Precise disclosure of methods and protocols is crucial for large scale uptake of stem cell therapies. Here, we present a protocol to isolate adipose-derived regenerative cells, used for a single intracavernous injection as treatment of erectile dysfunction (ED) following radical prostatectomy (RP).
Stem cells are used in many research areas within regenerative medicine in part because these treatments can be curative rather than symptomatic. Stem cells can be obtained from different tissues and several methods for isolation have been described. The presented method for the isolation of adipose-derived regenerative cells (ADRCs) can be used within many therapeutic areas because the method is a general procedure and, therefore, not limited to erectile dysfunction (ED) therapy. ED is a common and serious side effect to radical prostatectomy (RP) since ED often is not well treated with conventional therapy. Using ADRC’s as treatment for ED has attracted great interest due to the initial positive results after a single injection of cells into the corpora cavernosum. The method used for the isolation of ADRC’s is a simple, automated process, that is reproducible and ensures a uniform product. Furthermore, the sterility of the isolated product is ensured because the entire process takes place in a closed system. It is important to minimize the risk of contamination and infection since the stem cells are used for injection in humans. The whole procedure can be done within 2.5-3.5 hours and does not require a classified laboratory which eliminates the need for shipping tissue to an off-site. However, the procedure has some limitations since the minimum amount of drained lipoaspirate for the isolation device to function is 100 g.
Stem cells have the ability to differentiate into different cell types, and they secrete paracrine factors that are thought to promote the healing process in damaged tissue1,2,3,4. They are, therefore, attractive within the field of regenerative medicine, because they can represent a possible curative treatment.
Radical prostatectomy (RP) is the golden curative treatment for patients with low/intermediate risk localized prostate cancer and a life expectancy > 10 years. The aim of the surgery is eradication of the cancer, but it has several side effects. The prevalence of post-prostatectomy incontinence ranges from 2-60% and erectile dysfunction (ED) is experienced by 20-90% of the patients5. Nerve-sparing technique is an option in some patients (Gleason score < 7, low risk of extracapsular disease)5. This technique spares the nerves that are responsible for erection, but even though this is possible, many patients still report ED postoperatively.
Treatment options for penile rehabilitation after RP consist primarily of treatment with PDE-5 inhibitors, injection or instillation therapy and vacuum pumps. Medicaments used for penile rehabilitation differ pharmacologically, but their mechanism of action includes relaxation of the smooth muscle cells in the corpus cavernosum. However, many patients experience treatment failure and never achieve an effect of the medicine that enables intercourse6.
The ED that occurs after RP is thought to be due to structurally irreversible changes7. These changes occur in the cavernous tissue and include apoptosis of the smooth muscle- and endothelial cells and fibrosis. The veno-occlusive mechanism that is responsible for a central part of the erection, is impaired by the changes, resulting in poorer filling and hardness of the penis7.
Many of the patients report that the ED they experience has a negative impact on their quality of life8. They are not ready to give up their sexual activity after surgery and, therefore, a curative therapy for ED is attractive, when the other available treatments for penile rehabilitation fail.
In previous trials, including animal and small phase 1 trials on humans, stem cells have shown promising results as an alternative treatment for ED2,9,10,11,12. Results show that it is safe to use ADRCs, and that the erectile function is significantly improved after a single injection into the corpora cavernosum2,9,10,11,12. Adipose-derived regenerative cells (ADRCs) are thought to support the tissue regeneration by paracrine mechanisms through liberation of multiple hormones, neurotrophic- and other growth factors, cytokines and possibly, micro-RNAs13. In addition, ADRCs are able to differentiate into several mature cell-types including endothelial and vascular muscle cells, cartilage cells, osteocytes and neurons14,15. These properties make stem cells interesting for developing a permanent new treatment for ED.
Stem cells are divided into several groups, basically those derived from the early embryo (embryonic stem cells) and those from adult tissue (adult stem cells). Adult stem cells include mesenchymal stem cells (MSC) that are multipotent and can be found in the bone marrow, adipose tissue, umbilical cord blood, placenta and dental pulp17.
Stem cells from the adipose tissue are easy to get access to, unlike stem cells derived from bone marrow. Harvesting stem cells from bone marrow is a risky and painful procedure compared to liposuction. The number of cells possible to harvest from bone marrow will be limited, while only the patient’s depots of adipose tissue sets the limit for the number of cells that can be harvested. It is, therefore, possible to isolate a large amount of stem cells from the adipose tissue without a subsequent need to culture the cells to obtain a satisfactory amount. The adipose-derived regenerative cells, also often referred to as the stromal vascular fraction (SFV), is composed of many cell types including MSCs, endothelial cells, pericytes, immune cells and progenitors hereof18. These may all play a role in the regenerative process.
The aim of the present study is to investigate the effect of stem cells on ED after RP by using 4 mL of autologous ADRCs isolated from freshly harvested adipose tissue after injection into the corpora cavernosum.
All methods described in the protocol were approved by the Danish National Ethics Committee (No. 37054), The Danish Health and Medicines Authority (EUDRA-CT number 2013-004220-11) and the Danish Data Protection Agency (2008-58-0035). The study was registered at ClinicalTrials.gov (NCT02240823). The study was performed in accordance with the Declaration of Helsinki monitored by the Good Clinical Practice (GCP) unit at Odense University Hospital. ADRC preparation was carried out in an authorized tissue establishment for the handling of human tissues and cells at Odense University Hospital (Danish Health and Medicines Authority, Authorization no. 29035).
1. Recruitment of patient/participants
2. Liposuction
NOTE: Liposuction is an operation that removes fat or lipocytes from the subcutaneous area. This part of the protocol is performed as a standard liposuction and the procedure is performed under sterile conditions in an operating theater. All instruments used under the procedure must be sterile and the surgeon must wear scrubs, sterile surgical gown, sterile gloves, surgical mask and hat.
3. Isolation of ADRCs
NOTE: The isolation process of ADRCs is performed as described in detail in the user manual following the device (see Table of Materials). It is important that the procedure is performed under sterile conditions to ensure that the lipoaspirate is not exposed to any contaminants during the purification of the ADRCs. The time taken for the isolation of ADRCs depends of the volume of lipoaspirate, but the whole procedure will approximately take 2.5 h using the semi-automatic device as described here.
4. Implantation of the ADRCs into corpora cavernosum
NOTE: This is a sterile procedure. All instruments must be sterile, and the person injecting the solution containing the stem cells into the corpora cavernosum must wear sterile gloves. The patient is awake during this procedure and will receive his own stem cells. The ADRCs are injected without counting the cells prior to injection.
5. Postoperative care
The presented procedure has been used for an open-label Phase 1 clinical trial including 21 patients19. The primary endpoint of the trial was safety of the use of ADRC’s in humans and secondary endpoint was the effect of ADRC’s on the erectile function.
Twenty-one men were included in the trial with a mean age of 60 years (range 46-69) and a normal erection and active sex life before the RP due to prostate cancer. They all suffered from ED after the RP, with no signs of recovery from medicine available for penile rehabilitation. Six men suffered from incontinence as a side effect to the RP. All men received a single intracavernous injection of ADRC’s isolated with the presented method.
All 21 men were followed up with 4 visits in the outpatient clinic at 1,3,6 and 12 months after the injection. The sexual function was evaluated with validated questionnaires – the International Index of Erectile Function-5 (IIEF-5) and Erection Hardness Score (EHS) (Attached as appendices).
No serious events occurred during the in the time of observation. Eight men reported transient redness and swelling at the injection sites, three reported reaction in the penile area. Eight experienced reversible minor events related to the liposuction were reported such as light abdominal discomfort and minor abdominal hematomas. No patients reported discomfort at the 1 month follow up. Eight out of fifteen (53%) in the continent group reported the erectile function were sufficient for intercourse at 12 months. The group of 6 incontinent men did not show any improvement of erectile function.
Continent | Incontinent | |
Included patients | 15 | 6 |
Significant effect | 8 | 0 |
Table 1: The table shows the differences in significant effect of the treatment between continent and incontinent patients.
The presented procedure for isolating ADRCs is not limited to be used only for ED therapy, but can be used in multiple other forms of treatment and experiments. Our trial showed that autologous, freshly isolated ADRCs are safe to use, and the treatment is well tolerable in a 12 month follow up.
Before the procedure is used there are some considerations to be made. A disadvantage of this procedure is that the patient must be under general anesthesia during the liposuction. Liposuction is possible to perform under local anesthesia, but a previous trial has shown that a combination of local anesthetics and adrenaline may have a negative impact on cell growth of fibroblasts20. The risk of being under general anesthesia is generally low, but a negative outcome is still seen. This risk must be taken in mind when patients are selected for the treatment. Liposuction is a surgical procedure and will, therefore, always carry at risk of complications. As with all other surgical procedures, there is a risk of post-operative bleeding resulting in formation of hematomas and a risk of infection. Some of our patients did also report a transient reduced sensitivity of the abdominal skin. An immediate complication to liposuction is bleeding. It is known that patients risk getting systemic complications when large amounts of tissue is removed. The liposuction in this procedure was relatively small and therefore not considered a risk factor.
Complications to the injection of cells is reported as transient redness, tenderness, and hematomas.
The device used for the isolation of the ADRCs, was chosen because the system is CE approved. In Denmark, it is mandatory to use CE approved equipment because the authorities categorize treatment with stem cells as a drug testing trial, when the ADRC is used for injection in humans.
The device does have advantages such as the whole procedure being standardized and performed in a closed sterile environment without requiring a highly classified laboratory. The risk of contamination is, therefore, reduced. This ensures that the procedure is uniform and reproducible, and that the quality of the end-product is always the same each time (however, it also depends on the quality of the input tissue). Performing the isolation on the device is easy and does not require specially educated operators.
One limitation of the device is that the minimum input into the machine is 100 g drained lipoaspirate. As the liposuction is completely finished before the cell processing starts (and in our case, at a different location, not in the OR) in our experience, this will require the amount of lipoaspirate to be at least 125 mL using the rough measure of the 50 mL syringes. Otherwise there is a risk that there will not be enough material for the machine to proceed with. Also, using the upper end limit (max input is 425 mL) would result in a very long isolation procedure.
Adult stem cells from both adipose tissue and bone marrow seem to have capacity for self-renewal and differentiation like embryonic stem cells. One of the advantages of ADRCs over haemopoietic stem cells is a 100-500 times higher yield per tissue volume as compared to bone marrow21,22, and, therefore, ADRCs do not need to be cultured. Furthermore, haemopoietic stem cells are more difficult and more painful to harvest from the patient than adipose tissue. In many situations, adipose tissue is just a waste product after surgery. It is possible to culture stem cells to give a higher yield suitable for angiogenesis, however freshly isolated ADRC’s may have higher angiogenic potential than cultured23.
The authors have nothing to disclose.
This work has been founded by Odense University Hospital (11/31936), The Danish Centre for Regenerative Medicine (14/50427) and the Danish Cancer Society.
Liposuction | |||
Abdominal Binder | Dale | Size depent of the patient | |
Adhessive OP-towel | Mölnlycke Health Care | 906677 | 90×75 cm |
Adrenalin 1 mg/ml | Amgros I/s | 74 44 23 | 1 ml |
Basic OP supplies | Mölnlycke Health Care | 97010873-07 | |
Carbon Steel blade 11 | Swann-Morton | ||
Chlorhixidine Ethanol | Faarborg Pharma | 5% colored | |
Disposable set Lipocollector 3 | Human Med | 670200 | |
Extension hoses | Extrudan | 5.8/8.3 mm, Ch 25, 3,5 M long | |
Gaze Rags | Barrier | 175201 | 30×45 cm |
Jelonet | Smith and Nephew Medical Ltd | 90509225 | 10 x 10 cm |
Marcaine 5 mg/ml + Adrenaline 5 micrigram | Astra Zeneca | 20 mL | |
Mesorb Bandage | Mölnlycke Health Care | 677001 | 10×13 cm |
Microlance | Becton Dickinson | 304622 | 18 G + 23 G |
Monocryl suture | Ethicon | 04:00 | |
Ringer-lactat | Fresinus Kabi | ||
Sterile gloves | Gammex | 330052065 | |
Surgical Gown | Mölnlycke Health Care | 690103-01 | |
Surgical Marker | Richard-Allan | ||
Surgical Mask | 3M | ||
Syringe | Codan Medical | 6,28,402 | 50/60 ml cath tip |
Syringe | Becton Dickinson | 700016181 | 1 ml |
WAL- Applikator for cannulae 25/30 cm | Human Med | REF 500001 | |
Isolation of ADRC's | |||
1 ml Syringe | Becton Dickinson | REF 303172 | |
3 way stopcock | One Med | REF 10554-01 | |
Adhesive OP-towel | Mölnlycke Health Care AB | REF 906677 | 90×75 cm |
Cytori Celution 800IV device | Cytori | ||
Desinfection swaps | Mediq Danmark | 3340010 | |
Microlance | Becton Dickinson | 25G (0,5*25 mm) | |
Nitril Gloves | Abena | Powder free | |
OR drape Sheet, 2 layers | Lohmann & Rauscher | REF 33005 | |
Ringers Lactate | Fresinus Kabi | 06756 (DK) | |
Sterile gloves | |||
Sterile gown | |||
Supplemental kit for Cytori Celution 800IV devise | Cytori | ||
Termometer | Thomas Scientific | traceable | |
Injection of ADRC's | |||
Aperture drape | One Med | REF1565-01 | 75*90 cm |
Desinfection swap | Mediq Danmark | 3340010 | |
Pean | Leibinger | 32-01257 | |
Silicone Vessel Loop | Purple Surgical | REF PS3203 | |
Sterile gloves | Sempermed | Or Use your favorite |