Therapeutic drug monitoring in patients with tuberculosis and concurrent medical problems

Introduction Therapeutic drug monitoring (TDM) has been recommended for treatment optimization in tuberculosis (TB) but is only is used in certain countries e.g. USA, Germany, the Netherlands, Sweden and Tanzania. Recently, new drugs have emerged and PK studies in TB are continuing, which contributes further evidence for TDM in TB. The aim of this review is to provide an update on drugs used in TB, treatment strategies for these drugs, and TDM to support broader implementation. Areas covered This review describes the different drug classes used for TB, multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), along with their pharmacokinetics, dosing strategies, TDM and sampling strategies. Moreover, the review discusses TDM for patient TB and renal or liver impairment, patients co-infected with HIV or hepatitis, and special patient populations - children and pregnant women. Expert opinion TB treatment has a long history of using 'one size fits all.' This has contributed to treatment failures, treatment relapses, and the selection of drug-resistant isolates. While challenging in resource-limited circumstances, TDM offers the clinician the opportunity to individualize and optimize treatment early in treatment. This approach may help to refine treatment and thereby reduce adverse effects and poor treatment outcomes. Funding, training, and randomized controlled trials are needed to advance the use of TDM for patients with TB

Ethionamide Population Pharmacokinetic Model and Target Attainment in Multidrug-Resistant Tuberculosis

Ethionamide (ETA), an isonicotinic acid derivative, is part of the multidrug-resistant tuberculosis (MDR-TB) regimen. The current guidelines have deprioritized ETA because it is potentially less effective than other agents. Our aim was to develop a population pharmacokinetic (PK) model and simulate ETA dosing regimens in order to assess target attainment. This study included subjects from four different sites, including healthy volunteers and patients with MDR-TB. The TB centers included were two in the United States and one in Bangladesh. Patients who received ETA and had at least one drug concentration reported were included. The population PK model was developed, regimens with a total of 1,000 to 2,250 mg daily were simulated, and target attainment using published MICs and targets of 1.0-log kill and resistance suppression was assessed with the Pmetrics R package. We included 1,167 ethionamide concentrations from 94 subjects. The final population model was a one-compartment model with first-order elimination and absorption with a lag time. The mean (standard deviation [SD]) final population parameter estimates were as follows: absorption rate constant, 1.02 (1.11) h(-1); elimination rate constant, 0.69 (0.46) h(-1); volume of distribution, 104.16 (59.87) liters; lag time, 0.43 (0.32) h. A total daily dose of 1,500 mg or more was needed for >= 90% attainment of the 1.0-log kill target at a MIC of 1 mg/liter, and 2,250 mg/day led to 80% attainment of the resistance suppression target at a MIC of 0.5 mg/liter. In conclusion, we developed a population PK model and assessed target attainment for different ETA regimens. Patients may not be able to tolerate the doses needed to achieve the pre-defined targets supporting the current recommendations for ETA deprioritization

Blocking tumor-educated MSC paracrine activity halts osteosarcoma progression

Purpose: Human osteosarcoma is a genetically heterogeneous bone malignancy with poor prognosis despite the employment of aggressive chemotherapy regimens. Because druggable driver mutations have not been established, dissecting the interactions between osteosarcoma cells and supporting stroma may provide insights into novel therapeutic targets.Experimental Design: By using a bioluminescent orthotopic xenograft mouse model of osteosarcoma, we evaluated the effect of tumor extracellular vesicle (EV)-educated mesenchymal stem cells (TEMSC) on osteosarcoma progression. Characterization and functional studies were designed to assess the mechanisms underlying MSC education. Independent series of tissue specimens were analyzed to corroborate the preclinical findings, and the composition of patient serum EVs was analyzed after isolation with size-exclusion chromatography.Results: We show that EVs secreted by highly malignant osteosarcoma cells selectively incorporate a membrane-associated form of TGFβ, which induces proinflammatory IL6 production by MSCs. TEMSCs promote tumor growth, accompanied with intratumor STAT3 activation and lung metastasis formation, which was not observed with control MSCs. Importantly, intravenous administration of the anti-IL6 receptor antibody tocilizumab abrogated the tumor-promoting effects of TEMSCs. RNA-seq analysis of human osteosarcoma tissues revealed a distinct TGFβ-induced prometastatic gene signature. Tissue microarray immunostaining indicated active STAT3 signaling in human osteosarcoma, consistent with the observations in TEMSC-treated mice. Finally, we isolated pure populations of EVs from serum and demonstrated that circulating levels of EV-associated TGFβ are increased in osteosarcoma patients.Conclusions: Collectively, our findings suggest that TEMSCs promote osteosarcoma progression and provide the basis for testing IL6- and TGFβ-blocking agents as new therapeutic options for osteosarcoma patients

Blocking Tumor-Educated MSC Paracrine Activity Halts Osteosarcoma Progression

Purpose: Human osteosarcoma is a genetically heterogeneous bone malignancy with poor prognosis despite the employment of aggressive chemotherapy regimens. Because druggable driver mutations have not been established, dissecting the interactions between osteosarcoma cells and supporting stroma may provide insights into novel therapeutic targets.Experimental Design: By using a bioluminescent orthotopic xenograft mouse model of osteosarcoma, we evaluated the effect of tumor extracellular vesicle (EV)-educated mesenchymal stem cells (TEMSC) on osteosarcoma progression. Characterization and functional studies were designed to assess the mechanisms underlying MSC education. Independent series of tissue specimens were analyzed to corroborate the preclinical findings, and the composition of patient serum EVs was analyzed after isolation with size-exclusion chromatography.Results: We show that EVs secreted by highly malignant osteosarcoma cells selectively incorporate a membrane-associated form of TGF\u3b2, which induces proinflammatory IL6 production by MSCs. TEMSCs promote tumor growth, accompanied with intratumor STAT3 activation and lung metastasis formation, which was not observed with control MSCs. Importantly, intravenous administration of the anti-IL6 receptor antibody tocilizumab abrogated the tumor-promoting effects of TEMSCs. RNA-seq analysis of human osteosarcoma tissues revealed a distinct TGF\u3b2-induced prometastatic gene signature. Tissue microarray immunostaining indicated active STAT3 signaling in human osteosarcoma, consistent with the observations in TEMSC-treated mice. Finally, we isolated pure populations of EVs from serum and demonstrated that circulating levels of EV-associated TGF\u3b2 are increased in osteosarcoma patients.Conclusions: Collectively, our findings suggest that TEMSCs promote osteosarcoma progression and provide the basis for testing IL6- and TGF\u3b2-blocking agents as new therapeutic options for osteosarcoma patients. Clin Cancer Res; 23(14); 3721-33. \ua92017 AACR

Clinical standards for the dosing and management of TB drugs

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care

AB1323 Osteophytosis process suggest involvement of mast cells, revealed by whole transcriptome analysis of osteophytes from knee osteoarthritis patients

Background: Cartilage-loss is a central pathology of osteoarthritis while synovitis, sub-chondral bone sclerosis and osteophytes (OFs) formation are counted as integral phenomenon. Osteophytosis is a process of OFs formation, in which mesenchymal stem cells from periosteum and synovium, along with a number of cytokines, growth factors and biochemical factors gives out bony out-growth at margin of the affected joint. Although frequently associated, OFs are one of the less focused areas in OA research, particularly from the molecular mechanism point of view, involved in their formation. Also, it is a good ambiguity if OFs is a pathological condition linked with altered biochemical milieu or a functional adaptation for the joint instability. Objectives: Accounting its importance in clinical OA and the obscure biochemical background, this study strives for a deeper comprehension of molecular mechanism and active pathways, involved in OF formation Methods: We performed whole transcriptome analysis of OFs, collected from six knee OA patients during knee replacement surgery. Non-OF tissue from tibial plateau of the same patient was used as a control. After RNA isolation, RNA-seq was performed using SOLiD 5500W platform and fragment sequencing chemistry. For differential gene expression analysis, non- normalized raw counts were used for the EdgeR package. To find differential transcriptome between OF and control, we used group-wise comparisons where negative binomial fitting was followed by exact test. Finally, RT-PCR of significantly expressed genes was run for transcriptome validation. Results: After cluster analysis, total 597 genes were significantly expressed between OFs and controls out of which, 323 genes were seen up-regulated (LogFC≥ 2) while 274 were down-regulated (LogFC≤ -2). Further, 88 genes showed marked increase (P<0.01); here CPA3, Selectin E, MS4A2, PLA2G2A and CSN1S1 were prominent. Similarly, 23 genes were with a noteworthy down-regulation (P<0.01) and APOB, CADM2, TNEFF2, GNAZ and GABRA2 remained as first five. GO analysis of the best extracted genes indicated significant involvement of ECM proteoglycan, GABA A receptor pathway (Reactome 2016 - homo sapiens_R-HSA-3000178 and R-HSA-977441, respectively), osteoblast and TNF-α signalling pathways (WikiPathways 2016 -homo sapiens WP322 and homo sapiens WP231 respectively). Finally, transcriptome results were validated using RT-PCR of significantly expressed genes (CPA3, MMP-1, 3 and 13). Conclusion: Significant expression of CXCL9, 10, 11 and PGR4 indicate chemotaxis and immune cells deployment; outstanding CPA3 and MS4A2 indicate active involvement of mast cells. Accounting a previous knowledge that ‘mast cell products’ are linked with increased osteoblastic and osteoclastic activity and impose pathological changes in articular and peri-articular tissue, marked expressions of MC products or mediators here, enable us to propose an association between MCs and OF. Presence of E-selectin on endothelial cell surface is known to promote adhesion of neutrophils and further release of TNFα and IL1. Expression of PLA2G2A suggests increased prostaglandin synthesis and indicates activation of inflammatory cascade. In conclusion, this transcriptome analysis suggests a significant association of mast cells with osteophytosis. The genes involving chemotaxis, degranulation, cytokinin synthesis mark the initiation of OF. On the other hand, proteases metrixremodelling enzymes may indicate their growth. A host of different signalling molecules denotes involvement of canonical and non-cannonical pathways that warrants further investigations

Synovium-Synovial fluid axis in osteoarthritis pathology: A key regulator of the cartilage degradation process

Failure of conventional anti-inflammatory therapies in osteoarthritis (OA) underlines the insufficient knowledge about inflammatory mechanisms, patterns and their relationship with cartilage degradation. Considering non-linear nature of cartilage loss in OA, a better understanding of inflammatory milieu and MMP status at different stages of OA is required to design early-stage therapies or personalized disease management. For this, an investigation based on a synovium-synovial fluid (SF) axis was planned to study OA associated changes in synovium and SF along the progressive grades of OA. Gene expressions in synovial-biopsies from different grades OA patients (N = 26) revealed a peak of IL-1β, IL-15, PGE2 and NGF in early OA (Kellgren–Lawrence (KL) grade-I and II); the highest MMP levels were found in advanced stages (KL grade-III and IV). MMPs (MMP-1, 13, 2 and 9) abundance and FALGPA activity estimated in forty SFs of progressive grades showed the maximum protein levels and activity in KL grade-II and III. In an SF challenge test, SW982 and THP1 cells were treated with progressive grade SFs to study the dynamics of MMPs modulation in inflammatory microenvironment; the test yielded a result pattern, which matched with FALGPA and the protein-levels estimation. Inflammatory mediators in SFs served as steering factor for MMP up-regulation. A correlation-matrix of IL-1β and MMPs revealed expressional negative correlation

Influence of low-level supplementation with a high-protein feed on performance of beef cows grazing tallgrass-prairie range during the fall

An experiment was conducted to evaluate the effect of hand feeding a limited quantity of a high-protein supplement during the fall grazing period on cow and calf performance. The time of initiation of supplementation was also evaluated. One-hundred thirty-six multiparous, pregnant, spring-calving cows grazing native range were assigned to supplementation treatments. Control cows received no fall supplementation. Supplemented cows received 0.14% of body weight per day (1.5 lbs per day) of a high-protein supplement (40% crude protein, as-fed basis) approximately 2 months before and after weaning (Aug 15 to Dec 14; weaning = Oct 15) or only after weaning (Oct 15 to Dec 14). Supplement was fed 3 days per week (Monday, Wednesday, and Friday) and was prorated to deliver the designated daily amount. All cows received 4 lbs per day of the same supplement during the winter (Dec 14 until calving in early March). Fall and cumulative winter performance (body condition score and body weight) indicated that providing a limited amount of a high-protein supplement during the fall supplementation period can increase cow body condition and body weight, and in some cases, subsequent calf performance. Fall supplementation did not significantly affect the proportion of cows cycling prior to the breeding season or subsequent pregnancy rate

Analysis of alternative spicing in the transcriptome of osteosarcoma

Aim: We have assessed the extent of alternative splicing in osteosarcoma samples and further examined the relationship between alternative transcripts and gene expression. Methods: We performed whole transcriptome analysis of osteosarcoma bone samples and sequenced total RNA from 36 fresh‐frozen samples (18 tumour bone samples and 18 non‐tumour paired samples) in matched pairs for each osteosarcoma patient. Data were analysed with Python package HTSeq and R package DEXSeq developed to analyse differential exon usage in transcriptome data. FDR correction was used to adjust nominal P‐values to obtain genome‐wide statistical significance. Results: We identified statistically significant (FDR below .05) differences in alternative splicing of 4175 transcripts. Several different alternative transcripts from the same genes were expressed, in the leptin receptor overlapping transcript, LEPROT; we detected 26 transcripts to be differentially expressed between tumour and normal tissue. Some transcripts were over‐expressed in the tumour and some transcripts were over‐expressed in normal tissue. The function of LEPROT gene is not fully understood, but it is involved in the regulation of leptin by interacting with the leptin receptor. Also, LEPROT regulates growth hormone‐dependent signalling and activity of the growth hormone receptor. Most of the differentially expressed genes were expressed as different alternative forms indicating prevalent and massive alternative splicing in osteosarcoma. Conclusions: Alternative splicing is prevalent in osteosarcoma and its regulation may play a significant role in sarcoma development. This is a good example of how differential splicing could be involved in the tumorigenesis and further studies need to consider this as an important molecular mechanism