What is the Optimal Nail Length to Treat Osteoporotic Subtrochanteric Fractures?A Finite Element Analysis

Background@#Operative management with intramedullary nail fixation remains the definitive treatment of choice for osteoporotic subtrochanteric (ST) fractures; however, there remains no consensus regarding the proper nail length. We aimed to use 3-dimensional finite element (FE) analysis to determine the optimal nail length for the safe fixation of osteoporotic ST fractures. @*Methods@#Nine modes of FE models were constructed using 9 different lengths of cephalomedullary nails (short nails: 170, 180, and 200 mm; long nails: 280, 300, 320, 340, 360, and 380 mm) from the same company. The interfragmentary motion was analyzed. Additionally, the peak von Mises stress (PVMS) in the cortical bone, cancellous bone of the femoral head, and the nail were measured, and the yielding risk for each subject was investigated. @*Results@#Long nails were associated with less interfragmentary motion. In the cortical bone, the PVMS of short nails was observed at the distal locking screw holes of the femoral medial cortex; however, in long nails, the PVMS was observed at the lag screw holes on the lateral cortex. The mean yielding risk of long nails was 40.1% lower than that of short nails. For the cancellous bone of the femoral head, the PVMS in all 9 FE models was in the same area: at the apex of the femoral head. There was no difference in the yielding risk between short and long nails. For implants, the PVMS was at the distal locking screw hole of the nail body in the short nails and the nail body at the fracture level in the long nails. The mean yielding risk was 74.9% lower for long nails than that for short nails. @*Conclusions@#Compared to short nails, long nails with a length of 320 mm or more showed less interfragmentary motion and lower yielding risk in low-level osteoporotic ST fractures. The FE analysis supports long nails as a safer option than short nails, especially for treating transverse-type low-level osteoporotic ST fractures.

Outcomes of Angular Stable Locking System in Femoral Diaphyseal Fractures of Elderly Patients:A Multicenter Comparative Study

Background@#The angular stable locking system (ASLS) was developed to provide additional stability to the distal interlocking screw of the intramedullary (IM) nail. Effects of ASLS on the treatment of femoral diaphyseal fractures in the elderly remain unknown. The aim of this study was to compare radiological outcomes of IM nailing using ASLS screws to IM nails with conventional interlocking screws in elderly patients with femoral shaft fractures. @*Methods@#A multicenter retrospective review of 129 patients (average age, 73.5 years; 98 women and 31 men) aged 65 years or older who underwent IM nail fixation for femoral diaphyseal fractures (AO/Orthopaedic Trauma Association [OTA] classification 32) was conducted. Demographic information of patients, fracture site (subtrochanteric or shaft), fracture type (traumatic or atypical), and AO/OTA fracture classification were investigated. Reduction status was evaluated by postoperative plain radiography. Presence of union and time to union were evaluated through serial plain radiograph follow-up. Reoperation due to nonunion or implant failure was also evaluated. @*Results@#ASLS was used in 65 patients (50.3%). A total of 118 patients (91.5%) achieved union without additional surgery and the mean union time was 31.8 ± 13.0 weeks. In terms of reduction status, angulation was greater in the group using ASLS. There were no statistically significant differences of union rate, time to union, and reoperation rate according to the use of ASLS (p > 0.05). There was no difference in the outcomes according to the use of ASLS even when the analysis was divided in terms of fracture site or fracture type (p > 0.05). In further subgroup analysis, only the traumatic subtrochanteric area group showed statistically significantly shorter time to union when ASLS was used (p = 0.038). @*Conclusions@#In geriatric patients with femoral diaphyseal fractures, the use of ASLS was not considered to have a significant effect on fracture healing. Fracture healing seemed to be more affected by surgical techniques such as minimizing the gap and fracture characteristics such as atypical femoral fractures, rather than implants.

Usefulness of Sonication in Implant-Related Infection

Purpose@#This study determined whether the sonication of explants could improve the detection of bacteria and influence the optimal antibiotics treatment. @*Materials and Methods@#This retrospective study included the patients who underwent implant removal surgery followed by sonication culture as well as tissue culture in order to diagnose implant-related infection. A total of 37 consecutive patients with 41 cases were included. The patients’ demographic data, use of preoperative antibiotics, type of implants, change of antibiotics following the culture results, and recurrence of infection were all reviewed. @*Results@#Among 41 cases, 20 cases met the diagnostic requirements for implant-related infection as defined by musculoskeletal infection society criteria, while the other 21 cases had explant sonication to exclude indolent infection or residual infection. The latter showed negative results on the both explant cultures and tissue cultures. Among the 20 cases that met the requirements for implant-related infection, 19 cases (95.0%) were identified by any cultures. Of the 19 cases with positive culture results, 2 cases (10.5%) showed positive results only on sonication cultures, and one case (5.3%) showed positive results only on tissue culture. In 1 case of culture negative implant-related infection, a drain sinus was present preoperatively, but the cultures were negative according to both methods. The culture results made postoperative antibiotics change in 12 cases among the 19 culture (+) cases. Antibiotics changes were based on the tissue culture in 2 cases, 2 cases were based on the sonication culture, and the remaining 8 cases were based on both cultures. @*Conclusion@#The sonication culture improved the diagnosis of implant-related infection combined with conventional tissue culture and helped to determine administering the proper antibiotics.

Treatment of Proximal Femur Fracture with a Newly Designed Nail: Trochanteric Fixation Nail-Advanced (TFNA)

Purpose@#This study evaluated the clinical results and implant safety of a newly developed implant, Trochanteric Fixation Nail-Advanced (TFNA; DePuy Synthes), in the treatment of proximal femur fractures. @*Materials and Methods@#This was a retrospective cohort study of 26 patients diagnosed with proximal femur fracture and treated surgically with TFNA. The patients’ demographic data, surgical data, radiologic findings, and functional outcomes, including complications, were evaluated. @*Results@#The mean age of the patients was 71.2 years (95% confidence interval [CI], 68.2-74.2); 65.4% were female. The mean Carlson comorbidity index score was 5.4, and the mean Koval grade before fracture was 2.1. Fracture classification included four cases of AO/OTA 31.A1, nine cases of A2, six cases of A3, and seven cases of 32A including six cases of atypical femoral fractures. The mean operating time was 53.3 minutes (95% CI, 43.6-63.1). There were no early postoperative complications, such as postoperative infection, deep vein thrombosis, pulmonary embolism, or in-hospital death, except one case of pneumonia. The mean Koval score at the postoperative six-month follow-up was 2.9. EuroQol-5 Dimension (EQ-5D) increased from 0.05 to 0.54 after three months and 0.72 at six months postoperatively. Bone union was observed in all cases with a mean union time of 12.9 weeks. No implant failure occurred, and no cases required secondary revision surgery. @*Conclusion@#A new intramedullary nail system, TFNA, showed excellent outcomes and safety in the surgical treatment of proximal femur fractures.

Effect of Osteoporosis Medication on Fracture Healing: An Evidence Based Review

A systematic search was conducted and relevant studies that evaluated the influence of osteoporosis medications (bisphosphonates [BPs], denosumab, selective estrogen receptor modulators [SERMs], recombinant human parathyroid hormone teriparatide [TPTD], and strontium ranelate [SrR]) on wrist, hip, and spine fracture healing, were selected. BPs administration did not influence fracture healing and clinical outcomes after distal radius fracture (DRF). Similar results were observed in hip fracture, but evidence is lacking for spine fracture. Denosumab did not delay the non-vertebral fractures healing in one well-designed study. No studies evaluated the effect of SERMs on fracture healing in humans. One study reported shorter fracture healing times in TPTD treated DRF patients, which was not clinically meaningful. In hip fracture, recent studies reported better pain and functional outcomes in TPTD treated patients. However, in spine fracture, recent studies found no significant differences in fracture stability between TPTD treated patients and controls. Evidence is lacking for SrR, but it did not influence wrist fracture healing in one study. In comparisons between TPTD and BPs, fracture healing and physical scores were not significantly different in hip fracture by 1 study. In spine fracture, controversy exists for the role of each medication to the fracture stability, but several studies reported that fracture site pain was better in TPTD treated patients than BPs treated patients. Considering no clinical data of negative fracture healing of the antiresorptive medication and the danger of subsequent fracture after initial osteoporotic fracture, there is no evidence to delay initiation of osteoporosis medications after fracture.

Effect of Preoperative Bisphosphonate Treatment on Fracture Healing after Internal Fixation Treatment of Intertrochanteric Femoral Fractures / 대한고관절학회지

PURPOSE: There are concerns that administration of bisphosphonate (BP) can substantially suppress bone turnover, potentially interfering with fracture healing. We investigated the effects of preoperative BP administration before internal fixation of intertrochanteric femoral fractures using fracture healing and clinical outcomes. MATERIALS AND METHODS: We retrospectively analyzed data from 130 patients who underwent internal fixation for osteoporotic intertrochanteric femoral fractures between March 2012 and July 2016. Patients previously treated with BPs for at least 3 months (BP group; n=29) were compared with the remaining patients (BP-naïve group; n=101). Radiographs were used to assess and compare fracture healing 3 months and 1 year postsurgery. The primary clinical outcome measure assessed was change in Koval score. RESULTS: Fracture union at 3 months after surgery was verified in 72.4% of patients (21/29) in the BP group and 90.1% of patients (91/101) in the BP-naïve group (P=0.027). Fracture union at 1 year postsurgery (BP group, 93.1% [27/29] vs. BP-naïve group, 97.0% [98/101], P=0.310) and change in Koval score (1.1 vs. 1.0, P=0.694) were not significantly different between the groups. Multivariable logistic regression analysis revealed that a history of BP administration was associated with an increased risk of delayed union at 3 months postsurgery (P=0.014). CONCLUSION: Preoperative administration of BP was associated with a decreased fracture healing rate 3 months after internal fixation, compared with BP-naïve patients. Therefore, patients previously treated with a BP should be carefully allowed to wean off walking aids and transition to full weight-bearing in the early postoperative period.

Preventive Effects of Low Parathyroid Hormone Levels on Hip Fracture in Patients with Vitamin D Deficiency

BACKGROUND: The objective of the current study is to determine the role of serum parathyroid hormone (PTH) on hip fracture development by retrospectively analyzing the relationship between vitamin D and PTH levels and hip fracture prevalence. METHODS: Among 288 patients over 50 years of age, 113 patients with hip fracture and 111 controls without fracture were analyzed after excluding patients with conditions affecting bone metabolism. Bone mineral density and serum biochemical markers were measured, while demographic data were obtained. Patients were divided into 4 groups according to serum 25-hydroxy-vitamin D (25-[OH]D) and PTH levels: LowD+LowP (low 25[OH]D and PTH); LowD+HighP, (low 25[OH]D and high PTH); HighD+LowP (high 25[OH]D and low PTH); and HighD+HighP, patients with (high 25[OH]D and PTH). Measured values and percentages of patients with hip fracture in each group were then determined and compared. RESULTS: The number of patients included in the LowD+LowP, LowD+HighP, HighD+LowP, and HighD+HighP groups was 116, 17, 87, and 4, while the percentages of patients with hip fracture in the same groups were 60.3%, 88.2%, 27.6%, and 100%, respectively. The percentage of hip fracture was significantly lower in the LowD+LowP than the LowD+HighP group (P=0.049). CONCLUSIONS: Patients with low serum 25(OH)D and PTH levels showed lower hip fracture prevalence, indicating the potential protective role of low PTH levels on bone health in patients with vitamin D deficiency. Therefore, clinicians should pay more attention to the possibility of fractures in patients with vitamin D deficiency who present with high PTH levels.

Anterior Approach for the Acetabular Fractures

In the surgical treatment of acetabular fractures, the anterior approach is used widely for anterior column fractures with or without posterior column fractures. This paper reviews the anterior approach for the anatomical reduction and rigid fixation of acetabular fractures: traditional ilioinguinal approach, modified Stoppa approach, and new Pararectal approach.

Anterior Dislocation of the Radial Head Combined with Plastic Deformity of the Ulnar Shaft in an Adult: A Case Report

A 25-year-old woman presented to the emergency room with a painful and swollen right forearm. She had just sustained an injury from an accident during which her arm was tightly wound by a rope as she was lowering a net from a fishing boat. Before being released, her arm was rigidly trapped in the rope for approximately ten minutes. Radiographs revealed anterior dislocation of the radial head that was accompanied by plastic deformation of the proximal ulna, manifested as a reversal of the proximal dorsal angulation of the ulna (PUDA); suggested a Monteggia equivalent fracture. With the patient under general anesthesia, we reduced the radial head by posterior compression at 90° of elbow flexion and at neutral rotation of the forearm. However, the reduction was easily lost and the elbow re-dislocated with even slight supination or extension of the arm. After the osteotomy of the ulnar deformity to restore the PUDA to normal, the reduction remained stable even with manipulation of the arm. We found that the patient could exercise a full range of motion without pain at the 3-month follow-up, and neither residual instability nor degenerative changes were observed at the final 3-year follow-up.

Bone Substitutes and the Advancement for Enhancing Bone Healing

With an aging population and the development of surgical techniques, there is a growing demand for bone reconstruction in areas of trauma, arthroplasty, and spinal fusion Although autogenous bone grafting may be the best method for stimulating bone repair and regeneration, there are still problems and complications, including morbidity related to bone harvesting and limitation of harvest amount. Allogeneic bone grafts have a limited supply and risk of transmission of infectious diseases. Over the past several decades, the use of bone substitutes, such as calcium phosphate, has increased; however, they have limited indications. Biomedical research has suggested a possibility of stimulating the self-healing mechanism by locally transmitting the external growth factors or stimulating local production through a gene transfer. In this review, we evaluate recent advances, including bone graft, bone substitutes, and tissue engineering.

Current Role and Application of Teriparatide in Fracture Healing of Osteoporotic Patients: A Systematic Review

BACKGROUND: The use of osteoanabolic agents to facilitate fracture healing has been of heightened interest to the field of orthopaedic trauma. This study aimed to evaluate the evidence of teriparatide for fracture healing and functional recovery in osteoporotic patients. METHODS: We performed a literature search in PubMed, EMBASE, Web of Science, and the Cochrane Library using terms including “Fracture” [tiab] AND “Teriparatide [tiab] OR “PTH” [tiab]. RESULTS: This systematic review included 6 randomized clinical trials, 4 well-controlled retrospective studies, and 1 retrospective post hoc subgroup analysis. Fracture location was 2 in pelvis, 3 in proximal femur, 1 in distal femur, 1 in shoulder, 2 in wrist and 2 in spine. The use of teriparatide yielded positive effects on radiographic bone healing in 6 studies, but was not associated with better radiographic outcome in 3. In terms of functional recovery, teriparatide injection was related with decrease in pain or shorter time to mobilization in 6 studies, but not related with pain numerical scale and mobility in 3. CONCLUSIONS: Our findings suggest that teriparatide provide selective advantages to fracture healing or functional recovery in the management of osteoporotic fractures. A better understanding of the role of teriparatide on osteoporotic fractures requires greater evidences from large volume prospective trials.

Reduction Technique of Dome Impaction Using the Modified Stoppa Approach: A Technical Note

In elderly acetabular fractures, central dislocation of the femoral head and impacted superior dome of the acetabulum is common. Unreduced dome impaction can lead to degenerative arthritis and results in poor results. Herein, we present a case of operative reduction and fixation performed via the modified Stoppa approach in acetabular fracture with superior dome impaction.

Clinical Features and Outcomes of Pelvic Insufficiency Fractures

PURPOSE: The purpose of this study was to investigate the radiological and epidemiological characteristics, as well as the clinical course of pelvic insufficiency fractures in the elderly population. MATERIALS AND METHODS: At a Haeundae Paik Hospital, we retrospectively reviewed patients with pelvic insufficiency fractures between March 2010 and May 2017. The demographic data of patients were analyzed, and bone mineral density and bone turnover markers were evaluated to estimate the metabolic status of the bone. The radiological characteristics were evaluated by comparing the simple x-ray images with the computed tomography images, and the types of fractures were classified via computed tomography images. For clinical course evaluation, we investigated comorbid complications, and compared the walking ability scale before and 6 months after the fracture. RESULTS: A total of 42 patients were included, with an average age of 76.5 years. All were female except one case. In 5 cases where the initial medical examination was from another institution, the fracture was not found in 3 cases. All cases received conservative treatment. After the diagnosis of pelvic bone fracture using a simple x-ray imaging, additional fractures were found in 81.0% of the study population using a computed tomography. Initiation of gait occurred at an average of 2.8 weeks, and every case except 1 (97.6%) fully recovered their gait ability. CONCLUSION: We concluded that there was a limitation with diagnosing pelvic insufficiency fracture using only a simple x-ray imaging technique. In general, cases in this study showed conservative treatment yielded favorable clinical outcome with relatively less critical complications.

The outcome of endoscopic management of bile leakage after hepatobiliary surgery

BACKGROUND/AIMS: Despite improvements in surgical techniques and postoperative patient care, bile leakage can occur after hepatobiliary surgery and may lead to serious complications. The aim of this retrospective study was to evaluate the efficacy of endoscopic treatment of bile leakage after hepatobiliary surgery. METHODS: The medical records of 20 patients who underwent endoscopic retrograde cholangiopancreatography because of bile leakage after hepatobiliary surgery from August 2009 to September 2014 were reviewed retrospectively. Endoscopic treatment included insertion of an endoscopic retrograde biliary drainage stent after endoscopic sphincterotomy. RESULTS: Most cases of bile leakage presented as percutaneous bile drainage through a Jackson-Pratt bag (75%), followed by abdominal pain (20%). The sites of bile leaks were the cystic duct stump in 10 patients, intrahepatic ducts in five, liver beds in three, common hepatic duct in one, and common bile duct in one. Of the three cases of bile leakage combined with bile duct stricture, one patient had severe bile duct obstruction, and the others had mild strictures. Five cases of bile leakage also exhibited common bile duct stones. Concerning endoscopic modalities, endoscopic therapy for bile leakage was successful in 19 patients (95%). One patient experienced endoscopic failure because of an operation-induced bile duct deformity. One patient developed guidewire-induced microperforation during cannulation, which recovered with conservative treatment. One patient developed recurrent bile leakage, which required additional biliary stenting with sphincterotomy. CONCLUSIONS: The endoscopic approach should be considered a first-line modality for the diagnosis and treatment of bile leakage after hepatobiliary surgery.

Surgical Treatment of Clavicle Midshaft Fractures Using a Locking Compression Plate: Conventional Open Reduction and Plating with Internal Fixation versus Minimal Invasive Plate Osteosynthesis / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to make a comparison between minimally invasive plate osteosynthesis (MIPO) and conventional open reduction and plating (COP) to treat displaced clavicle shaft fractures. MATERIALS AND METHODS: We retrospectively reviewed patients with clavicle shaft fractures, who underwent surgery by using a locking plate between May 2011 and August 2016. The inclusion criteria were: 1) displaced ≥20 mm, 2) acute fracture of less than 2 weeks from injury, 3) skeletally mature patients, and 4) follow-up of at least 6 months. The demographic data and clinical outcomes, including operation time, fracture union rate, union time, shortening of clavicle, shoulder functional score (University of California at Los Angeles score), and complications, were evaluated. The clavicle length ratio was measured to evaluate shortening. We compared the clinical outcomes between two groups: the COP group that included 21 patients treated with COP (group 1) and the MIPO group that included 19 patients treated with MIPO (group 2). RESULTS: In all cases, union of fractures was successfully achieved. The mean union time was 14.9 weeks in group 1 and 14.2 weeks in group 2 (p=0.713). Both groups had good functional scores (34.0 vs. 33.7, p=0.658). Group 2 had shorter operation time and less bleeding. There were no secondary interventions or infections. The clavicle length ratio was similar between the two groups; and all patients in both groups showed no shortening (less than 3%). There were no implant failures in either group. CONCLUSION: The clinical and radiologic outcomes were satisfactory in both groups. We suggest that MIPO may be a safe and effective method for displaced clavicle shaft fractures.

Risk Stratification for Avascular Necrosis of the Femoral Head After Internal Fixation of Femoral Neck Fractures by Post-Operative Bone SPECT/CT / 대한핵의학회잡지

PURPOSE: Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN.METHODS: We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months.RESULTS: Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2??0 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively.CONCLUSION: According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients.

Dental implant treatment after healing of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in the same region: a case report

Although pathophysiology, incidence, and factors associated with the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ) and management strategies for patients treated with bisphosphonates or patients with BRONJ are well-established, few guidelines or recommendations are available for patients with a history of successfully healed BRONJ. We present a case of successful dental implant treatment after healing of BRONJ in the same region of the jaw, and speculate that implant placement is possible after healing of BRONJ surgery in select cases.

Frequency of bone graft in implant surgery / 대한악안면성형재건외과학회지

BACKGROUND: Implant surgery has become popular with the advance of surgical techniques such as sinus lifting, guided bone regeneration, and block bone graft. However, there were no data about the frequency of bone graft during implant surgery. The purpose of this study was to report the frequency and types of bone graft depending on dental implant patients' profile to complement the database regarding implant surgery. METHODS: The implant operations had been performed from January 2006 to October 2014. The upper and lower jaws were divided into six sextants. A total of 792 sextants were included in this study. Patient information including sex, age, sites, bone graft, and types of bone were investigated. RESULTS: A total of 1512 implants had been placed. Male and female sextants were 421 and 371, respectively (M:F = 1:0.88). Average age was 54.3 (ranging from 20 to 88 years old). Implants were placed in the posterior maxilla (322 sextants, 40.7 %), posterior mandible (286 sextants, 36.1 %), anterior maxilla (127 sextants, 16.1 %), and anterior mandible (57 sextants, 7.2 %). Bone graft was performed in 50.3 % of the sextants. Among the bone grafted sites, sinus lifting with lateral approach (22.1 %) and guided bone regeneration (22.7 %) were performed most frequently. CONCLUSIONS: Bone graft in implant surgery was necessary to augment defects. More than half of the sextants needed bone graft for implant installation.

Surgical implications of anatomical variation in anterolateral thigh flaps for the reconstruction of oral and maxillofacial soft tissue defects: focus on perforators and pedicles

OBJECTIVES: To gain information on anatomical variation in anterolateral thigh (ALT) flaps in a series of clinical cases, with special focus on perforators and pedicles, for potential use in reconstruction of oral and maxillofacial soft tissue defects. MATERIALS AND METHODS: Eight patients who underwent microvascular reconstructive surgery with ALT free flaps after ablative surgery for oral cancer were included. The number of perforators included in cutaneous flaps, location of perforators (septocutaneous or musculocutaneous), and the course of vascular pedicles were intraoperatively investigated. RESULTS: Four cases with a single perforator and four cases with multiple perforators were included in the ALT flap designed along the line from anterior superior iliac spine to patella. Three cases had perforators running the septum between the vastus lateralis and rectus femoris muscle (septocutaneous type), and five cases had perforators running in the vastus lateralis muscle (musculocutaneous type). Regarding the course of vascular pedicles, five cases were derived from the descending branch of the lateral circumflex femoral artery (type I), and three cases were from the transverse branch (type II). CONCLUSION: Anatomical variation affecting the distribution of perforators and the course of pedicles might prevent use of an ALT free flap in various reconstruction cases. However, these issues can be overcome with an understanding of anatomical variation and meticulous surgical dissection. ALT free flaps are considered reliable options for reconstruction of soft tissue defects of the oral and maxillofacial area.

Vanilloid Receptor 1 Agonists, Capsaicin and Resiniferatoxin, Enhance MHC Class I-restricted Viral Antigen Presentation in Virus-infected Dendritic Cells

DCs, like the sensory neurons, express vanilloid receptor 1 (VR1). Here we demonstrate that the VR1 agonists, capsaicin (CP) and resiniferatoxin (RTX), enhance antiviral CTL responses by increasing MHC class I-restricted viral antigen presentation in dendritic cells (DCs). Bone marrow-derived DCs (BM-DCs) were infected with a recombinant vaccinia virus (VV) expressing OVA (VV-OVA), and then treated with CP or RTX. Both CP and RTX increased MHC class I-restricted presentation of virus-encoded endogenous OVA in BM-DCs. Oral administration of CP or RTX significantly increased MHC class I-restricted OVA presentation by splenic and lymph node DCs in VV-OVA-infected mice, as assessed by directly measuring OVA peptide SIINFEKL-Kb complexes on the cell surface and by performing functional assays using OVA-specific CD8 T cells. Accordingly, oral administration of CP or RTX elicited potent OVA-specific CTL activity in VV-OVA-infected mice. The results from this study demonstrate that VR1 agonists enhance anti-viral CTL responses, as well as a neuro-immune connection in anti-viral immune responses.