Itt írjon a(z) spinal_cord_injuries-ról/ről

University of Veterinary Medicine, Budapest

Department of Physiology

Treatment of spinal cord injuries with modern methods

Pia-Charlotte Bertram

Erzsebet Pal

Flora Kinga Muranyi

Supervisor: Gergely Jócsák

Table of Contents

1. Introduction

2. Treatments

2.1 Tetanus Neurotoxin Injections

2.2 Stem Cell Intraspinal Transplantation

2.3 Electroacupuncture

3. Conclusion

4. References

1. Introduction

Spinal cord injuries are not foreign in the Veterinary studies and are relatively common in the clinics as well. Its many forms such as fractures, dislocation, or subluxation of the vertebral column might be a challenge in treatment and prognosis while time is an essential factor. In most cases if the patient is not treated within eight hours the inflammatory response with the vascular and biochemical events may cause such severe secondary tissue damage scaling up in the next 48 hours after injury that the primary tissue damage can be suppressed beside it. Risks following these factors are non-negligible thus a quick and effective treatment is needed.

In the last twenty years a considerable of drug trials has been published causing controversy in the profession. Previously spinal cord injury has been treated via surgery aiming for the decompression of the spinal cord with fixation and mandatory rest. Because of the lack of proper models for the experiments the fresh solutions are still at their initial stages but with the proper clinical trials they may be introduced to clinical practice soon. Presented here are three of the current methods which are currently under development by researchers and producing satisfactory results.

2. Treatments

2.1 Tetanus Neurotoxin Injections

Different veterinary clinics in Berlin, Germany tested the effect of intramuscular tetanus neurotoxin (TeNT) injections for the improvement of motor functions due to spinal cord injuries (SCI) in dogs. The experiment (Hesse et al., 2020) took place over 2-157 weeks on four dogs, which had previous unsuccessful treatments for their paraplegia, such as operative decompression and physiotherapy. As the name states, naturally emerged Tetanus is a neurotoxin that can be very dangerous, especially as a fault of wound infections. It may result in uncontrolled muscle spasms, rigidity, and autonomic symptoms. Nevertheless, low doses of TeNT have been shown to have a therapeutic effect on muscle weaknesses.

The use of TeNT which is a protein produced by the bacterium Clostridium tetani causes disinhibition and enablement of motor neuron activity by prohibiting the fusion of vesicles containing the inhibitory neurotransmitters glycine and GABA. Those two amino acids are known to be the most abundant inhibitory neurotransmitters in the spinal cord and brainstem. They participate in the information exchange of motor and sensory information that permits movement.

Before administration, the TeNT was diluted within phosphate-buffered saline (PBS) with bovine serum albumin (BSA) to reach the final concentration. The quantification of the TeNT dose for each dog was developed on previous experiments in vivo mice, based on the dog’s body weight in ratio to the mice’s weight, motor deficits, and also depended on the chosen muscle. Each dog had different injections sides and intervals based on their needs and damaged muscles.

4 and 6 weeks after injections, the dogs' recovery was evaluated on whether they had painful muscle spasms at rest and during movement, as well as checking for possible side effects on different body parts. During the entire experiment, the owners were obligated to report any painful muscle spasms.

The assessment of effects of intramuscular tetanus neurotoxins injections was established on five stages of recovery, each stage was subdivided into 3 interstages which resulted all together in a scale from 0 to 14 scores. The main focus of this scale was the motor function such as standing and walking ability (“Table 1”, Hesse et al., 2020).

"Table 1": "Modified functional scoring system in dogs (mFSSD)", (Hesse et al., 2020).

At the end of the study, it can be stated that the injection procedures caused no harm or stress to the animals, nor did they suffer any side effects or muscle cramps. Dog #1 went from a scale score of 0 to a score of 3 on the right side and had no improvement on the left (“Figure 1” Hesse et al., 2020). It was able to stand on all four limbs without any support for 30 seconds. However, as soon as head or forelimb movement occurred the hindlimbs collapsed and walking was not possible even with full-weight support. The right limb showed a big improvement during crawling by actively supporting the change of position.

Bild1.png

"Figure 1”: “Pre and Post Tetanus Injections Dog #1”, (Hesse et al., 2020)

Dog #2 went from a scale score of 8 to a score of 11 on the right side, with no treatment on the left uninjured side (“Figure 2”, Hesse et al., 2020). The dog’s main problem before the treatment was a chronic wounded right paw because of misalignment. After four weeks the dog was able to walk without injuring the right paw.

Bild2.png

"Figure 2”: “Pre and Post Tetanus Injections Dog #2”, (Hesse et al., 2020)

Dog #3 started on a scale score of 5 on the left side and a score of 6 on the right side and progressed to a score of 10 on both sides (“Figure 3more than a minute and take 10-15 full-weight-bearing steps.

Bild3.png

"Figure 3”: “Pre and Post Tetanus Injections Dog #3” (Hesse et al., 2020)

The initial score of dog #4 was 3 on the right and 4 on the left side and its final score was 9 (“Figure 4” Hesse et al., 2020). It was able to stand for 30 seconds even with additional head movements. It was able to crawl/walk up to ten weight-bearing steps.

Bild4.png

"Figure 4”: “Pre and Post Tetanus Injections Dog #4” (Hesse et al., 2020)

The small doses of TeNT have been shown only to have a local, temporary, and none spread/ generalized effect, not like TeNT toxication produced by wound infections. The experimental dogs have only shown positive effects of this treatment, such as an increased activity and tone of the hind limb muscles, restored gait cycles, and reactivation of the central pattern generators (CPGs). The CPGs are biological neural circuits that are identified as neuron networks located in the lumbar spinal cord, which is responsible for the production of central commands and controlling rhythmic motor behavior.

Due to the short research time, the reasoning behind each improvement was not found but it can be declared that the greatest progress was the increase of muscle mass throughout the treatment. Almost full recovery of the muscle has been seen after the injections. This might be due to the increased alpha-motor neuron activity and/or higher levels of spontaneous or reflective motor neuron activation which resulted due to the disinhibition and enablement of motor neuron activity effect by TeNT.

2.2 Stem Cell Intrspinal Transplantation

This study (Escalhão et al., 2017) investigates the use of adipose stem cells in dogs with severe spinal cord injuries. Previous studies have tested dogs in the acute phase of spinal cord injuries, however very few tested in the chronic phase. Treatment of an acute spinal cord injury (SCI) includes surgically decompressing and stabilizing the spinal cord to avoid chronic development and promote internal repairing.

In the chronic stage, deep pain perception is lost. There are no standard treatments for chronic dogs. Experimental methods focus on new connections between neurons (synaptic plasticity) to regain deep pain perception, axonal sprouting to reinnervate muscle and sustain mobility, and axonal regeneration to reinnervate previously denervated organs or tissue.

"Table 2”: Breed, Sex, Age, and Weight of each dog” (Escalhão et al., 2017)

Table 2 (Escalhão et al., 2017) shows the breed, sex, age, and weight of each dog in the study. It shows how the injury occurred and its location in the spine. The method to examine the injury is shown. It includes the time between the injury and start of the study.

In this study, 6 dogs with chronic lesions from trauma or IVDD (intervertebral disc disease) were used. All dogs lost deep pain perception at least 6 months prior to experimentation. Three had surgery for the injury before the injection.

Mesenchymal stem cells (MSC) for regeneration and tissue repairs have previously been isolated from several areas, adipose tissue being the most abundant and available source. These MSCs are called adipose tissue-derived mesenchymal stem cells (AT-MSCs).

AT-MSCs produce neurotrophic factors which control cell proliferation and differentiation in the nervous system. AT-MSCs can protect against hypoxic ischemic encephalopathy (HIE), a condition when the brain doesn't receive enough oxygen or blood. They can also prevent glutamate neurotoxicity, which can cause neuronal damage and cell death.

AT-MSCs have been studied in acute phase SCIs, showing neurological gains, improved locomotion, and reduced lesion size. Astrogliosis was observed which minimizes and repairs damage after neural injuries.

The AT-MSCs were collected from a healthy 2-year-old dog. They were isolated and expanded in cell cultures then stained with detectable Technetium-99m. The AT-MSCs were injected percutaneously using X-ray imaging. This study focuses on validating the use of this nonsurgical cell transplantation method as safe for further research.

"Figure 5": "Location of Injection site" (Escalhão et al., 2017)

Intravenous chlorpromazine was used as a sedative and propofol was used to induce anesthesia. The dogs were kept anesthetized by isoflurane under continuous monitoring. Each dog was X-rayed to identify the injection site (“Figure 5”, Escalhão et al., 2017) of the labeled AT-MSC into the lesion. Special scans were taken one hour and twenty-four hours after administering the injection to visualize localization of the labeled cells (“Figure 6”, Escalhão et al., 2017)).

"Figure 6”: “Visual localization of the cells” (Escalhão et al., 2017)

After 1 hour, scans showed a labeled spot in the injured spinal segment in 5 dogs. The last dog had smaller labels throughout the body most likely from puncturing a small vessel. These same results were observed 24 hours after. The injected cells remained in the segment with the lesion and did not get into CSF and spread. This technique gave the desired outcome and is simpler than previous methods such as fluoroscopic percutaneous injection or surgical cell grafting.

Postoperative care and daily rehabilitative exercises were maintained for 16 weeks. Complete blood work was done. Renal and liver functions were evaluated before, a week after, and two weeks after the injection. Each dog had physical exams before the injection, 1 week and 2 weeks after, as well as each month for 4 months after the injection. Neurological examinations tested each dogs’ posture, reflexes, sensitivity, and cranial nerve functions. None showed decreased function. Mobility evaluations were performed using the Olby scale between 0 and 14 (14 being normal) focusing on the hindlimbs. This evaluation was completed before the injection and each month for four months afterward. The Olby scale does not differentiate between the two hindlimbs however, it provides a quantitative scale for the progression of the ability to walk independently.

The complete blood work as well as the renal and liver functions remained normal in every dog. None of the dogs recovered deep pain perception or bladder functions. Below each individuals’ results are summarized.

Animal 1 showed no improvement and remained at score 4. The lesion was located at the end of the spinal cord which may be why no improvement was detected. An additional injury may have also been a factor.

Animal 2 had prior surgery for the injury. This animal remained at score 3 but showed improved body movement. Position awareness was absent and changed to diminished 1 month after the injection. This animal stopped self-mutilating its hindlimb paws showing improved sensitivity.

Animal 3 started at a score of 0 and improved to 7 after 4 months. It regained the ability to walk independently after 2 months and continuously stabilized. Future experimentation could test whether a second injection promotes further recovery in chronic SCI patients.

Animal 4 started with 0 and improved to 4 after the injection. It gained joint mobility.

Animal 5 had surgery for the injury but showed no clinical signs of improvement. This dog scored 3 both before and after the injection. This dog was the oldest and most chronic out of the 6.

Animal 6 also had prior surgery and scored 0 before the injection and 3 a month afterward. It gained joint mobility.

2.3 Electroacupuncture

Electroacupuncture is a form of general acupuncture which involves electricity introduced into the needles used to find the disorder in the animal’s body. Acupuncture is a form of alternative treatment which uses the vital force or Chi in other word of the body to help it heal itself. The needles are inserted into special points throughout the body stimulating them and by that the body recognizes the puncture points and invests more energy to restore the given area. Electroacupuncture is best used in cases when the patients suffer from painful neurologic and muscle conditions which became more and more common in pets.

The technique of Electroacupuncture is to insert filiform needles into the acupoinst, which will conduct the electric current that passes through it. Some authors (Dragomir et al., 2021) say that pain and muscle spasm can be best treated with continuous high frequency (80–120 Hz) since it triggers the body to releases endorphins. Low frequency (5–20 Hz) can help with the recovery of motor neurons in paralysis and in general it can boost recuperation from neuralgia and degenerative lesions of the nervous system. Electroacupuncture can be useful as well when a patient can’t go under surgery however it can take from weeks to years until the patient shows progress.

The most frequent condition related to the topic is the intervertebral disc disease. The severity of the condition can be measured from 1 to 5 in connection with the neurological disfunction where 1 is concerning animals with no neurological symptoms whereas 5 is regarding patients with no deep pain perception. In this discussion dogs with specific criteria were examined such as dogs with different stages of intervertebral disc disease and the final diagnosis was made with the help of different imaging techniques like magnetic resonance imaging or computed tomography scans. According to previous treatments, the dogs can be separated to five groups: Group A was composed of dogs that underwent spinal decompression surgery (hemilaminectomy), Group B included dogs who had electro acupuncture before the surgery, and dogs who underwent corticosteroids which are the comparison treatment against the electroacupuncture were put into Group C. In view of this Group E dogs were treated with both Electroacupuncture and corticosteroids and Group E only received the electroacupuncture treatment. The members of the last two groups didn’t get surgery but, in all cases, the neurological recovery rate was examined with the short- and long-term effects. Overall, nine studies could be evaluated according to the different treatments (“Table 3”, Dragomir et al., 2021).

“Table 3”: “Neurological dysfunction recovery” (Dragomir et al., 2021)

In the first study the conclusion that could be made was that the Group D treatment was the most effective in dog diagnosed with ambulatory paresis diagnosed with spinal cord injury. 20 dogs with grade 2 and 3 of neurological dysfunction were examined with Group C, D, and E treatment with an additional control group (no treatment). While the recovery rate for Group D was significantly shorter than the rest there was no remarkable difference between Group C and E.

The second study only involved Group C and D treatment. Dogs with a wide range of neurological disorder from 1 to 5 were registered so success was measured in different ways. The ones with high grade disorders could “succeed” if they could walk with no difficulty and improved their conscious proprioception. Group D was the most successful here as well since it led to outpatient recovery and in-depth pain perception even in dogs with a high rate of neurological disfunction. It was measured via functional neurology score which was set for three weeks, one treatment per week.

To summarize the rest of the studies the 3^rd 7^th and 8^th were including patients with grade 3 and 4 and received electroacupuncture with Chinese herbal medicine treatment and coticotherapy. Four out of five animals could recover without help and they were assigned to Group B and D. The combination or single treatment of surgery and electric acupuncture were inspected in the 4th, 5th, 7th, and 9^th study completed with corticotherapy and herbal medicine in some cases. The results can be seen in table 1. In the case of the 1^st second and 6^th study were based on conventional therapy including Group C and D. From Group C almost half of the dogs could show improvement without neurological deficits, almost one third could walk without assistance. From Group D more than half of the participants recovered ambulance and a little bit less than half could walk without assistance.

3. Conclusion

In conclusion, the three different modern treatment methods for spinal cord injuries that were discussed are very promising for further research. Since there are no standard treatment options for chronic spinal cord injuries in dogs it is vital for researchers to continue studying treatment options to develop a standard treatment. None of the above methods showed disadvantages or negative effects. Despite having a small sample size in the tetanus and adipose stem cell studies, these methods can be further tested on a larger scale to help find new treatment options. The electroacupuncture study used a larger sample size however, it is still not widely used despite the promising results. Further studies on it could show the benefits of combining modern and traditional medical techniques. Overall, these 3 methods could aid in developing a standard treatment method with further research in a wider variety of samples.

4. References

Bennett, J., M Das, J., & Emmady, P. D. (2021). Spinal Cord Injuries. In StatPearls. StatPearls Publishing.

Bowery, N. G., & Smart, T. G. (2006). GABA and glycine as neurotransmitters: a brief history. British journal of pharmacology, 147 Suppl 1(Suppl 1), S109–S119.

Dragomir, M. F., Pestean, C. P., Melega, I., Danciu, C. G., Purdoiu, R. C., & Oana, L. (2021). Current Aspects Regarding the Clinical Relevance of Electroacupuncture in Dogs with Spinal Cord Injury: A Literature Review. Animals : an open access journal from MDPI, 11(1), 219.

Escalhão, C., Ramos, I. P., Hochman-Mendez, C., Brunswick, T., Souza, S., Gutfilen, B., Dos Santos Goldenberg, R. C., & Coelho-Sampaio, T. (2017). Safety of Allogeneic Canine Adipose Tissue-Derived Mesenchymal Stem Cell Intraspinal Transplantation in Dogs with Chronic Spinal Cord Injury. Stem cells international, 2017, 3053759.

Gakiya, H. H., Silva, D. A., Gomes, J., Stevanin, H., & Cassu, R. N. (2011). Electroacupuncture versus morphine for the postoperative control pain in dogs. Acta cirurgica brasileira, 26(5), 346–351.

Hesse, S., Kutschenko, A., Bryl, B., Deutschland, M., & Liebetanz, D. (2020). Therapeutic effects of Tetanus neurotoxin in spinal cord injury: a case series on four dogs. Spinal cord series and cases, 6(1), 9.

Olby N. (1999). Current concepts in the management of acute spinal cord injury. Journal of veterinary internal medicine, 13(5), 399–407.