Inflammatory Bowel Disease: A Review of Pre-Clinical Murine Models of Human Disease

Crohn’s disease (CD) and ulcerative colitis (UC) are both highly inflammatory diseases of the gastrointestinal tract, collectively known as inflammatory bowel disease (IBD). Although the cause of IBD is still unclear, several experimental IBD murine models have enabled researchers to make great inroads into understanding human IBD pathology. Here, we discuss the current pre-clinical experimental murine models for human IBD, including the chemical-induced trinitrobenzene sulfonic acid (TNBS) model, oxazolone and dextran sulphate sodium (DSS) models, the gene-deficient I-kappa-B kinase gamma (Iκκ-γ) and interleukin(IL)-10 models, and the CD4⁺ T-cell transfer model. We offer a comprehensive review of how these models have been used to dissect the etiopathogenesis of disease, alongside their limitations. Furthermore, the way in which this knowledge has led to the translation of experimental findings into novel clinical therapeutics is also discussed.

Pegilodecakin as monotherapy or in combination with anti-PD-1 or tyrosine kinase inhibitor in heavily pretreated patients with advanced renal cell carcinoma: Final results of cohorts A, G, H and I of IVY Phase I study

Interleukin (IL)‐10 has anti‐inflammatory and CD8+ T‐cell‐stimulating properties. Pegilodecakin (pegylated recombinant human IL‐10) induces intratumoral antigen‐specific CD8 + T‐cells and upregulates IFNγ and major histocompatibility complexes (MHC) I and II. Pegilodecakin has single‐agent activity with manageable toxicity in advanced renal cell carcinama (aRCC) (data cutoff 24 March 2016). Pegilodecakin with pembrolizumab or nivolumab revealed clinical activity in aRCC (data cutoff 1 July 2018). Here, we report for the first time the results of pegilodecakin+ pazopanib, and final results for monotherapy and long‐term follow‐up with pegilodecakin + anti‐programmed cell death 1 (anti‐PD‐1) inhibitors (data cutoff 19 February 2019). Phase 1/1b multi‐cohort dose escalation IVY study enrolled 353 patients. Sixty‐six patients with aRCC were treated with pegilodecakin alone or with pazopanib or anti‐PD‐1 inhibitor in cohorts A, G, H and I (data cutoff 19 February 2019). Primary endpoints included safety and tolerability. Secondary endpoint was tumor response by immune‐related response criteria (irRC). Pegilodecakin plus nivolumab or pembrolizumab yielded median progression‐free survival (mPFS) of 13.9 months and 6‐month PFS probability of 60%, 76% 1‐year overall survival (OS) probability and 61% 2‐year OS probability. Pegilodecakin monotherapy produced mPFS of 1.8 months, 6‐month PFS probability 25%, 1‐year OS 50%, and 2‐year OS 17%. Median OS was not reached in both combinations. Objective response rates (ORRs) were 33% with pazopanib and 43% with anti‐PD‐1. Most common Grade 3/4 treatment‐related adverse events included anemia, thrombocytopenia and hypertriglyceridemia. In these heavily pretreated renal cell carcinama cohorts of IVY, pegilodecakin+anti‐PD‐1 inhibitor showed promising clinical activity. Safety profile of pegilodecakin alone and with anti‐PD‐1 inhibitors was consistent as previously reported.

What's new?

Despite recent progress in the treatment of renal cell cancer (RCC), there is still an urgent need for treatments that will further improve the prognosis of patients with advanced RCC. Pegilodecakin is a promising IL‐10 analogue that induces CD8+T‐cell‐mediated immune activation. Does a combination regimen yield better outcomes in heavily pretreated RCC patients than pegilodecakin alone? In this study, the authors found that the most promising clinical activity was obtained using a combination of pegilodecakin plus an anti‐PD‐1 inhibitor. Combination with a tyrosine‐kinase inhibitor of VEGFR was also better than pegilodecakin monotherapy.

Association between Inflammatory Cytokine Levels and Thrombocytopenia during Plasmodium falciparum and P. vivax Infections in South-Western Coastal Region of India

Background

Thrombocytopenia is a most commonly observed complication during malaria infections. Inflammatory cytokines such as IL-1, IL-6, and IL-10 have been documented in malaria induced thrombocytopaenia. This study was aimed to understand the possible relationship between inflammatory cytokines across varying degrees of thrombocytopenia during P. vivax, P. falciparum, and mixed infections.

Methods

A hospital-based cross sectional study was conducted at District Wenlock Hospital in Mangaluru, a city situated along the south-western coastal region of Arabian Sea in India. In this study, blood samples from 627 malaria patients were analyzed for infected parasite species, clinical conditions, platelet levels, and key cytokines that are produced in response to infection; samples from 176 uninfected healthy individuals were used as controls.

Results

The results of our study showed a high prevalence of malarial thrombocytopenia (platelets <150 ×10³/μl) in this endemic settings. About 62.7% patients had mild-to-moderate levels of thrombocytopenia and 16% patients had severe thrombocytopenia (platelets <50 × 10³/μl). Upon comparison of cytokines across varying degrees of thrombocytopenia, irrespective of infecting species, the levels of TNF-α and IL-10 were significantly higher during thrombocytopenia, whereas IL-6 levels were considerably lower in severe thrombocytopenia patients suffering from P. vivax or P. falciparum infections. The severe clinical complications observed in patients with malarial thrombocytopenia included severe anemia (17.5%), acute renal failure (12.7%), jaundice (27.0%), metabolic acidosis (36.5%), spontaneous bleeding (3.2%), hypoglycemia (25.4%), hyperparasitemia (4.8%), acute respiratory distress syndrome (1.6%), pulmonary edema (19.0%), and cerebral malaria (1.6%) in various combinations.

Conclusion

Overall, the results of our study suggest that inflammatory cytokines influence the transformation of mild forms of thrombocytopenia into severe forms during malarial infections. Further studies are needed to understand the association of inflammatory cytokine responses with severe malaria complications and thrombocytopenia.

Persistent janus kinase-signaling in chronic lymphocytic leukemia patients on ibrutinib: Results of a phase I trial

Methods to deepen clinical responses to ibrutinib are needed to improve outcomes for patients with chronic lymphocytic leukemia (CLL). This study aimed to determine the safety and efficacy of combining a janus kinase (JAK)‐inhibitor with ibrutinib because JAK‐mediated cytokine‐signals support CLL cells and may not be inhibited by ibrutinib. The JAK1/2 inhibitor ruxolitinib was prescribed to 12 CLL patients with abnormal serum beta‐2 microglobulin levels after 6 months or persistent lymphadenopathy or splenomegaly after 12 months on ibrutinib using a 3 + 3 phase 1 trial design (NCT02912754). Ibrutinib was continued at 420 mg daily and ruxolitinib was added at 5, 10, 15, or 20 mg BID for 3 weeks out of five for seven cycles. The break was mandated to avoid anemia and thrombocytopenia observed with ruxolitinib as a single agent in CLL. The combination was well‐tolerated without dose‐limiting toxicities. Cyclic changes in platelets, lymphocytes, and associated chemokines and thrombopoietic factors were observed and partial response criteria were met in 2 of 12 patients. The results suggest that JAK‐signaling helps CLL cells persist in the presence of ibrutinib and ruxolitinib with ibrutinib is well‐tolerated and may be a useful regiment to use in combination therapies for CLL.

A Novel Function of Interleukin-10 Promoting Self-Renewal of Hematopoietic Stem Cells

Self-renewal of hematopoietic stem cells (HSCs) is key to their reconstituting ability, but the factors regulating the process remain poorly understood. Here, we show that Interleukin-10 (IL-10), a pleiotropic immune modulating cytokine, can also play a role in regulating HSC self-renewal. First, a quantitative decrease of primitive hematopoietic cell populations, but not more matured cells, was observed in the bone marrows of IL-10 disrupted mice as determined by long-term in vitro cultures or in vivo competitive repopulation assays. In contrast, normal HSCs from 5-fluorouracil treated marrows cultured on the IL-10 secreting stroma displayed an enhanced repopulating activity compared with cells grown on control stroma, with ninefold higher numbers of donor-derived HSCs in the reconstituted recipient marrows. Moreover, limiting dilution transplantation assay demonstrated that exogenous addition of IL-10 in the stroma-free cultures of purified Lin- Sca-1+ c-kit+ cells caused three- to fourfold higher frequencies of HSCs in the 5-day short-term culture without indirect inhibitory effect of IL-10 on tumor necrosis factor-alpha or interferon-gamma secretion. Interestingly, primitive hematopoietic cells, including Lin- Sca-1+ c-kit+ or side population cells, expressed the surface receptor for IL-10, and microenvironmental production of IL-10 was sharply increased in the osteoblasts lining the trabecular regions of the radiation-stressed marrow but not in the steady-state marrows. These results show that IL-10 may be a ligand that can stimulate self-renewal of HSCs to promote their regeneration in addition to being a ligand for immune regulation. Disclosure of potential conflicts of interest is found at the end of this article.