Optimizing study design in LPS challenge studies for quantifying drug induced inhibition of TNFα response: Did we miss the prime time?

In this work we evaluate the study design of LPS challenge experiments used for quantification of drug induced inhibition of TNFα response and provide general guidelines of how to improve the study design. Analysis of model simulated data, using a recently published TNFα turnover model, as well as the optimal design tool PopED have been used to find the optimal values of three key study design variables - time delay between drug and LPS administration, LPS dose, and sampling time points - that in turn could make the resulting TNFα response data more informative. Our findings suggest that the current rule of thumb for choosing the time delay should be reconsidered, and that the placement of the measurements after maximal TNFα response are crucial for the quality of the experiment. Furthermore, a literature study summarizing a wide range of published LPS challenge studies is provided, giving a broader perspective of how LPS challenge studies are usually conducted both in a preclinical and clinical setting.

Combined expression of HOXA11 and CD10 identifies endometriosis versus normal tissue and tumors.

The gold standard for diagnosing endometriosis is by laparoscopic visual demonstration of ectopic endometrial lesions outside the uterus, preferably verified by biopsy and microscopical examination. Molecular markers to facilitate the microscopical diagnosis of endometriosis and for distinguishing endometriosis from other benign and malignant lesions are lacking. Our aim was to test and validate an immunohistochemical antibody panel for improved diagnostic accuracy of endometriosis. Both CD10 and HOXA11 have been implicated in regulation of endometrial homeostasis. Here we have analyzed the expression pattern of these two proteins using immunohistochemistry on human tissues in a tissue microarray format. CD10 and HOXA11 expression in endometriosis lesions were compared to expression patterns in a range of normal tissues and in primary- and metastatic lesions of endometrial-, cervical- and ovarian cancer. HOXA11 and CD10 were expressed in 98% and 91% of endometriosis lesions and the combined double-positive expression profile of both HOXA11 and CD10 was highly sensitive for ectopic endometrial tissue (90%). The specificity and sensitivity for this double-positive signature in endometriosis was significantly different from all investigated tissues, cancers and metastases except normal, eutopic endometrial- and cervical mucosa. The combination of HOXA11 and CD10 expression profiles provides a useful tool to identify ectopic endometrial tissue and for distinguishing endometriosis from various types of gynecological malignancies and metastases.

Second-generation TNFα turnover model for improved analysis of test compound interventions in LPS challenge studies.

This study presents a non-linear mixed effects model describing tumour necrosis factor alpha (TNFα) release after lipopolysaccharide (LPS) provocations in absence or presence of anti-inflammatory test compounds. Inter-occasion variability and the pharmacokinetics of two test compounds have been added to this second-generation model, and the goal is to produce a framework of how to model TNFα response in LPS challenge studies in vivo and demonstrate its general applicability regardless of occasion or type of test compound. Model improvements based on experimental data were successfully implemented and provided a robust model for TNFα response after LPS provocation, as well as reliable estimates of the median pharmacodynamic parameters. The two test compounds, Test Compound A and roflumilast, showed 81.1% and 74.9% partial reduction of TNFα response, respectively, and the potency of Test Compound A was estimated to 0.166 µmol/L. Comparing this study with previously published work reveals that our model leads to biologically reasonable output, handles complex data pooled from different studies, and highlights the importance of accurately distinguishing the stimulatory effect of LPS from the inhibitory effect of the test compound.

Haploidentical stem cell transplantation in two children with mucopolysaccharidosis VI: clinical and biochemical outcome.

BACKGROUND: Mucopolysaccharidosis VI (MPS VI) is an autosomal recessive progressive multiorgan disorder due to mutation in the gene encoding the enzyme Arylsulfatase B (ARSB). Dysfunctional ARSB causes lysosomal accumulation of glycosaminoglycans (GAG). Currently, enzyme replacement therapy (ERT) is preferred to hematopoietic stem cell transplantation (SCT) due to the treatment-related risks of the latter. However, ERT constitutes an expensive life-long treatment. Increased experience and safety of SCT-procedures in recent years suggest that SCT should be further explored as a treatment option.This is the first report on haploidentical SCT in patients with MPS VI. The primary objective was to assess the treatment safety and clinical and biochemical outcome. PATIENTS AND METHODS: Two siblings diagnosed with MPS VI at 10 months of age and at birth with genotype p.C192R, reported as mild to intermediate phenotype, underwent unrelated umbilical cord blood transplantation pre-symptomatic. Due to graft failure, both patients were urgently re-transplantated with haploidentical SCT with the father as donor. Continuous clinical and biochemical status was monitored and concluded 3.8 and 4.6 years after the haploidentical SCT. RESULTS: Haploidentical SCT resulted in prompt and sustained engraftment. Complete donor chimerism was achieved in both patients, apart from mixed B cells chimerism in patient 2. ARSB activity in leukocytes post transplant increased from 0.0 to 19.0 µkat/kg protein (patient 1) and from 3.6 to 17.9 µkat/kg protein (patient 2) (ref. 17-40). Total urinary GAG normalized in both patients, although patient 2's values slightly exceed normal range since 6 months. However, dermatan sulfaturia was substantially normalized since 16 months and 12 months post-SCT, respectively. Height was -1.85 SD and -1.27 SD at follow-up. Patient 1 had impaired visual acuity and discrete hepatomegaly. Patient 2 had elevated intraocular pressure and X-ray revealed steep acetabular angles and slightly flattened lumbar vertebrae. CONCLUSION: This study demonstrates that young children with MPS VI tolerate haploidentical SCT. Normalization of enzyme production and dermatan sulfaturia indicates correction of the inborn error of metabolism and coincide with no obvious symptoms of progressive MPS VI up to 4.6 years post-SCT.