Characterisation of markers associated with systemic inflammation in children with Chronic Kidney Disease.

Abstract

Chronic Kidney Disease (CKD) is a progressive condition that in the majority of cases leads to End Stage Renal Failure (ESRD) and the need for dialysis, with the only cure being renal transplant. CKD affects both adults and children; however the underlying causes of the disease are different. CKD in adults is most commonly secondary to diabetes and/or hypertension while CKD in children is usually caused by congenital structural abnormalities that result directly in renal dysfunction. There have been numerous reports of inflammatory and immunological disturbances in adult CKD that involve both the cellular and humoral immune systems. Consequences of these include an increased rate of cardiovascular disease (CVD), decreased response to vaccinations, as well as increased rates of infection, anaemia and malnutrition. Children with CKD display many of the clinical complications seen in adult kidney disease that are associated with inflammatory and immunological changes. In adults however, many of the primary conditions associated with CKD are inherently pro-inflammatory; therefore it is not clear whether the inflammatory changes observed in adults with CKD are due to pre-existing inflammatory conditions, renal disease per se or a combination of both. The majority of CKD in children is caused by conditions that are not inflammatory in nature. This presents a unique opportunity to study the inflammatory consequences of CKD alone, without the added complication of underlying inflammatory disorders. Despite this, there has been little investigation of the inflammatory and immunological status of children with CKD. Some very recent studies have shown that children with CKD have an increased systemic inflammatory state[1-3], however the nature of these immunological and inflammatory changes remains poorly defined. Identification of the specific inflammatory processes that occur in CKD may provide new treatment targets and the opportunity to develop urgently needed new therapies. The purpose of this thesis is to investigate the presence of immunological changes associated with inflammation in children with CKD. This is the first study to include children with very mild disease, and the significant changes that are present in the early stages of the disease are of particular note. I have shown that CKD in children is an intrinsically inflammatory condition, with increased accumulation of markers of oxidative stress and production of pro-inflammatory cytokines. The inflammatory markers identified in this study may be applied as a foundation for more sensitive diagnostic markers of disease progression as well as provide a basis for novel treatment strategies in this group of patients. Early identification of increased inflammation is a prerequisite for the application of preventive strategies. In addition, a better understanding of the level and mechanisms of systemic inflammation in children with CKD may enable a more accurate assessment of their risk of other inflammatory conditions such as CVD, anaemia, muscle wasting, and malnutrition. Future research that specifically focuses on the reasons and mechanisms for different rates of disease progression may emerge as a result of this study. Importantly, the findings of this study may have implications in the long term treatment of disease and may allow identification of new treatment strategies to achieve better patient outcomes. The outcomes of the study are: • Better definition of inflammatory profiles in paediatric CKD and correlation with disease severity and progression, which should contribute to improved management strategies. • Identification of new treatment targets to reduce the damage caused by chronic systemic inflammation. • Mechanistic understanding of the relationship of the inflammatory profile in regard to source leucocytes or other contributing cell types.