Low vitamin D levels are associated with increased rejection and infections after lung transplantation

Relationship between immune cells and the development of chronic lung allograft dysfunction

A major cause of death for lung transplant recipients (LTRs) is the advent of chronic lung allograft dysfunction (CLAD), which has long plagued the long-term post-transplant prognosis and quality of survival of transplant patients. The intricacy of its pathophysiology and the irreversibility of its illness process present major obstacles to the clinical availability of medications. Immunotherapeutic medications are available, but they only aim to slow down the course of CLAD rather than having any therapeutic impact on the disease's development. For this reason, understanding the pathophysiology of CLAD is essential for both disease prevention and proven treatment. The immunological response in particular, in relation to chronic lung allograft dysfunction, has received a great deal of interest recently. Innate immune cells like natural killer cells, eosinophils, neutrophils, and mononuclear macrophages, as well as adaptive immunity cells like T and B cells, play crucial roles in this process through the release of chemokines and cytokines. The present review delves into changes and processes within the immune microenvironment, with a particular focus on the quantity, subtype, and characteristics of effector immune cells in the peripheral and transplanted lungs after lung transplantation. We incorporate and solidify the documented role of immune cells in the occurrence and development of CLAD with the advancements in recent years.

Evaluation of Vitamin D Levels in Children With Liver Transplant

OBJECTIVES

Vitamin D deficiency is common in pediatric chronic liver disease despite oral replacement. We evaluated vitamin D deficiency before and after liver transplant and the relationship between posttransplant and pretransplant vitamin D deficiency and graft rejection.

MATERIALS AND METHODS

Pediatric recipients with chronic liver disease (N =138) were divided into 4 groups: cholestatic liver diseases, cirrhosis, metabolic disorders, and acute liver failure. Pretransplant and posttransplant vitamin D levels, liver function tests, Pediatric End-Stage Liver Disease scores, rejection activity index scores by graft liver biopsy, and posttransplant patient survival were recorded.

RESULTS

There were 62 (45%) female and 76 (55%) male participants (mean transplant age, 6.1 ± 5.6 years). Pretransplant mean available vitamin D of 90 patients was 25.2 ± 20.9 ng/mL, with 36 (40%) within reference range. Posttransplant level for 109 patients was 27.3 ± 18 ng/mL, with 64 (58.7%) within reference range. Pretransplant and posttransplant levels were available for 61 patients, and mean pretransplant levels were lower than posttransplant levels (23.7 ± 19.3 vs 28.3 ± 16.9 ng/mL; P = .01). Patients with cholestatic liver disease had lower pretransplant vitamin D levels (P = .04), which disappeared after transplant. Pretransplant vitamin D levels were positively correlated with serum albumin levels (r = 0.20) in all patients and negatively correlated with total/direct bilirubin (r = 0.29 and r = -0.30) in those with liver diseases and cirrhosis. No correlations were found between pretransplant vitamin D levels and Pediatric End-Stage Liver Disease scores, rejection activity index scores, and posttransplant mortality.

CONCLUSIONS

Vitamin D deficiency is prevalent in pediatric chronic liver disease before and after transplant, especially for cholestatic liver diseases. However, no association between vitamin D levels and liver graft rejection or patient survival was noted. We recommend close monitoring and individualized vitamin D supplementation before and after liver transplant.

Impact of air pollution on postoperative outcomes following organ transplantation: Evidence from clinical investigations

INTRODUCTION

Air pollution is a worldwide problem affecting human health via various body systems, resulting in numerous significant adverse events. Air pollutants, including particulate matter < or = 2.5 microns (PM2.5), particulate matter < or = 10 microns (PM10), ozone (O3 ), nitrogen dioxide (NO2 ), and traffic-related air pollution (TRAP), have demonstrated the negative effects on human health (e.g., increased cerebrovascular, cardiovascular, and respiratory diseases, malignancy, and mortality). Organ transplant patients, who are taking immunosuppressive agents, are especially vulnerable to the adverse effects of air pollutants. The evidence from clinical investigation has shown that exposure to air pollution after organ transplantation is associated with organ rejection, cardiovascular disease, coronary heart disease, cerebrovascular disease, infection-related mortality, and vitamin D deficiency.

OBJECTIVES AND METHOD

This review aims to summarize and discuss the association of exposure to air pollutants and serum 25-hydroxyvitamin D level and outcomes after transplantation. Controversial findings are also included and discussed.

CONCLUSION

All of the findings suggest that air pollution results in a hazardous environment, which not only impacts human health worldwide but also affects post-transplant outcomes.

Vitamin D status as a predictor for liver transplant outcomes

It is well known that vitamin D plays a pivotal role in immune system modulation; however, its role in liver transplantation (LT) has not yet been well elucidated. This study aimed to assess the association between vitamin D status and LT outcomes. This retrospective cohort study was conducted on 335 registered cirrhotic patients with end-stage liver disease (ESLD) who underwent LT during 2019-2021 and had measurement of serum vitamin D before LT. The association of vitamin D levels before LT with the odds of acute cellular rejection (ACR) and risk mortality was assessed by applying logistic and cox regression, respectively. The mean MELD-Na and serum level of vitamin D were 20.39 ± 9.36 and 21.52 ± 15.28 ng/ml, respectively. In the final adjusted model, there was a significant association between vitamin D deficiency in the pre-transplant period and odds of ACR (odds ratio [OR] 2.69; 95% confidence interval [CI] 1.50-4.68). Although in the crude model, vitamin D deficiency in the pre-transplant period was significantly associated with an increased risk of mortality after two years of follow-up (Hazard ratio (HR) = 2.64, 95% CI 1.42-4.33), after adjustment for potential confounders, the association of vitamin D status and mortality became non-significant (HR = 1.46, 95% CI 0.71-3.00). The present study provides evidence that pre-transplant serum vitamin D levels may be a predictor for ACR in patients with cirrhosis undergoing LT.

Body Mass Index and Cause-Specific Mortality after Lung Transplantation in the United States

Rationale: Low and high body mass index (BMI) are associated with increased mortality after lung transplantation. Why extremes of BMI might increase risk of death is unknown. Objectives: To estimate the association of extremes of BMI with causes of death after transplantation. Methods: We performed a retrospective study of the United Network for Organ Sharing database, including 26,721 adults who underwent lung transplantation in the United States between May 4, 2005, and December 2, 2020. We mapped 76 reported causes of death into 16 distinct groups. We estimated cause-specific hazards for death from each cause using Cox models. Results: Relative to a subject with a BMI of 24 kg/m2, a subject with a BMI of 16 kg/m2 had 38% (hazard ratio [HR], 1.38; 95% confidence interval [95% CI], 0.99-1.90), 82% (HR, 1.82; 95% CI, 1.34-2.46), and 62% (HR, 1.62; 95% CI, 1.18-2.22) increased hazards of death from acute respiratory failure, chronic lung allograft dysfunction (CLAD), and infection, respectively, and a subject with a BMI of 36 kg/m2 had 44% (HR, 1.44; 95% CI, 0.97-2.12), 42% (HR, 1.42; 95% CI, 0.93-2.15), and 185% (HR, 2.85; 95% CI, 1.28-6.33) increased hazards of death from acute respiratory failure, CLAD, and primary graft dysfunction, respectively. Conclusions: Low BMI is associated with increased risk of death from infection, acute respiratory failure, and CLAD after lung transplantation, whereas high BMI is associated with increased risk of death from primary graft dysfunction, acute respiratory failure, and CLAD.

Interplay of Vitamin D and SIRT1 in Tissue-Specific Metabolism-Potential Roles in Prevention and Treatment of Non-Communicable Diseases Including Cancer

The importance of the prevention and control of non-communicable diseases, including obesity, metabolic syndrome, type 2 diabetes, cardiovascular diseases, and cancer, is increasing as a requirement of the aging population in developed countries and the sustainability of healthcare. Similarly, the 2013-2030 action plan of the WHO for the prevention and control of non-communicable diseases seeks these achievements. Adequate lifestyle changes, alone or with the necessary treatments, could reduce the risk of mortality or the deterioration of quality of life. In our recent work, we summarized the role of two central factors, i.e., appropriate levels of vitamin D and SIRT1, which are connected to adequate lifestyles with beneficial effects on the prevention and control of non-communicable diseases. Both of these factors have received increased attention in relation to the COVID-19 pandemic as they both take part in regulation of the main metabolic processes, i.e., lipid/glucose/energy homeostasis, oxidative stress, redox balance, and cell fate, as well as in the healthy regulation of the immune system. Vitamin D and SIRT1 have direct and indirect influence of the regulation of transcription and epigenetic changes and are related to cytoplasmic signaling pathways such as PLC/DAG/IP3/PKC/MAPK, MEK/Erk, insulin/mTOR/cell growth, proliferation; leptin/PI3K-Akt-mTORC1, Akt/NFĸB/COX-2, NFĸB/TNFα, IL-6, IL-8, IL-1β, and AMPK/PGC-1α/GLUT4, among others. Through their proper regulation, they maintain normal body weight, lipid profile, insulin secretion and sensitivity, balance between the pro- and anti-inflammatory processes under normal conditions and infections, maintain endothelial health; balance cell differentiation, proliferation, and fate; and balance the circadian rhythm of the cellular metabolism. The role of these two molecules is interconnected in the molecular network, and they regulate each other in several layers of the homeostasis of energy and the cellular metabolism. Both have a central role in the maintenance of healthy and balanced immune regulation and redox reactions; therefore, they could constitute promising targets either for prevention or as complementary therapies to achieve a better quality of life, at any age, for healthy people and patients under chronic conditions.

Nutritional Strategies to Manage Malnutrition and Sarcopenia following Liver Transplantation: A Narrative Review

Persisting or newly developed malnutrition and sarcopenia after liver transplant (LT) are correlated with adverse health outcomes. This narrative review aims to examine the literature regarding nutrition strategies to manage malnutrition and sarcopenia after LT. The secondary aims are to provide an overview of the effect of nutrition strategies on the incidence of infections, hospital length of stay (LOS), acute cellular rejection (ACR), and mortality after LT. Four databases were searched. A total of 25 studies, mostly of mid-high quality, were included. Six studies found a beneficial effect on nutritional parameters using branched-chain amino acids (BCAA), immunomodulating diet (IMD), or enteral nutrition (EN) whereas two studies using beta-hydroxy-beta-methylbutyrate (HMB) found a beneficial effect on muscle mass and function. Fourteen studies using pre- or pro-biotics, IMD, and EN were effective in lowering infection and six studies using IMD, BCAA or HMB reported reduced hospital LOS. Finally, four studies using HMB and vitamin D were effective in reducing ACR and one study reported reduced mortality using vitamin D after LT. In conclusion, nutritional intervention after LT has different beneficial effects on malnutrition, sarcopenia, and other advert outcomes. Additional large and well-constructed RCTs using validated tools to assess nutritional status and sarcopenia are warranted to ensure more robust conclusions.

Update on Lung Transplantation for Cystic Fibrosis

Lung transplantation provides a treatment option for many individuals with advanced lung disease due to cystic fibrosis (CF). Since the first transplants for CF in the 1980s, survival has improved and the opportunity for transplant has expanded to include individuals who previously were not considered candidates for transplant. Criteria to be a transplant candidate vary significantly among transplant programs, highlighting that the engagement in more than one transplant program may be necessary. Individuals with highly resistant CF pathogens, malnutrition, osteoporosis, CF liver disease, and other comorbidities may be suitable candidates for lung transplant, or if needed, multi-organ transplant. The transplant process involves several phases, from discussion of prognosis and referral to a transplant center, to transplant evaluation, to listing, transplant surgery, and care after transplant. While the availability of highly effective CF transmembrane conductance regulator (CFTR) modulators for many individuals with CF has improved lung function and slowed progression to respiratory failure, early discussion regarding transplant as a treatment option and referral to a transplant program are critical to maximizing opportunity and optimizing patient and family experience. The decision to be evaluated for transplant and to list for transplant are distinct, and early referral may provide a treatment option that can be urgently executed if needed. Survival after transplant for CF is improving, to a median survival of approximately 10 years, and most transplant survivors enjoy significant improvement in quality of life.

Influences of exocrine pancreatic insufficiency on nutrient digestibility, growth parameters as well as anatomical and histological morphology of the intestine in a juvenile pig model

In a pig model, pancreatic duct ligation (PL) leads to a complete loss of exocrine function, causing an exocrine pancreatic insufficiency (EPI) without affecting endocrine function, allowing research of clinical effects and therapy options. This study aimed to investigate effects of experimentally induced EPI in juvenile pigs on digestion and intestinal morphology. Eight female juvenile cross-bred pigs (BW 54.8 kg at the start of the study) were included. Three animals were considered as a control (CON group), and in five animals the ductus pancreaticus accessorius was ligated (PL group). During the 10-week trial period, body weight and body measurements were recorded regularly. At the end of the trial, gastrointestinal tract (GIT) was investigated macroscopically and histologically and weight and digesta samples of individual segments were obtained. The pigs in the CON showed a significantly higher apparent total tract digestibility of crude protein and crude fat (87.8 and 79.9%, respectively) compared to PL (52.4 and 16.6%, respectively). Significant differences were noted in relative weights of duodenum, jejunum and colon (with and without digesta) and also in absolute weights of jejunum and colon. The mean number of nuclei in the transverse section in stratum circulare were significantly higher in all intestinal segments in CON compared to PL. Overall, EPI results in impaired nutrient digestibility with a greater filling of the GIT with digesta. The elongation of the small intestine does not represent "stretching" of the intestine, but rather increased synthesis of intestinal tissue.

Pharmacotherapy of chronic lung allograft dysfunction post lung transplantation

Chronic lung allograft dysfunction (CLAD) remains the primary cause of death in lung transplant recipients (LTRs) in spite of improvements in immunosuppression management. Despite advances in knowledge regarding the pathogenesis of CLAD, treatments that are currently available are usually ineffective and delay progression of disease at best. There are currently no evidence-based guidelines for the optimal treatment of CLAD, and management varies widely across transplant centers. Additionally, there are minimal publications available to summarize data for currently available therapies and outcomes in LTRs. We identified the major domains of the medical management of CLAD and conducted a comprehensive search of PubMed and Embase databases to identify articles published from inception to December 2021 related to CLAD in LTRs. Studies published in English pertaining to the pharmacologic prevention and treatment of CLAD were included; highest priority was given to prospective, randomized, controlled trials if available. Prospective observational and retrospective controlled trials were prioritized next, followed by retrospective uncontrolled studies, case series, and finally case reports if the information was deemed to be pertinent. Reference lists of qualified publications were also reviewed to find any other publications of interest that were not found on initial search. In the absence of literature published in the aforementioned databases, additional articles were identified by reviewing abstracts presented at the International Society for Heart and Lung Transplantation and American Transplant Congress annual meetings between 2010-2021. This document serves to provide a comprehensive review of the literature and considerations for the prevention and medical management of CLAD. This article is protected by copyright. All rights reserved.

Prevalence of vitamin D deficiency and impact on clinical outcomes after kidney transplantation: a systematic review and meta-analysis

CONTEXT

The prevalence of vitamin D deficiency (VDD) and its impact on clinical outcomes after kidney transplant (KT) remain poorly defined.

OBJECTIVES

We conducted a meta-analysis to evaluate the impact of early VDD on clinical outcomes after KT.

DATA SOURCES

Electronic databases (PubMed, Embase, Web of Science, and The Cochrane Library) were systematically searched for eligible publications up to April 30, 2020.

DATA EXTRACTION

Relative risk was presented as hazard ratios (HRs) or odds ratios (ORs) and 95%CIs for dichotomous outcomes. Mean difference (MD) and 95%CIs were presented for continuous outcomes.

RESULTS

A total of 28 studies (13 prospective and 15 retrospective) were included. VDD was common early after KT, with a prevalence of 52% (95%CI: 41%-64%) at transplant, 34% (95%CI: 17%-51%) at 3 months, and 23% (95%CI: 10%-35%) at 6 months. Early VDD was associated with higher mortality rate after KT (HR, 1.56; 95%CI: 1.32-1.84; P < 0.001). In addition, early VDD led to higher risk of bacterial infection (OR, 1.82; 95%CI: 1.40-2.36; P < 0.001), BK polyomavirus infection (OR, 2.11, 95%CI: 1.23-3.61; P = 0.006), and cytomegalovirus infection (OR, 1.69; 95%CI: 1.24-2.31; P = 0.001). Early VDD increased the risk of acute rejection as well (HR, 2.28; 95%CI: 1.57-3.30; P < 0.001). Recipients with early VDD had lower estimated glomerular filtration rates (mean difference: -5.06; 95%CI: -7.28 to 2.83 mL/min; P < 0.001). Sensitivity analyses showed good stability of the pooled results.

CONCLUSION

VDD was common early after KT and associated with higher risk of death and adverse outcomes.

Vitamin D Insufficiency Prior to Paediatric Liver Transplantation Is Associated with Early T-Cell Mediated Rejection

Objectives: T-cell mediated rejection (TCMR) can compromise long-term liver allograft survival. The immunomodulatory properties of vitamin D are increasingly recognized. We investigated whether perturbations in vitamin D metabolism prior to LT may predispose to TCMR in a representative cohort of paediatric LT recipients. Methods: In this retrospective single-center study of children who underwent liver transplantation between 2005 and 2017, we collected serum 25(OH) vitamin D levels and other parameters related to vitamin D metabolism. Post-transplant variables were collected from medical records during the first year following LT. Results: Eighty-two patients were included. Twenty-six (32%) developed TCMR, 52 (65%) presented at least one event of 25(OH) D insufficiency during the year before the transplant, while 23 (32%) had at least one documented elevated plasma parathyroid hormone level. Forty-six patients benefited from nutritional support (56%). The development of TCMR was associated with vitamin D insufficiency pre-LT (p = 0.01). No significant correlations were identified between PTH levels and incidence of TCMR. The association was stronger in patients transplanted for cholestatic diseases (p = 0.004). Conclusions: Vitamin D insufficiency before a liver transplant may be associated with TCMR during the first year post-LT. These findings warrant further investigation.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

Nutrition Support in Liver Transplantation and Postoperative Recovery: The Effects of Vitamin D Level and Vitamin D Supplementation in Liver Transplantation

Vitamin D plays an important role in the arena of liver transplantation. In addition to affecting skeletal health significantly, it also clinically exerts immune-modulatory properties. Vitamin D deficiency is one of the nutritional issues in the perioperative period of liver transplantation (LT). Although vitamin D deficiency is known to contribute to higher incidences of acute cellular rejection (ACR) and graft failure in other solid organ transplantation, such as kidneys and lungs, its role in LT is not well understood. The aim of this study was to investigate the clinical implication of vitamin D deficiency in LT. LT outcomes were reviewed in a retrospective cohort of 528 recipients during 2014-2019. In the pre-transplant period, 55% of patients were vitamin-D-deficient. The serum vitamin D level was correlated with the model for end-stage liver disease (MELD-Na) score. Vitamin D deficiency in the post-transplant period was associated with lower survival after LT, and the post-transplant supplementation of vitamin D was associated with a lower risk of ACR. The optimal vitamin D status and vitamin D supplementation in the post-transplant period may prolong survival and reduce ACR incidence.

Comparison of outcomes in lung and heart transplant recipients from the same multiorgan donor

BACKGROUND

Primary graft dysfunction (PGD) and acute cellular rejection (ACR) are important causes of early morbidity and mortality following lung and heart transplantation. While many studies have elucidated donor-related risk factors of PGD and ACR, these complications often occur even with "ideal" donors. Therefore, we investigated potential associations of PGD and ACR between bilateral lung and heart transplant recipients from the same multiorgan donor, respectively.

METHODS

Between 2011 and 2017, 100 donors contributed 100 bilateral lung transplants and 100 heart transplants performed. Logistic regression analysis for PGD and Cox proportional hazards regression analysis for ACR were used to estimate the relationship of heart and lung transplants.

RESULTS

The incidence of PGD was 33% among lung and 17% among heart transplant recipients. Similarly, the incidence of ACR grade ≥ A2 for lung recipients was 38% (30/80), and the incidence of ACR grade ≥ 2R for heart recipients was 19% (15/80). There was no association between the development of PGD and ACR in lung and heart transplant recipients from the same donor, respectively.

CONCLUSIONS

These findings suggest that inherent donor factors are not critical to the development of PGD and ACR after lung and heart transplantation.

Vitamin D status and risk of infections after liver transplantation in the Swiss Transplant Cohort Study

Increasing evidence indicates a role of vitamin D in the immune system affecting response to infections. We aimed to characterize the role of vitamin D status, i.e. deficiency [25-OH vitamin D (25-OHD) <50 nmol/l] and no deficiency (25-OHD ≥50 nmol/l) in incident infections after liver transplantation. In 135 liver transplant recipients, blood samples drawn at time of liver transplantation and 6 months afterwards were used to determine 25-OHD levels. Incident infections episodes were prospectively collected within the Swiss Transplant Cohort Study database. Poisson regression was applied to address associations between vitamin D status and incident infections. Vitamin D deficiency was common at time of transplantation and 6 months afterwards without a significant change in median 25-OHD levels. In univariable analyses, vitamin D deficiency was a risk factor for incident infections in the first 6 months post-transplant incidence rate ratio (IRR 1.52, 95% CI 1.08-2.15, P = 0.018) and for bacterial infections occurring after 6 up to 30 months post-transplant (IRR 2.29, 95% CI 1.06-4.94, P = 0.034). These associations were not detectable in multivariable analysis with adjustment for multiple confounders. Efforts to optimize vitamin D supplementation in liver transplant recipients are needed. Our data question the role of vitamin D deficiency in incident infections.

Nutritional Requirements of Lung Transplant Recipients: Challenges and Considerations

An optimal nutritional status is associated with better post-transplant outcomes and survival. Post-lung transplant nutrition management is however particularly challenging as lung recipients represent a very heterogeneous group of patients in terms of age, underlying diseases, weight status and presence of comorbidities. Furthermore, the post-transplant period encompasses several stages characterized by physiological and pathophysiological changes that affect nutritional status of patients and necessitate tailored nutrition management. We provide an overview of the current state of knowledge regarding nutritional requirements in the post-lung transplant period from the immediate post-operative phase to long-term follow-up. In the immediate post-transplantation phase, the high doses of immunosuppressants and corticosteroids, the goal of maintaining hemodynamic stability, the presence of a catabolic state, and the wound healing process increase nutritional demands and lead to metabolic perturbations that necessitate nutritional interventions. As time from transplantation increases, complications such as obesity, osteoporosis, cancer, diabetes, and kidney disease, may develop and require adjustments to nutrition management. Until specific nutritional guidelines for lung recipients are elaborated, recommendations regarding nutrient requirements are formulated to provide guidance for clinicians caring for these patients. Finally, the management of recipients with special considerations is also briefly addressed.

Impact of nutritional status on pulmonary function after lung transplantation for cystic fibrosis

Background

Nutritional status is an important prognostic factor in patients with cystic fibrosis (CF) prior to lung transplantation.

Objective

To investigate the impact of nutritional status on pulmonary function in CF transplant recipients.

Methods

Adult double lung transplanted CF patients were consecutively included. The predictive value of nutritional status on lung function - measured by spirometry - was longitudinally assessed by body composition serially evaluated by a three-compartment model bioelectrical impedance analysis (BIA) in comparison to body mass index (BMI).

Results

Overall, 147 spirometries and 147 BIAs were performed in 58 patients (59% female, median age: 30.1 years, median BMI: 19.6 kg/m²). Malnourished patients (BMI < 18.5 kg/m²; 27.6%) had a significantly reduced lung function compared to normal/overweight patients (forced expiratory volume in 1 second in percent (FEV1%pred), 57% vs 77%; p = 0.024). BMI, as well as the BIA parameters phase angle, total body water, fat free mass, body cell mass (BCM) and extracellular mass (ECM)/BCM ratio, were univariate predictors of FEV1%pred. When included in a linear mixed model, ECM/BCM ratio remained the only significant predictor of lung function (p = 0.012).

Conclusion

Nutritional status assessed by BIA predicted lung function in CF transplant recipients. Serial BIA measurements to monitor patients' nutritional status might help to improve or maintain lung function.

Pathology of Lung Rejection: Cellular and Humoral Mediated

Acute rejection is an important risk factor for bronchiolitis obliterans syndrome, the clinical manifestation of chronic airway rejection in lung allograft recipients. Patients with acute rejection might be asymptomatic or present with symptoms that are not specific and can be also seen in other conditions. Clinical tests such as pulmonary function tests and imaging studies among others usually are abnormal; however, their results are also not specific for acute rejection. Histopathologic features of acute rejection in adequate samples of transbronchial lung biopsy of the lung allograft are currently the gold standard to assess for acute rejection in lung transplant recipients. Acute alloreactive injury can affect both the vasculature and the airways. Currently, the guidelines of the 2007 International Society of Heart and Lung Transplantation consensus conference are recommended for the histopathologic assessment of rejection. There are no specific morphologic features recognized to diagnose antibody-mediated rejection (AMR) in lung allografts. Therefore, the diagnosis of AMR currently requires a “triple test” including clinical features, serologic evidence of donor-specific antibodies, and pathologic findings supportive of AMR. Complement 4d deposition is used to support a diagnosis of AMR in many solid organ transplants; however, its significance for the diagnosis of AMR in lung allografts is not entirely clear. This chapter discusses the currently recommended guidelines for the assessment of cellular rejection of lung allografts and summarizes our knowledge about morphologic features and immunophenotypic tests that might help in the diagnosis of AMR.

Fewer Complications Following Revision Hip and Knee Arthroplasty in Patients With Normal Vitamin D Levels

BACKGROUND

Surgeons and hospitals increasingly face penalty for complications and readmission following total joint arthroplasty; therefore, optimization of modifiable risk factors is paramount. Literature associates low vitamin D with risk of periprosthetic joint infection, and we hypothesized low vitamin D to be predictive of increased rate of complications and readmissions.

METHODS

A retrospective review of 126 revision total joint arthroplasty patients between 2010 and 2014 was performed.

RESULTS

Low vitamin D was not associated with risk of 30-day readmission but was found to be associated with an increased risk of 90-day complications as well as periprosthetic joint infection as the reason for revision surgery.

CONCLUSION

Preoperative vitamin D level should be considered a modifiable risk factor for complications following revision arthroplasty.

Bone Mineral Density and Fat-Soluble Vitamin Status in Adults with Cystic Fibrosis Undergoing Lung Transplantation: A Pilot Study

Purpose: Patients with cystic fibrosis (CF) often experience low bone mineral density (BMD) pre- and post-lung transplantation (LTX). The study purpose was to describe BMD and micronutrient status in adults with CF pre- and post-LTX.

Methods: Twelve patients with CF (29 ± 8 years) were recruited from the CF clinic at the University of Alberta Lung Transplant Program. BMD and vitamins A, D, E, K status, and parathyroid hormone were measured pre- and post-LTX.

Results: No significant differences pre- and post-LTX were observed at the different bone sites measured (lumber–spine, femoral–neck (FN), hip, and femoral–trochlea) (P > 0.05). BMD T-scores (<−2) was present in lumbar–spine, FN, hip, and femoral–trochlea in 33%, 17%, 17%, and 25% of individuals pre-LTX and 58%, 33%, 58%, and 33% of individuals post-LTX, respectively. More than 50% of patients had suboptimal vitamin K levels (PIVKA-II values >3 ng/mL) pre- and post-LTX.

Conclusion: Adults with CF pre- and post-LTX had reduced BMD and suboptimal vitamin K status.

Clinical effects of pre-transplant serum 25-hydroxyvitamin D level on post-transplant immunologic and non-immunologic outcomes in kidney transplant recipients

BACKGROUND

The aim of this study was to investigate the effects of pre-transplant serum 25-hydroxyvitamin D (25(OH)D) level on non-immunologic and immunologic aspects of post-transplant clinical outcomes in kidney transplant recipients (KTRs).

METHODS

We investigated 174 KTRs with low immunologic risk at baseline. We divided the patients into three groups according to baseline serum 25(OH)D level and compared the post-transplant clinical outcomes of acute rejection, infectious complications, and osteoporosis among the groups.

RESULT

Thirty cases of biopsy-proven acute rejection (BPAR) were detected during the first year after KT. In the highest tertile, the rate of acute rejection (8.6%) was significantly lower than that in the lowest tertile (25.4%) (p=0.016), and a high 25(OH)D level was independently associated with a low incidence of BPAR in multivariate analysis. In contrast, serum 25(OH)D level did not show a significant association with overall or any specific type of infectious complication. Lipid profile, intact parathyroid hormone (PTH) level, and hemoglobin level were similar among the three tertile groups. The incidence of osteoporosis and bone mineral density (BMD) score were also similar across all three groups.

CONCLUSIONS

Pre-transplant serum 25(OH)D level is a significant predictor of acute rejection, but it does not predict infection or metabolic complications.

Impact of Immune-Modulatory Drugs on Regulatory T Cell

Immunosuppression strategies that selectively inhibit effector T cells while preserving and even enhancing CD4FOXP3 regulatory T cells (Treg) permit immune self-regulation and may allow minimization of immunosuppression and associated toxicities. Many immunosuppressive drugs were developed before the identity and function of Treg were appreciated. A good understanding of the interactions between Treg and immunosuppressive agents will be valuable to the effective design of more tolerable immunosuppression regimens. This review will discuss preclinical and clinical evidence regarding the influence of current and emerging immunosuppressive drugs on Treg homeostasis, stability, and function as a guideline for the selection and development of Treg-friendly immunosuppressive regimens.

Vitamin D insufficiency and deficiency in patients with fractures of the fifth metatarsal

INTRODUCTION

The fifth metatarsal is a common site for both acute and stress fractures in the foot. They are usually isolated low-energy or stress fractures. Vitamin D deficiency has been associated with fragility fractures in many parts of the body. We believe that low Vitamin D could be a significant aetiological factor in fractures of the fifth metatarsal.

METHODOLOGY

A prospective study of patients with fractures of the fifth metatarsal was conducted. Patients presenting to fracture clinic with these fractures had their vitamin D and calcium levels measured. We also conducted a literature review of studies of vitamin D levels in the Northern Hemisphere between 1990 and 2014.

RESULTS

Forty patients with fifth metatarsal fractures were studied (22 metatarsal base fractures, 6 shaft fractures, and 2 stress fractures). The average patient age was 49 (range 22-83). 12 patients (30%) had a Vitamin D level consistent with deficiency, and a further 14 (35%) had a level consistent with insufficiency. Average Vitamin D levels in winter fractures were significantly lower (52.23nmol/L) than for those sustained in summer (76.73nmol/L).

CONCLUSIONS

Hypovitaminosis D was common in patients with fifth metatarsal fractures. Vitamin D supplementation has been shown in animal studies to improve fracture healing rates, and in humans to decrease the risk of fragility fracture. It should be part of regular practice to check Vitamin D levels in these patients, and supplement where necessary.

Osteoporosis in the adult solid organ transplant population: underlying mechanisms and available treatment options

The prevention and treatment of osteoporosis is an increasingly important topic in the solid organ transplant (SOT) population. Compared to the general population, these patients are at an elevated risk of developing osteoporosis due to progressive disease, lifelong immunosuppressant therapy, and malnutrition. As patients live longer after transplant, chronic disease management is increasingly more important. Supplementation with calcium and vitamin D is often necessary in the SOT population due to a high incidence of vitamin D deficiency. Bisphosphonate therapy is most commonly used for prevention and treatment of osteoporosis, but therapy can be limited by renal dysfunction which is common in transplant recipients. Alternative agents such as teriparatide and calcitonin have not been shown to provide a significant impact on the rate of fractures in this population. Additionally, denosumab may be a promising treatment option due to its novel mechanism of action, and is currently being studied in renal transplant patients. Timely initiation of supplementation and treatment, and minimizing glucocorticoid exposure prior to and after transplantation will aid in the prevention and proper management of osteoporosis in these patients.

Risks and Epidemiology of Infections After Lung or Heart–Lung Transplantation

Nowadays, lung transplantation is an established treatment option of end-stage pulmonary parenchymal and vascular disease. Post-transplant infections are a significant contributor to overall morbidity and mortality in the lung transplant recipient that, in turn, are higher than in other solid organ transplant recipients. This is likely due to several specific factors such as the constant exposure to the outside environment and the colonized native airway, and the disruption of usual mechanisms of defense including the cough reflex, bronchial circulation, and lymphatic drainage. This chapter will review the common infections that develop in the lung or heart–lung transplant recipient, including the general risk factors for infection in this population, and specific features of prophylaxis and treatment for the most frequent bacterial, viral, and fungal infections. The effects of infection on lung transplant rejection will also be discussed.

Calcitriol inhibits bleomycin-induced early pulmonary inflammatory response and epithelial-mesenchymal transition in mice

Early pulmonary inflammation and epithelial-mesenchymal transition (EMT) play important roles during lung fibrosis. Increasing evidence demonstrates that calcitriol, the active form of vitamin D3, has anti-inflammatory activities. The aim of this study was to investigate the effects of calcitriol on bleomycin (BLM)-induced early pulmonary inflammation and subsequent EMT. Mice were intratracheally injected with BLM (3.0mg/kg). In three calcitriol+BLM groups, mice were intraperitoneal (i.p.) injected with different doses of calcitriol (0.2, 1.0 or 5.0 μg/kg) daily, beginning at 48 h before BLM injection. Twenty-four hours, seven and fourteen days after BLM injection, pulmonary inflammation and EMT were evaluated. As expected, BLM-induced infiltration of inflammatory cells in the lungs was attenuated by calcitriol. BLM-induced pulmonary inflammatory cytokines were repressed by calcitriol. Moreover, BLM-induced nuclear translocation of nuclear factor kappa B (NF-κB) p65 was blocked by calcitriol. In addition, BLM-induced phosphorylation of pulmonary p38 MAPK and protein kinase B (Akt) was inhibited by calcitriol. Further analysis showed that BLM-induced α-smooth muscle actin (α-SMA), a marker for EMT in the lungs, was significantly attenuated by calcitriol. BLM-induced transforming growth factor-beta 1 (TGF-β1) up-regulation and Smad phosphorylation were attenuated by calcitriol. In conclusion, calcitriol inhibits BLM-induced early pulmonary inflammation and subsequent EMT.

Nutrition Management of Cystic Fibrosis in the 21st Century

Despite significant advancements made in life expectancy over the past century, cystic fibrosis remains a life-threatening genetic disease that affects the gastrointestinal tract, and it has significant impact on the nutrition status of those with the disease. Nutrition management includes a high-calorie/high-fat diet, pancreatic enzyme replacement therapy, vitamin and mineral replacement, and enteral support as needed. As patients are living longer, clinicians may encounter patients with cystic fibrosis in obstetrician offices, endocrine clinics, or hospital settings, owing to lung transplantation or for treatment for distal intestinal obstruction syndrome.

Vitamin D status and surgical outcomes: a systematic review

The importance of vitamin D for musculoskeletal health has long been recognized, and awareness of significant extra-skeletal effects in health and disease is rapidly emerging. Although it has been possible for many decades to quantify serum markers of vitamin D deficiency, and to correct deficiency at low cost and with high safety, the influence of vitamin D status on post-surgical outcomes has only recently been identified as a research topic of interest. To the present, these data have not been the subject matter of formal review. Accordingly, we conducted a systematic review to assess the association between perioperative vitamin D status and outcomes after surgery. The databases of PubMed, Ovid MEDLINE, EMBASE, AMED, CINAHL (EBSCOHost), The Cochrane Databases of Systematic Review, and PROSPERO were searched through December, 2014 for studies relating to vitamin D and surgery. The initial search yielded 90 manuscripts. After applying exclusion criteria, 31 studies were eligible for inclusion. Fifteen studies employed prospective observational designs, 3 used prospective randomized protocols, and 13 report retrospective database interrogations. The main finding of the present review is that 26 of 31 studies (84%) report at least one statistically significant worse outcome in patients with low vitamin D status. Five of 31 studies (16%) found no association. In conclusion, this review supports the hypothesis that hypovitaminosis D is associated with adverse outcomes after diverse surgical procedures. Future studies should focus on additional surgeries and outcomes, and on the role of vitamin D supplementation in the improvement of patient safety in participants with low vitamin D status at the time of surgery.

The relationship between serum vitamin D levels and spinal fusion success: a quantitative analysis

STUDY DESIGN

An in vivo dosing study of vitamin D in a rat posterolateral spinal fusion model with autogenous bone grafting. Rats randomized to 4 levels of vitamin D-adjusted rat chow, longitudinal serum validation, surgeons/observers blinded to dietary conditions, and rats followed prospectively for fusion endpoint.

OBJECTIVE

To assess the impact of dietary and serum levels of vitamin D on fusion success, consolidation of fusion mass, and biomechanical stiffness after posterolateral spinal fusion procedure.

SUMMARY OF BACKGROUND DATA

Metabolic risk factors, including vitamin D insufficiency, are often overlooked by spine surgeons. Currently, there are no published data on the causal effect of insufficient or deficient vitamin D levels on the success of establishing solid bony union after a spinal fusion procedure.

METHODS

Fifty rats were randomized to 4 experimentally controlled rat chow diets: normal control, vitamin D-deficient, vitamin D-insufficient, and a nontoxic high dose of vitamin D, 4 weeks prior to surgery and maintained postsurgery until sacrifice. Serum levels of 25(OH)D were determined at surgery and sacrifice using radioimmunoassay. Posterolateral fusion surgery with tail autograft was performed. Rats were sacrificed 12 weeks postoperatively, and fusion was evaluated via manual palpation, high-resolution radiographs, micro-computed tomographic scans, and biomechanical testing.

RESULTS

Serum 25(OH)D and calcium levels were significantly correlated with vitamin D-adjusted chow (P < 0.001). There was a dose-dependent relationship between vitamin D-adjusted chow and manual palpation fusion, with greatest differences found in measures of radiographical density between high and deficient vitamin D (P < 0.05). Adequate levels of vitamin D (high and normal control) yielded stiffer fusion than inadequate levels (insufficient and deficient) (P < 0.05).

CONCLUSION

Manual palpation fusion rates increased with supplementation of dietary vitamin D. Biomechanical stiffness, bone volume, and density were also positively related to vitamin D and calcium.

LEVEL OF EVIDENCE

N/A.

Prevalence and prognostic implications of vitamin D deficiency in chronic kidney disease

Vitamin D is an important nutrient involved in bone mineral metabolism, and vitamin D status is reflected by serum total 25-hydroxyvitamin D (25[OH]D) concentrations. Vitamin D deficiency is highly prevalent in patients with chronic kidney disease (CKD), and nutritional vitamin D supplementation decreases elevated parathyroid hormone concentrations in subgroups of these patients. Furthermore, vitamin D is supposed to have pleiotropic effects on various diseases such as cardiovascular diseases, malignancies, infectious diseases, diabetes, and autoimmune diseases. Indeed, there is cumulative evidence showing the associations of low vitamin D with the development and progression of CKD, cardiovascular complication, and high mortality. Recently, genetic polymorphisms in vitamin D-binding protein have received great attention because they largely affect bioavailable 25(OH)D concentrations. This finding suggests that the serum total 25(OH)D concentrations would not be comparable among different gene polymorphisms and thus may be inappropriate as an index of vitamin D status. This finding may refute the conventional definition of vitamin D status based solely on serum total 25(OH)D concentrations.

Circulating levels of 25-hydroxyvitamin D and acute cellular rejection in kidney allograft recipients

BACKGROUND

Vitamin D, in addition to its established role in bone metabolism, may regulate the immune system and affect the outcome of allografts.

METHODS

We identified 351 kidney allograft recipients who had serum levels of 25-hydroxyvitamin D (25[OH]D) measured within the first 30 days of transplantation. We evaluated the relationship between the circulating levels of 25(OH)D and acute cellular rejection (ACR), cytomegalovirus (CMV) disease, BK virus nephropathy, and kidney graft function.

RESULTS

Vitamin D deficiency (circulating levels of 25[OH]D ≤20 ng/mL, defined using The Endocrine Society Clinical Practice 2011 Guideline) was observed in 216 (61.5%) of 351 kidney graft recipients. Vitamin D deficiency was more frequent in female recipients (P=0.007, Fisher exact test) and African American recipients (P<0.001) and was less frequent in preemptive kidney graft recipients (P=0.002). Biopsy-confirmed ACR was more frequent in the vitamin D-deficient group than in the sufficient group (10.2% vs. 3.7%, P=0.04). By multivariable Cox regression analysis, vitamin D deficiency was an independent risk factor for ACR (hazard ratio=3.3, P=0.02). Vitamin D deficiency was not associated with CMV disease, BK virus nephropathy, or kidney allograft function at 1 year. 1,25-Dihydroxyvitamin D3 supplementation initiated within the first 90 days of transplantation was associated with a lesser incidence of ACR compared to no treatment with 1,25-dihydroxyvitamin D3 (5.1% vs. 13.0%, P=0.099).

CONCLUSIONS

Vitamin D deficiency is an independent risk factor for development of ACR within the first year of kidney transplantation and 1,25-dihydroxyvitamin D3 supplementation may help reduce the occurrence of ACR in the vitamin D-deficient group.

Pre-transplant impedance measures of reflux are associated with early allograft injury after lung transplantation

BACKGROUND

Acid reflux has been associated with poorer outcomes after lung transplantation. Standard pre-transplant reflux assessment has not been universally adopted. Non-acid reflux may also induce a pulmonary inflammatory cascade, leading to acute and chronic rejection. Esophageal multichannel intraluminal impedance and pH testing (MII-pH) may be valuable in standard pre-transplant evaluation. We assessed the association between pre-transplant MII-pH measures and early allograft injury in lung transplant patients.

METHODS

This was a retrospective cohort study of lung transplant recipients who underwent pre-transplant MII-pH at a tertiary center from 2007 to 2012. Results from pre-transplant MII-pH, cardiopulmonary function testing, and results of biopsy specimen analysis of the transplanted lung were recorded. Time-to-event analyses were performed using Cox proportional hazards and Kaplan-Maier methods to assess the associations between MII-pH measures and development of acute rejection or lymphocytic bronchiolitis.

RESULTS

Thirty patients (46.7% men; age, 54.2 years) met the inclusion criteria. Pre-transplant cardiopulmonary function and pulmonary diagnoses were similar between outcome groups. Prolonged bolus clearance (hazard ratio [HR], 4.11; 95% confidence interval [CI], 1.34-12.57; p = 0.01), increased total distal reflux episodes (HR, 4.80; 95% CI, 1.33-17.25; p = 0.02), and increased total proximal reflux episodes (HR, 4.43; 95% CI, 1.14-17.31; p = 0.03) were significantly associated with decreased time to early allograft injury. Kaplan-Meier curves also demonstrated differences in time to rejection by prolonged bolus clearance (p = 0.01) and increased total distal reflux episodes (p = 0.01). Sub-group analysis including only patients with MII-pH performed off proton pump inhibitors (n = 24) showed similar results.

CONCLUSIONS

Prolonged bolus clearance, increased total distal reflux episodes, and increased total proximal reflux episodes on pre-transplant MII-pH were associated with decreased time to early allograft injury after lung transplantation. Routine pre-transplant MII-pH may provide clinically relevant data regarding transplant outcomes and peri-transplant care.

Vitamin D: a new player in kidney transplantation?

Vitamin D is a hormone with pleiotropic effects. It mainly regulates calcium and phosphate metabolism through interactions with FGF23 and its receptor klotho. In addition, it has been shown that Vitamin D also regulates the immune response and has protective effects from cardiovascular disease, cancer and infections. Most renal transplant recipients have overt Vitamin D deficiency, a condition that may be associated with a decline in graft function and other complications. After kidney transplantation, elevated levels of FGF23 may predict increased risks of death and allograft loss. Theoretically, an optimal Vitamin D supplementation might favor operational tolerance and protect transplant recipients from the triad cardiovascular disease-cancer-infection. However, more solid data are needed to confirm this and to set the optimal level of serum Vitamin D supplementation in order to attain the best clinical outcome.

Vitamin D as an anti-microbial and anti-inflammatory therapy for Cystic Fibrosis

Cystic fibrosis (CF) is characterized by chronic infection and inflammation in the airways that lead to progressive lung damage and early death. Current anti-inflammatory therapies are limited by extensive adverse effects or insufficient efficacy. There is a large body of studies indicating beneficial anti-microbial and anti-inflammatory properties of vitamin D. Since most patients with CF present with vitamin D deficiency, and serum vitamin D levels demonstrate a positive correlation with lung function and negative correlation with airway inflammation and infection, correcting vitamin D deficiency may be an attractive therapeutic strategy in CF. The function of vitamin D is intricately tied to its metabolism, which may be impaired at multiple steps in patients with CF, with a potential to limit the efficacy of vitamin D supplementation. It is likely that the aforementioned beneficial properties of vitamin D require supplementation with doses of vitamin D markedly higher than those recommended to maintain proper bone function. This review will illustrate the potential for supplementation with vitamin D or its metabolites to modulate inflammation and improve defence against chronic infection in CF lung, as well as appropriate vitamin D supplementation strategies for improving lung function in CF.

A computer simulation model of the cost-effectiveness of routine Staphylococcus aureus screening and decolonization among lung and heart-lung transplant recipients

Our objective was to model the cost-effectiveness and economic value of routine peri-operative Staphylococcus aureus screening and decolonization of lung and heart-lung transplant recipients from hospital and third-party payer perspectives. We used clinical data from 596 lung and heart-lung transplant recipients to develop a model in TreeAge Pro 2009 (Williamsport, MA, USA). Sensitivity analyses varied S. aureus colonization rate (5-15 %), probability of infection if colonized (10-30 %), and decolonization efficacy (25-90 %). Data were collected from the Cardiothoracic Transplant Program at the University of Pittsburgh Medical Center. Consecutive lung and heart-lung transplant recipients from January 2006 to December 2010 were enrolled retrospectively. Baseline rates of S. aureus colonization, infection and decolonization efficacy were 9.6 %, 36.7 %, and 31.9 %, respectively. Screening and decolonization was economically dominant for all scenarios tested, providing more cost savings and health benefits than no screening. Savings per case averted (2012 $US) ranged from $73,567 to $133,157 (hospital perspective) and $10,748 to $16,723 (third party payer perspective), varying with the probability of colonization, infection, and decolonization efficacy. Using our clinical data, screening and decolonization led to cost savings per case averted of $240,602 (hospital perspective) and averted 6.7 S. aureus infections (4.3 MRSA and 2.4 MSSA); 89 patients needed to be screened to prevent one S. aureus infection. Our data support routine S. aureus screening and decolonization of lung and heart-lung transplant patients. The economic value of screening and decolonization was greater than in previous models of other surgical populations.

Vitamin D deficiency predicts decline in kidney allograft function: a prospective cohort study

CONTEXT

Vitamin D, often deficient in kidney transplant (KTx) recipients, has potential immunomodulatory effects.

OBJECTIVE

This study aimed to evaluate whether vitamin D status affects the rate of decline in kidney allograft function.

DESIGN, SETTING, AND PATIENTS

The study included a prospective cohort of 264 ambulatory KTx recipients at a single Japanese center.

MAIN OUTCOME MEASURES

We measured the baseline 25-hydroxyvitamin D (25D) concentration and examined its association with annual decline in estimated glomerular filtration rate (eGFR). Secondary outcome was rescue treatment with iv methylprednisolone (IV-MP) as an index of rejection episodes.

RESULTS

The mean serum 25D concentration was 17.1 (SD 6.5) ng/mL, and 68.4% patients had vitamin D inadequacy or deficiency. Time after KTx was a significant effect modifier for the association of serum 25D concentration with annual eGFR change and need for IV-MP (P for interaction < .1). We divided patients according to the median time after KTx (10 y) and found that low vitamin D was significantly associated with a rapid eGFR decline at less than 10 years after KTx but not at 10 or more years after KTx. The same was true for rescue treatment with IV-MP. Overall, propensity score matching showed independent associations of low vitamin D with both outcomes. Stratified matching confirmed pronounced associations at less than 10 years after KTx.

CONCLUSIONS

Vitamin D deficiency predicts a rapid decline in eGFR and need for IV-MP at less than 10 years after KTx. Future studies are warranted to evaluate the clinical efficacy of vitamin D supplementation.

The role of vitamin D in chronic obstructive pulmonary disease, asthma and other respiratory diseases

There has been growing interest in recent years in the extraosseous effects of vitamin D. In this article, we review the physiology of vitamin D, the physiopathological effects associated with vitamin D deficit and the available evidence on its etiopathogenic role in respiratory diseases. Given the pleiotropic actions of vitamin D, it is biologically plausible that the deficit of this vitamin could play a pathogenic role of in the development of various respiratory diseases. However, the many epidemiological studies that have shown an association between low vitamin D levels and a higher risk of developing various respiratory diseases or a poorer prognosis if they do appear, were unable to show causality. Post-hoc analyses of some clinical trials, particularly in chronic obstructive pulmonary disease (COPD) and asthma, appear to suggest that some patient subtypes may benefit from correction of a vitamin D deficit. In this respect, it would be interesting to determine if the interindividual differences found in the effect of vitamin D deficit and responses to correcting this deficit could be explained by the genetic variants involved in vitamin D metabolism. Ultimately, only appropriately designed clinical trials will determine whether 25-OHD supplements can prevent or improve the course of the various respiratory diseases in which an epidemiological association between prognosis and vitamin D deficit has been described.

Incidence of fractures after cardiac and lung transplantation: a single center experience

Osteoporotic fractures are well-known complications of organ transplantation. Fracture rates up to 35% have been previously reported following heart and lung transplantations. Our institutional pretransplant protocols include DXA scans, vitamin D screening, and appropriate antiresorptive therapy. We aimed to assess the incidence of fragility fractures following cardiac or lung transplantation. In a retrospective study 210 electronic medical records of patients who underwent LT (110 men, 100 women) and 105 HT (88 men, 17 women) between 2005 and 2010 were analyzed. Both clinical and radiographic fractures were recorded. DXA scans were obtained immediately after transplant. 17 out of 210 LT patients (8.0%) had fractures after transplantation and 9 out of 105 HT patients (8.6%) had fractures. The median time to the first fracture was 12 months and the mean time was 18 months for both LT and HT. In the HT recipients, the median femoral neck T score was statistically lower in the fracture group versus the nonfracture group. Similar results were seen in the LT patients. Conclusion. Our findings demonstrate a much lower incidence of fractures in heart and lung transplant recipients in comparison with earlier reports. Comprehensive bone care and early initiation of antiresorptive therapy are possible contributors to these improved outcomes.

Beneficial role of vitamin D3 in the prevention of certain respiratory diseases

There is evidence of aberrations in the vitamin D-endocrine system in subjects with respiratory diseases. Vitamin D deficiency is highly prevalent in patients with respiratory diseases, and patients who receive vitamin D have significantly larger improvements in inspiratory muscle strength and maximal oxygen uptake. Studies have provided an opportunity to determine which proteins link vitamin D to respiratory pathology, including the major histocompatibility complex class II molecules, vitamin D receptor, vitamin D-binding protein, chromosome P450, Toll-like receptors, poly(ADP-ribose) polymerase-1, and the reduced form of nicotinamide adenine dinucleotide phosphate. Vitamin D also exerts its effect on respiratory diseases through cell signaling mechanisms, including matrix metalloproteinases, mitogen-activated protein kinase pathways, the Wnt/β-catenin signaling pathway, prostaglandins, reactive oxygen species, and nitric oxide synthase. In conclusion, vitamin D plays a significant role in respiratory diseases. The best form of vitamin D for use in the treatment of respiratory diseases is calcitriol because it is the active metabolite of vitamin D3 and modulates inflammatory cytokine expression. Further investigation of calcitriol in respiratory diseases is needed.

Calcidiol deficiency in end-stage organ failure and after solid organ transplantation: status quo

Among patients with organ failure, vitamin D deficiency is extremely common and frequently does not resolve after transplantation. This review crystallizes and summarizes existing data on the status quo of vitamin D deficiency in patients with organ failure and in solid organ transplant recipients. Interventional studies evaluating different treatment strategies, as well as current clinical practice guidelines and recommendations on the management of low vitamin D status in these patients are also discussed.