Laboratory prediction of the requirement for renal replacement in acute falciparum malaria

BACKGROUND: Acute renal failure is a common complication of severe malaria in adults, and without renal replacement therapy (RRT), it carries a poor prognosis. Even when RRT is available, delaying its initiation may increase mortality. Earlier identification of patients who will need RRT may improve outcomes. METHOD: Prospectively collected data from two intervention studies in adults with severe malaria were analysed focusing on laboratory features on presentation and their association with a later requirement for RRT. In particular, laboratory indices of acute tubular necrosis (ATN) and acute kidney injury (AKI) that are used in other settings were examined. RESULTS: Data from 163 patients were available for analysis. Whether or not the patients should have received RRT (a retrospective assessment determined by three independent reviewers) was used as the reference. Forty-three (26.4%) patients met criteria for dialysis, but only 19 (44.2%) were able to receive this intervention due to the limited availability of RRT. Patients with impaired renal function on admission (creatinine clearance < 60 ml/min) (n = 84) had their laboratory indices of ATN/AKI analysed. The plasma creatinine level had the greatest area under the ROC curve (AUC): 0.83 (95% confidence interval 0.74-0.92), significantly better than the AUCs for, urinary sodium level, the urea to creatinine ratio (UCR), the fractional excretion of urea (FeUN) and the urinary neutrophil gelatinase-associated lipocalcin (NGAL) level. The AUC for plasma creatinine was also greater than the AUC for blood urea nitrogen level, the fractional excretion of sodium (FeNa), the renal failure index (RFI), the urinary osmolality, the urine to plasma creatinine ratio (UPCR) and the creatinine clearance, although the difference for these variables did not reach statistical significance. CONCLUSIONS: In adult patients with severe malaria and impaired renal function on admission, none of the evaluated laboratory indices was superior to the plasma creatinine level when used to predict a later requirement for renal replacement therapy

Genome-wide RNA-Sequencing analysis reveals a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery

Fibrosis-related events play a part in most blinding diseases worldwide. However, little is known about the mechanisms driving this complex multifactorial disease. Here we have carried out the first genome-wide RNA-Sequencing study in human conjunctival fibrosis. We isolated 10 primary fibrotic and 7 non-fibrotic conjunctival fibroblast cell lines from patients with and without previous glaucoma surgery, respectively. The patients were matched for ethnicity and age. We identified 246 genes that were differentially expressed by over two-fold and p < 0.05, of which 46 genes were upregulated and 200 genes were downregulated in the fibrotic cell lines compared to the non-fibrotic cell lines. We also carried out detailed gene ontology, KEGG, disease association, pathway commons, WikiPathways and protein network analyses, and identified distinct pathways linked to smooth muscle contraction, inflammatory cytokines, immune mediators, extracellular matrix proteins and oncogene expression. We further validated 11 genes that were highly upregulated or downregulated using real-time quantitative PCR and found a strong correlation between the RNA-Seq and qPCR results. Our study demonstrates that there is a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery and provides new insights into the mechanistic pathways driving the complex fibrotic process in the eye and other tissues

Validation of the Glaucoma Filtration Surgical Mouse Model for Antifibrotic Drug Evaluation

Glaucoma is a progressive optic neuropathy, which, if left untreated, leads to blindness. The most common and most modifiable risk factor in glaucoma is elevated intraocular pressure (IOP), which can be managed surgically by filtration surgery. The postoperative subconjunctival scarring response, however, remains the major obstacle to achieving long-term surgical success. Antiproliferatives such as mitomycin C are commonly used to prevent postoperative scarring. Efficacy of these agents has been tested extensively on monkey and rabbit models of glaucoma filtration surgery. As these models have inherent limitations, we have developed a model of glaucoma filtration surgery in the mouse. We show, for the first time, that the mouse model typically scarred within 14 d, but when augmented with mitomycin C, more animals maintained lower intraocular pressures for a longer period of time concomitant with prolonged bleb survival to beyond 28 d. The morphology of the blebs following mitomycin C treatment also resembled well-documented clinical observations, thus confirming the validity and clinical relevance of this model. We demonstrate that the antiscarring response to mitomycin C is likely to be due to its effects on conjunctival fibroblast proliferation, apoptosis and collagen deposition and the suppression of inflammation. Indeed, we verified some of these properties on mouse conjunctival fibroblasts cultured in vitro. These data support the suitability of this mouse model for studying the wound healing response in glaucoma filtration surgery, and as a potentially useful tool for the in vivo evaluation of antifibrotic therapeutics in the eye

BILBO1 Is a Scaffold Protein of the Flagellar Pocket Collar in the Pathogen Trypanosoma brucei

The flagellar pocket (FP) of the pathogen Trypanosoma brucei is an important single copy structure that is formed by the invagination of the pellicular membrane. It is the unique site of endo- and exocytosis and is required for parasite pathogenicity. The FP consists of distinct structural sub-domains with the least explored being the annulus/horseshoe shaped flagellar pocket collar (FPC). To date the only known component of the FPC is the protein BILBO1, a cytoskeleton protein that has a N-terminus that contains an ubiquitin-like fold, two EF-hand domains, plus a large C-terminal coiled-coil domain. BILBO1 has been shown to bind calcium, but in this work we demonstrate that mutating either or both calcium-binding domains prevents calcium binding. The expression of deletion or mutated forms of BILBO1 in trypanosomes and mammalian cells demonstrate that the coiled-coil domain is necessary and sufficient for the formation of BILBO1 polymers. This is supported by Yeast two-hybrid analysis. Expression of full-length BILBO1 in mammalian cells induces the formation of linear polymers with comma and globular shaped termini, whereas mutation of the canonical calcium-binding domain resulted in the formation of helical polymers and mutation in both EF-hand domains prevented the formation of linear polymers. We also demonstrate that in T. brucei the coiled-coil domain is able to target BILBO1 to the FPC and to form polymers whilst the EF-hand domains influence polymers shape. This data indicates that BILBO1 has intrinsic polymer forming properties and that binding calcium can modulate the form of these polymers. We discuss whether these properties can influence the formation of the FPC

The control of conjunctival fibrosis as a paradigm for the prevention of ocular fibrosis-related blindness. “Fibrosis has many friends”

The processes involved in ocular fibrosis after disease or ocular tissue injury, including surgery play an important part in the development or failure of treatment of most blinding diseases. Ocular fibrosis is one of the biggest areas of unmet need in ophthalmology. Effective anti-scarring therapies could potentially revolutionise the management of many diseases like glaucoma worldwide. The response of a quiescent or activated conjunctiva to glaucoma surgery and aqueous flow with different stimulatory components and the response to different interventions and future therapeutics is a paradigm for scarring prevention in other parts of the eye and orbit. Evolution in our understanding of molecular and cellular mechanisms in ocular fibrosis is leading to the introduction of new and re-purposed therapeutic agents, targeting a wide range of key processes. This review provides current and futures perspectives on different approaches to conjunctival fibrosis following glaucoma surgery and highlights the challenges faced in implementing these therapies with maximal effect and minimal side effects