Critical telomerase activity for uncontrolled cell growth.

The lengths of the telomere regions of chromosomes in a population of cells are modelled using a chemical master equation formalism, from which the evolution of the average number of cells of each telomere length is extracted. In particular, the role of the telomere-elongating enzyme telomerase on these dynamics is investigated. We show that for biologically relevant rates of cell birth and death, one finds a critical rate, R crit, of telomerase activity such that the total number of cells diverges. Further, R crit is similar in magnitude to the rates of mitosis and cell death. The possible relationship of this result to replicative immortality and its associated hallmark of cancer is discussed.

From the Lab to Patients: a Systematic Review and Meta-Analysis of Mesenchymal Stem Cell Therapy for Stroke.

There may be the potential to improve stroke recovery with mesenchymal stem cells (MSCs); however, questions about the efficacy and safety of this treatment remain. To address these issues and inform future studies, we performed a preclinical and clinical systematic review of MSC therapy for subacute and chronic ischemic stroke. MEDLINE, Embase, the Cochrane Register of Controlled Trials, and PubMed were searched. For the clinical review, interventional and observational studies of MSC therapy in ischemic stroke patients were included. For the preclinical review, interventional studies of MSC therapy using in vivo animal models of subacute or chronic stroke were included. Measures of safety and efficacy were assessed. Eleven clinical and 76 preclinical studies were included. Preclinically, MSC therapy was associated with significant benefits for multiple measures of motor and neurological function. Clinically, MSC therapy appeared to be safe, with no increase in adverse events reported (with the exception of self-limited fever immediately following injection). However, the efficacy of treatment was less apparent, with significant heterogeneity in both study design and effect size being observed. Additionally, in the only randomized phase II study to date, efficacy of MSC therapy was not observed. Preclinically, MSC therapy demonstrated considerable efficacy. Although MSC therapy demonstrated safety in the clinical setting, efficacy has yet to be determined. Future studies will need to address the discordance in the continuity of evidence as MSC therapy has been translated from "bench-to-bedside".

A systematic review on the efficacy and safety of low molecular weight heparin as an anticancer therapeutic in preclinical animal models.

OBJECTIVE: The therapeutic effects of low molecular weight heparins (LMWH) may extend past thrombosis prevention, with preclinical evidence demonstrating anti-metastatic properties. Clinical evidence on the topic, however, remains controversial. A systematic review of preclinical evidence may help elucidate reasons for this contradictory evidence. The objective of our systematic review is to assess the anti-metastatic properties of LMWHs in solid tumour animal models. METHODS: MEDLINE, Embase, Web of Science and PubMed were searched from inception to May 12th, 2020. All articles were screened independently and in duplicate. Studies that compared LMWH to a placebo or no treatment arm in solid tumour animal models were included. The primary outcome was the burden of metastasis. Secondary outcomes included primary tumour growth and mortality. The risk of bias was assessed in duplicate using a modified Cochrane Risk of Bias tool. RESULTS: Forty-two studies were included in the review. Administration of a LMWH was associated with a significant decrease in the burden of metastasis (SMD -2.18; 95% CI -2.66 to -1.70). Additionally, the administration of a LMWH was also associated with a significant reduction in primary tumour growth (SMD -1.95; 95% CI -2.56 to -1.34) and risk of death (RR 0.39; 95% CI 0.16-0.97). All included studies were deemed to be at an unclear risk of bias for at least one methodological criterion. CONCLUSIONS: Our results demonstrate that LMWH can effectively reduce metastatic burden and reduce tumour growth in preclinical animal models of solid tumour malignancies. Reasons for the contradiction with clinical evidence require further exploration.

Identifying and understanding factors that affect the translation of therapies from the laboratory to patients: a study protocol.

Background: The process of translating preclinical findings into a clinical setting takes decades. Previous studies have suggested that only 5-10% of the most promising preclinical studies are successfully translated into viable clinical applications. The underlying determinants of this low success rate (e.g. poor experimental design, suboptimal animal models, poor reporting) have not been examined in an empirical manner. Our study aims to determine the contemporary success rate of preclinical-to-clinical translation, and subsequently determine if an association between preclinical study design and translational success/failure exists. Methods: Established systematic review methodology will be used with regards to the literature search, article screening and study selection process. Preclinical, basic science studies published in high impact basic science journals between 1995 and 2015 will be included. Included studies will focus on publicly available interventions with potential clinical promise. The primary outcome will be successful clinical translation of promising therapies - defined as the conduct of at least one Phase II trial (or greater) with a positive finding. A case-control study will then be performed to evaluate the association between elements of preclinical study design and reporting and the likelihood of successful translation. Discussion: This study will provide a comprehensive analysis of the therapeutic translation from the laboratory bench to the bedside. Importantly, any association between factors of study design and the success of translation will be identified. These findings may inform future research teams attempting preclinical-to-clinical translation. Results will be disseminated to identified knowledge users that fund/support preclinical research.

Regenerative cell therapy for pulmonary arterial hypertension in animal models: a systematic review.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease characterized by widespread loss of the pulmonary microcirculation and elevated pulmonary arterial pressures leading to pathological right ventricular remodeling and ultimately right heart failure. Regenerative cell therapies could potentially restore the effective lung microcirculation and provide a curative therapy for PAH. The objective of this systematic review was to compare the efficacy of regenerative cell therapies in preclinical models of PAH. METHODS: A systematic search strategy was developed and executed. We included preclinical animal studies using regenerative cell therapy in experimental models of PAH. Primary outcomes were right ventricular systolic pressure (RVSP) and mean pulmonary arterial pressure (mPAP). The secondary outcome was right ventricle/left ventricle + septum weight ratio (RV/LV+S). Pooled effect sizes were undertaken using random effects inverse variance models. Risk of bias and publication bias were assessed. RESULTS: The systematic search yielded 1285 studies, of which 44 met eligibility criteria. Treatment with regenerative cell therapy was associated with decreased RVSP (SMD - 2.10; 95% CI - 2.59 to - 1.60), mPAP (SMD - 2.16; 95% CI - 2.97 to - 1.35), and RV/LV+S (SMD - 1.31, 95% CI - 1.64 to - 0.97). Subgroup analysis demonstrated that cell modification resulted in greater reduction in RVSP. The effects on RVSP and mPAP remained statistically significant even after adjustment for publication bias. The majority of studies had an unclear risk of bias. CONCLUSIONS: Preclinical studies of regenerative cell therapy demonstrated efficacy in animal models of PAH; however, future studies should consider incorporating design elements to reduce the risk of bias. SYSTEMATIC REVIEW REGISTRATION: Suen CM, Zhai A, Lalu MM, Welsh C, Levac BM, Fergusson D, McIntyre L and Stewart DJ. Efficacy and safety of regenerative cell therapy for pulmonary arterial hypertension in animal models: a preclinical systematic review protocol. Syst Rev. 2016;5:89. TRIAL REGISTRATION: CAMARADES-NC3Rs Preclinical Systematic Review & Meta-analysis Facility (SyRF). http://syrf.org.uk/protocols/ . Syst Rev 5:89, 2016.

Assessing the Completeness of Reporting in Preclinical Oncolytic Virus Therapy Studies.

Irreproducibility of preclinical findings could be a significant barrier to the "bench-to-bedside" development of oncolytic viruses (OVs). A contributing factor is the incomplete and non-transparent reporting of study methodology and design. Using the NIH Principles and Guidelines for Reporting Preclinical Research, a core set of seven recommendations, we evaluated the completeness of reporting of preclinical OV studies. We also developed an evidence map identifying the current trends in OV research. A systematic search of MEDLINE and Embase identified all relevant articles published over an 18 month period. We screened 1,554 articles, and 236 met our a priori-defined inclusion criteria. Adenovirus (43%) was the most commonly used viral platform. Frequently investigated cancers included colorectal (14%), skin (12%), and breast (11%). Xenograft implantation (61%) in mice (96%) was the most common animal model. The use of preclinical reporting guidelines was listed in 0.4% of articles. Biological and technical replicates were completely reported in 1% of studies, statistics in 49%, randomization in 1%, blinding in 2%, sample size estimation in 0%, and inclusion/exclusion criteria in 0%. Overall, completeness of reporting in the preclinical OV therapy literature is poor. This may hinder efforts to interpret, replicate, and ultimately translate promising preclinical OV findings.

Reporting preclinical anesthesia study (REPEAT): Evaluating the quality of reporting in the preclinical anesthesiology literature.

Poor reporting quality may contribute to irreproducibility of results and failed 'bench-to-bedside' translation. Consequently, guidelines have been developed to improve the complete and transparent reporting of in vivo preclinical studies. To examine the impact of such guidelines on core methodological and analytical reporting items in the preclinical anesthesiology literature, we sampled a cohort of studies. Preclinical in vivo studies published in Anesthesiology, Anesthesia & Analgesia, Anaesthesia, and the British Journal of Anaesthesia (2008-2009, 2014-2016) were identified. Data was extracted independently and in duplicate. Reporting completeness was assessed using the National Institutes of Health Principles and Guidelines for Reporting Preclinical Research. Risk ratios were used for comparative analyses. Of 7615 screened articles, 604 met our inclusion criteria and included experiments reporting on 52 490 animals. The most common topic of investigation was pain and analgesia (30%), rodents were most frequently used (77%), and studies were most commonly conducted in the United States (36%). Use of preclinical reporting guidelines was listed in 10% of applicable articles. A minority of studies fully reported on replicates (0.3%), randomization (10%), blinding (12%), sample-size estimation (3%), and inclusion/exclusion criteria (5%). Statistics were well reported (81%). Comparative analysis demonstrated few differences in reporting rigor between journals, including those that endorsed reporting guidelines. Principal items of study design were infrequently reported, with few differences between journals. Methods to improve implementation and adherence to community-based reporting guidelines may be necessary to increase transparent and consistent reporting in the preclinical anesthesiology literature.