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Dive into the research topics where Jan H. Spaas is active.

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Featured researches published by Jan H. Spaas.


Cellular Physiology and Biochemistry | 2015

Regenerative Skin Wound Healing in Mammals: State-of-the-Art on Growth Factor and Stem Cell Based Treatments

Bizunesh Mideksa Borena; Ann Martens; Sarah Broeckx; Evelyne Meyer; Koen Chiers; Luc Duchateau; Jan H. Spaas

Mammal skin has a crucial function in several life-preserving processes such as hydration, protection against chemicals and pathogens, initialization of vitamin D synthesis, excretion and heat regulation. Severe damage of the skin may therefore be life-threatening. Skin wound repair is a multiphased, yet well-orchestrated process including the interaction of various cell types, growth factors and cytokines aiming at closure of the skin and preferably resulting in tissue repair. Regardless various therapeutic modalities targeting at enhancing wound healing, the development of novel approaches for this pathology remains a clinical challenge. The time-consuming conservative wound management is mainly restricted to wound repair rather than restitution of the tissue integrity (the so-called “restitutio ad integrum”). Therefore, there is a continued search towards more efficacious wound therapies to reduce health care burden, provide patients with long-term relief and ultimately scarless wound healing. Recent in vivo and in vitro studies on the use of skin wound regenerative therapies provide encouraging results, but more protracted studies will have to determine whether the effect of observed effects are clinically significant and whether regeneration rather than repair can be achieved. For all the aforementioned reasons, this article reviews the emerging field of regenerative skin wound healing in mammals with particular emphasis on growth factor- and stem cell-based therapies.


PLOS ONE | 2014

Regenerative Therapies for Equine Degenerative Joint Disease: A Preliminary Study

Sarah Broeckx; Marieke Zimmerman; Sara Crocetti; Marc Suls; Tom Mariën; Stephen J. Ferguson; Koen Chiers; Luc Duchateau; Alfredo Franco-Obregón; Karin Wuertz; Jan H. Spaas

Degenerative joint disease (DJD) is a major cause of reduced athletic function and retirement in equine performers. For this reason, regenerative therapies for DJD have gained increasing interest. Platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) were isolated from a 6-year-old donor horse. MSCs were either used in their native state or after chondrogenic induction. In an initial study, 20 horses with naturally occurring DJD in the fetlock joint were divided in 4 groups and injected with the following: 1) PRP; 2) MSCs; 3) MSCs and PRP; or 4) chondrogenic induced MSCs and PRP. The horses were then evaluated by means of a clinical scoring system after 6 weeks (T1), 12 weeks (T2), 6 months (T3) and 12 months (T4) post injection. In a second study, 30 horses with the same medical background were randomly assigned to one of the two combination therapies and evaluated at T1. The protein expression profile of native MSCs was found to be negative for major histocompatibility (MHC) II and p63, low in MHC I and positive for Ki67, collagen type II (Col II) and Vimentin. Chondrogenic induction resulted in increased mRNA expression of aggrecan, Col II and cartilage oligomeric matrix protein (COMP) as well as in increased protein expression of p63 and glycosaminoglycan, but in decreased protein expression of Ki67. The combined use of PRP and MSCs significantly improved the functionality and sustainability of damaged joints from 6 weeks until 12 months after treatment, compared to PRP treatment alone. The highest short-term clinical evolution scores were obtained with chondrogenic induced MSCs and PRP. This study reports successful in vitro chondrogenic induction of equine MSCs. In vivo application of (induced) MSCs together with PRP in horses suffering from DJD in the fetlock joint resulted in a significant clinical improvement until 12 months after treatment.


Current Stem Cell Research & Therapy | 2014

Allogenic Mesenchymal Stem Cells as a Treatment for Equine Degenerative Joint Disease: A Pilot Study

Sarah Broeckx; Marc Suls; Charlotte Beerts; Aurélie Vandenberghe; Bert Seys; Karin Wuertz-Kozak; Luc Duchateau; Jan H. Spaas

Cell-based therapies, such as treatments with mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) are thought to have beneficial effects on the clinical outcome of orthopedic injuries, but very few animal studies with large sample size are published so far. Therefore, the aim of this study was to assess the safety and report the clinical outcome of allogenic, immature or chondrogenic induced MSCs in combination with PRP for the treatment of degenerative joint disease (DJD) in 165 horses. MSCs and PRP were isolated from a 6-year-old donor horse and transplanted either in their native state or after chondrogenic induction in combination with PRP into degenerated stifle (n=30), fetlock (n=58), pastern (n=34) and coffin (n=43) joints. Safety was assessed by means of clinical evaluation and the outcome was defined as failure to return to work (score 0), rehabilitation (score 1), return to work (score 2) and return to previous level (score 3), shortly (6 weeks) after treatment or at 18 weeks for the patients that returned for long-term follow-up (n=91). No adverse effects were noticed, except for three patients who showed a moderate flare reaction within one week after treatment of the fetlock joint without long-term effects (1.8% of 165 horses). Already after 6 weeks, 45% (native MSCs) and 60% (chondrogenic induced MSCs) of the treated patients returned to work (→ score 2+3) and the beneficial effects of the treatment further increased after 18 weeks (78% for native MSCs and 86% for chondrogenic induced MSCs). With the odds ratio of 1.47 for short-term and 1.24 for long-term, higher average scores (but statistically not significant) could be noticed using chondrogenic induced MSCs as compared to native MSCs. For all three lower limb joints a higher percentage of the treated patients returned to work after chondrogenic induced MSC treatment, whereas the opposite trend could be noticed for stifle joints. Nevertheless, more protracted follow-up data should confirm the sustainability of these joints.


Current Stem Cell Research & Therapy | 2014

Intravenous Application of Allogenic Peripheral Blood-Derived Mesenchymal Stem Cells: A Safety Assessment in 291 Equine Recipients

Sarah Broeckx; Bizunesh Mideksa Borena; Marieke Zimmerman; Tom Mariën; Bert Seys; Marc Suls; Luc Duchateau; Jan H. Spaas

It has been reported that mesenchymal stem cells (MSCs) have homing capacities and immunomodulating effects after an intravenous injection. However, transplanting MSCs in murine tail veins can result in pulmonary reactions and even death of the animals. Unfortunately, only a few intravenous MSC transplantations have been reported in large animal species and these were performed in a limited number of individuals. To assess the safety of MSC transplantations, a large study on 291 recipient horses is reported here. MSCs were isolated from the peripheral blood (PB) of a 4-year-old and 6-year-old donor horse after having tested their PB for a wide range of transmittable diseases. The MSC samples from both donor horses were characterized and resuspended in 1 ml of Dulbeccos Modified Eagle Medium (DMEM) supplemented with 10% Dimethyl Sulfoxide (DMSO). After hand-thawing in the field, 291 horses with ages ranging from 3-months to 33-years were directly injected into their jugular vein. 281 horses (97%) received a single injection of a physiological dose of 0.2 x10(6) MSCs, 5 horses (1.7%) were re-injected after approximately 6 weeks (using the same dose and donor cells) and a single superphysiological dose of 10(6) MSCs was administered to 5 horses as well. In total, 176 recipients were injected with MSCs from the 4-year-old donor and 115 recipients received MSCs from the 6-year-old donor. From all the injected horses (n=291) no acute clinical adverse effects were noticed. Apart from one horse that died of colic 7 months after the treatment, no deaths were registered and all the horses were monitored for 1 year after the injection. In conclusion, no adverse effects were noticed in 291 recipients after an intravenous injection of allogenic PBderived MSCs. Nevertheless, further research is warranted in order to verify the immunogenic properties of these cells after allogenic transplantation into various (patho)physiological sites.


Clinical and Experimental Dermatology | 2013

The effects of equine peripheral blood stem cells on cutaneous wound healing: a clinical evaluation in four horses.

Jan H. Spaas; Sarah Broeckx; Gerlinde R. Van de Walle; Marco Polettini

Stem‐cell therapy represents a promising strategy for the treatment of challenging pathologies, such as large, infected wounds that are unresponsive to conventional therapies. The present study describes the clinical application of peripheral blood stem cells (PBSCs) for the treatment of four adult Warmblood horses with naturally occurring wounds, which were unresponsive to conventional therapies for at least 3 months. A visual assessment was performed, and a number of wound‐healing parameters (granulation tissue, crust formation and scar formation) were evaluated. In all cases, tissue overgrowth was visible within 4 weeks after PBSC injection, followed by the formation of crusts and small scars in the centre of the wound, with hair regeneration at the edges. In conclusion, this is the first report of PBSC therapy of skin wounds in horses, and it produced a positive visual and clinical outcome.


Stem Cells and Development | 2014

Equine epidermis: a source of epithelial-like stem/progenitor cells with in vitro and in vivo regenerative capacities.

Sarah Broeckx; Sofie Maes; Tiziana Martinello; Désirée Aerts; Koen Chiers; Tom Mariën; Marco Vincenzo Patruno; Alfredo Franco-Obregón; Jan H. Spaas

Besides the presence of somatic stem cells in hair follicles and dermis, the epidermis also contains a subpopulation of stem cells, reflecting its high regenerative capacity. However, only limited information concerning epidermis-derived epithelial-like stem/progenitor cells (EpSCs) is available to date. Nonetheless, this stem cell type could prove itself useful in skin reconstitution after injury. After harvesting from equine epidermis, the purified cells were characterized as EpSCs by means of positive expression for CD29, CD44, CD49f, CD90, Casein Kinase 2β, p63, and Ki67, low expression for cytokeratin (CK)14 and negative expression for CD105, CK18, Wide CK, and Pan CK. Furthermore, their self-renewal capacity was assessed in adhesion as well as in suspension. Moreover, the isolated cells were differentiated toward keratinocytes and adipocytes. To assess the regenerative capacities of EpSCs, six full-thickness skin wounds were made: three were treated with EpSCs and platelet-rich-plasma (EpSC/PRP-treated), while the remaining three were administered carrier fluid alone (PRP-treated). The dermis of EpSC/PRP-treated wounds was significantly thinner and exhibited more restricted granulation tissue than did the PRP-treated wounds. The EpSC/PRP-treated wounds also exhibited increases in EpSCs, vascularization, elastin content, and follicle-like structures. In addition, combining EpSCs with a PRP treatment enhanced tissue repair after clinical application.


Sports Medicine | 2012

Tendon Regeneration in Human and Equine Athletes

Jan H. Spaas; Deborah J. Guest; Gerlinde R. Van de Walle

Tendon injuries are one of the most common orthopaedic problems in both human and equine athletes. When a damaged tendon heals naturally, it loses a substantial part of the original strength and elasticity. Therefore, tendons recover structurally (reparation) but not functionally (regeneration) after conservative medical or surgical treatment. Since the structure and matrix composition of human and equine tendons share many similarities, the nature of tendon injuries are also strongly comparable in both species. Therefore, the evaluation of regenerative therapies in horses may have applications for future human medicine and vice versa. The current review focuses briefly on the physiology of human and equine tendon in order to better comprehend the modus operandi of this structure under pathophysiological circumstances. In addition, the reparative effects of conservative medical and surgical interventions are discussed concisely, and an extensive overview is given on the regenerative therapies that are currently being explored. For the latter, the results of equine clinical studies might prove invaluable for gaining additional insights into the treatment of human tendinopathies, since not all of these novel regenerative therapies have been evaluated in humans yet.


Journal of Tissue Science and Engineering | 2012

Tenogenesis of Equine Peripheral Blood-Derived Mesenchymal Stem Cells: In vitro Versus In vivo

Sarah Broeckx; Marieke Zimmerman; Désirée Aerts; Bert Seys; Marc Suls; Tom Mariën; Jan H. Spaas; Equine Veterinary

Background: Tendon injuries are a major cause of orthopaedic injuries, and often compromise the return to the same performance level. Therefore, different regenerative therapies, such as Mesenchymal Stem Cells (MSCs) and Platelet-rich Plasma (PRP) have been explored to improve tendon healing in horses. However, ectopic bone formation of undifferentiated cells is a major concern, because of reports of this phenomenon, after intralesional injections of MSCs in rabbit Achilles tendons. Methods: After MSC and PRP isolation of the Peripheral Blood (PB) of a donor horse, tenogenic induction of the MSCs (Tendo-Cell®) was confirmed through morphological changes and immunohistochemistry stainings. Secondly, the safety and clinical effects (ultrasound imaging) of Tendo-Cell®, in combination with PRP, was evaluated after a single intralesional injection in the lateral edge of the Superficial Digital flexor tendon (SDFT) (n=10) and the lateral branch of the suspensory ligament (SL) (n=15) in 25 horses. Different independent veterinary practitioners were asked to give a score from 0-5, at approximately 6 weeks after treatment (0=no ultrasonic improvement and 5=no ultrasonic abnormalities, the tendon has the same consistency and fiber orientation as the contralateral tendon). Results: In 96% of the patients, the same positive evolution was noticed on the ultrasound images, and this was translated to a score 3 or more (= 60% improvement or better than a successful conservative therapy). In addition, for both tendons (SDFT & SL), 40% of the horses received a score 5. Conclusion: In conclusion, the present study is the first to describe the treatment of lesions in the SDFT and SL, with allogenic tenogenic induced PB-derived MSCs, in combination with PRP, with a positive outcome in 24 out of the 25 horses.


Sports Medicine | 2012

Tendon regeneration in human and equine athletes: Ubi Sumus-Quo Vadimus (where are we and where are we going to)?

Jan H. Spaas; Deborah J. Guest; Gerlinde R. Van de Walle

Tendon injuries are one of the most common orthopaedic problems in both human and equine athletes. When a damaged tendon heals naturally, it loses a substantial part of the original strength and elasticity. Therefore, tendons recover structurally (reparation) but not functionally (regeneration) after conservative medical or surgical treatment. Since the structure and matrix composition of human and equine tendons share many similarities, the nature of tendon injuries are also strongly comparable in both species. Therefore, the evaluation of regenerative therapies in horses may have applications for future human medicine and vice versa. The current review focuses briefly on the physiology of human and equine tendon in order to better comprehend the modus operandi of this structure under pathophysiological circumstances. In addition, the reparative effects of conservative medical and surgical interventions are discussed concisely, and an extensive overview is given on the regenerative therapies that are currently being explored. For the latter, the results of equine clinical studies might prove invaluable for gaining additional insights into the treatment of human tendinopathies, since not all of these novel regenerative therapies have been evaluated in humans yet.


Stem Cells and Development | 2012

Stem/Progenitor Cells in Non-Lactating Versus Lactating Equine Mammary Gland

Jan H. Spaas; Koen Chiers; Leen Bussche; Christian Burvenich; Gerlinde R. Van de Walle

The mammary gland is a highly regenerative organ that can undergo multiple cycles of proliferation, lactation, and involution. Based on the facts that (i) mammary stem/progenitor cells (MaSC) are proposed to be the driving forces behind mammary growth and function and (ii) variation exists between mammalian species with regard to physiological and pathological functioning of this organ, we believe that studying MaSC from different mammals is of great comparative interest. Over the years, important data has been gathered on MaSC of men and mice, although knowledge on MaSC in other mammals remains limited. Therefore, the aim of this work was to isolate and characterize MaSC from the mammary gland of horses. Hereby, our salient findings were that the isolated equine cells met the 2 in vitro hallmark properties of stem cells, namely the ability to self-renew and to differentiate into multiple cell lineages. Moreover, the cells were immunophenotyped using markers for CD29, CD44, CD49f, and Ki67. Finally, we propose the mammosphere assay as a valuable in vitro assay to study MaSC during different physiological phases since it was observed that equine lactating mammary gland contains significantly more mammosphere-initiating cells than the inactive, nonlactating gland (a reflection of MaSC self-renewal) and, moreover, that these spheres were significantly larger in size upon initial cultivation (a reflection of progenitor cell proliferation). Taken together, this study not only extends the current knowledge of mammary gland biology, but also benefits the comparative approach to study and compare MaSC in different mammalian species.

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