The gut microbiome tango in the progression of chronic kidney disease and potential therapeutic strategies

Fueling the success of transplantation through nutrition: recent insights into nutritional interventions, their interplay with gut microbiota and cellular mechanisms

PURPOSE OF REVIEW

The role of nutrition in organ health including solid organ transplantation is broadly accepted, but robust data on nutritional regimens remains scarce calling for further investigation of specific dietary approaches at the different stages of organ transplantation. This review gives an update on the latest insights into nutritional interventions highlighting the potential of specific dietary regimens prior to transplantation aiming for organ protection and the interplay between dietary intake and gut microbiota.

RECENT FINDINGS

Nutrition holds the potential to optimize patients' health prior to and after surgery, it may enhance patients' ability to cope with the procedure-associated stress and it may accelerate their recovery from surgery. Nutrition helps to reduce morbidity and mortality in addition to preserve graft function. In the case of living organ donation, dietary preconditioning strategies promise novel approaches to limit ischemic organ damage during transplantation and to identify the underlying molecular mechanisms of diet-induced organ protection. Functioning gut microbiota are required to limit systemic inflammation and to generate protective metabolites such as short-chain fatty acids or hydrogen sulfide.

SUMMARY

Nutritional intervention is a promising therapeutic concept including the pre- and rehabilitation stage in order to improve the recipients' outcome after solid organ transplantation.

Gut permeability, circulating bacterial fragments and measures of congestion in peritoneal dialysis

Background

Limited data exist on the association between gut permeability, circulating bacterial fragment and volume overload in peritoneal dialysis (PD) patients. We measured circulating bacterial fragments, N-terminal pro B-type natriuretic peptide (NT-proBNP), calprotectin and zonulin levels, and evaluate their association with the clinical outcomes in PD patients.

Methods

This was a single-center prospective study on 108 consecutive incident PD patients. Plasma endotoxin and bacterial DNA, and serum NT-proBNP, calprotectin and zonulin levels were measured. Primary outcomes were technique and patient survival, secondary outcomes were hospitalization data.

Results

There was no significant correlation between plasma endotoxin and bacterial DNA, and serum NT-proBNP, calprotectin and zonulin levels. The Homeostatic Model Assessment for Insulin Resistance (HOMA)-2β index, which represents insulin resistance, positively correlated with plasma bacterial DNA (r = 0.421, P < .001) and calprotectin levels (r = 0.362, P = .003), while serum NT-proBNP level correlated with the severity of volume overload and residual renal function. Serum NT-proBNP level was associated with technique survival even after adjusting for confounding factors [adjusted hazard ratio (aHR) 1.030, 95% confidence interval 1.009-1.051]. NT-proBNP level was also associated with patient survival by univariate analysis, but the association became insignificant after adjusting for confounding factors (aHR 1.010, P = .073). Similarly, NT-proBNP correlated with the number of hospitalizations and duration of hospitalization by univariate analysis, but the association became insignificant after adjusting for confounding factors.

Conclusion

There was no correlation between markers of gut permeability, circulating bacterial fragments and measures of congestion in PD patients. Bacterial fragments levels and gut permeability are both associated with insulin resistance. Serum NT-proBNP level is associated with the severity of volume overload and technique survival. Further studies are required to delineate the mechanism of high circulating bacterial fragment levels in PD patients.

Conservative Management in End-Stage Kidney Disease between the Dialysis Myth and Neglected Evidence-Based Medicine

In the last few decades, the aging of the general population has significantly increased the number of elderly patients with end-stage kidney disease (ESKD) who require renal replacement therapy. ESKD elders are often frail and highly comorbid with social issues and seem to not benefit from dialysis in terms of survival and quality of life. Conservative management (CM) could represent a valid treatment option, allowing them to live for months to years with a modest impact on their habits. Despite these possible advantages, CM remains underused due to the myth of dialysis as the only effective treatment option for all ESKD patients regardless of its impact on quality of life and survival. Both CM and dialysis remain valid alternatives in the management of ESKD. However, assessing comorbidities, disabilities, and social context should drive the choice of the best possible treatment for ESKD, while in elderly patients with short life expectancies, referring them to palliative care seems the most reasonable choice.

Gut-Kidney-Heart: A Novel Trilogy

The microbiota represents a key factor in determining health and disease. Its role in inflammation and immunological disorders is well known, but it is also involved in several complex conditions, ranging from neurological to psychiatric, from gastrointestinal to cardiovascular diseases. It has recently been hypothesized that the gut microbiota may act as an intermediary in the close interaction between kidneys and the cardiovascular system, leading to the conceptualization of the "gut-kidney-heart" axis. In this narrative review, we will discuss the impact of the gut microbiota on each system while also reviewing the available data regarding the axis itself. We will also describe the role of gut metabolites in this complex interplay, as well as potential therapeutical perspectives.