FK506 and the role of immunophilins in nerve regeneration

Sustained Release of Tacrolimus Embedded in a Mixed Thermosensitive Hydrogel for Improving Functional Recovery of Injured Peripheral Nerves in Extremities

Vascularized composite allotransplantation is an emerging strategy for the reconstruction of unique defects such as amputated limbs that cannot be repaired with autologous tissues. In order to ensure the function of transplanted limbs, the functional recovery of the anastomosed peripheral nerves must be confirmed. The immunosuppressive drug, tacrolimus, has been reported to promote nerve recovery in animal models. However, its repeated dosing comes with risks of systemic malignancies and opportunistic infections. Therefore, drug delivery approaches for locally sustained release can be designed to overcome this issue and reduce systemic complications. We developed a mixed thermosensitive hydrogel (poloxamer (PLX)-poly(l-alanine-lysine with Pluronic F-127) for the time-dependent sustained release of tacrolimus in our previous study. In this study, we demonstrated that the hydrogel drug degraded in a sustained manner and locally released tacrolimus in mice over one month without affecting the systemic immunity. The hydrogel drug significantly improved the functional recovery of injured sciatic nerves as assessed using five-toe spread and video gait analysis. Neuroregeneration was validated in hydrogel-drug-treated mice using axonal analysis. The hydrogel drug did not cause adverse effects in the mouse model during long-term follow-up. The local injection of encapsulated-tacrolimus mixed thermosensitive hydrogel accelerated peripheral nerve recovery without systemic adverse effects.

Electrical stimulation or tacrolimus (FK506) alone enhances nerve regeneration and recovery after nerve surgery, while dual use reduces variance and combines strengths of each in promoting enhanced outcomes

INTRODUCTION/AIMS

Repaired nerve injuries can fail to achieve functional recovery. Therapeutic options beyond surgery, such as systemic tacrolimus (FK506) and electrical stimulation (E-stim), can improve recovery. We tested whether dual administration of FK506 and E-stim enhances regeneration and recovery more than either therapeutic alone.

METHODS

Rats were randomized to four groups: E-stim, FK506, FK506 + E-stim, and repair alone. All groups underwent tibial nerve transection and repair. Two sets of animals were created to measure outcomes of early nerve regeneration using nerve histology (n = 36) and functional recovery (n = 42) (21- and 42-day endpoints, respectively). Functional recovery was measured by behavioral analyses (walking track and grid walk) and, at the endpoint, muscle mass and force.

RESULTS

Dual E-stim and FK506 administration produced histomorphometric measurements of nerve regeneration no different than either therapeutic alone. All treatments were superior to repair alone (FK506, P < .0001; E-stim, P < .05; FK506 + E-stim, P < .05). The E-stim and FK506 + E-stim groups had improved behavioral recovery compared with repair alone (at 6 weeks: E-stim, P < .05; FK506 + E-stim, P < .01). The FK506 group had improved recovery based on walking-track analysis (at 6 weeks: P < .001) and muscle force and mass (P < .05). The concurrent use of both therapies ensured earlier functional recovery and decreased variability in functional outcomes compared with either therapy alone, suggesting a moderate benefit.

DISCUSSION

Dual administration of FK506 and E-stim showed minimal additive effects to further improve regeneration or recovery compared with either therapy alone. The data suggest the combination of FK506 and E-stim appears to combine the relative strengths of each therapeutic.

Synthetic Pharmacotherapy for Systemic Lupus Erythematosus: Potential Mechanisms of Action, Efficacy, and Safety

The pharmacological treatment of systemic lupus erythematosus (SLE) aims to decrease disease activity, progression, systemic compromise, and mortality. Among the pharmacological alternatives, there are chemically synthesized drugs whose efficacy has been evaluated, but which have the potential to generate adverse events that may compromise adherence and response to treatment. Therapy selection and monitoring will depend on patient characteristics and the safety profile of each drug. The aim of this review is to provide a comprehensive understanding of the most important synthetic drugs used in the treatment of SLE, including the current treatment options (mycophenolate mofetil, azathioprine, and cyclophosphamide), review their mechanism of action, efficacy, safety, and, most importantly, provide monitoring parameters that should be considered while the patient is receiving the pharmacotherapy.

Tyrphostin A9 protects axons in experimental autoimmune encephalomyelitis through activation of ERKs

AIMS

Small molecule compound tyrphostin A9 (A9), an inhibitor of platelet-derived growth factor (PDGF) receptor, was previously reported by our group to stimulate extracellular signal-regulated kinase 1 (ERK1) and 2 (ERK2) in neuronal cells in a PDGF receptor-irrelevant manner. The study aimed to investigate whether A9 could protect axons in experimental autoimmune encephalomyelitis through activation of ERKs.

MAIN METHODS

A9 treatment on the protection on neurite outgrowth in SH-SY5Y neuroblastoma cells and primary substantia nigra neuron cultures from the neurotoxin MPP+ were analyzed. Then, clinical symptoms as well as ERK1/2 activation, axonal protection induction, and the abundance increases of the regeneration biomarker GAP-43 in the CNS in the relapsing-remitting experimental autoimmune encephalomyelitis (EAE) model were verified.

KEY FINDINGS

A9 treatment could stimulate neurite outgrowth in SH-SY5Y neuroblastoma cells and protect primary substantia nigra neuron cultures from the neurotoxin MPP+. In the relapsing-remitting EAE model, oral administration of A9 successfully ameliorated clinical symptoms, activated ERK1/2, induced axonal protection, and increased the abundance of the regeneration biomarker GAP-43 in the CNS. Interestingly, gene deficiency of ERK1 or ERK2 disrupted the beneficial effects of A9 in MOG-35-55-induced EAE.

SIGNIFICANCE

These results demonstrated that small molecule compounds that stimulate persistent ERK activation in vitro and in vivo may be useful in protective or restorative treatment for neurodegenerative diseases.

Tacrolimus Decreases Cognitive Function by Impairing Hippocampal Synaptic Balance: a Possible Role of Klotho

The influence of long-term tacrolimus treatment on cognitive function remains to be elucidated. Using a murine model of chronic tacrolimus neurotoxicity, we evaluated the effects of tacrolimus on cognitive function, synaptic balance, its regulating protein (Klotho), and oxidative stress in the hippocampus. Compared to vehicle-treated mice, tacrolimus-treated mice showed significantly decreased hippocampal-dependent spatial learning and memory function. Furthermore, tacrolimus caused synaptic imbalance, as demonstrated by decreased excitatory synapses and increased inhibitory synapses, and downregulated Klotho in a dose-dependent manner; the downregulation of Klotho was localized to excitatory hippocampal synapses. Moreover, tacrolimus increased oxidative stress and was associated with activation of the PI3K/AKT pathway in the hippocampus. These results indicate that tacrolimus impairs cognitive function via synaptic imbalance, and that these processes are associated with Klotho downregulation at synapses through tacrolimus-induced oxidative stress in the hippocampus.

Is it Worth Starting Sexual Rehabilitation Before Radical Prostatectomy? Results From a Systematic Review of the Literature

Background and Purpose: Sexual dysfunction (SD) is a frequent side effect associated with radical prostatectomy (RP) for prostate cancer (PCa). Some studies have showed the benefit associated with preoperative sexual rehabilitation (prehabilitation) and Enhanced Recovery After Surgery (ERAS) for RP, but no clear clinical recommendations are available yet. Our aim was to conduct a systematic review on sexual prehabilitation prior to RP for patients with a localized PCa and analyze the impact on postoperative sexual health compared with the standard post-operative care. Methods: We performed a systematic review of the literature following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) recommendations. Results: Four randomized control trials and one retrospective comparative study were included in the analyses. Three of the five studies showed an improved EF recovery post-RP in the prehabilitation group compared to the standard of care represented by: higher International Index of Erectile Function 5 score (IIEF5) or IIEF score (p < 0.0001) and a higher percentage of patients reporting return of EF based on the Sexual Encounter Profile (SEP) (56 vs. 24%, p = 0.007). Self-confidence, therapeutic alliance, and adherence to treatment were stronger for patients with preoperative consultations (p < 0.05) and EF recovery was better in cases of a higher number of follow-up visits (OR 4-5 visits vs. 1:12.19, p = 0.002). Discussion: Despite heterogenous methods and high risks of bias in this systematic review, starting sexual rehabilitation prior to surgery seems to ensure better EF recovery. This prehabilitation should include information of both the patient and his or her partner, with a closer follow up and the use of a multimodal treatment approach that still remains to be defined and validated (oral medication, vacuum devices, pelvic floor muscle training, etc.).

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Innovations and Future Directions in Head and Neck Microsurgical Reconstruction

Head and neck reconstructive microsurgery is constantly innovating because of a combination of multidisciplinary advances. This article examines recent innovations that have affected the field as well as presenting research leading to future advancement. Innovations include the use of virtual surgical planning and three-dimensional printing in craniofacial reconstruction, advances in intraoperative navigation and imaging, as well as postoperative monitoring, development of minimally invasive reconstructive microsurgery techniques, integration of regenerative medicine and stem cell biology with reconstruction, and the dramatic advancement of face transplant.

Local delivery of FK506 to injured peripheral nerve enhances axon regeneration after surgical nerve repair in rats

Administration of FK506, an FDA approved immunosuppressant, has been shown to enhance nerve regeneration following peripheral nerve injuries. However, the severe side effects of the systemically delivered FK506 has prevented clinicians from the routine use of the drug. In this study, we analyzed the effectiveness of our fibrin gel-based FK506 delivery system to promote axon regeneration in a rat peripheral nerve transection and immediate surgical repair model. In addition, biodistribution of FK506 from the local delivery system to the surrounding tissues was analyzed in vivo. Rats in the negative control groups either did not receive any delivery system treatment or received fibrin gel with empty microspheres. The experimental groups included rats treated with fibrin gel loaded with solubilized, particulate, and poly(lactic-co-glycolic) acid microspheres-encapsulated FK506. Rats in experimental groups receiving FK506 microspheres and the particulate FK506 regenerated the highest number of motor and sensory neurons. Histomorphometric analysis also demonstrated greater numbers of myelinated axons following particulate FK506 and FK506 microspheres treatment compared to the negative control groups. In biodistribution studies, FK506 was found at the nerve repair site, the sciatic nerve, and spinal cord, with little to no drug detection in other vital organs. Hence, the local application of FK506 via our delivery systems enhanced axon regeneration whilst avoiding the toxicity of systemic FK506. This local delivery strategy represents a new opportunity for clinicians to use for cases of peripheral nerve injuries. STATEMENT OF SIGNIFICANCE: This work for the first time investigated the influence of locally administered FK506 to the site of nerve injury and immediate repair directly on the number of motor and sensory neurons that regenerated their axons. Furthermore, using the immediate nerve repair model, we obtained valuable information about the biodistribution of FK506 within the nervous system following its release from the delivery system implanted at the site of nerve injury and repair. The strategy of local FK506 delivery holds a great promise in the clinical translation, as the localized delivery circumvents the main limitation of the systemic delivery of FK506, that of immunosuppression and toxicity.

Local FK506 delivery at the direct nerve repair site improves nerve regeneration

INTRODUCTION

The objective of this study is to assess the efficacy of local tacrolimus (FK506) delivery to improve outcomes in the setting of nerve transection injury.

METHODS

FK506 embedded poly(lactide-co-caprolactone) films capable of extended, localized release of FK506 were developed. FK506 rate of release testing and bioactivity assay was performed. Mouse sciatic nerve transection and direct repair model was used to evaluate the effect extended, local delivery of FK506 had on nerve regeneration outcomes.

RESULTS

Linear release of FK506 was observed for 30 days and released FK506 matched control levels of neurite extension in the dorsal root ganglion assay. Groups treated with local FK506 had greater gastrocnemius muscle weight, foot electromyogram, and number of axons distal of the repair site than non-FK506 groups.

DISCUSSION

Results of this study indicate that extended, localized delivery of FK506 to nerve injuries can improve nerve regeneration outcomes in a mouse sciatic nerve transection and repair.

Comparing electrical stimulation and tacrolimus (FK506) to enhance treating nerve injuries

INTRODUCTION

Neuroenhancing therapies are desired because repair of nerve injuries can fail to achieve recovery. We compared two neuroenhancing therapies, electrical stimulation (ES) and systemic tacrolimus (FK506), for their capabilities to enhance regeneration in the context of a rat model.

METHODS

Rats were randomized to four groups: ES 0.5 mA, ES 2.0 mA, FK506, and repair alone. All groups underwent tibial nerve transection and repair, and outcomes were assessed by using twice per week walking track analysis, cold allodynia response, relative muscle mass, and nerve histology.

RESULTS

Electrical stimulation and FK506 groups demonstrated improved functional recovery and myelinated axon counts distal to the repair compared with repair alone. Electrical stimulation provided improvements in nerve regeneration that were not different from optimized FK506 systemic administration.

DISCUSSION

Providing ES after nerve repair improved regeneration and recovery in rats, with minimal differences in therapeutic efficacy to FK506, further demonstrating its clinical potential to improve management of nerve injuries.

FKBP Ligands-Where We Are and Where to Go?

In recent years, many members of the FK506-binding protein (FKBP) family were increasingly linked to various diseases. The binding domain of FKBPs differs only in a few amino acid residues, but their biological roles are versatile. High-affinity ligands with selectivity between close homologs are scarce. This review will give an overview of the most prominent ligands developed for FKBPs and highlight a perspective for future developments. More precisely, human FKBPs and correlated diseases will be discussed as well as microbial FKBPs in the context of anti-bacterial and anti-fungal therapeutics. The last section gives insights into high-affinity ligands as chemical tools and dimerizers.

Controlled release of FK506 from micropatterned PLGA films: potential for application in peripheral nerve repair

After decades of research, peripheral nerve injury and repair still frequently results in paralysis, chronic pain and neuropathies leading to severe disability in patients. Current clinically available nerve conduits only provide crude guidance of regenerating axons across nerve gap without additional functionality. FK506 (Tacrolimus), an FDA approved immunosuppressant, has been shown to enhance peripheral nerve regeneration but carries harsh side-effects when delivered systemically. The objective of this study was to develop and evaluate a bioresorbable drug delivery system capable of local extended delivery of FK506 that also provides topological guidance cues to guide axon growth via microgrooves. Photolithography was used to create micropatterned poly(lactide-co-glycolic acid) (PLGA) films embedded with FK506. Non-patterned, 10/10 μm (ridge/groove width), and 30/30 μm patterned films loaded with 0, 1, and 3 μg/cm² FK506 were manufactured and characterized. In vitro FK506 rate of release testing indicated that the films are capable of an extended (at least 56 days), controlled, and scalable release of FK506. Neurite extension bioactivity assay indicated that FK506 released from the films (concentration of samples tested ranged between 8.46–19.7 ng/mL) maintained its neural bioactivity and promoted neurite extension similar to control FK506 dosages (10 ng/mL FK506). The multi-functional FK506 embedded, micropatterned poly(lactide-co-glycolic acid) films developed in this study have potential to be used in the construction of peripheral nerve repair devices.

Tacrolimus as an adjunct to autologous minced muscle grafts for the repair of a volumetric muscle loss injury

BACKGROUND

Volumetric muscle loss (VML) following extremity orthopaedic trauma or surgery results in chronic functional deficits and disability. A current translational approach to address the devastating functional limitations due to VML injury is the use of an autologous minced muscle graft (~1 mm3 pieces of muscle tissue) replacement into the injured defect area, although limitations related to donor site morbidity are still unaddressed. This study was designed to explore adjunct pharmacological immunomodulation to enhance graft efficacy and promote muscle function following VML injury, and thereby reduce the amount of donor tissue required.

FINDINGS

Using a validated VML porcine injury model in which 20% of the muscle volume was surgically removed, this study examined muscle function over 3 months post-VML injury. In vivo isometric torque of the peroneus teritus (PT) muscle was not different before surgery among sham, non-repaired, non-repaired with tacrolimus, graft-repaired, and graft-repaired with tacrolimus VML groups. Bi-weekly torque analysis of the VML injured musculature presented a significant strength deficit of ~26% compared to pre-injury in the non-repaired, non-repaired with tacrolimus, and graft-repaired groups. Comparatively, the strength deficit in the graft-repair with systemic tacrolimus was marginally improved (~19%; p = 0.056). Both of the minced graft repaired groups presented a greater proportion of muscle tissue in full-thickness histology specimen.

CONCLUSIONS

We demonstrate that adjunctive use of tacrolimus with an ~50% minced muscle graft replacement resulted in modest improvements in muscle function 3 months after injury and repair, but the magnitude of improvement is not expected to elicit clinically meaningful functional improvements.

Impairment of early fracture healing by skeletal muscle trauma is restored by FK506

Background

Heightened local inflammation due to muscle trauma or disease is associated with impaired bone regeneration.

Methods

We hypothesized that FK506, an FDA approved immunomodulatory compound with neurotrophic and osteogenic effects, will rescue the early phase of fracture healing which is impaired by concomitant muscle trauma in male (~4 months old) Lewis rats. FK506 (1 mg/kg; i.p.) or saline was administered systemically for 14 days after an endogenously healing tibia osteotomy was created and fixed with an intermedullary pin, and the overlying tibialis anterior (TA) muscle was either left uninjured or incurred volumetric muscle loss injury (6 mm full thickness biopsy from middle third of the muscle).

Results

The salient observations of this study were that 1) concomitant TA muscle trauma impaired recovery of tibia mechanical properties 28 days post-injury, 2) FK506 administration rescued the recovery of tibia mechanical properties in the presence of concomitant TA muscle trauma but did not augment mechanical recovery of an isolated osteotomy (no muscle trauma), 3) T lymphocytes and macrophage presence within the traumatized musculature were heightened by trauma and attenuated by FK506 3 days post-injury, and 4) T lymphocyte but not macrophage presence within the fracture callus were attenuated by FK506 at 14 days post-injury. FK506 did not improve TA muscle isometric torque production

Conclusion

Collectively, these findings support the administration of FK506 to ameliorate healing of fractures with severe muscle trauma comorbidity. The results suggest one potential mechanism of action is a reduction in local T lymphocytes within the injured musculoskeletal tissue, though other mechanisms to include direct osteogenic effects of FK506 require further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1617-y) contains supplementary material, which is available to authorized users.

Chaperone Proteins in the Central Nervous System and Peripheral Nervous System after Nerve Injury

Injury to axons of the central nervous system (CNS) and the peripheral nervous system (PNS) is accompanied by the upregulation and downregulation of numerous molecules that are involved in mediating nerve repair, or in augmentation of the original damage. Promoting the functions of beneficial factors while reducing the properties of injurious agents determines whether regeneration and functional recovery ensues. A number of chaperone proteins display reduced or increased expression following CNS and PNS damage (crush, transection, contusion) where their roles have generally been found to be protective. For example, chaperones are involved in mediating survival of damaged neurons, promoting axon regeneration and remyelination and, improving behavioral outcomes. We review here the various chaperone proteins that are involved after nervous system axonal damage, the functions that they impact in the CNS and PNS, and the possible mechanisms by which they act.

Effect Of combining FK506 and neurotrophins on neurite branching and elongation

INTRODUCTION

There is a clinical need to improve the outcomes of peripheral nerve regeneration and repair after injury. In addition to its immunosuppressive effects, FK506 (tacrolimus) has been shown to have neuroregenerative properties. To determine biologically relevant local FK506 and growth factor concentrations, we performed an in vitro bioassay using dorsal root ganglion (DRG) from chicken embryos.

METHODS

Neurite elongation and neurite branching were analyzed microscopically after addition of FK506, glial cell line-derived neurotrophic factor (GDNF), and nerve growth factor (NGF), each alone and in combination.

RESULTS

FK506 induced modest neurite elongation (∼500-800 µm) without improving neurite branching significantly. The combination of FK506 with NGF, GDNF, or both, exerted a potentiating or competitive effect on neurite elongation (∼700-1100 µm) based on dosage and competitive effect on neurite branching (∼0.2-0.4).

CONCLUSIONS

These results strongly suggest that the interaction of FK506 with GDNF and NGF mediates distinct enhancement of neurite growth. Muscle Nerve 55: 570-581, 2017.

Robust Axonal Regeneration in a Mouse Vascularized Composite Allotransplant Model Undergoing Delayed Tissue Rejection

Background: Nerve regeneration in vascularized composite allotransplantation (VCA) is not well understood. Allogeneic transplant models experience complete loss of nerve tissue and axonal regeneration without immunosuppressive therapy. The purpose of this study was to determine the impact of incomplete immunosuppression on nerve regeneration. Methods: In this study, transgenic mice (4 groups in total) with endogenous fluorescent protein expression in axons (Thy1-YFP) and Schwann cells (S100-GFP) were used to evaluate axonal regeneration and Schwann cell (SC) migration in orthotopic-limb VCA models with incomplete immunosuppression using Tacrolimus (FK506). Survival and complication rates were assessed to determine the extent of tissue rejection. Nerve regeneration was assessed using serial imaging of axonal progression and SC migration and viability. Histomorphometry quantified the extent of axonal regeneration. Results: Incomplete immunosuppression with FK506 resulted in delayed rejection of skin, muscle, tendon, and bone in the transplanted limb. In contrast, the nerve demonstrated robust axonal regeneration and SC viability based on strong fluorescent protein expression by SCs and axons in transgenic donors and recipients. Total myelinated axon numbers measured at 8 weeks were comparable in all VCA groups and not statistically different from the syngeneic donor control group. Conclusions: Our data suggest that nerve and SCs are much weaker antigens compared with skin, muscle, tendon, and bone in VCA. To our knowledge, this study is the first to prove the weak antigenicity of nerve tissue in the orthotopic VCA mouse model.

Review : c-Jun and the c-Jun Amino-Terminal Kinases: Bipotential Components of the Neuronal Stress Response

Expression of the inducible transcription factor c-Jun in neurons is a common finding after neuronal injury or 'stress,' such as ischemia, excitotoxicity, axon transection, UV irradiation, stimulation by cytokines, or production of such lipid messengers as ceramide. The neuronal 'stress response' displays striking similarities to the stress response of other cell types such as lymphocytes or tumor cells and is characterized by the activation of programs that lead to apoptosis or survival. It is accepted knowledge that c-Jun can act as neuronal 'killer' under in vitro conditions (with the death inducing ligand fas-ligand as novel AP-1 controlled target gene), but there is also growing evidence that c-Jun is linked to neuronal repair or survival. The control of this dichotomous function of c-Jun is not fully understood. Similar to the expression of c-Jun, the transcriptional activation of c-Jun by amino-terminal phosphorylation and the activation of the catalyzing c- Jun amino-terminal kinases (JNK), also called stress activated protein kinases, can also be linked to both neuronal survival and apoptosis. We suggest a model for the control of gene transcription after neuronal stress with activation of JNK and phosphorylation of c-Jun as transcriptional prerequisites, and with asso ciated partners as transcriptional effectors, e.g., by the expression and/or suppression of other transcription factors as activating transcription factor 2 (ATF-2), c-Fos, or JunD. This scenario is complicated by the observation that activity of JNK does not lead automatically to c-Jun phosphorylation. This review summa rizes the role of c-Jun and JNK as down-stream mediators of neuronal stressors and places the function of these molecules in the context of other stressful stimuli and intraneuronal responses. NEUROSCIENTIST 5:147-154, 1999

Assessing the itching intensity using visual analogue scales in atopic dermatitis patients against the background of a therapy with calcineurin inhibitors

Goal. To assess the effect of topical treatment of atopic dermatitis patients with the 0.1% tacrolimus ointment on the itching intensity and skin expression level of growth factor proteins affecting the intensity of cutaneous innervation. Materials and methods. Fifteen patients suffering from atopic dermatitis underwent treatment with the 0.1% tacrolimus ointment. The SCORAD index was calculated to assess the severity of clinical manifestations. The itching intensity was assessed using a visual analogue scale. The skin expression of nerve growth factors, amphiregulin, semaphorin 3A and PGP9.5 protein (a nerve fiber marker) was assessed by the indirect immunofluorescence method. Results. An increased expression of the nerve growth factor and reduced semaphorin 3A expression levels were noted in the patients’ epidermis; there was an increase in the quantity, mean length and fluorescence intensity of PGP9.5+ nerve fibers. As a result of the treatment, the disease severity and itching intensity were reduced, the nerve growth factor expression level was reduced while semaphorin 3A expression level increased in the epidermis, and the mean length and fluorescence intensity of PGP9.5+ nerve fibers was also reduced. A positive correlation among the itching intensity and nerve growth factor expression level, quantity and mean length of PGP9.5+ nerve fibers in the epidermis was revealed, and negative correlation between the itching intensity and semaphorin 3A expression level in the epidermis was established. Conclusion. Topical treatment with the 0.1% Tacrolimus ointment reduces the itching intensity in atopic dermatitis patients, which is related to the therapy-mediated reduction in the epidermis innervation level, decreased expression of epidermal nerve growth factor and increased semaphorin 3A expression level.

Timcodar (VX-853) Is a Non-FKBP12 Binding Macrolide Derivative That Inhibits PPARγ and Suppresses Adipogenesis

Nutrient overload and genetic factors have led to a worldwide epidemic of obesity that is the underlying cause of diabetes, atherosclerosis, and cardiovascular disease. In this study, we used macrolide drugs such as FK506, rapamycin, and macrolide derived, timcodar (VX-853), to determine their effects on lipid accumulation during adipogenesis. Rapamycin and FK506 bind to FK506-binding proteins (FKBPs), such as FKBP12, which causes suppression of the immune system and inhibition of mTOR. Rapamycin has been previously reported to inhibit the adipogenic process and lipid accumulation. However, rapamycin treatment in rodents caused immune suppression and glucose resistance, even though the mice lost weight. Here we show that timcodar (1 μM), a non-FKBP12-binding drug, significantly (p < 0.001) inhibited lipid accumulation during adipogenesis. A comparison of the same concentration of timcodar (1 μM) and rapamycin (1 μM) showed that both are inhibitors of lipid accumulation during adipogenesis. Importantly, timcodar potently (p < 0.01) suppressed transcriptional regulators of adipogenesis, PPARγ and C/EBPα, resulting in the inhibition of genes involved in lipid accumulation. These studies set the stage for timcodar as a possible antiobesity therapy, which is rapidly emerging as a pandemic.

Posterior Reversible Encephalopathy Syndrome After Transplantation: a Review

Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disease. Recently, an increase in the number of transplantations has led to more cases being associated with PRES than what was previously reported. Calcineurin inhibitors (CNIs) are major risk factors for PRES in posttransplantation patients. The mechanisms of the development of PRES remain to be unclear. The typical clinical symptoms of PRES include seizures, acute encephalopathy syndrome, and visual symptoms. The hyperintense signal on fluid-attenuated inversion recovery image is the characteristic of the imaging appearance in these patients. In addition, other abnormal signals distributed in multiple locations are also reported in some atypical cases. Unfortunately, PRES is often not recognized or diagnosed too late due to complicated differential diagnoses, such as ischemic stroke, progressive multifocal leukoencephalopathy, and neurodegenerative diseases. Thus, this review emphasizes the importance of considering the possibility of PRES when neurological disturbances appear after solid organ transplantation or hematopoietic cell transplantation. Moreover, this review demonstrates the molecular mechanisms of PRES associated with CNIs after transplantation, which aims to help clinicians further understand PRES in the transplantation era.

Computational insights into the suicide inhibition of Plasmodium falciparum Fk506-binding protein 35

Malaria is a parasite affecting millions of people worldwide. With the risk of malarial resistance reaching catastrophic levels, novel methods into the inhibition of this disease need to be prioritized. The exploitation of active site differences between parasitic and human peptidyl-prolyl cis/trans isomerases can be used for suicide inhibition, effectively poisoning the parasite without affecting the patient. This method of inhibition was explored using Plasmodium falciparum and Homo sapiens Fk506-binding proteins as templates for quantum mechanics/molecular mechanics calculations. Modification of the natural substrate has shown suicide inhibition is a valid approach for novel anti-malarials with little risk for parasitic resistance.

Landmarks in erectile function recovery after radical prostatectomy

The description of the nerve-sparing technique of radical prostatectomy by Walsh was one of the major breakthroughs in the surgical treatment of prostate cancer in the 20(th) century. However, despite this advance and consequent technological refinements to nerve-sparing surgery, a large proportion of men still suffer from erectile dysfunction (ED) as a complication of prostatectomy. A plethora of therapeutic approaches have been proposed to optimize erectile function recovery in these patients. Several preclinical and translational studies have shown benefits of therapies including PDE5 inhibitor (PDE5I) treatment, immunomodulation, neurotrophic factor administration, and regenerative techniques, such as stem cell therapy, in animal models. However, most of these approaches have either failed to translate to clinical use or have yet to be studied in human subjects. Penile rehabilitation with PDE5Is is currently the most commonly used clinical strategy, in spite of the absence of solid clinical evidence to support its use.

Use of FK506 and bone marrow mesenchymal stem cells for rat hind limb allografts

Dark Agouti rat donor hind limbs were orthotopically transplanted into Lewis rat recipients to verify the effects of bone marrow mesenchymal stem cells on neural regeneration and functional recovery of allotransplanted limbs in the microenvironment of immunotolerance. bone marrow mesenchymal stem cells were intramuscularly (gluteus maximus) injected with FK506 (tacrolimus) daily, and were transplanted to the injured nerves. Results indicated that the allograft group not receiving therapy showed severe rejection, with transplanted limbs detaching at 10 days after transplantation with complete necrosis. The number of myelinated axons and Schwann cells in the FK506 and FK506 + bone marrow mesenchymal stem cells groups were significantly increased. We observed a lesser degree of gastrocnemius muscle degeneration, and increased polymorphic fibers along with other pathological changes in the FK506 + bone marrow mesenchymal stem cells group. The FK506 + bone marrow mesenchymal stem cells group showed significantly better recovery than the autograft and FK506 groups. The results demonstrated that FK506 improved the immune microenvironment. FK506 combined with bone marrow mesenchymal stem cells significantly promoted sciatic nerve regeneration, and improved sensory recovery and motor function in hind limb allotransplant.

FKBP12 regulates the localization and processing of amyloid precursor protein in human cell lines

One of the pathological hallmarks of Alzheimer's disease is the presence of insoluble extracellular amyloid plaques. These plaques are mainly constituted of amyloid beta peptide (A beta), a proteolytic product of amyloid precursor protein (APP). APP processing also generates the APP intracellular domain (AICD). We have previously demonstrated that AICD interacts with FKBP12, a peptidyl-prolyl cis-trans isomerase (PPIase) ubiquitous in nerve systems. This interaction was interfered by FK506, a clinically used immunosuppressant that has recently been reported to be neuroprotective. To elucidate the roles of FKBP12 in the pathogenesis of Alzheimer's disease, the effect of FKBP12 overexpression on APP processing was evaluated. Our results revealed that APP processing was shifted towards the amyloidogenic pathway, accompanied by a change in the subcellular localization of APP, upon FKBP12 overexpression. This FKBP12-overexpression-induced effect was reverted by FK506. These findings support our hypothesis that FKBP12 may participate in the regulation of APP processing. FKBP12 overexpression may lead to the stabilization of a certain isomer (presumably the cis form) of the Thr668-Pro669 peptide bond in AICD, therefore change its affinity to flotillin-1 or other raft-associated proteins, and eventually change the localization pattern and cause a shift in the proteolytic processing of APP.

Analysis of FK506, timcodar (VX-853) and FKBP51 and FKBP52 chaperones in control of glucocorticoid receptor activity and phosphorylation

The immunosuppressive ligand FK506 and the FK506-binding protein FKBP52 are stimulatory to glucocorticoid receptor (GR) activity. Here, we explore the underlying mechanism by comparing GR activity and phosphorylation status in response to FK506 and the novel nonimmunosuppressive ligand timcodar (VX-853) and in the presence and absence of FKBP52 and the closely related protein FKBP51. Using mouse embryonic fibroblast cells (MEFs) deficient knockout (KO) in FKBP51 or FKBP52, we show decreased GR activity at endogenous genes in 52KO cells, but increased activity in 51KO cells. In 52KO cells, elevated phosphorylation occurred at inhibitory serine 212 and decreased phosphorylation at the stimulatory S220 residue. In contrast, 51KO cells showed increased GR phosphorylation at the stimulatory residues S220 and S234. In wild-type (WT) MEF cells, timcodar, like FK506, potentiated dexamethasone-induced GR transcriptional activity at two endogenous genes. Using 52KO and 51KO MEF cells, FK506 potentiated GR activity in 51KO cells but could not do so in 52KO cells, suggesting FKBP52 as the major target of FK506 action. Like FK506, timcodar potentiated GR in 51KO cells, but it also increased GR activity in 52KO cells. Knock-down of FKBP51 in the 52KO cells showed that the latter effect of timcodar required FKBP51. Thus, timcodar appears to have a dual specificity for FKBP51 and FKBP52. This work demonstrates phosphorylation as an important mechanism in FKBP control of GR and identifies the first nonimmunosuppressive macrolide capable of targeting GR action.

Profiling of drug binding proteins by monolithic affinity chromatography in combination with liquid chromatography-tandem mass spectrometry

A new approach for proteome-wide profiling drug binding proteins by using monolithic capillary affinity chromatography in combination with HPLC-MS/MS is reported. Two immunosuppresive drugs, namely FK506 and cyclosporin A, were utilized as the experimental models for proof-of-concept. The monolithic capillary affinity columns were prepared through a single-step copolymerization of the drug derivatives with glycidyl methacrylate and ethylene dimethacrylate. The capillary chromatography with the affinity monolithic column facilitates the purification of the drug binding proteins from the cell lysate. By combining the capillary affinity column purification and the shot-gun proteomic analysis, totally 33 FK506- and 32 CsA-binding proteins including all the literature reported target proteins of these two drugs were identified. Among them, two proteins, namely voltage-dependent anion-selective channel protein 1 and serine/threonine-protein phosphatase PGAM5 were verified by using the recombinant proteins. The result supports that the monolithic capillary affinity chromatography is likely to become a valuable tool for profiling of binding proteins of small molecular drugs as well as bioactive compounds.

Pharmacological mobilization of endogenous stem cells significantly promotes skin regeneration after full-thickness excision: the synergistic activity of AMD3100 and tacrolimus

Stem cell therapy has shown promise in treating a variety of pathologies including skin wounds, but practical applications remain elusive. Here, we demonstrate that endogenous stem cell mobilization produced by AMD3100 and low-dose tacrolimus is able to reduce by 25% the time of complete healing of full-thickness wounds created by surgical excision. Equally important, healing was accompanied by reduced scar formation and regeneration of hair follicles. Searching for mechanisms, we found that AMD3100 combined with low-dose tacrolimus mobilized increased number of lineage-negative c-Kit+, CD34+, and CD133+ stem cells. Low-dose tacrolimus also increased the number of SDF-1-bearing macrophages in the wound sites amplifying the "pull" of mobilized stem cells into the wound. Lineage tracing demonstrated the critical role of CD133 stem cells in enhanced capillary and hair follicle neogenesis, contributing to more rapid and perfect healing. Our findings offer a significant therapeutic approach to wound healing and tissue regeneration.

Calcineurin regulates coordinated outgrowth of zebrafish regenerating fins

Vertebrates develop organs and appendages in a proportionally coordinated manner, and animals that regenerate them do so to the same dimensions as the original structures. Coordinated proportional growth involves controlled regulation between allometric and isometric growth programs, but it is unclear what executes this control. We show that calcineurin inhibition results in continued allometric outgrowth of regenerating fins beyond their original dimensions. Calcineurin inhibition also maintains allometric growth of juvenile fins and induces it in adult fins. Furthermore, calcineurin activity is low when the regeneration rate is highest, and its activity increases as the rate decreases. Growth measurements and morphometric analysis of proximodistal asymmetry indicate that calcineurin inhibition shifts fin regeneration from a distal growth program to a proximal program. This shift is associated with the promotion of retinoic acid signaling. Thus, we identified a calcineurin-mediated mechanism that operates as a molecular switch between position-associated isometric and allometric growth programs.

The effects of cold preservation and subimmunosuppressive doses of FK506 on axonal regeneration in murine peripheral nerve isografts

BACKGROUND

FK506 is a frequently used immunosuppressant with neuroregenerative effects. The neuroregenerative and immunosuppressive mechanisms of FK506, however, are distinct, suggesting that FK506 may stimulate nerve regeneration at lower doses than are needed to induce immunosuppression. The effects of cold preservation, a technique known to improve axonal regeneration through nerve allografts, are not well studied in nerve isografts and are also reported here.

OBJECTIVES

To determine the effects of subimmunosuppressive doses of FK506 and cold preservation on nerve regeneration in isografts.

METHODS

The neuroregenerative properties of immunosuppressive and subimmunosuppressive doses of FK506 were compared in a murine model receiving either fresh or cold preserved nerve isografts. Sixty female BALB/cJ mice were randomized into six groups. Animals in groups I, III and V received fresh nerve isografts. Animals in groups II, IV and VI received cold-preserved nerve isografts. Mice in groups I and II received no medical therapy, while those in groups III and IV received subimmunosuppressive doses of FK506, and those in groups V and VI received immunosuppressive doses as confirmed by mixed lymphocyte reactivity assays. Nerve regeneration was evaluated with histomorphometry and functional recovery was evaluated with walking track analysis.

RESULTS

Pretreatment with cold preservation did not significantly affect neural regeneration. The potent neuroregenerative effect of immunosuppressive doses of FK506 was confirmed, and the ability of subimmunosuppressive doses of FK506 to stimulate axonal regeneration in murine nerve isografts is reported.

CONCLUSIONS

Less toxic subimmunosuppressive doses of FK506 retaining some neuroregenerative properties may have a clinical role in treating extensive nerve injuries.

Molecular Dissection of Cyclosporin A's Neuroprotective Effect Reveals Potential Therapeutics for Ischemic Brain Injury

After the onset of brain ischemia, a series of events leads ultimately to the death of neurons. Many molecules can be pharmacologically targeted to protect neurons during these events, which include glutamate release, glutamate receptor activation, excitotoxicity, Ca²⁺ influx into cells, mitochondrial dysfunction, activation of intracellular enzymes, free radical production, nitric oxide production, and inflammation. There have been a number of attempts to develop neuroprotectants for brain ischemia, but many of these attempts have failed. It was reported that cyclosporin A (CsA) dramatically ameliorates neuronal cell damage during ischemia. Some researchers consider ischemic cell death as a unique process that is distinct from both apoptosis and necrosis, and suggested that mitochondrial dysfunction and Δψ collapse are key steps for ischemic cell death. It was also suggested that CsA has a unique neuroprotective effect that is related to mitochondrial dysfunction. Here, I will exhibit examples of neuroprotectants that are now being developed or in clinical trials, and will discuss previous researches about the mechanism underlying the unique CsA action. I will then introduce the results of our cDNA subtraction experiment with or without CsA administration in the rat brain, along with our hypothesis about the mechanism underlying CsA’s effect on transcriptional regulation.

Effects of topically administered FK506 on sciatic nerve regeneration and reinnervation after vein graft repair of short nerve gaps

Object

Despite the development of various nerve coaptation materials and techniques, achievement of desired functional peripheral nerve regeneration is still inadequate, and repair of peripheral nerve injuries is still one of the most challenging tasks and concerns in neurosurgery. The effect of an FK506-loaded vein graft as an in situ delivery system for FK506 in bridging the defects was studied using a rat sciatic nerve regeneration model.

Methods

A 10-mm sciatic nerve defect was bridged using an inside-out vein graft (IOVG) filled with 10 μl of a carrier-drug dilution (10 ng/ml FK506) in the IOVG/FK506 group. In the IOVG control group, the vein was filled with the same volume of carrier dilution alone. The regenerated fibers were studied 4, 8, and 12 weeks after surgery.

Results

Functional study confirmed faster recovery of the regenerated axons in the IOVG/FK506 group than in the IOVG group (p < 0.05). There was a statistically significant difference between the mean gastrocnemius muscle weight ratios of the IOVG/FK506 and IOVG control groups (p < 0.05). Morphometric indices of regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in the IOVG/FK506 group than in the IOVG control group. Immunohistochemical analysis showed more positive immunoreactivity to S100 protein in the IOVG/FK506 group than in the IOVG control group.

Conclusions

When loaded in a vein graft, FK506 resulted in improvement of functional recovery and quantitative morphometric indices of sciatic nerve. Topical application of this readily available agent offers the benefit of cost savings as well as avoiding the complications associated with systemic administration.

Neuroprotective effects of Tacrolimus (FK-506) and Cyclosporin (CsA) in oxidative injury

The detrimental effects of hypoxic damage to central nervous system lead to energy depletion, free radical formation, lipid peroxidation (LPO), and increased calcium. We hypothesized that in vitro tacrolimus (FK-506) and cyclosporine A (CsA) could be protective against hypoxic damage in spinal cord. Dorsal columns were isolated from the spinal cord of adult rats and injured by exposure to hypoxic condition for 1 h, and treated with FK-506 (0.1 μM) and CsA (0.1 μM). After injury, reperfusion was carried out for 2 h. Tissues were collected, processed for biochemical assays, and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Spinal cord hypoxia caused a significant decrease (P < 0.001) in mitochondrial ATP (30.64%) and tissue reduced glutathione (GSH) (60.14%) content. Conversely, a significant increase (P < 0.001) in tissue LPO level (57.77%) and myeloperoxidase (MPO) activity (461.24%) was observed in hypoxic group. Mitochondrial swelling was also significantly increased in hypoxic group (90.0%). Treatment with either FK-506 or CsA showed that significant neuroprotective effects (P < 0.05-0.01) were measured in various parameters in hypoxic groups. FK-506 and CsA treatment showed increase in ATP by 11.19% and 16.14% while GSH content increased by 66.46% and 77.32%, respectively. Conversely, LPO content decreased by 18.97% and 24.06% and MPO level by 42.86% and 18.66% after FK-506 and CsA treatment. Calcium uptake was also decreased in mitochondria as exhibited by the increase in absorbance by 11.19% after FK-506 treatment. TTC staining also showed increased viability after FK-506 and CsA treatment. In conclusion, present study demonstrates the neuroprotective effect of FK-506 and CsA treatment against spinal cord hypoxia induced damage is mediated via their antioxidant actions.

Effects of FK506 on Hippocampal CA1 Cells Following Transient Global Ischemia/Reperfusion in Wistar Rat

Transient global cerebral ischemia causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the neurotrophic effect of the immunosuppressant agent FK506 in rat after global cerebral ischemia. Both common carotid arteries were occluded for 20 minutes followed by reperfusion. In experimental group 1, FK506 (6 mg/kg) was given as a single dose exactly at the time of reperfusion. In the second group, FK506 was administered at the beginning of reperfusion, followed by its administration intraperitoneally (IP) 6, 24, 48, and 72 hours after reperfusion. FK506 failed to show neurotrophic effects on CA1 region when applied as a single dose of 6 mg/kg. The cell number and size of the CA1 pyramidal cells were increased, also the number of cell death decreased in this region when FK506 was administrated 48 h after reperfusion. This work supports the possible use of FK506 in treatment of ischemic brain damage.

Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration

Surgical repair of severe peripheral nerve injuries represents not only a pressing medical need, but also a great clinical challenge. Autologous nerve grafting remains a golden standard for bridging an extended gap in transected nerves. The formidable limitations related to this approach, however, have evoked the development of tissue engineered nerve grafts as a promising alternative to autologous nerve grafts. A tissue engineered nerve graft is typically constructed through a combination of a neural scaffold and a variety of cellular and molecular components. The initial and basic structure of the neural scaffold that serves to provide mechanical guidance and optimal environment for nerve regeneration was a single hollow nerve guidance conduit. Later there have been several improvements to the basic structure, especially introduction of physical fillers into the lumen of a hollow nerve guidance conduit. Up to now, a diverse array of biomaterials, either of natural or of synthetic origin, together with well-defined fabrication techniques, has been employed to prepare neural scaffolds with different structures and properties. Meanwhile different types of support cells and/or growth factors have been incorporated into the neural scaffold, producing unique biochemical effects on nerve regeneration and function restoration. This review attempts to summarize different nerve grafts used for peripheral nerve repair, to highlight various basic components of tissue engineered nerve grafts in terms of their structures, features, and nerve regeneration-promoting actions, and finally to discuss current clinical applications and future perspectives of tissue engineered nerve grafts.

The calcineurin inhibitor, FK506, does not alter glutamate transport in the ischaemic mouse retina

The protein phosphatase 2B inhibitor, FK506, is an immunomodulatory polypeptide that has neuroprotective properties, the mechanisms of which have not been elucidated. A possible mechanism may be phosphorylation-mediated regulation of glutamate transporter activity. In the present study, we investigated the effect of FK506 on glutamate transporter localization and activity in the ischaemic mouse retina. FK506 did not appear to modulate the localization or activity of glutamate transporters under simulated ischaemic conditions. Our present data suggest that the mechanism by which FK506 exerts its neuroprotective action is not attributable to alterations in retinal glutamate transport.

Tacrolimus (FK506): Safety and Applications in Reconstructive Surgery

Tacrolimus (FK506) is a macrolide immunosuppressive drug that is approved for the prevention of allograft rejection. It is a standard component of immunosuppressive regimens currently in use for organ and reconstructive tissue transplants. The experimental literature has demonstrated potential efficacy in the management of other diseases for which transplantation does not play a role. The ability of tacrolimus to modulate the immune system and inhibit T cell activation provides a potential benefit for the treatment of disorders in which autoimmune phenomena are central to their pathogenesis such as rheumatoid arthritis and inflammatory bowel disease. Tacrolimus also has well-established neuroprotective and neuroregenerative properties through both similar and different mechanisms that have been extensively demonstrated in both small and large animal models. However, as a potent immunosuppressive agent, it can cause serious adverse effects, some of which are irreversible and potentially life threatening. This article reviews its safety under different therapeutic requirements and applications in both allogeneic and autogenous tissue reconstruction.

A role for FKBP52 in Tau protein function

Tau is a microtubule-associated protein, which is widely expressed in the central nervous system, predominantly in neurons, where it regulates microtubule dynamics, axonal transport, and neurite outgrowth. The aberrant assembly of Tau is the hallmark of several human neurodegenerative diseases, collectively known as tauopathies. They include Alzheimer's disease, Pick's disease, progressive supranuclear palsy, and frontotemporal dementia and parkinsonism linked to chromosome 17. Several abnormalities in Tau, such as hyperphosphorylation and aggregation, alter its function and are central to the pathogenic process. Here, we describe biochemical and functional interactions between FKBP52 and Tau. FKBP52 is a member of the FKBP (FK506-binding protein) family that comprises intracellular protein effectors of immunosuppressive drugs (such as FK506 and rapamycin). We found that FKBP52, which is abundant in brain, binds directly and specifically to Tau, especially in its hyperphosphorylated form. The relevance of this observation was confirmed by the colocalization of both proteins in the distal part of the axons of cortical neurons and by the antagonistic effect of FKBP52 on the ability of Tau to promote microtubule assembly. Overexpression of FKBP52 in differentiated PC12 cells prevented the accumulation of Tau and resulted in reduced neurite length. Taken together, these findings indicate a role for FKBP52 in Tau function and may help to decipher and modulate the events involved in Tau-induced neurodegeneration.

[Organ transplantation, composite tissue allotransplantation, and plastic surgery]

Transplantations play an increasing role for plastic reconstructive surgeons. The increasing number of solid organ transplantations and the improved long-term survival rates lead to increased numbers of these patients also undergoing plastic and reconstructive procedures. Free flap transfer in solid organ transplant patients is feasible with no higher risk to both transplant function and postoperative complications than for nontransplant patients, even during immune suppression. Composite tissue allotransplantation (CTA) is an evolving field in plastic reconstructive surgery with hands, arms, partial faces, abdominal walls, and knee joints being transferred in clinical settings. However only an interdisciplinary approach using all available resources in highly selected patients after exhausting all other plastic reconstructive procedures is able to achieve reasonable results. The potential complications of long-term immune suppression and patient compliance have to be balanced with the expected and achieved functional result of CTA, whose procedures must be discussed as a potential tissue or organ transplantation, given the legal and logistic implications. The interdisciplinary cooperation of transplant surgeons, microsurgeons, psychologists, and ergo- and physiotherapists is mandatory to achieve successful CTA results.

[Retrospective monocentric comparative evaluation by sifting of vein grafts versus nerve grafts in palmar digital nerves defects. Report of 32 cases]

AIM

Palmar digital nerves defects can be treated by conventional nerve grafts or by means of a conduit, such as a vein. We compared a vein graft technique to a nerve graft technique in a retrospective monocentric study.

MATERIAL AND METHOD

A surgeon who was not involved in the treatment reviewed blind 15 nerve grafts and 17 vein grafts. The evaluation concerned sensitivity, pain, donor site morbidity, social integration and autoassessment of the benefits by the patient. Data were compacted by a sifting method eliminating bad results. The classical functional scores (British Medical Research Council, Möberg, Chanson, Alnot, Dumontier) were also used.

RESULTS

The evaluation was carried out at least 11 months after treatment. Defect was never greater than 30 mm. After sifting, vein grafts appeared less efficient than nerve grafts (41% good results against 73%), except in emergencies (86% good results).

CONCLUSION

For defect loss of no more than 30 mm in emergencies, the authors propose to use vein grafting. In other situations, the surgeon must take into account the patient's profile and the hemi-pulp concerned, dominant or non-dominant, before opting for a nerve or a vein graft.