Serum endotrophin, a type VI collagen cleavage product, is associated with increased mortality in chronic kidney disease

Background

Patients with chronic kidney disease (CKD) are at increased risk of end-stage renal disease (ESRD) and early mortality. The underlying pathophysiological processes are not entirely understood but may include dysregulation of extracellular matrix formation with accelerated systemic and renal fibrosis. We assessed the relationship between endotrophin (ETP), a marker of collagen type VI formation, and adverse outcomes in a cohort of patients with CKD.

Methods

We measured serum ETP levels in 500 patients from the Renal Impairment in Secondary Care (RIISC) study, a prospective observational study of patients with high-risk CKD. Patients were followed up until death or progression to ESRD. Cox regression analysis was used to assess the relationship between ETP and risk of adverse outcomes.

Results

During a median follow-up time of 37 months, 104 participants progressed to ESRD and 66 died. ETP level was significantly associated with progression to ESRD (HR 1.79 [95% CI 1.59–2.02] per 10 ng/mL increase; HR 11.05 [4.98–24.52] for highest vs lowest quartile; both P<0.0001). ETP level was also significantly associated with mortality (HR 1.60 [1.35–1.89] per 10 ng/mL increase; HR 12.14 [4.26–34.54] for highest vs lowest quartile; both P<0.0001). After adjustment for confounding variables, ETP was no longer significantly associated with progression to ESRD but remained independently associated with mortality (HR 1.51 [1.07–2.12] per 10 ng/mL increase, P = 0.019).

Conclusions

Serum ETP level is independently associated with mortality in CKD. This study provides the basis for further exploratory work to establish whether collagen type VI formation is mechanistically involved in the increased mortality risk associated with CKD.

Health-Related Quality of Life Impacts Mortality but Not Progression to End-Stage Renal Disease in Pre-Dialysis Chronic Kidney Disease: A Prospective Observational Study

Background

Chronic kidney disease (CKD) is associated with reduced health-related quality of life (HRQL). However, the relationship between pre-dialysis CKD, HRQL and clinical outcomes, including mortality and progression to end-stage renal disease (ESRD) is unclear.

Methods

All 745 participants recruited into the Renal Impairment In Secondary Care study to end March 2014 were included. Demographic, clinical and laboratory data were collected at baseline including an assessment of HRQL using the Euroqol EQ-5D-3L. Health states were converted into an EQ-5D_index score using a set of weighted preferences specific to the UK population. Multivariable Cox proportional hazards regression and competing risk analyses were undertaken to evaluate the association of HRQL with progression to ESRD or all-cause mortality. Regression analyses were then performed to identify variables associated with the significant HRQL components.

Results

Median eGFR was 25.8 ml/min/1.73 m² (IQR 19.6–33.7ml/min) and median ACR was 33 mg/mmol (IQR 6.6–130.3 mg/mmol). Five hundred and fifty five participants (75.7%) reported problems with one or more EQ-5D domains. When adjusted for age, gender, comorbidity, eGFR and ACR, both reported problems with self-care [hazard ratio 2.542, 95% confidence interval 1.222–5.286, p = 0.013] and reduced EQ-5D_index score [hazard ratio 0.283, 95% confidence interval 0.099–0.810, p = 0.019] were significantly associated with an increase in all-cause mortality. Similar findings were observed for competing risk analyses. Reduced HRQL was not a risk factor for progression to ESRD in multivariable analyses.

Conclusions

Impaired HRQL is common in the pre-dialysis CKD population. Reduced HRQL, as demonstrated by problems with self-care or a lower EQ-5D_index score, is associated with a higher risk for death but not ESRD. Multiple factors influence these aspects of HRQL but renal function, as measured by eGFR and ACR, are not among them.

Serum tryptase concentration and progression to end-stage renal disease

BACKGROUND

Mast cell activation can lead to nonclassical activation of the Renin-Angiotensin-Aldosterone System. However, the relevance of this to human chronic kidney disease is unknown. We assessed the association between serum tryptase, a product of mast cell activation, and progression to end-stage renal disease or mortality in patients with advanced chronic kidney disease. We stratified patients by use of angiotensin-converting enzyme inhibitors/angiotensin receptor II blockers (ACEi/ARB).

MATERIALS AND METHODS

This was a prospective cohort study of 446 participants recruited into the Renal Impairment in Secondary Care study. Serum tryptase was measured at recruitment by sandwich immunoassay. Cox regression analysis was undertaken to determine variables associated with progression to end-stage renal disease or death.

RESULTS

Serum tryptase concentration was independently associated with progression to end-stage renal disease but not with death. In patients treated with ACEi or ARB, there was a strong independent association between higher tryptase concentrations and progression to end-stage renal disease; when compared to the lowest tertile, tryptase concentrations in the middle and highest tertiles had hazard ratios [HR] of 5·78 (95% confidence interval [CI] 1·19-28·03, P = 0·029) and 6·19 (95% CI 1·49-25·69, P = 0·012), respectively. The other independent risk factors for progression to end-stage renal disease were lower age, male gender, lower estimated glomerular filtration rate and higher urinary albumin creatinine ratio.

CONCLUSION

Elevated serum tryptase concentration is an independent prognostic factor for progression to end-stage renal disease in patients with chronic kidney disease who are receiving treatment with an ACEi or ARB.

Reported co-infection deaths are more common in early adulthood and among similar infections

BACKGROUND

Many people have multiple infections at the same time, but the combined contribution of those infections to disease-related mortality is unknown. Registered causes of death offer a unique opportunity to study associations between multiple infections.

METHODS

We analysed over 900,000 death certificates that reported infectious causes of death. We tested whether reports of multiple infections (i.e., co-infections) differed across individuals' age or sex. We also tested whether each pair of infections were reported together more or less often than expected by chance, and whether this co-reporting was associated with the number of biological characteristics they had in common.

RESULTS

In England and Wales, and the USA, 10 and 6 % respectively of infection-related deaths involved co-infection. Co-infection was reported reported most often in young adults; 30 % of infection-related deaths among those aged 25-44 from the USA, and 20 % of infection-related deaths among those aged 30-39 from England and Wales, reported multiple infections. The proportion of infection-related deaths involving co-infection declined with age more slowly in males than females, to less than 10 % among those aged >65. Most associated pairs of infections co-occurred more often than expected from their frequency of being reported alone (488/683 [71 %] in the USA, 129/233 [55 %] in England and Wales), and tended to share biological characteristics (taxonomy, transmission mode, tropism or timescale).

CONCLUSIONS

Age, sex, and biologically similar infections are associated with death from co-infection, and may help indicate patients at risk of severe co-infection.

Microleakage of Posterior Composite Restorations Lined with Self-adhesive Resin Cements

Two self-adhesive resin cements resulted in minimal microleakage scores when used as liners in Class II composite restorations.

Rates of very preterm birth in Europe and neonatal mortality rates

OBJECTIVE

To estimate the influence of variation in the rate of very preterm delivery on the reported rate of neonatal death in 10 European regions.

DESIGN

Comparison of 10 separate geographically defined European populations, from nine European countries, over a 1-year period (7 months in one region).

PARTICIPANTS

All births that occurred between 22(+0) and 31(+6) weeks of gestation in 2003.

MAIN OUTCOME MEASURE

Neonatal death rate adjusted for rate of delivery at this gestation.

RESULTS

Rate of delivery of all births at 22(+0)-31(+6) weeks of gestation and live births only were calculated for each region. Two regions had significantly higher rates of very preterm delivery per 1000 births: Trent UK (16.8, 95% CI 15.7 to 17.9) and Northern UK (17.1, 95% CI 15.6 to 18.6); group mean 13.2 (95% CI 12.9 to 13.5). Four regions had rates significantly below the group average: Portugal North (10.7, 95% CI 9.6 to 11.8), Eastern and Central Netherlands (10.6, 95% CI 9.7 to 11.6), Eastern Denmark (11.2, 95% CI 10.1 to 12.4) and Lazio in Italy (11.0, 95% CI 10.1 to 11.9). Similar trends were seen in live birth data. Published rates of neonatal death for each region were then adjusted by applying (a) a standardised rate of very preterm delivery and (b) the existing death rate for babies born at this gestation in the individual region. This produced much greater homogeneity in terms of neonatal mortality.

CONCLUSIONS

Variation in the rate of very preterm delivery has a major influence on reported neonatal death rates.

The impact of parasite dispersal on antagonistic host-parasite coevolution

Coevolving populations of hosts and parasites are often subdivided into a set of patches connected by dispersal. Higher relative rates of parasite compared with host dispersal are expected to lead to parasite local adaptation. However, we know of no studies that have considered the implications of higher relative rates of parasite dispersal for other aspects of the coevolutionary process, such as the rate of coevolution and extent of evolutionary escalation of resistance and infectivity traits. We investigated the effect of phage dispersal on coevolution in experimental metapopulations of the bacterium Pseudomonas fluorescens SBW25 and its viral parasite, phage SBW25Phi2. Both the rate of coevolution and the breadth of evolved infectivity and resistance ranges peaked at intermediate rates of parasite dispersal. These results suggest that parasite dispersal can enhance the evolutionary potential of parasites through provision of novel genetic variation, but that high rates of parasite dispersal can impede the evolution of parasites by homogenizing genetic variation between patches, thereby constraining coevolution.

Squamous cell carcinoma arising in a dermoid cyst of the ovary: a case series

OBJECTIVE

Malignant transformation in a dermoid cyst of the ovary is a rare complication, occurring in only 1-2% of cases, with squamous cell carcinoma being the most common type. Preoperative diagnosis is difficult because of the lack of specific symptoms and signs to suggest malignancy. Because of the small numbers of women involved, our knowledge of this rare tumour type is limited. This study aims to further characterise the population of women affected, the disease itself and the most appropriate management strategy.

DESIGN

We identified 14 women with this diagnosis between 1989 and 2006. This is a descriptive study, looking at the patient characteristics, mode of presentation and the role of tumour markers and radiological imaging in diagnosis. We also examined the stage and pathological features of the tumour at presentation and the subsequent course of the disease. We have also described our experiences using surgery, chemotherapy and radiotherapy in the management of these women.

RESULTS

We found that these tumours present at an age older than that of mature teratomas and that there are no reliable diagnostic tools or prognostic indicators. The behaviour of these tumours is unpredictable, and the role of chemotherapy and radiotherapy remains unclear. We suggest that repeated surgical resection of disease at the time of relapse could give a very durable response in selected women.

THE IMPACT OF PARASITE MANIPULATION AND PREDATOR FORAGING BEHAVIOR ON PREDATOR–PREY COMMUNITIES

Parasites are known to directly affect their hosts at both the individual and population level. However, little is known about their more subtle, indirect effects and how these may affect population and community dynamics. In particular, trophically transmitted parasites may manipulate the behavior of intermediate hosts, fundamentally altering the pattern of contact between these individuals and their predators. Here, we develop a suite of population dynamic models to explore the impact of such behavioral modifications on the dynamics and structure of the predator-prey community. We show that, although such manipulations do not directly affect the persistence of the predator and prey populations, they can greatly alter the quantitative dynamics of the community, potentially resulting in high amplitude oscillations in abundance. We show that the precise impact of host manipulation depends greatly on the predator's functional response, which describes the predator's foraging efficiency under changing prey availabilities. Even if the parasite is rarely observed within the prey population, such manipulations extend beyond the direct impact on the intermediate host to affect the foraging success of the predator, with profound implications for the structure and stability of the predator-prey community.

Pathogen responses to host immunity: the impact of time delays and memory on the evolution of virulence

Current analytical models of the mammalian immune system typically assume a specialist predator-prey relationship between invading pathogens and the active components of the immune response. However, in reality, the specific immune system is not immediately effective following invasion by a novel pathogen. First, there may be an explicit time delay between infection and immune initiation and, second, there may be a gradual build-up in immune efficacy (for instance, during the period of B-cell affinity maturation) during which the immune response develops, before reaching maximal specificity to the pathogen. Here, we use a novel theoretical approach to show that these processes, together with the presence of long-lived immune memory, decouple the immune response from current pathogen levels, greatly changing the dynamics of the pathogen-immune system interaction and the ability of the immune response to eliminate the pathogen. Furthermore, we use this model to show how distributed primary immune responses combine with immune memory to greatly affect the optimal virulence of the pathogen, potentially resulting in the evolution of highly virulent pathogens.

The relationship between polychlorinated biphenyls in blubber and levels of nematode infestations in harbour porpoises, Phocoena phocoena

Post-mortem examinations of harbour porpoises, Phocoena phocoena, regularly reveal heavy parasitic worm burdens. These same post-mortem records show varying levels of polychlorinated biphenyls (PCBs) accumulating in the blubber of porpoises. Although a number of papers have documented geospatial and temporal changes of PCBs and their detrimental effects on marine mammal health, as yet none have examined their role in determining nematode burdens in wild marine mammal populations. Using a data set consisting of harbour porpoises stranded in the UK between 1989 and 2002, we found a significant, positive association between PCB levels and nematode burdens, although the nature of the relationship was confounded with porpoise sex, age and cause of death. It was also apparent that individuals with the heaviest infestations of nematodes did not have the highest PCB level: while PCBs are important, they are clearly not the sole determinants of nematode burdens in wild populations of the harbour porpoise around the UK.