Building a Predictive PBPK Model for Human OATP Substrates: a Strategic Framework for Early Evaluation of Clinical Pharmacokinetic Variations Using Pitavastatin as an Example.

To select a drug candidate for clinical development, accurately and promptly predicting human pharmacokinetic (PK) profiles, assessing drug-drug interactions (DDIs), and anticipating potential PK variations in disease populations are crucial steps in drug discovery. The complexity of predicting human PK significantly increases when hepatic transporters are involved in drug clearance (CL) and volume of distribution (Vss). A strategic framework is developed here, utilizing pitavastatin as an example. The framework includes the construction of a monkey physiologically-based PK (PBPK) model, model calibration to obtain scaling factors (SF) of in vitro-in vivo extrapolation (IVIVE) for various clearance parameters, human model development and validation, and assessment of DDIs and PK variations in disease populations. Through incorporating in vitro human parameters and calibrated SFs from the monkey model of 3.45, 0.14, and 1.17 for CLint,active, CLint,passive, and CLint,bile, respectively, and together with the relative fraction transported by individual transporters obtained from in vitro studies and the optimized Ki values for OATP inhibition, the model reasonably captured observed pitavastatin PK profiles, DDIs and PK variations in human subjects carrying genetic polymorphisms, i.e., AUC within 20%. Lastly, when applying the functional reduction based on measured OATP1B biomarkers, the model adequately predicted PK changes in the hepatic impairment population. The present study presents a strategic framework for early-stage drug development, enabling the prediction of PK profiles and assessment of PK variations in scenarios like DDIs, genetic polymorphism, and hepatic impairment-related disease states, specifically focusing on OATP substrates.

The benefits of a percutaneous supplemental screw to reinforce the hinge of a medial open wedge tibial osteotomy.

INTRODUCTION: Our earlier studies reported that an additional lag screw placed from the opposite side increases the stability of the fixation construct in medial open wedge high tibia osteotomy (MOWHTO). The aim of the study was to evaluate the clinical relevance of the use of a supplemental screw with immediate post-operative full weight-bearing and its benefits in terms of functional outcome, radiographic outcome and complications. MATERIALS AND METHODS: A retrospective study was performed comparing the historical cohort (MOWHTO without opposite screw) (group A) with the current cohort (MOWHTO with opposite screw) (group B). The patients underwent clinical and radiological assessments. We evaluated the WOMAC (The Western Ontario and McMaster Universities) score, IKDC (International Knee Documentation Committee) scores, and Lysholm knee score. Patients' return to sports and work were also recorded. RESULTS: We included 123 knees receiving MOWHTO alone (group A) with 114 knees (group B) receiving MOWHTO with an opposite screw. A shorter bone union time (18.3 ± 2.1 weeks v.s. 11.5 ± 2.6 weeks, p < 0.001), earlier return to sports (6.1 months vs. 4.6 months, p < 0.001) and return to works (3.2 months vs. 2.3 months, p < 0.001) and better 6-month functional outcomes were found in group B (p < 0.001). The complications were similar in both groups. One patient experienced irritation at the site of the screw entrance and the screw was removed after union. CONCLUSION: The current study evaluated the clinical efficacy of a supplemental lag screw placed from the opposite side in MOWHTO. Comparing to the plate alone, the additional opposite screw improved the implant and fixation stability under immediate weight-bearing without causing complications. A shorter time for returning to sports and work was noted, and a better functional outcome at 6-month follow-up was registered.

Inhaled remdesivir reduces viral burden in a nonhuman primate model of SARS-CoV-2 infection.

Remdesivir (RDV) is a nucleotide analog prodrug with demonstrated clinical benefit in patients with coronavirus disease 2019 (COVID-19). In October 2020, the US FDA approved intravenous (IV) RDV as the first treatment for hospitalized COVID-19 patients. Furthermore, RDV has been approved or authorized for emergency use in more than 50 countries. To make RDV more convenient for non-hospitalized patients earlier in disease, alternative routes of administration are being evaluated. Here, we investigated the pharmacokinetics and efficacy of RDV administered by head dome inhalation in African green monkeys (AGM). Relative to an IV administration of RDV at 10 mg/kg, an approximately 20-fold lower dose administered by inhalation produced comparable concentrations of the pharmacologically active triphosphate in lower respiratory tract tissues. Distribution of the active triphosphate into the upper respiratory tract was also observed following inhaled RDV exposure. Inhalation RDV dosing resulted in lower systemic exposures to RDV and its metabolites as compared with IV RDV dosing. An efficacy study with repeated dosing of inhaled RDV in an AGM model of SARS-CoV-2 infection demonstrated reductions in viral replication in bronchoalveolar lavage fluid and respiratory tract tissues compared with placebo. Efficacy was observed with inhaled RDV administered once daily at a pulmonary deposited dose of 0.35 mg/kg beginning approximately 8 hours post-infection. Moreover, the efficacy of inhaled RDV was similar to that of IV RDV administered once at 10 mg/kg followed by 5 mg/kg daily in the same study. Together, these findings support further clinical development of inhalation RDV.

Identification of a Proteomic Signature of Senescence in Primary Human Mammary Epithelial Cells.

Senescence is a permanent cell cycle arrest that occurs in response to cellular stress and promotes age-related disease. Because senescence differs greatly depending on cell type and senescence inducer, continued progress in the characterization of senescent cells is needed. Here, we analyzed primary human mammary epithelial cells (HMECs), a model system for aging and cancer, using mass spectrometry-based proteomics. By integrating data from replicative senescence, immortalization by telomerase reactivation, and quiescence, we identified a robust proteomic signature of HMEC senescence consisting of 34 upregulated and 10 downregulated proteins. This approach identified known senescence biomarkers including ß-galactosidase (GLB1) as well as novel senescence biomarkers including catechol O-methyltransferase (COMT), synaptic vesicle membrane protein VAT-1 homolog (VAT1), and plastin-1/3 (PLS1/PLS3). Gene ontology enrichment analysis demonstrated that senescent HMECs upregulated lysosomal proteins and downregulated RNA metabolic processes. In addition, a classification model based on our proteomic signature successfully discriminated proliferating and senescent HMECs at the transcriptional level. Finally, we found that the HMEC senescence signature was positively and negatively correlated with proteomic alterations in HMEC aging and breast cancer, respectively. Taken together, our results demonstrate the power of proteomics to identify cell type-specific signatures of senescence and advance the understanding of senescence in HMECs.

Benefits of opposite screw insertion technique in medial open-wedge high tibial osteotomy: A virtual biomechanical study.

BACKGROUND: Alignment correction of the lower limb by medial open-wedge high tibial osteotomy (HTO) is an efficient technique, but loss of correction and hardware failure can occur owing to inadequate fixation. A surgical technique using opposite screw insertion was previously applied for salvage of the lateral hinge fracture, but evidence for its utility as a protective strategy was unclear. METHODS: Finite element models were reconstructed using artificial bone models, commercial bone plate, and locking screws in the HTO model. The 6.5-mm cancellous or 6.5/8.0-mm pretensioned lag screw was virtually inserted from the opposite cortex to the medial tibial plateau. Testing loads were applied for simulating standing and initial sit-to-stand postures. The axial displacement of the posteromedial tibial plateau, which represents the loss of the posteromedial tibial plateau in clinical observation, and stresses on the bone plate, locking screws, and opposite screws were evaluated. RESULTS: Pretensioned lag screw insertion effectively reduced the loss of posteromedial reduction compared with the HTO model without opposite screw insertion [6.5-mm lag screw, by 50.8% (standing)/56.3% (sit-to-stand); 8.0-mm lag screws, by 51.9% (standing)/57.5% (sit-to-stand); normalised by the performance in the intact model]. The noncompressed opposite cancellous screw slightly reduced the stresses on the bone plate and screws, but did not contribute to the control of reduction loss at the posteromedial tibial plateau. Stresses on screws were lower than those on the corresponding bone plates, so the risk of screw breakage may be low. CONCLUSION: The present study revealed that pretensioned opposite lag screw insertion is a simple and effective technique to improve the structural stability in medial open-wedge HTO. Further biomechanical and clinical verification will be required to enhance user confidence in this technique. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The efficacy and advantages of additional opposite lag screw insertion in medial wedge high tibial osteotomy surgery have been described in this current study by a virtual biomechanical evaluation. Basing on this observation, it would worth further clinical trials for clarification and verification in reality.

Inhibition of nucleotide synthesis promotes replicative senescence of human mammary epithelial cells.

Cellular senescence is a mechanism by which cells permanently withdraw from the cell cycle in response to stresses including telomere shortening, DNA damage, or oncogenic signaling. Senescent cells contribute to both age-related degeneration and hyperplastic pathologies, including cancer. In culture, normal human epithelial cells enter senescence after a limited number of cell divisions, known as replicative senescence. Here, to investigate how metabolic pathways regulate replicative senescence, we used LC-MS-based metabolomics to analyze senescent primary human mammary epithelial cells (HMECs). We did not observe significant changes in glucose uptake or lactate secretion in senescent HMECs. However, analysis of intracellular metabolite pool sizes indicated that senescent cells exhibit depletion of metabolites from nucleotide synthesis pathways. Furthermore, stable isotope tracing with 13C-labeled glucose or glutamine revealed a dramatic blockage of flux of these two metabolites into nucleotide synthesis pathways in senescent HMECs. To test whether cellular immortalization would reverse these observations, we expressed telomerase in HMECs. In addition to preventing senescence, telomerase expression maintained metabolic flux from glucose into nucleotide synthesis pathways. Finally, we investigated whether inhibition of nucleotide synthesis in proliferating HMECs is sufficient to induce senescence. In proliferating HMECs, both pharmacological and genetic inhibition of ribonucleotide reductase regulatory subunit M2 (RRM2), a rate-limiting enzyme in dNTP synthesis, induced premature senescence with concomitantly decreased metabolic flux from glucose into nucleotide synthesis. Taken together, our results suggest that nucleotide synthesis inhibition plays a causative role in the establishment of replicative senescence in HMECs.

Pancreatic Cancer Gene Therapy Delivered by Nanoparticles.

Pancreatic cancer is one of the most lethal forms of cancer and has proven to be difficult to treat through conventional methods, including surgery and chemotherapy. Gene therapy serves as a potential novel treatment to interfere with genes that make this cancer so aggressive, but free nucleic acids have low cell uptake due to their negative charge and are unstable in circulation. Nanoparticles can serve as an effective carrier for a wide variety of gene therapies for pancreatic cancer as they can improve the circulation time, decrease the recognition by the immune system, and be functionalized to target specific surface proteins. In this review, we focus on therapeutic strategies using nanoparticles as carriers of small interfering RNA (siRNA), microRNA (miRNA), and gene augmentation (DNA) therapies in the context of pancreatic cancer. Lastly, we discuss the future outlook of nanoparticle-based therapies, including challenges in the clinical setting.

Clinical Experience Using a 3D-Printed Patient-Specific Instrument for Medial Opening Wedge High Tibial Osteotomy.

PURPOSE: High tibial osteotomy (HTO) has been adopted as an effective surgery for medial degeneration of the osteoarthritis (OA) knee. However, satisfactory outcomes necessitate the precise creation and distraction of osteotomized wedges and the use of intraoperative X-ray images to continually monitor the wedge-related manipulation. Thus HTO is highly technique-demanding and has a high radiation exposure. We report a patient-specific instrument (PSI) guide for the precise creation and distraction of HTO wedge. METHODS: This study first parameterized five HTO procedures to serve as a design rationale for an innovative PSI guide. Preoperative X-ray and computed tomography- (CT-) scanning images were used to design and fabricate PSI guides for clinical use. The weight-bearing line (WBL) of the ten patients was shifted to the Fujisawa's point and instrumented using the TomoFix system. The radiological results of the PSI-guided HTO surgery were evaluated by the WBL percentage and tibial slope. RESULTS: All patients consistently showed an increased range of motion and a decrease in pain and discomfort at about three-month follow-up. This study demonstrates the satisfactory accuracy of the WBL adjustment and tibial slope maintenance after HTO with PSI guide. For all patients, the average pre- and postoperative WBL are, respectively, 14.2% and 60.2%, while the tibial slopes are 9.9 and 10.1 degrees. The standard deviations are 2.78 and 0.36, respectively, in postoperative WBL and tibial slope. The relative errors of the pre- and postoperative WBL percentage and tibial slope averaged 4.9% and 4.1%, respectively. CONCLUSION: Instead of using navigator systems, this study integrated 2D and 3D preoperative planning to create a PSI guide that could most likely render the outcomes close to the planning. The PSI guide is a precise procedure that is time-saving, radiation-reducing, and relatively easy to use. Precise osteotomy and good short-term results were achieved with the PSI guide.

Chest Pain During Chemotherapy: A Case of Severe Myocardial Bridging.

A cancer patient presented with acute chest pain at rest 40 hours after IV fluorouracil infusion. Angiography showed evidence of myocardial bridging.

Evaluation of complication rates of pediatric cranial procedures in which a polyethylene glycol sealant was used.

OBJECT: Polyethylene glycol (PEG) sealant in conjunction with standard closure techniques is effective in preventing CSF leaks after cranial procedures in adult patients, but the safety of PEG sealant in the pediatric population has not been shown. METHODS: The authors performed a retrospective analysis of pediatric neurosurgery patients (0-18 years of age) treated from 2005 to 2010 at The Johns Hopkins Hospital. There were 163 patients who underwent cranial surgery with the use of PEG sealant as an adjunct to standard closure techniques. There were 92 males and 71 females with an average age of 10.2 years. The incidences of revision surgery, CSF leak, meningitis, and neurological deficit were recorded. RESULTS: In the cohort's 90-day postoperative clinical course, the authors found that 4 patients (2.5%) required revision surgery, 2 patients (1.2%) developed a CSF leak, 4 patients (2.5%) developed a superficial skin infection, and 1 patient developed meningitis (0.6%) with no deaths or neurological deficits observed. CONCLUSIONS: PEG sealant appears to be a safe adjunct to standard dural closure in pediatric cranial surgery patients to augment dural closure.

Evaluation of complication rates of pediatric spinal procedures in which a polyethylene glycol sealant was used.

OBJECT: Cerebrospinal fluid leakage following durotomy in spinal surgery can lead to significant patient morbidity and mortality, including meningitis and even death. Usage of a polyethylene glycol (PEG) sealant in combination with standard closure techniques has been shown to be effective in preventing CSF leaks in animal models and adult patients, but the results of its use have not been reported in the pediatric population. METHODS: A retrospective analysis was performed of pediatric neurosurgery patients (0-18 years of age) treated at The Johns Hopkins Hospital from 2003 to 2010. There were 93 spinal surgery patients identified in whom PEG was applied. The incidence of CSF leakage, meningitis, and neurological injury was recorded. There were 54 males and 39 females in this study with an average age of 8.7 years. Of the identified patients, 16.1%, 28%, and 55.9% underwent surgery in the cervical region, thoracic region, and lumbar region, respectively. RESULTS: At 90-day follow-up, 5 patients (5.4%) had a CSF leak, 4 patients (4.3%) required a reoperation, and 1 patient (1.1%) had meningitis within this time period. No deaths or associated neurological deficits were observed. CONCLUSIONS: The use of a PEG sealant to augment dural closure in pediatric spine surgery appears to be a safe adjunct to standard dural closure in pediatric spine patients.

Glycerol rhizotomy via a retrosigmoid approach as an alternative treatment for trigeminal neuralgia.

OBJECTIVES: Trigeminal neuralgia is a sensory nerve disorder characterized by lancinating pain and treated most commonly with carbamazepine, rhizotomy treatment, or open surgical management with microvascular decompression. We describe a novel technique to complement surgical treatment for trigeminal neuralgia via direct injection of the trigeminal nerve with glycerin in the cisternal portion of the nerve. PATIENTS AND METHODS: We performed a retrospective analysis of patients who received standard microvascular decompression and injection of glycerin to the inferior third of the cisternal portion of the nerve anterior to the root entry zone with lack of a compressive vessel on MRI as the primary indication. Fourteen patients were identified and demographic information, post-operative course and complications were recorded. RESULTS: There were eleven females and three males with an average age at time of surgery of 54.8 years. 100% of patients reported that their trigeminal pain was significantly improved following surgical intervention. Four out of fourteen patients reported a 50-80% decrease from the pre-surgery baseline pain at one month and three month follow up. One patient developed a CSF leak, and no surgical site infections or motor deficits were observed. CONCLUSION: Intra-operative glycerin rhizotomy in conjunction with microvascular decompression can be used to safely treat patients suffering from trigeminal neuralgia.

Antiproliferation of human prostate cancer cells by ethanolic extracts of Brazilian propolis and its botanical origin.

Propolis is a resinous substance collected by bees (Apis mellifera) from various tree buds which they then use to coat hive parts and to seal cracks and crevices in the hive. Propolis, a known ancient folk medicine, has been extensively used in diet to improve health and to prevent disease. In the present study, we have evaluated the effects of ethanolic extracts of Brazilian propolis group l2 and bud resins of botanical origin (B. dracunculifolia), and propolis group 3 on proliferation of metastasis (DU145 and PC-3) and primary malignant tumor (RC58T/h/SA#4)-derived human prostate cancer cells. The strongest inhibition was observed in propolis group 3 (sample #3) extracts whereas moderate growth inhibition was observed in human prostate epithelial cells. In the RC58T/h/SA#4 cells, resins of botanical origin of propolis group 12 (sample #1) and propolis group 12 (sample #2) induced growth inhibition that was associated with S phase arrest whereas propolis group 3 (sample #3) induced growth inhibition that was associated with G2 arrest. The mechanisms of cell cycle effects of propolis were investigated. The resins of botanical origin of propolis group 12 and propolis group 12 showed similar inhibition of cyclin D1, CDK4 and cyclin B1 expression. Propolis group 3 showed higher induction of p21 expression but no inhibition of cyclin D1, CDK4 and cyclin B1 expression. The results obtained here demonstrate that the Brazilian propolis extracts have significant inhibitory effect on proliferation of human prostate cancer cells. Inhibition was achieved through regulation of protein expression of cyclin D1, B1 and cyclin dependent kinase (CDK) as well as p21. Our results indicate that the Brazilian propolis extracts show promise as chemotherapeutic agents as well as preventive agents against prostate cancer.