, the concentration of dextrose diminished rapidly, suggesting that intra-articular cells, tissue, and anatomic structures are exposed to an initially high dextrose concentration for a very short time. This likely affects the mechanism of action of DPT and should inform in vitro study methods.

Is Dextrose Prolotherapy More Effective Than Steroids in the Treatment of Distal Semimembranous Tendinopathy?

OBJECTIVE

Distal semimembranous (SM) tendinopathy is one of the rare causes of posteromedial knee pain. Steroid injections are included in the treatment of resistant cases. The effectiveness of dextrose prolotherapy is not fully known. This study aimed to investigate the effectiveness of dextrose prolotherapy in distal SM tendinopathy and to compare it with the effectiveness of steroid injections.

METHODOLOGY

 The study included 12 patients who received ultrasound-guided steroid injections and 13 patients who received dextrose prolotherapy treatment with the diagnosis of distal SM tendinopathy. The patient's visual analog scale (VAS) and International Knee Documentation Committee Subjective Knee Assessment (IKDC) scores were analyzed before the procedure, as well as one week and four weeks afterward.

RESULTS

 Pre-procedure VAS scores were similar in the dextrose and steroid groups (4.00 ± 0.70, 4.33 ± 0.88 P = 0.308), while they were significantly lower in the steroid group at week 1 (1.84 ± 0.55, 1.16 ± 0.93, P = 0.036). Fourth-week VAS scores were significantly lower in the dextrose group (0.61 ± 0.65, 1.33 ± 0.65, P = 0.011). IKDC scores were similar in the dextrose and steroid groups before the procedure (48.34 ± 6.01, 46.66 ± 3.34, P = 0.402). In the first week, it was observed to be similar in the dextrose and steroid groups (55.03 ± 8.52, 53.30 ± 1.56, P = 0.496) and higher in the dextrose group in the fourth week (62.50 ± 14.46, 53.13 ± 1.60, P = 0.036).

CONCLUSIONS

It was observed that both dextrose prolotherapy and steroid injections were effective in reducing pain and improving functionality in the treatment of distal SM tendinopathy. Steroid injections showed better results in the first week, while dextrose prolotherapy yielded better outcomes by the fourth week.

Effectiveness of Hypertonic Dextrose Injection (Prolotherapy) in Plantar Fasciopathy: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To systematically review the effectiveness of hypertonic dextrose prolotherapy (DPT) in plantar fasciopathy (PF) compared with other non-surgical treatments.

DATA SOURCES

PubMed/MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, Allied and Complementary Medicine Database, Global Health, Ovid Nursing Database, Dimensions, and WHO ICTRP were searched from inception to April 30th, 2022.

STUDY SELECTION

Two independent reviewers selected randomized controlled trials (RCTs) that evaluated the effectiveness of DPT in PF compared with non-surgical treatments. Outcomes included pain intensity, foot and ankle function, and plantar fascia thickness.

DATA EXTRACTION

Two independent reviewers conducted data extraction. Risk of bias (RoB) assessment was conducted using the Cochrane Risk of Bias 2 (RoB 2) tool, and certainty of evidence was assessed with Grading of Recommendation Assessment, Development, and Evaluation (GRADE).

DATA SYNTHESIS

Eight RCTs (n=469) met the inclusion criteria. Pooled results favored the use of DPT versus normal saline (NS) injections in reducing pain (weighted mean difference [WMD] -41.72; 95% confidence interval [CI] -62.36 to -21.08; P<.01; low certainty evidence) and improving function [WMD -39.04; 95% CI -55.24 to -22.85; P<.01; low certainty evidence] in the medium term. Pooled results also showed corticosteroid (CS) injections was superior to DPT in reducing pain in the short term [standardized mean difference 0.77; 95% CI 0.40 to 1.14; P<.01; moderate certainty evidence]. Overall RoB varied from "some concerns" to "high". The overall certainty of evidence presented ranges from very low to moderate based on the assessment with the GRADE approach.

CONCLUSION

Low certainty evidence demonstrated that DPT was superior to NS injections in reducing pain and improving function in the medium term, but moderate certainty evidence showed that it was inferior to CS in reducing pain in the short term. Further high-quality RCTs with standard protocol, longer-term follow-up, and adequate sample size are needed to confirm its role in clinical practice.

The Potential of Glucose Treatment to Reduce Reactive Oxygen Species Production and Apoptosis of Inflamed Neural Cells In Vitro

Neuroinflammation is a key feature in the pathogenesis of entrapment neuropathies. Clinical trial evidence suggests that perineural injection of glucose in water at entrapment sites has therapeutic benefits beyond a mere mechanical effect. We previously demonstrated that 12.5-25 mM glucose restored normal metabolism in human SH-SYFY neuronal cells rendered metabolically inactive from TNF-α exposure, a common initiator of neuroinflammation, and reduced secondary elevation of inflammatory cytokines. In the present study, we measured the effects of glucose treatment on cell survival, ROS activity, gene-related inflammation, and cell cycle regulation in the presence of neurogenic inflammation. We exposed SH-SY5Y cells to 10 ng/mL of TNF-α for 24 h to generate an inflammatory environment, followed by 24 h of exposure to 3.125, 6.25, 12.5, and 25 mM glucose. Glucose exposure, particularly at 12.5 mM, preserved apoptotic SH-SY5Y cell survival following a neuroinflammatory insult. ROS production was substantially reduced, suggesting a ROS scavenging effect. Glucose treatment significantly increased levels of CREB, JNK, and p70S6K (p < 0.01), pointing to antioxidative and anti-inflammatory actions through components of the MAPK family and Akt pathways but appeared underpowered (n = 6) to reach significance for NF-κB, p38, ERK1/2, Akt, and STAT5 (p < 0.05). Cell regulation analysis indicated that glucose treatment recovered/restored function in cells arrested in the S or G2/M-phases. In summary, glucose exposure in vitro restores function in apoptotic nerves after TNF-α exposure via several mechanisms, including ROS scavenging and enhancement of MAPK family and Akt pathways. These findings suggest that glucose injection about entrapped peripheral nerves may have several favorable biochemical actions that enhance neuronal cell function.

Ultrasound-Guided Injection of Dextrose Versus Corticosteroid in Chronic Plantar Fasciitis Management: A Randomized, Double-Blind Clinical Trial

DESIGN

Chronic plantar fasciitis (PF) is a common cause of chronic heel pain, with different conventional treatment options. In this randomized clinical trial, the effect of ultrasound-guided injection of dextrose versus corticosteroid in chronic PF was evaluated and compared.

METHODS

A total of 44 patients suffering from chronic PF who visited the physical medicine and rehabilitation clinic were enrolled in the study. Two table-randomized groups were formed. They received an ultrasonography-guided, single injection of either 40 mg methylprednisolone or 20% dextrose. Numeric Rating Scale (NRS), Foot and Ankle Ability Measure questionnaire with 2 subscales, Activities of Daily Living (FAAM-A) and Sports (FAAM-S), along with ultrasonographic parameters were evaluated before and at 2 and 12 weeks after the injection. Results. A total of 40 participants completed the study. Both interventions significantly improved pain and function at 2 and 12 weeks postinjection. After 2 weeks, compared with the dextrose prolotherapy, the corticosteroid group had significantly lower daytime and morning NRS scores (2.55 vs 4.1, P = .012, and 2.75 vs 4.65, P = .004), higher FAAM-S (66.84 vs 54.19; P = .047), and lower plantar fascia thickness at insertion and 1 cm distal to the insertion zone (3.89 vs 4.29 mm, P = .004, and 3.13 vs 3.48 mm, P = .002), whereas FAAM-A was similar in both groups (P = .219). After 12 weeks, all study variables were statistically similar between corticosteroid and dextrose prolotherapy groups. No injection-related side effects were recorded in either group.

CONCLUSION

Both methods are effective. Compared with dextrose prolotherapy, our results show that corticosteroid injection may have superior therapeutic effects early after injection, accompanied by a similar outcome at 12 weeks postinjection.

LEVELS OF EVIDENCE

Level II.

A protocol for a randomized clinical trial assessing the efficacy of hypertonic dextrose injection (prolotherapy) in chronic ankle instability

BACKGROUND

Lateral ankle sprain (LAS) is a common injury. Conservative care is not uniformly effective. Chronic ankle instability (CAI) results in up to 70% of patients with LAS in the physically active population. LAS, together with subsequent osteochondral lesions and pain in many patients, leads to the development of post-traumatic osteoarthritis, resulting in a substantial direct and indirect personal and societal health burden. Dextrose prolotherapy (DPT) is an injection-based therapy for many chronic musculoskeletal conditions but has not been tested for CAI. This protocol describes a randomized controlled trial to test the efficacy of DPT versus normal saline (NS) injections for chronic ankle instability (CAI).

METHODS AND ANALYSIS

A single-center, parallel-group, randomized controlled trial will be conducted at a university-based primary care clinic in Hong Kong. A total of 114 patients with CAI will be randomly allocated (1:1) to DPT and NS groups. The primary outcome will be the Cumberland Ankle Instability Tool scores at 1 year. The secondary outcomes will be the number of re-sprains in 1 year, the Star Excursion Balance Test, the 5-level of EuroQol 5-dimension questionnaire, and the Foot and Ankle Ability Measure. All outcomes will be evaluated at baseline and at 16, 26, and 52 weeks using a linear mixed model.

DISCUSSION

We hypothesized the DPT is a safe, easily accessible, and effective treatment for patients with CAI. This RCT study will inform whether DPT could be a primary non-surgical treatment for CAI.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000040213 . Registered on 25 November 2020.

Patellar Tendinopathy: Critical Analysis Review of Current Nonoperative Treatments

»

Patellar tendinopathy is an attritional injury of the patellar tendon that is frequently identified in jumping athletes. Through repetitive or explosive movements, considerable loads and high peak strains are generated across the patellar tendon.

»

This leads to microinjury of tendon fibers, local mucoid degeneration, and loss of the fibrocartilaginous tissue that attaches tendon to bone.

»

Management of patellar tendinopathy often begins with nonoperative modalities: progressive tendon loading and eccentric rehabilitative exercise programs are the most effective. While a variety of additional treatment modalities are available, the comparative efficacy of these supportive treatments is not well differentiated at this time.

»

In this article, we analyze the existing literature regarding nonoperative treatment of patellar tendinopathy and provide additional insight on the effectiveness of current modalities.

Effects of Hypertonic Dextrose Injection (Prolotherapy) in Lateral Elbow Tendinosis: A Systematic Review and Meta-analysis

OBJECTIVE

To systematic review the effectiveness of hypertonic dextrose prolotherapy (DPT) on pain intensity and physical functioning in patients with lateral elbow tendinosis (LET) compared with other active non-surgical treatments.

DATA SOURCES

Systematic search of CENTRAL, MEDLINE, EMBASE, Web of Science, PubMed, Dimensions, Global Health, NHS Health Technology Assessment, AMED and OVID nursing database from inception to 15 June 2021, without language restrictions.

STUDY SELECTION

Two reviewers independently identified parallel or cross-over RCTs that evaluated the effectiveness of DPT in LET. The search identified 245 records; data from 8 studies (354 patients) were included.

DATA EXTRACTION

Two reviewers independently extracted data and assessed included studies. The Cochrane Risk of Bias 2 tool was used to evaluate risk of bias. The Grading of Recommendation Assessment, Development, and Evaluation approach was used to assess quality of the evidence.

DATA SYNTHESIS

Pooled results favored the use of DPT in reducing tennis elbow pain intensity compared with active controls at 12 weeks post-enrollment, with standardized mean difference (SMD) of -0.44 (95% CI -0.88 to -0.01, P =0.04) and of moderate heterogeneity (I²= 49%). Pooled results also favored the use of DPT on physical functioning compared with active controls at 12 weeks, with DASH score achieving mean difference (MD) -15.04 (95% CI -20.25 to -9.82, P < 0.001) and of low heterogeneity (I²= 0.0%). No major related adverse events have been reported.

CONCLUSIONS

DPT is superior to active controls at 12 weeks for decreasing pain intensity and functioning by margins that meet criteria for clinical relevance in the treatment of LET. While existing studies are too small to assess rare adverse events, for LET patients, especially those refractory to first-line treatments, DPT can be considered a non-surgical treatment option in carefully selected patients. Further high-quality trials with comparison with other injection therapies are needed.

Hypertonic Dextrose Stimulates Chondrogenic Cells to Deposit Collagen and Proliferate

OBJECTIVE

Hypertonic dextrose (HD) injections (prolotherapy) for osteoarthritis are reported to reduce pain. Cartilage regeneration is hypothesized as a mechanism. This in vitro study identifies an HD concentration that stimulates chondrogenic cells to increase metabolic activity and assesses whether this concentration affects collagen deposition and proliferation.

DESIGN

ATDC5 chondrogenic cells were cultured in normoglycemic DMEM/F12 medium, treated with concentrations of HD (4-400 mM), and assessed with PrestoBlue. Advanced light microscopy was used to conduct live imaging of collagen deposition through second harmonic generation microscopy (SHG) and proliferation via 2-photon excitation microscopy. Proliferation was additionally assessed with hemocytometer counts.

RESULTS

A linear regression model found that, relative to the 4 mM baseline control, cells treated with 200 mM had a higher mean absorbance (P = 0.023) and cells treated with 250 mM were trending toward a higher mean absorbance (P = 0.076). Polynomial regression interpolated 240 mM as producing the highest average absorbance. Hemocytometer counts validated 250 mM as stimulating proliferation compared with the 4 mM control (P < 0.01). A concentration of 250 mM HD led to an increase in collagen deposition compared with that observed in control (P < 0.05). This HD concentration also led to increases in proliferation of ATDC5 cells relative to that of control (P < 0.001).

CONCLUSIONS

A 250 mM HD solution appears to be associated with increased metabolic activity of chondrocytes, increased collagen deposition, and increased chondrocyte proliferation. These results support clinical prolotherapy research suggesting that intra-articular HD joint injections reduce knee pain. Further study of HD and cellular processes is warranted.

Stem Cell-Derived Exosomes Potential Therapeutic Roles in Cardiovascular Diseases

Owing to myocardial abnormalities, cardiac ailments are considered to be the major cause of morbidity and mortality worldwide. According to a recent study, membranous vesicles that are produced naturally, termed as "exosomes", have emerged as the potential candidate in the field of cardiac regenerative medicine. A wide spectrum of stem cells has also been investigated in the treatment of cardiovascular diseases (CVD). Exosomes obtained from the stem cells are found to be cardioprotective and offer great hope in the treatment of CVD. The basic nature of exosomes is to deal with the intracellular delivery of both proteins and nucleic acids. This activity of exosomes helps us to rely on them as the attractive pharmaceutical delivery agents. Most importantly, exosomes derived from microRNAs (miRNAs) hold great promise in assessing the risk of CVD, as they serve as notable biomarkers of the disease. Exosomes are small, less immunogenic, and lack toxicity. These nanovesicles harbor immense potential as a therapeutic entity and would provide fruitful benefits if consequential research were focused on their upbringing and development as a useful diagnostic and therapeutic tool in the field of medicine.

Role of Human Mesenchymal Stem Cells in Regenerative Therapy

Mesenchymal stem cells (MSCs) are multipotent cells which can proliferate and replace dead cells in the body. MSCs also secrete immunomodulatory molecules, creating a regenerative microenvironment that has an excellent potential for tissue regeneration. MSCs can be easily isolated and grown in vitro for various applications. For the past two decades, MSCs have been used in research, and many assays and tests have been developed proving that MSCs are an excellent cell source for therapy. This review focusses on quality control parameters required for applications of MSCs including colony formation, surface markers, differentiation potentials, and telomere length. Further, the specific mechanisms of action of MSCs under various conditions such as trans-differentiation, cell fusion, mitochondrial transfer, and secretion of extracellular vesicles are discussed. This review aims to underline the applications and benefits of MSCs in regenerative medicine and tissue engineering.

Prolotherapy agent P2G is associated with upregulation of fibroblast growth factor-2 genetic expression in vitro

Purpose

Osteoarthritis (OA) is a prevalent, progressively degenerative disease. Researchers have rigorously documented clinical improvement in participants receiving prolotherapy for OA. The mechanism of action is unknown; therefore, basic science studies are required. One hypothesized mechanism is that prolotherapy stimulates tissue proliferation, including that of cartilage. Accordingly, this in vitro study examines whether the prolotherapy agent phenol-glycerin-glucose (P2G) is associated with upregulation of proliferation-enhancing cytokines, primarily fibroblast growth factor-2 (FGF-2).

Methods

Murine MC3T3-E1 cells were cultured in a nonconfluent state to retain an undifferentiated osteochondroprogenic status. A limitation of MC3T3-E1 cells is that they do not fully reproduce primary human chondrocyte phenotypes; however, they are useful for modeling cartilage regeneration in vitro due to their greater phenotypic stability than primary cells. Two experiments were conducted: one in duplicate and one in triplicate. Treatment consisted of phenol-glycerin-glucose (P2G, final concentration of 1.5%). The results were assessed by quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR) to detect mRNA expression of the FGF-2, IGF-1, CCND-1 (Cyclin-D), TGF-β1, AKT, STAT1, and BMP2 genes.

Results

P2G - treated preosteoblasts expressed higher levels of FGF-2 than water controls (hour 24, p < 0.001; hour 30, p < 0.05; hour 38, p < 0.01). Additionally, CCND-1 upregulation was observed (p < 0.05), possibly as a cellular response to FGF-2 upregulation.

Conclusions

The prolotherapy agent P2G appears to be associated with upregulation of the cartilage cell proliferation enhancer cytokine FGF-2, suggesting an independent effect of P2G consistent with clinical evidence. Further study investigating the effect of prolotherapy agents on cellular proliferation and cartilage regeneration is warranted.

Effects of dextrose prolotherapy on tendinopathy, fasciopathy, and ligament injuries, fact or myth?: A systematic review and meta-analysis

OBJECTIVES

Prolotherapy or proliferative therapy is a treatment option for damaged connective tissues involving the injection of a solution (proliferant) which theoretically causes an initial cell injury and a subsequent "proliferant" process of wound healing via modulation of the inflammatory process. Nonetheless, the benefits of dextrose prolotherapy have not been adequately evaluated. Therefore, the present study assesses the effectiveness and superiority of prolotherapy separately in treating dense fibrous connective tissue injuries.

METHODS

PubMed, Scopus, and Embase were searched from the earliest record to February 18, 2019. This study included randomized controlled trials whichBoth analysis at individual studies level and pooled meta-analysis were performed.

RESULTS

Ten trials involving 358 participants were included for review. At study level, the majority of comparisons did not reveal significant differences between dextrose prolotherapy and no treatment (or placebo) regarding pain control. The meta-analysis showed dextrose prolotherapy was effective in improving activity only at immediate follow-up (i.e., 0-1 month) (standardized mean difference [SMD]: 0.98; 95% confidence interval [CI]: 0.40-1.50; I = 0%); and superior to corticosteroid injections only in pain reduction at short-term follow-up (i.e., 1-3 month) (SMD: 0.70; 95% CI: 0.14-1.27; I = 51%). No other significant SMDs were found in this analysis.

CONCLUSIONS

There is insufficient evidence to support the clinical benefits of dextrose prolotherapy in managing dense fibrous tissue injuries. More high-quality randomized controlled trials are warranted to establish the benefits of dextrose prolotherapy.

REVIEW REGISTRATION

PROSPERO (CRD42019129044).

Effects of Hyperosmolar Dextrose Injection in Patients With Rotator Cuff Disease and Bursitis: A Randomized Controlled Trial

OBJECTIVE

To determine whether dextrose prolotherapy offers clinical benefits in patients with shoulder pain and bursitis.

DESIGN

Double-blinded, randomized controlled trial.

SETTING

Outpatient rehabilitation department of a single medical center.

PARTICIPANTS

Patients (N=50) who had received a diagnosis of shoulder pain and bursitis through clinical tests and ultrasound examination.

INTERVENTIONS

Participants were randomly assigned to the 15% dextrose injection (D15W) group or the placebo group to receive either D15W or normal saline injection, respectively. All participants received ultrasound-guidance bursal injection every 2 weeks for a total of 3 injections.

MAIN OUTCOME MEASURES

The primary outcome was maximal pain level while performing activities. The secondary outcomes included resting pain level, function and disability assessment results, and ultrasonographic parameters. Participants were followed up for 3 months after completion of the injection course.

RESULTS

No significant differences in baseline characteristics were observed between the D15W and placebo groups. Significant time effects were observed for all outcome parameters (all P<.05); however, time × group effects were nonsignificant for all outcomes, except for tissue elasticity (P=.026).

CONCLUSIONS

Supporting evidence is insufficient regarding the clinical benefits of 15% dextrose bursal injection administered through 3 sessions in patients with chronic shoulder pain and bursitis. The findings indicate that these injections may increase the tissue stiffness of the supraspinatus tendon, as indicated by elastography assessment results, but further research is required to determine the nature of such changes in elastography findings.

Single-walled carbon nanohorns modulate tenocyte cellular response and tendon biomechanics

Subfailure ligament and tendon injury remain a significant burden to global healthcare. Here, we present the use of biocompatible single-walled carbon nanohorns (CNH) as a potential treatment for the repair of sub-failure injury in tendons. First, in vitro exposure of CNH to human tenocytes revealed no change in collagen deposition but a significant decrease in cell metabolic activity after 14 days. Additionally, gene expression studies revealed significant downregulation of collagen Types I and III mRNA at 7 days with some recovery after 14 days of exposure. Biomechanical tests with explanted porcine digitorum tendons showed the ability of CNH suspensions to modulate tendon biomechanics, most notably elastic moduli immediately after treatment. in vivo experiments demonstrated the ability of CNH to persist in the damaged matrix of stretch-injured Sprague Dawley rat Achilles tendon but not significantly modify tendon biomechanics after 7 days of treatment. Although these results demonstrate the early feasibility of utility of CNH as a potential modality for tendon subfailure injury, additional work is needed to further validate and ensure clinical efficacy.

Tendinopathy: Pathophysiology, Therapeutic Options, and Role of Nutraceutics. A Narrative Literature Review

Tendinopathies are very common in general population and a huge number of tendon-related procedures take place annually worldwide, with significant socio-economic repercussions. Numerous treatment options are commonly used for tendon disorders. Besides pharmacological and physical therapy, nutrition could represent an additional tool for preventing and treating this complex pathology that deserve a multidisciplinary approach. In recent years, nutraceutical products are growing up in popularity since these seem to favor the prevention and the healing processes of tendon injuries. This narrative literature review aims to summarize current understanding and the areas of ongoing research about the management of tendinopathies with the help of oral supplementation.

Prolotherapy: Potential for the Treatment of Chronic Wounds?

Significance: Chronic skin ulcers, including venous, diabetic, and pressure ulcers, constitute a major health care burden, affecting 2-6 million people in the United States alone, with projected increases in incidence owing to the aging population and rising epidemic of diabetes. The ulcers are often accompanied by pain. Standard of care fails to heal ∼50% of diabetic foot ulcers and 25% of venous leg ulcers. Even advanced therapies do not heal >60%. Thus there is an unmet need for novel therapies that promote healing and also address the concomitant pain issue. Recent Advances: Prolotherapy involves injection of small amounts of an irritant material to the site of degenerated or painful joints, ligaments, and tendons. Multiple irritants are reported to be efficacious, but the focus here is on dextrose prolotherapy. In vitro and in vivo studies support translation to clinical use. Concentrations as low as 5% dextrose have resulted in production of growth factors that have critical roles in repair. Numerous clinical trials report pro-reparative effects of dextrose prolotherapy in joint diseases, tendon, and ligament damage, and for painful musculoskeletal issues. However, most of the studies have limitations that result in low-quality evidence. Critical Issues: The preclinical data support a role for dextrose prolotherapy in promoting tissue repair that is required for healing chronic wounds and ameliorating the associated pain. Critical issues include provision of evidence of efficacy in human chronic wounds. Another potential obstacle is limitation of reimbursement by third-party payers for a therapy with as yet limited evidence. Future Directions: Preclinical studies in models of chronic wounds would support clinical translation. As dextrose prolotherapy has some mechanistic similarities to already approved honey therapies, it may have a shortened pathway for clinical translation. The gold standard for widespread adoption would be a well-designed clinical trial.

Regenerative Sports Medicine: Past, Present, and Future (Adapted From the PASSOR Legacy Award Presentation; AAPMR; October 2016)

Regenerative medicine has shown dramatic expanse and evolution in the past decade. Within that milieu, physiatrists are taking an active role in research, clinical care delivery, and education. The purpose of this review is to provide a balance among evidence, theory, experience, clinical trends, and the foreseeable future. We focus on the literature that reports the research with the best methodology in each practice area, recognizing that the level of evidence varies substantially among different treatment modalities and conditions. The following elements are included: an overview of the evolution of currently available regenerative techniques, evidence base for each available modality (prolotherapy, platelet rich plasma, bone marrow aspirate concentrate and stem cells, adipose-derived stem cells, and amniotic tissue products), general principles in the application of these treatments, and discussion and a vision of what lies ahead. We expect that practitioners will use this review to facilitate clinical decision making and to provide a core knowledge base to assist when counseling patients. LEVEL OF EVIDENCE: IV.