Medicinal leech therapy in pain syndromes: a narrative review

Prostaglandin E1 Is an Efficient Molecular Tool for Forest Leech Blood Sucking

From a survival perspective, it is hypothesized that leech saliva exhibits certain physiological effects to ensure fast blood-feeding, including analgesia, anesthesia, and anti-inflammation to stay undetected by the host and vasodilatation and anti-hemostasis to ensure a steady, rapid, and sustained blood flow to the feeding site. Many anti-hemostatic compounds have been identified in leech saliva, such as hirudin, calin, and bdellin A. However, no specific substance with direct vasodilatory and anti-inflammatory function has been reported from forest leech saliva. Herein, using activity-guided analysis, prostaglandin E1 (PGE1) was identified for the first time as an efficient molecular tool for forest leech blood sucking. The structure of PGE1 was analyzed by nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectroscopy. PGE1 was found to be primarily distributed in the leech salivary gland (1228.36 ng/g body weight). We also analyzed how forest leech PGE1 affects platelet aggregation, skin vascular permeability, bleeding time, and pain. Results indicated that PGE1 efficiently inhibited platelet aggregation induced by adenosine diphosphate (ADP) (5 μM) with an IC50 of 21.81 ± 2.24 nM. At doses of 10, 100 nM, and 1 μM, PGE1 increased vascular permeability by 1.18, 5.8, and 9.2 times. It also prolonged bleeding time in a concentration-independent manner. In the formalin-induced mouse paw pain model, PGE1 suppressed acute pain. To the best of our knowledge, this is the first report on PGE1 in invertebrates. The functions of PGE1, such as vasodilation, platelet aggregation inhibition, anti-inflammation, and pain alleviation, may facilitate the ingestion of host blood by leeches.

Liposomes for Intra-Articular Analgesic Drug Delivery in Orthopedics: State-of-Art and Future Perspectives. Insights from a Systematic Mini-Review of the Literature

Background and objectives: Liposomal structures are artificial vesicles composed of one or several lamellae of phospholipids which surround an inner aqueous core. Given the amphoteric nature of phospholipids, liposomes are promising systems for drug delivery. The present review provides an updated synthesis of the main techniques for the production of liposomes for orthopedic applications, focusing on the drawbacks of the conventional methods and on the advantages of high pressure techniques. Materials and Methods: Articles published in any language were systematically retrieved from two major electronic scholarly databases (PubMed/MEDLINE and Scopus) up to March 2020. Nine articles were retained based on the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines. Results: Liposome vesicles decrease the rate of inflammatory reactions after local injections, and significantly enhance the clinical effectiveness of anti-inflammatory agents providing controlled drug release, reducing toxic side effects. Conclusions: This review presents an update on the improvement in musculoskeletal ailments using liposome treatment.

The Effectiveness of Leech Therapy in Chronic Low Back Pain

BACKGROUND

Leech therapy has been found to be effective in the treatment of a number of chronic musculoskeletal pain syndromes. Leeches are also often used empirically to treat chronic low back pain, but data from clinical trials have been lacking to date. We therefore conducted the first randomized trial of leech therapy for chronic low back pain.

METHODS

Patients with chronic low back pain were randomized to receive either a single session of local treatment with 4-7 leeches or four weekly sessions of exercise therapy (1 hour each) led by a physical therapist. The primary endpoint was a change in average back pain intensity, as measured using a 100-mm visual analog scale (VAS), after 28 days. Secondary end- points included functional impairment (Roland-Morris Disability Questionnaire, Hannover Functional Ability Questionnaire), quality of life (Short-Form Health Questionnaire [SF 36]), pain perception (pain perception scale = Schmerzempfindungsskala [SES]), depressivity (Center for Epidemiological Studies Depression Scale [CES-D]), and analgesic consumption (questionnaire/ diary). Trial visits took place before treatment and on days 28 ± 3 and 56 ± 5 after the start of treatment; the overall duration of the trial was 56 ± 5 days.

RESULTS

The mean low back pain score improved from 61.2 ± 15.6 before treatment to 33.1 ± 22.4 on day 28 in the leech ther- apy group (n = 25) and from 61.6 ± 14.8 to 59.8 ± 16.7 in the exercise therapy group (n = 19) (group difference -25.2; 95% con- fidence interval [-41.0; -9.45]; p = 0.0018). Significant benefits of leech therapy were also found at both time points with respect to physical impairment and function as well as physical quality of life. The patients' expectations from treatment were higher in the leech therapy group but did not significantly affect the findings.

CONCLUSION

A single session of leech therapy is more effective over the short term in lowering the intensity of pain over the short term and in improving physical function and quality of life over the intermediate term (4 weeks and 8 weeks, respectively). The limitations of this trial are the lack of blinding and the small number of patients. Leech therapy appears to be an effective treat- ment for chronic low back pain.

Novel Sodium Channel Inhibitor From Leeches

Considering blood-sucking habits of leeches from surviving strategy of view, it can be hypothesized that leech saliva has analgesia or anesthesia functions for leeches to stay undetected by the host. However, no specific substance with analgesic function has been reported from leech saliva although clinical applications strongly indicated that leech therapy produces a strong and long lasting pain-reducing effect. Herein, a novel family of small peptides (HSTXs) including 11 members which show low similarity with known peptides was identified from salivary glands of the leech Haemadipsa sylvestris. A typical HSTX is composed of 22-25 amino acid residues including four half-cysteines, forming two intra-molecular disulfide bridges, and an amidated C-terminus. HSTX-I exerts significant analgesic function by specifically inhibiting voltage-gated sodium (Na_V) channels (Na_V1.8 and Na_V1.9) which contribute to action potential electrogenesis in neurons and potential targets to develop analgesics. This study reveals that sodium channel inhibitors are analgesic substances in the leech. HSTXs are excellent candidates or templates for development of analgesics.

Effectiveness of topical gel of medical leech (Hirudo medicinalis) saliva extract on patients with knee osteoarthritis: A randomized clinical trial

Leech saliva extract (LSE) in the liposome-based gel was used as a supplementary treatment to relief the signs and symptoms of osteoarthritis (OA). The saliva of medical leech was extracted and nano liposomes were used to formulate the supplement to enhance skin absorption. A clinical trial was designed to evaluate the therapeutic effects of LSE liposomal gel. Lenquesne and VAS questionnaires were used as indexes of this supplement therapy efficacy for 30 days. Questionnaires analysis showed that after one-month administration of LSE liposomal gel, patients' pain was relieved approximately up to 50%; also, due to reduction in joint inflammation and stiffness, the range of motion was increased and the patients' quality of life was enhanced (p < 0.001). LSE nano scaled liposomal gel as an innovative supplement therapy in OA patients, makes desirable therapeutic approach, which seems to make a significant impact on patient's quality of life and self-care capability.