The Last Mile: Translational Research to Improve CKD Outcomes

The National Institute of Diabetes and Digestive and Kidney Diseases–supported Kidney Research National Dialogue asked the scientific community to formulate and prioritize research objectives that would enhance understanding of kidney function and disease and improve clinical outcomes. An engaged and growing group of investigators working in type 2 translation (from clinical evidence to implementation in the community) identified barriers to improving patient care in CKD and suggested research priorities to test translational strategies that have been effective for other chronic diseases.     

CTLA‐4 (CD152) enhances the Tc17 differentiation program

Although CD8⁺ T cells that produce IL‐17 (Tc17 cells) have been linked to host defense, Tc17 cells show reduced cytotoxic activity, which is the characteristic function of CD8⁺ T cells. Here, we show that CTLA‐4 enhances the frequency of IL‐17 in CD8⁺ T cells, indicating that CTLA‐4 (CD152) specifically promotes Tc17 differentiation. Simultaneous stimulation of CTLA‐4^+/+ and CTLA‐4^?/? T cells in cocultures and agonistic CTLA‐4 stimulation unambiguously revealed a cell‐intrinsic mechanism for IL‐17 control by CTLA‐4. The quality of CTLA‐4‐induced Tc17 cells was tested in vivo, utilizing infection with the facultative intracellular bacterium Listeria monocytogenes (LM). Unlike CTLA‐4^+/+ Tc17 cells, CTLA‐4^?/? were nearly as efficient as Tc1 CTLA‐4^+/+ cells in LM clearance. Additionally, adoptively transferred CTLA‐4^?/? Tc17 cells expressed granzyme B after rechallenge, and produced Tc1 cytokines such as IFN‐γ and TNF‐α, which strongly correlate with bacterial clearance. CTLA‐4^+/+ Tc17 cells demonstrated a high‐quality Tc17 differentiation program ex vivo, which was also evident in isolated IL‐17‐secreting Tc17 cells, with CTLA‐4‐mediated enhanced upregulation of Tc17‐related molecules such as IL‐17A, RORγt, and IRF‐4. Our results show that CTLA‐4 promotes Tc17 differentiation that results in robust Tc17 responses. Its inactivation might therefore represent a central therapeutic target to enhance clearance of infection.     

Risk of renal disease in patients with both type 1 diabetes and coeliac disease

Aims/hypothesis

Our aim was to study the risk of renal disease in patients with type 1 diabetes (T1D) and coexisting coeliac disease (CD).

Methods

Individuals with T1D were defined as having a diagnosis of diabetes recorded at ≤30 years of age in the Swedish Patient Register between 1964 and 2009. Individuals with CD were identified through biopsy reports with villous atrophy (Marsh stage 3) from 28 pathology departments in Sweden between 1969 and 2008. We identified 954 patients with both T1D and CD. For each patient with T1D + CD, we selected five age- and sex-matched reference individuals with T1D only (n?=?4,579). Cox regression was used to estimate the following risks: (1) chronic renal disease and (2) end-stage renal disease in patients with CD + T1D compared with T1D patients only.

Results

Forty-one (4.3%) patients with CD + T1D and 143 (3.1%) patients with T1D only developed chronic renal disease. This corresponded to an HR of 1.43 for chronic renal disease (95% CI 0.94, 2.17) in patients with CD + T1D compared with T1D only. In addition, for end-stage renal disease there was a positive (albeit statistically non-significant) HR of 2.54 (95% CI 0.45, 14.2). For chronic renal disease, the excess risk was more pronounced after >10 years of CD (HR 2.03, 95% CI 1.08, 3.79). Risk estimates were similar when we restricted our cohort to the following T1D patients: (1) those who had an inpatient diagnosis of T1D; (2) those who had never received oral glucose-lowering medication; and (3) those who had not received their first diabetes diagnosis during pregnancy.

Conclusions/interpretation

Overall this study found no excess risk of chronic renal disease in patients with T1D and CD. However, in a subanalysis we noted a positive association between longstanding CD and chronic renal disease in T1D.     

Asparaginase‐associated pancreatitis in children with acute lymphoblastic leukaemia in the NOPHO ALL2008 protocol

L‐asparaginase is an important drug in the treatment of childhood acute lymphoblastic leukaemia (ALL). Treatment is associated with several toxicities, including acute pancreatitis. Clinical course, presentation, re‐exposure to L‐asparginase after pancreatitis and risk of recurrent pancreatitis within an asparaginase‐intensive protocol has been poorly reported. Children (1–17 years) on the ongoing Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol with asparaginase‐associated pancreatitis (AAP) diagnosed between 2008 and 2012 were identified through the online NOPHO ALL toxicity registry. NOPHO ALL2008 includes eight or 15 doses of intramuscular pegylated L‐asparginase (PEG‐asparaginase) 1000 iu/m²/dose at 2–6 weeks intervals, with a total of 30 weeks of exposure to PEG‐asparaginase (clinicaltrials.gov no: NCT00819351). Of 786 children, 45 were diagnosed with AAP with a cumulative risk of AAP of 5·9%. AAP occurred after a median of five doses (range 1–13), and 11 d (median) from the latest administration of PEG‐Asparaginase. Thirteen patients developed pseudocysts (30%) and 11 patients developed necrosis (25%). One patient died from pancreatitis. Twelve AAP patients were re‐exposed to L‐asparginase, two of whom developed mild AAP once more, after four and six doses respectively. In conclusion, re‐exposure to PEG‐asparaginase in ALL patients with mild AAP seems safe.     

Inhibiting conjugation as a tool in the fight against antibiotic resistance

Antibiotic resistance, especially in gram-negative bacteria, is spreading globally and rapidly. Development of new antibiotics lags behind; therefore, novel approaches to the problem of antibiotic resistance are sorely needed and this commentary highlights one relatively unexplored target for drug development: conjugation. Conjugation is a common mechanism of horizontal gene transfer in bacteria that is instrumental in the spread of antibiotic resistance among bacteria. Most resistance genes are found on mobile genetic elements and primarily spread by conjugation. Furthermore, conjugative elements can act as a reservoir to maintain antibiotic resistance in the bacterial population even in the absence of antibiotic selection. Thus, conjugation can spread antibiotic resistance quickly between bacteria of the microbiome and pathogens when selective pressure (antibiotics) is introduced. Potential drug targets include the plasmid-encoded conjugation system and the host-encoded proteins important for conjugation. Ideally, a conjugation inhibitor will be used alongside antibiotics to prevent the spread of resistance to or within pathogens while not acting as a growth inhibitor itself. Inhibiting conjugation will be an important addition to our arsenal of strategies to combat the antibiotic resistance crisis, allowing us to extend the usefulness of antibiotics.