Metastatic Infiltration of Nervous Tissue and Periosteal Nerve Sprouting in Multiple Myeloma-Induced Bone Pain in Mice and Human.

Multiple myeloma (MM) is a neoplasia of B plasma cells that often induces bone pain. However, the mechanisms underlying myeloma-induced bone pain (MIBP) are mostly unknown. Using a syngeneic MM mouse model, we show that periosteal nerve sprouting of calcitonin gene-related peptide (CGRP+) and growth associated protein 43 (GAP43+) fibers occurs concurrent to the onset of nociception and its blockade provides transient pain relief. MM patient samples also showed increased periosteal innervation. Mechanistically, we investigated MM induced gene expression changes in the dorsal root ganglia (DRG) innervating the MM-bearing bone of male mice and found alterations in pathways associated with cell cycle, immune response and neuronal signaling. The MM transcriptional signature was consistent with metastatic MM infiltration to the DRG, a never-before described feature of the disease that we further demonstrated histologically. In the DRG, MM cells caused loss of vascularization and neuronal injury, which may contribute to late-stage MIBP. Interestingly, the transcriptional signature of a MM patient was consistent with MM cell infiltration to the DRG. Overall, our results suggest that MM induces a plethora of peripheral nervous system alterations that may contribute to the failure of current analgesics and suggest neuroprotective drugs as appropriate strategies to treat early onset MIBP.SIGNIFICANCE STATEMENT Multiple myeloma (MM) is a painful bone marrow cancer that significantly impairs the quality of life of the patients. Analgesic therapies for myeloma-induced bone pain (MIBP) are limited and often ineffective, and the mechanisms of MIBP remain unknown. In this manuscript, we describe cancer-induced periosteal nerve sprouting in a mouse model of MIBP, where we also encounter metastasis to the dorsal root ganglia (DRG), a never-before described feature of the disease. Concomitant to myeloma infiltration, the lumbar DRGs presented blood vessel damage and transcriptional alterations, which may mediate MIBP. Explorative studies on human tissue support our preclinical findings. Understanding the mechanisms of MIBP is crucial to develop targeted analgesic with better efficacy and fewer side effects for this patient population.

Impact of the COVID-19 pandemic on care for anorexia and bulimia nervosa in US military-connected adolescents and young adults.

OBJECTIVE: This study examined the impact of the COVID-19 pandemic on healthcare engagement for anorexia nervosa (AN) and bulimia nervosa (BN) in a large, geographically diverse population. METHOD: This repeated monthly, cross-sectional study queried Military Health System records of individuals aged 10-21 before and during the pandemic (February 2019-January 2022). ICD-10 codes identified encounters for AN and BN. Monthly rates of care were modeled as the number of unique individuals with an ICD-10-identified eating disorder-related encounter per month divided by the enrolled population. Poisson regression analysis evaluated rates of care stratified by eating disorder, clinical setting, and sex. RESULTS: In a population of 1.76 million adolescents and young adults, 1629 individuals with AN or BN received care during the pre-pandemic period; 3256 received care during the pandemic. The monthly rate of care for females with AN during the pandemic increased in inpatient settings (adjusted relative risk [aRR]: 1.31 [1.16-1.49]) and outpatient settings (aRR: 1.42 [1.37-1.47]); monthly care rates in males with AN increased in the outpatient setting (aRR: 1.46 [1.28-1.67]). Females with BN had increased engagement in outpatient settings (aRR: 1.09 [1.03-1.16]); BN care for males showed no significant monthly changes during the pandemic period in either healthcare setting. DISCUSSION: With increased rates of AN and BN disorder-related care during the pandemic, screening for eating disorder symptomatology may allow for timely diagnosis and intervention in periods of heightened stress. Pandemic-related increases in healthcare engagement may strain limited resources, emphasizing a need to expand accessibility of clinical expertise. PUBLIC SIGNIFICANCE: This study indicates that monthly rates of healthcare engagement during the COVID-19 pandemic for AN and BN varied based on clinical setting and sex in an adolescent and young adult population. The increased number of individuals seeking eating disorder-related care, especially outpatient care, attributed to heightened stressors necessitates accessible professionals with eating disorder clinical expertise.

Multiple myeloma-A painful disease of the bone marrow.

Multiple myeloma is a bone marrow neoplasia with an incidence of 6/100,000/year in Europe. While the disease remains incurable, the development of novel treatments such as autologous stem cell transplantation, proteasome inhibitors and monoclonal antibodies has led to an increasing subset of patients living with long-term myeloma. However, more than two thirds of patients suffer from bone pain, often described as severe, and knowledge on the pain mechanisms and its effect on their health-related quality of life (HRQoL) is limited. In this review, we discuss the mechanisms of myeloma bone disease, the currently available anti-myeloma treatments and the lessons learnt from clinical studies regarding HRQoL in myeloma patients. Moreover, we discuss the mechanisms of cancer-induced bone pain and the knowledge that animal models of myeloma-induced bone pain can provide to identify novel analgesic targets. To date, information regarding bone pain and HRQoL in myeloma patients is still scarce and an effort should be made to use standardised questionnaires to assess patient-reported outcomes that allow inter-study comparisons of the available clinical data.

Heterologous effect of influenza vaccination on molluscum contagiosum infection; a case report of siblings.

BACKGROUND: Molluscum contagiosum virus (MCV) is a benign, common cutaneous infection predominantly affecting the younger pediatric population. Traditional treatments may be time consuming with variable efficacy. Time to spontaneous resolution is variable and treatment is often sought to shorten duration of infection, prevent further autoinoculation, prevent infectious spread to others and treat cosmetic intolerability. CASE PRESENTATION: We present the case of two patients with complete, simultaneous clearance of their molluscum contagiosum infections after receiving a routine 2018 quadrivalent influenza vaccination. Neither patient has had recurrence of molluscum contagiosum or permanent scarring. We review trials of intralesional immunotherapy in treatment of cutaneous infections to theorize the mechanism of MCV infection clearance post influenza vaccination. CONCLUSION: We propose a delayed-type hypersensitivity reaction was induced as a heterologous effect of the influenza vaccination, similar to that seen in current immunotherapy treatments. This is the first reported case of MCV-directed immune reaction with infection clearance after influenza vaccination.

Delay of fixation increases 30-day complications and mortality in traumatic pelvic ring injuries.

PURPOSE: While decreased time to fixation in femur fractures improves mortality, it remains unclear if the same relationship exists for pelvic fractures. The National Trauma Data Bank (NTDB) is a data repository for trauma hospitals in the United States (injury characteristics, perioperative data, procedures, 30-day complications), and we used this to investigate early, significant complications after pelvic-ring injuries. METHODS: The NTDB (2015-2016) was queried to capture operative pelvic ring injuries in adult patients with injury severity score (ISS) ≥ 15. Complications included medical and surgical complications, as well as 30-day mortality. Multivariable logistic regression was used to investigate the association between days to procedure and complications after adjusting for demographic characteristics and comorbidities. RESULTS: 2325 patients met inclusion criteria. 532 (23.0%) sustained complications, and 72 (3.2%) died within the first 30 days. The most common complications were deep vein thrombosis (DVT) (5.7%), acute kidney injury (AKI) (4.6%), and unplanned intensive care unit (ICU) admission (4.4%). In a multivariate analysis, days to procedure was independently significantly associated with complications, with an adjusted odds ratio (95% confidence interval) of 1.06 (1.03-1.09, P < 0.001), best interpreted as a 6% increase in the odds of complication or death for each additional day. CONCLUSION: Time to pelvic fixation is a significant and modifiable risk factor for major complications and death. This suggests we should prioritize time to pelvic fixation on trauma patients to minimize mortality and major complications.

Radiographic bladder shift is a harbinger of intraoperative blood loss in acetabular surgical fixation.

PURPOSE: The purpose of this study was to characterize the relationship between a novel radiographic measurement on initial AP pelvis radiograph (termed "bladder shift," BS) to intraoperative blood loss (IBL) during acetabular surgical fixation. METHODS: All adult patients receiving unilateral acetabular fixation (Level 1 academic trauma; 2008-18) were reviewed. AP pelvis radiographs were reviewed for visible bladder outlines and then measured to determine the percentage deformation toward the midline. Hemoglobin & hematocrit data were then used to calculate quantitative blood loss between pre- and post- operative blood counts for data analysis. RESULTS: 371 patients with unilateral traumatic acetabular fractures requiring fixation were reviewed; 99 of these had visible bladder outlines, complete blood count and transfusion data (2008-2018; 66% associated patterns). Median bladder shift (BS) was 13.3%. Every 10% of bladder shift was associated with 123 mL greater IBL. Patients with full bladder shift to midline sustained a median 1.5L IBL (interquartile range [IQR] 0.8 to 1.6). Associated patterns had a threefold greater median BS (associated: 16.5% [15.4 to 45.9] vs. elementary: 5.6% [1.1 to 15.4], p < 0.05) and received intraoperative pRBC twice as frequently (57% vs. 24%, p < 0.01). CONCLUSIONS: Radiographic bladder shift is an easily available visual marker, in patients sustaining acetabular fractures, that may predict intraoperative hemorrhage and need for transfusions.

JZL184, A Monoacylglycerol Lipase Inhibitor, Induces Bone Loss in a Multiple Myeloma Model of Immunocompetent Mice.

Multiple myeloma (MM) patients develop osteolysis characterised by excessive osteoclastic bone destruction and lack of osteoblast bone formation. Pharmacological manipulation of monoacylglycerol lipase (MAGL), an enzyme responsible for the degradation of the endocannabinoid 2-arachidonoyl glycerol (2-AG), reduced skeletal tumour burden and osteolysis associated with osteosarcoma and advanced breast and prostate cancers. MM and hematopoietic, immune and bone marrow cells express high levels of type 2 cannabinoid receptor and osteoblasts secrete 2-AG. However, the effects of MAGL manipulation on MM have not been investigated. Here, we report that treatment of pre-osteoclasts with non-cytotoxic concentrations of JZL184, a verified MAGL inhibitor, enhanced MM- and RANKL-induced osteoclast formation and size in vitro. Exposure of osteoblasts to JZL184 in the presence of MM cell-derived factors reduced osteoblast growth but had no effect on the ability of these cells to mature or form bone nodules. In vivo, administration of JZL184 induced a modest, yet significant, bone loss at both trabecular and cortical compartments of long bones of immunocompetent mice inoculated with the syngeneic 5TGM1-GFP MM cells. Notably, JZL184 failed to inhibit the in vitro growth of a panel of mouse and human MM cell lines, or reduce tumour burden in mice. Thus, MAGL inhibitors such as JZL184 can exacerbate MM-induced bone loss.

Targeted magnetic nanoparticle hyperthermia for the treatment of oral cancer.

INTRODUCTION: Patients with oral squamous cell carcinoma currently experience a five-year survival rate of approximately 60% with conventional surgical, chemotherapy and radiotherapy treatments. Magnetic hyperthermia offers an alternative treatment method by utilising the heating properties of magnetic nanoparticles to produce thermal ablation of the tumour site when exposed to an alternating magnetic field. In this study, we investigate in vitro if targeted magnetic hyperthermia offers a potential treatment for oral squamous cell carcinoma. MATERIALS AND METHODS: Magnetic iron oxide nanoparticles, with a biocompatible silica coating, were produced and conjugated with antibodies to target integrin αvß6, a well-characterised oral squamous cell carcinoma biomarker. Utilising the heating properties of the magnetic nanoparticles, we exposed them to an alternating magnetic field to produce thermo ablation of tumour cells either negative for or overexpressing integrin αvß6. RESULTS: The cell surface biomarker, αvß6 integrin, was upregulated in tissue biopsies from oral squamous cell carcinoma patients compared to normal tissue. Functionalisation of the silica coating with anti-αvß6 antibodies enabled direct targeting of the nanoparticles to αvß6 overexpressing cells and applying thermal therapy significantly increased killing of the targeted tumour cells compared to control cells. CONCLUSION: Combining antibody-targeting magnetic nanoparticles with thermal ablation offers a promising therapy for the targeted treatment of oral squamous cell carcinoma.

New agents in the Treatment of Myeloma Bone Disease.

Patients with multiple myeloma develop a devastating bone disease driven by the uncoupling of bone remodelling, excess osteoclastic bone resorption and diminished osteoblastic bone formation. The bone phenotype is typified by focal osteolytic lesions leading to pathological fractures, hypercalcaemia and other catastrophic bone events such as spinal cord compression. This causes bone pain, impaired functional status, decreased quality of life and increased mortality. Early in the disease, malignant plasma cells occupy a niche environment that encompasses their interaction with other key cellular components of the bone marrow microenvironment. Through these interactions, osteoclast-activating factors and osteoblast inhibitory factors are produced, which together uncouple the dynamic process of bone remodelling, leading to net bone loss and focal osteolytic lesions. Current management includes antiresorptive therapies, i.e. bisphosphonates, palliative support and orthopaedic interventions. Bisphosphonates are the mainstay of treatment for myeloma bone disease (MBD), but are only partially effective and do have some significant disadvantages; for example, they do not lead to the repair of existing bone destruction. Thus, newer agents to prevent bone destruction and also promote bone formation and repair existing lesions are warranted. This review summarises novel ways that MBD is being therapeutically targeted.

Mitotic quiescence, but not unique "stemness," marks the phenotype of bone metastasis-initiating cells in prostate cancer.

This study aimed to identify subpopulations of prostate cancer cells that are responsible for the initiation of bone metastases. Using rapidly dividing human prostate cancer cell lines, we identified mitotically quiescent subpopulations (<1%), which we compared with the rapidly dividing populations for patterns of gene expression and for their ability to migrate to the skeletons of athymic mice. The study used 2-photon microscopy to map the presence/distribution of fluorescently labeled, quiescent cells and luciferase expression to determine the presence of growing bone metastases. We showed that the mitotically quiescent cells were very significantly more tumorigenic in forming bone metastases than fast-growing cells (55 vs. 15%) and had a unique gene expression profile. The quiescent cells were not uniquely stem cell like, with no expression of CD133 but had the same level expression of other putative prostate stem cell markers (CD44 and integrins α2/ß1), when compared to the rapidly proliferating population. In addition, mitotic quiescence was associated with very high levels of C-X-C chemokine receptor type 4 (CXCR4) production. Inhibition of CXCR4 activity altered the homing of quiescent tumor cells to bone. Our studies suggest that mitotic dormancy is a unique phenotype that facilitates tumor cell colonization of the skeleton in prostate cancer.

FTO variant associated with malformation syndrome.

Common FTO variants are associated with obesity. However, it has recently been shown that homozygous FTO c.947G>A variant, which predicts p.R316Q, and c.956C>T, which predicts p.S319F, are associated with a malformation syndrome inherited in an autosomal recessive pattern. We present a similar homozygous FTO c.965G>A variant that predicts p.R322Q, associated with a lethal malformation syndrome in a consanguineous Yemeni family. Functional studies showed that the p.R316Q, p.S219F, and p.R322Q variants render the FTO protein inactive. We further expand on the phenotype of homozygous FTO loss-of-function mutations to include eye abnormalities, gingival overgrowth, craniosynostosis, and cutaneous photosensitivity.

Myeloma bone disease: pathogenesis, current treatments and future targets.

INTRODUCTION: Patients with myeloma develop localized and generalized bone loss leading to hypercalcaemia, accelerated osteoporosis, vertebral wedge fractures, other pathological fractures, spinal cord compression and bone pain. Bone loss is mediated by a variety of biological modifiers including osteoclast-activating factors (OAF) and osteoblast (OB) inhibitory factors produced either directly by malignant plasma cells (MPCs) or as a consequence of their interaction with the bone marrow microenvironment (BMM). Raised levels of OAFs such as receptor activator of nuclear factor-kappa B ligand (RANKL), macrophage inflammatory protein 1 alpha, tumour necrosis factor-alpha and interleukin 6 stimulate bone resorption by recruiting additional osteoclasts. Via opposing mechanisms, increases in OB inhibitory factors, such as dickkopf-1 (Dkk-1), soluble frizzled-related protein-3 and hepatocyte growth factor (HGF), suppress bone formation by inhibiting the differentiation and recruitment of OBs. These changes result in an uncoupling of physiological bone remodelling, leading to myeloma bone disease (MBD). Moreover, the altered BMM provides a fertile ground for the growth and survival of MPCs. Current clinical management of MBD is both reactive (to pain and fractures) and preventive, with bisphosphonates (BPs) being the mainstay of pharmacological treatment. However, side effects and uncertainties associated with BPs warrant the search for more targeted treatments for MBD. This review will summarize recent developments in understanding the intimate relationship between MBD and the BMM and the novel ways in which they are being therapeutically targeted. SOURCES OF DATA: All data included were sourced and referenced from PubMed. AREAS OF AGREEMENT: The clinical utility of BP therapy is well established. However, there is general acknowledgement that BPs are only partially successful in the treatment of MBD. The number of skeletal events attributable to myeloma are reduced by BPs but not totally eliminated. Furthermore, existing damage is not repaired. It is widely recognized that more effective treatments are needed. AREAS OF CONTROVERSY: There remains controversy concerning the duration of BP therapy. Whether denosumab is a viable alternative to BP therapy is also contested. Many of the new therapeutic strategies discussed are yet to translate to clinical practice and demonstrate equal efficacy or superiority to BP therapy. It also remains controversial whether reported anti-tumour effects of bone-modulating therapies are clinically significant. GROWING POINTS: The potential clinical utility of bone anabolic therapies including agents such as anti-Dkk-1, anti-sclerostin and anti-HGF is becoming increasingly recognized. AREAS TIMELY FOR DEVELOPING RESEARCH: Further research effectively targeting the mediators of MBD, targeting both bone resorption and bone formation, is urgently needed. This should translate promptly to clinical trials of combination therapy comprising anti-resorptives and bone anabolic therapies to demonstrate efficacy and improved outcomes over BPs.

Sialic acid blockade inhibits the metastatic spread of prostate cancer to bone.

BACKGROUND: Bone metastasis is a common consequence of advanced prostate cancer. Bisphosphonates can be used to manage symptoms, but there are currently no curative treatments available. Altered tumour cell glycosylation is a hallmark of cancer and is an important driver of a malignant phenotype. In prostate cancer, the sialyltransferase ST6GAL1 is upregulated, and studies show ST6GAL1-mediated aberrant sialylation of N-glycans promotes prostate tumour growth and disease progression. METHODS: Here, we monitor ST6GAL1 in tumour and serum samples from men with aggressive prostate cancer and using in vitro and in vivo models we investigate the role of ST6GAL1 in prostate cancer bone metastasis. FINDINGS: ST6GAL1 is upregulated in patients with prostate cancer with tumours that have spread to the bone and can promote prostate cancer bone metastasis in vivo. The mechanisms involved are multi-faceted and involve modification of the pre-metastatic niche towards bone resorption to promote the vicious cycle, promoting the development of M2 like macrophages, and the regulation of immunosuppressive sialoglycans. Furthermore, using syngeneic mouse models, we show that inhibiting sialylation can block the spread of prostate tumours to bone. INTERPRETATION: Our study identifies an important role for ST6GAL1 and α2-6 sialylated N-glycans in prostate cancer bone metastasis, provides proof-of-concept data to show that inhibiting sialylation can suppress the spread of prostate tumours to bone, and highlights sialic acid blockade as an exciting new strategy to develop new therapies for patients with advanced prostate cancer. FUNDING: Prostate Cancer Research and the Mark Foundation For Cancer Research, the Medical Research Council and Prostate Cancer UK.

Optimal bone strength and mineralization requires the type 2 iodothyronine deiodinase in osteoblasts.

Hypothyroidism and thyrotoxicosis are each associated with an increased risk of fracture. Although thyroxine (T4) is the predominant circulating thyroid hormone, target cell responses are determined by local intracellular availability of the active hormone 3,5,3'-L-triiodothyronine (T3), which is generated from T4 by the type 2 deiodinase enzyme (D2). To investigate the role of locally produced T3 in bone, we characterized mice deficient in D2 (D2KO) in which the serum T3 level is normal. Bones from adult D2KO mice have reduced toughness and are brittle, displaying an increased susceptibility to fracture. This phenotype is characterized by a 50% reduction in bone formation and a generalized increase in skeletal mineralization resulting from a local deficiency of T3 in osteoblasts. These data reveal an essential role for D2 in osteoblasts in the optimization of bone strength and mineralization.

Post Post-Mobilization Films for LC1 Pelvic Ring Injuries: Follow up Stress Imaging Demonstrates Minimal Utility.

OBJECTIVE: To assess the utility of outpatient postmobilization radiographs in the nonoperative treatment of lateral compression type I (LC1) (OTA/AO 61-B1) pelvic ring injuries. DESIGN: Retrospective series. SETTING: Academic, Level 1 trauma center, 2008-2018. PATIENTS/PARTICIPANTS: A series of 173 patients with nonoperatively treated LC1 pelvic ring injuries was identified. Of these, 139 received a complete set of outpatient pelvic radiographs with which to assess displacement. INTERVENTION: Outpatient pelvic radiographs to assess additional fracture displacement and potential need for surgical intervention. MAIN OUTCOME MEASUREMENTS: Rate of conversion to late operative intervention based on radiographic displacement. RESULTS: No patient in this cohort received late operative intervention. A majority of the patients sustained incomplete sacral fractures (82.6%) and unilateral rami fractures (75.1%), and 92.8% demonstrated less than 10 mm of displacement on their final radiographs. CONCLUSIONS: There is a low utility of repeat outpatient radiographs of stable, nonoperative LC1 pelvic ring injuries as they do not undergo late displacement. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Fracture Surgery in Patients With Escalating Hemoglobin A1C in the Setting of Unmanaged Diabetes.

OBJECTIVE: To determine whether there is a threshold of elevated hemoglobin A1C (HbA1c) above which the complication risk is so high that fracture fixation should be avoided. DESIGN: Retrospective cohort study. SETTING: Academic Level I trauma center. PATIENTS/PARTICIPANTS: A cohort of 187 patients with HbA1c values >7 and operatively treated extremity fractures. INTERVENTION: Surgical fixation of extremity fractures. MAIN OUTCOME MEASUREMENTS: Rate of major orthopaedic complication (loss of reduction, nonunion, infection, and need for salvage procedure). RESULTS: 34.8% demonstrated HbA1c > 9% and 12.3% with HbA1c > 11. Major complications occurred in 31.4%; HbA1c values were not predictive. We found no evidence of a clinically or statistically significant relationship between HbA1c and risk of major complication. The odds ratio for a one-point increase in HbA1c was 1.006 ( P = 0.9439), and the area under the receiver operating characteristic curve, which reflects the average probability that someone with a major complication will have a higher HbA1c than someone without, was 0.51 (95% confidence interval 0.42-0.61), equivalent to random chance. CONCLUSION: Diabetic patients with fracture demonstrated an extremely high overall rate of complications, with 30.5% experiencing a major complication. However, patients with extreme diabetic neglect did not have higher complication rates after extremity fracture fixation when compared with patients with controlled and uncontrolled diabetes. There was no correlation between rate of complication and level of HbA1c. In addition, there was no difference in complication rate between upper and lower extremity fractures or between fractures treated with open or percutaneous fixation. This suggests that fracture treatment decision-making should not be altered for patients with poor diabetic control, and that surgery is not contraindicated in patients with an extremely high HbA1c. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The strategy and clinical relevance of in vitro models of MAP resistance in osteosarcoma: a systematic review.

Over the last 40 years osteosarcoma (OS) survival has stagnated with patients commonly resistant to neoadjuvant MAP chemotherapy involving high dose methotrexate, adriamycin (doxorubicin) and platinum (cisplatin). Due to the rarity of OS, the generation of relevant cell models as tools for drug discovery is paramount to tackling this issue. Four literature databases were systematically searched using pre-determined search terms to identify MAP resistant OS cell lines and patients. Drug exposure strategies used to develop cell models of resistance and the impact of these on the differential expression of resistance associated genes, proteins and non-coding RNAs are reported. A comparison to clinical studies in relation to chemotherapy response, relapse and metastasis was then made. The search retrieved 1891 papers of which 52 were relevant. Commonly, cell lines were derived from Caucasian patients with epithelial or fibroblastic subtypes. The strategy for model development varied with most opting for continuous over pulsed chemotherapy exposure. A diverse resistance level was observed between models (2.2-338 fold) with 63% of models exceeding clinically reported resistance levels which may affect the expression of chemoresistance factors. In vitro p-glycoprotein overexpression is a key resistance mechanism; however, from the available literature to date this does not translate to innate resistance in patients. The selection of models with a lower fold resistance may better reflect the clinical situation. A comparison of standardised strategies in models and variants should be performed to determine their impact on resistance markers. Clinical studies are required to determine the impact of resistance markers identified in vitro in poor responders to MAP treatment, specifically with respect to innate and acquired resistance. A shift from seeking disputed and undruggable mechanisms to clinically relevant resistance mechanisms may identify key resistance markers that can be targeted for patient benefit after a 40-year wait.

HSV1716 Prevents Myeloma Cell Regrowth When Combined with Bortezomib In Vitro and Significantly Reduces Systemic Tumor Growth in Mouse Models.

Multiple myeloma remains largely incurable due to refractory disease; therefore, novel treatment strategies that are safe and well-tolerated are required. Here, we studied the modified herpes simplex virus HSV1716 (SEPREHVIR®), which only replicates in transformed cells. Myeloma cell lines and primary patient cells were infected with HSV1716 and assessed for cell death using propidium iodide (PI) and Annexin-V staining and markers of apoptosis and autophagy by qPCR. Myeloma cell death was associated with dual PI and Annexin-V positivity and increased expression of apoptotic genes, including CASP1, CASP8, CASP9, BAX, BID, and FASL. The combination of HSV1716 and bortezomib treatments prevented myeloma cell regrowth for up to 25 days compared to only transient cell growth suppression with bortezomib treatment. The viral efficacy was tested in a xenograft (JJN-3 cells in NSG mice) and syngeneic (murine 5TGM1 cells in C57BL/KaLwRijHsd mice) systemic models of myeloma. After 6 or 7 days, the post-tumor implantation mice were treated intravenously with the vehicle or HSV1716 (1 × 107 plaque forming units/1 or 2 times per week). Both murine models treated with HSV1716 had significantly lower tumor burden rates compared to the controls. In conclusion, HSV1716 has potent anti-myeloma effects and may represent a novel therapy for multiple myeloma.

Distribution of Bacterial Species and Resistance Patterns in Surgical Site Infection after Prior Administration of Vancomycin and Tobramycin Intrawound Powdered Antibiotic Prophylaxis.

OBJECTIVE: Evaluate the species distribution and resistance patterns of bacterial pathogens causing surgical site infection (SSI) after operative fracture repair, with and without the use of intrawound powdered antibiotic (IPA) prophylaxis during the index surgery. DESIGN: Retrospective cohort study. SETTING: Academic, level 1 trauma center, 2018-2020. PATIENTS/PARTICIPANTS: Fifty-nine deep SSIs were identified in a sample of 734 patients with 846 fractures (IPA [n = 320], control [n = 526]; open [n = 157], closed fractures [n = 689]) who underwent orthopaedic fracture care. Among SSIs, 28 (48%) patients received IPA prophylaxis and 25 (42%) of the fractures were open. INTERVENTION: Intrawound powdered vancomycin and tobramycin. MAIN OUTCOME MEASUREMENTS: Distribution of bacterial species and resistance patterns causing deep surgical site infections requiring operative debridement. RESULTS: Zero patients developed infections caused by resistant strains of streptococci, enterococci, gram-negative enterics, Pseudomonas , or Cutibacterium species. The only resistant strains isolated were methicillin resistance (19%) and oxacillin-resistant coagulase-negative staphylococci (16%). There was no associated statistical difference in the proportion of bacterial species isolated, their resistance profiles, or rate of polymicrobial infections between the IPA and control group. Most (93%) cases using IPAs included vancomycin and tobramycin powders. There were 59 SSIs; 28 (9%) in the IPA cohort and 31 (6%) in the control cohort ( P = 0.13). CONCLUSION: The use of local antibiotic prophylaxis resulted in no measurable increase in the proportion of infections caused by resistant bacterial pathogens after operative treatment of fractures. However, the small sample size and limited time frame of these preliminary data require continued investigation into their role as an adjunct to SSI prophylaxis. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.