Insights Into the Role of Vitamin D as a Biomarker in Stem Cell Transplantation

Characterization and Predictors of Fractures Following Hematopoietic Stem Cell Transplantation

CONTEXT

Bone loss and fractures are common and serious complications following hematopoietic stem cell transplantation (HSCT), and identifying risk predictors for fractures in transplant recipients remains challenging. The Taiwan Bone Marrow Donation Center is the largest databank of donors in Asia. However, no population-based studies have yet been conducted in Asia to accurately assess the risk of fractures.

OBJECTIVE

The aims of this study were to determine the incidence and risk factors for fractures in HSCT recipients.

METHODS

We conducted a retrospective cohort study of patients older than 18 years who received a HSCT from January 1, 2003 to September 30, 2015, using the Taiwan National Health Insurance Research Database. Fractures following HSCT were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes. Cox regression analysis was used to identify risk factors for fractures.

RESULTS

A total of 3327 patients underwent a HSCT, of whom 126 (3.8%) had a fracture after HSCT. The cumulative incidence of fractures was 5.3% at 5 years, and 10.8% at 10 years. Multivariable analysis showed that a fracture in the 3 years prior to transplant (HR = 3.79; 95% CI, 2.39-6.03) was associated with a higher risk of fractures post HSCT. With a daily dose equivalent of more than 0.50-3.75 mg, more than 3.75-15.23 mg, and more than 15.23 mg prednisolone, the risk of fractures increased by 1.70-fold (95% CI, 1.07-2.71), 2.23-fold (95% CI 1.32-3.76), and 2.93-fold (95% CI, 1.43-6.01), respectively.

CONCLUSION

Regular screening to monitor bone loss should be initiated early, and counseling about the importance of general preventive measures for bone loss is warranted in HSCT recipients with a prior fracture and mean daily dose of steroids more than 0.50 mg.

Vitamin D and reproductive disorders: a comprehensive review with a focus on endometriosis

Vitamin D is a fat-soluble steroid hormone that was initially known only for regulating calcium and phosphorus levels and maintaining bone health. However, it was later discovered that many organs express vitamin D metabolizing enzymes and have a ligand for vitamin D, which regulates the expression of an extensive assortment of genes. As a result, vitamin D is indispensable for the proper function of organs, and its deficiency is believed to be a critical factor in symptoms and disorders such as cardiovascular diseases, autoimmune diseases, and cancers. The significance of vitamin D in reproductive tissues was recognized later, and studies have revealed its crucial role in male and female fertility, as well as proper reproductive function during pregnancy. Vitamin D deficiency has been identified as a risk factor for infertility, gonadal cancers, pregnancy complications, polycystic ovary syndrome, and endometriosis. However, data investigating the association between vitamin D levels and reproductive disorders, including endometriosis, have encountered inconsistencies. Therefore, the present study aims to review existing research on the effect of vitamin D on proper reproductive function, and the role of deficiency in reproductive diseases and specifically focuses on endometriosis.

Exploring the Significance of Vitamin D Levels as a Biomarker in Ear Diseases: A Narrative Review

This narrative review examines the role of vitamin D as a biomarker in ear disorders, including benign paroxysmal positional vertigo (BPPV), otitis media, bell's palsy, Meniere's disease, and hearing loss. PubMed, The Cochrane Library, and Google Scholar were utilized to conduct a comprehensive literature search, and findings were combined from studies from 2014 to 2024. As highlighted in this review, there is a consistent association between vitamin D deficiency and an increased risk and recurrence of disease especially in BPPV and otitis media. Its importance as a prognostic biomarker is emphasized in Bell's palsy, where higher levels of deficiencies in vitamin D are associated with higher grades of severity on the House Brackmann grading system. Vitamin D deficiency can also lead to sensorineural hearing loss due to its receptors present in the inner ear or its effect on calcium metabolism. Serum levels of vitamin D have also been shown to influence treatment outcome of sensorineural hearing loss. The role of vitamin D in Meniere's disease is unclear as no cause has been identified for the increase in endolymphatic fluid. The findings of this review emphasize the importance of serum vitamin D as a biomarker in ear disorders and advocate for more studies to be conducted to assess the importance of optimal dosing of vitamin D for the progression and outcome of these diseases.

Variability of contribution of 1,25 (OH)2D3 (vitamin D) level to hematopoietic stem cell transplantation outcome

BACKGROUND

The impact of vitamin D status on the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) has recently been the focus of interest with a lot of controversy. In this study we aimed to evaluate the impact of pre-transplant vit. D level on the outcome of HSCT.

METHODS

In this study, we evaluated the impact of vitamin D level on the risk of development of graft versus host disease (GVHD) and survival after HSCT. The study included 97 patients who received allogeneic HSCT from an identical sibling. Serum vitamin D level was measured before conditioning using ELIZA. Student t-test, Mann-Whitney U test, ANOVA F-test and Kruskal-Wallis H tests were used to determine significance of difference for quantitative data. Pearson correlation, Spearman correlation and Chi-square test were used to determine correlations and associations. Kaplan-Meier and Log rank (Mantel-Cox) tests were used for analysis of survival. P value ≤ 0.05 was considered significant.

RESULTS

Vitamin D level showed a range of 18.24-84.6 with a mean of 38.14 ± 9.73 and a median of 36.26 ng/ml. Two patients had vitamin D level <20 and 17 had a level <30 ng/ml. Acute GVHD occurred in 33 (34 %) and chronic GVHD in 29 (29.9 %) patients. Vitamin D level had no impact on frequency or severity of GVHD; either did it impact survival. This might be attributable to the relatively normal level in the majority of our patients on account of the sunny weather of Egypt. This might also be a potential explanation for the inconsistency of the different studies with variable levels of vitamin D.

CONCLUSIONS

The current study failed to demonstrate an impact of pre-transplant vitamin D level on the outcome of HSCT. This might be attributed to the low prevalence of vitamin D deficiency in our population on account of our almost always sunny weather. The marked variability in the level of vitamin D that is considered sufficient interferes with objective comparison between studies; a consensus on what is considered sufficient, insufficient, or deficient is essential.

Loading dose vitamin D3 improves vitamin D insufficiency in adults undergoing hematopoietic stem cell transplantation: A randomized controlled trial

Allogeneic hematopoietic stem cell transplant (aHSCT) patients are well known to be at high risk of vitamin D (vit D) deficiency. This study assessed whether a loading dose (100,000 IU) of vitamin D3 pre-aHSCT could effectively achieve and maintain sufficient post-transplant vit D levels (serum total 25 hydroxy vitamin D (25(OH)D) ≥ 75nmol/L). Dual-energy X-ray absorptiometry (DXA) was also conducted for bone health evaluation. 74 patients were enrolled and randomly assigned, in a 1:1 ratio, either to the high vit D group (single loading dose (100,000 IU) plus 2,000 IU vit D3 daily) or the control group (2,000 IU vit D3 daily). Vit D levels were measured at three time points (baseline, day 30 and day 100 post-aHSCT). At baseline, fewer than 50% patients had a sufficient 25(OH)D (control: 42.9%; high vit D: 43.6%). The proportion of patients with sufficient 25(OH)D (nmol/L) was increased at day 30 and day 100, with a trend of higher proportion in the high vit D group at day 30 (high vit D vs. control: 89.7% vs. 74.3%, p = 0.08). The increased 25(OH)D was significantly higher in the high vit D group at day 30 (high vit D vs. control: 29±25.2 vs. 14 ±21.9, p = 0.01). Insufficient vit D level before transplant (baseline) was an independent risk factor for vit D insufficiency (serum 25(OH)D < 75nmol/L) post-aHSCT (OR = 4.16, p = 0.03). DXA suggested significant bone loss for total hip in both groups, and in the femoral neck for the control group only. In conclusion, single loading dose vitamin D3 significantly increased total 25(OH)D levels at day 30 post-transplant, and the intervention was especially beneficial for patients with baseline vit D insufficiency. We acknowledge that the primary outcome at day 100 post-aHSCT indicating superiority of loading dose versus daily dose supplementation was not met.

Vitamin D Influences the Activity of Mast Cells in Allergic Manifestations and Potentiates Their Effector Functions against Pathogens

Mast cells (MCs) are abundant at sites exposed to the external environment and pathogens. Local activation of these cells, either directly via pathogen recognition or indirectly via interaction with other activated immune cells and results in the release of pre-stored mediators in MC granules. The release of these pre-stored mediators helps to enhance pathogen clearance. While MCs are well known for their protective role against parasites, there is also significant evidence in the literature demonstrating their ability to respond to viral, bacterial, and fungal infections. Vitamin D is a fat-soluble vitamin and hormone that plays a vital role in regulating calcium and phosphorus metabolism to maintain skeletal homeostasis. Emerging evidence suggests that vitamin D also has immunomodulatory properties on both the innate and adaptive immune systems, making it a critical regulator of immune homeostasis. Vitamin D binds to its receptor, called the vitamin D receptor (VDR), which is present in almost all immune system cells. The literature suggests that a vitamin D deficiency can activate MCs, and vitamin D is necessary for MC stabilization. This manuscript explores the potential of vitamin D to regulate MC activity and combat pathogens, with a focus on its ability to fight viruses.

From support to therapy: rethinking the role of nutrition in acute graft-versus-host disease

Allogeneic Hematopoietic stem cell transplantation (HSCT) offers a potential cure for patients with hematologic malignancies. Unfortunately, graft-versus-host disease (GVHD) remains a major obstacle to the greater success of this treatment. Despite intensive research efforts over the past several decades, GVHD is still a major cause of morbidity and mortality in patients receiving allogeneic HSCT. The genetic disparity between donor and recipient is the primary factor that dictates the extent of alloimmune response and the severity of acute GVHD (aGVHD). However, some nongenetic factors are also actively involved in GVHD pathogenesis. Thus, identifying host factors that can be readily modified to reduce GVHD risk is of important clinical significance. We are particularly interested in the potential role of nutrition, as a nongenetic factor, in the etiology and management of aGVHD. In this article, we summarize recent findings regarding how different routes of nutritional support and various dietary factors affect aGVHD. Since diet is one of the most important factors that shape gut microbiota, we also provide evidence for a potential link between certain nutrients and gut microbiota in recipients of allogeneic HSCT. We propose a shifting role of nutrition from support to therapy in GVHD by targeting gut microbiota.

Impact of Allogeneic Hematopoietic Stem Cell Transplantation on Nutritional Status and Intake in Children

OBJECTIVES

This study aimed to describe the impact of allogeneic/haploidentical hematopoietic stem cell transplantation on nutritional status and intake in a group of children aged 2 to 18 years.

METHODS

In an observational study, data were collected prospectively. Patients were prescribed individual nutritional support by hospital routines. Anthropometrics were measured pre-transplant at hospital admission and weekly from the day of transplant (day 0) until day +28. z scores for weight, height, and BMI were calculated using Norwegian growth references to assess nutritional status. Pre-transplant diet was assessed on the day of hospitalization. Nutrient provision from enteral nutrition (EN = oral and tube) and parenteral nutrition (PN) was assessed by daily records from day +1 until day +28, or previous discharge, and compared with recommendations (RI) from the Nordic Nutrition Recommendations and ESPGHAN guidelines. Total energy intake was presented as the percentage (%) of basal metabolic rate (BMR) calculated by the Schofield equation. Macro- and micronutrient provisions were presented as medians (interquartile range) and the % of RI.

RESULTS

Twenty-eight patients, mean age 10.3 years (range 3.5-16.6), were included. Two-thirds (n = 18) had malignant diseases. At admission, mean weight Z-score was -0.3, height z scores -0.7, and BMI Z-score 0.1. Eighteen percent (n = 5) were stunted and 25% (n = 7) had overweight. At admission, 25% (n = 7) had established tube feeding, and 7% (n = 2) also had PN. No significant changes in weight z scores were detected during the studied weeks ( P = 0.454). The median daily energy provision was 115% (110-123) of BMR and proteins 1.5 (1.3-1.8) g/kg. EN was provided during a median of 93% of the studied days and provided 21% of the energy. PN was given on a median of 96% of the studied days and provided 79% of energy. RI for vitamins, magnesium, and zinc was met. Provision of copper, iodine, selenium, calcium, and phosphate was below RI.

CONCLUSIONS

Combined EN and PN providing 115% of BMR and 1.5 g/kg protein ensured stable weight by day +28 and covered RI, except for trace elements and minerals.

Vitamin D Receptor affects male mouse fertility via regulation of lipid metabolism and testosterone biosynthesis in testis

Vitamin D and vitamin D receptor (VD/VDR) plays a vital role in the development of spermatozoa, which is largely determined by the testosterone level in serum. Testosterone biosynthesis is closely related to lipid metabolism in gonadal adipose around testes. VDR could regulate lipid metabolism in adipocytes as well. However, it still remains unknown how VDR regulates lipid metabolism to impact testosterone biosynthesis in testis. Hereby, various parameters of male fertility were compared between wildtype (WT) and Vdr knockout (Vdr-KO) male mouse. For Vdr-KO mice, the size of testis and gonadal adipose was smaller than that of WT, and the sperm quality and testosterone level were lower than WT. Subsequently, testis proteome data between Vdr-KO and WT mice indicated that dysregulation of lipid metabolism was closely associated with decreased testosterone biosynthesis in Vdr-deficient mouse. And further evaluation of VDR functions in Leydig cells verified that VDR impacted lipid metabolism and regulated the expression of a range of genes involved in testosterone biosynthesis. Knockdown VDR could significantly decrease testosterone synthesis and secretion in Leydig cells. Meanwhile, expression of genes involved in androgen synthesis was decreased but genes related to lipolysis were up-regulated. Collectively, the present study unveiled the relationship between lipid metabolism and testosterone biosynthesis mediated by VDR in mouse testis and its effect on male fertility. These findings will greatly enhance our current understanding of VDR intermediate in lipid metabolism and androgen synthesis.

Effect of Vitamin D on Graft-versus-Host Disease

The different cell subsets of the immune system express the vitamin D receptor (VDR). Through the VDR, vitamin D exerts different functions that influence immune responses, as previously shown in different preclinical models. Based on this background, retrospective studies explored the impacts of vitamin D levels on the outcomes of patients undergoing allogeneic hematopoietic stem-cell transplantation, showing that vitamin D deficiency is related to an increased risk of complications, especially graft-versus-host disease. These results were confirmed in a prospective cohort trial, although further studies are required to confirm this data. In addition, the role of vitamin D on the treatment of hematologic malignancies was also explored. Considering this dual effect on both the immune systems and tumor cells of patients with hematologic malignancies, vitamin D might be useful in this setting to decrease both graft-versus-host disease and relapse rates.

Vitamin D Effects on Selected Anti-Inflammatory and Pro-Inflammatory Markers of Obesity-Related Chronic Inflammation

BACKGROUND

Obesity is related to changes in adipokine secretion, activity of adipose tissue macrophages, helper T cells, and regulatory T cells. It has been confirmed that vitamin D has potent anti-inflammatory properties. It contributes to reduction in pro-inflammatory mediators and an increase in anti-inflammatory cytokines. There is also evidence that vitamin D could decrease C-reactive protein (CRP) and affect selected haematological indices.

AIM OF THE STUDY

We aimed to evaluate the effect of vitamin D on interleukin (IL)-10, IL-17, CRP, blood leukocyte profile, and platelet (PLT) count in overweight and obese children before and after six months of vitamin D supplementation.

MATERIAL AND METHODS

The study group consisted of 67 overweight and obese children aged 9.08-17.5 years. The control group included 31 normal weight peers age- and sex-matched. None of the studied children had received vitamin D supplementation before the study. Data were analyzed at baseline and after vitamin D supplementation.

RESULTS

The study group had lower baseline 25(OH)D (p<0.001) and higher white blood cell (WBC) (p=0.014), granulocyte (p=0.015), monocyte (p=0.009) and CRP (p=0.002) compared to the control group. In the study group, vitamin D levels were related negatively to nutritional status. Leukocyte profile parameters, PLT, CRP, IL-10 or IL-17 were not related to baseline 25(OH)D. Baseline IL-17 levels correlated with monocytes (R= 0.36, p=0.003) independently on 25(OH)D deficit. In children with vitamin D <15ng/ml, the baseline 25(OH)D was related to CRP (R=-0.42, p=0.017). After six months of vitamin D supplementation, we noticed a decrease in CRP levels (p=0.0003). Serum 25(OH)D correlated with IL-10 in that period (R=0.27, p=0.028). Moreover, we noticed that IL-10 correlated with monocyte (R=-0.28, p=0.023). We did not find any significant associations between 25(OH)D and leukocyte profile parameters, PLT, or IL-17. The multivariable stepwise regression analysis identified IL-10 as the parameter positively associated with 25(OH)D.

CONCLUSIONS

Our study confirmed beneficial effects of vitamin D supplementation in overweight and obese paediatric populations. Vitamin D intake seems to exert its anti-inflammatory effect mainly via decreasing the CRP level and protecting stabile values of IL-10, rather than its impact on pro-inflammatory factors such as lL-17 and leukocyte profile parameters.

Vitamin D deficiency after allogeneic hematopoietic cell transplantation promotes T-cell activation and is inversely associated with an EZH2-ID3 signature

Vitamin D promotes a shift from a proinflammatory to a more tolerogenic immune state in allogeneic hematopoietic cell transplant (HCT) recipients. The dominant mechanism responsible for this shift has not been elucidated. We took a multifaceted approach to evaluating the clinical and immunologic impact of low vitamin D levels in 53 HCT recipients. We used 28-plex flow cytometry for immunophenotyping, serum cytokine levels, T-cell cytokine production, and T-cell whole genome transcription. The median day-30 vitamin D level was 20 ng/mL, and deficiency was common in younger patients undergoing myeloablative transplantation. Low vitamin D levels were associated with a high CD8/Treg ratio, increased serum levels and T-cell production of proinflammatory cytokines, and a gene expression signature of unrestrained T-cell proliferation and epigenetic modulation through the PRC2/EZH2 complex. Immunophenotyping confirmed a strong association between high levels of vitamin D and an activated EZH2 signature, characterized by overexpression of ID3, which has a role in effector T-cell differentiation. Our findings demonstrate the critical role of vitamin D in modulating T-cell function in human GVHD and identify a previously undescribed interaction with EZH2 and ID3, which may impact effector differentiation and has implications to cell therapies and other forms of cancer immunotherapy. © 20XX American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Causal Links between Hypovitaminosis D and Dysregulation of the T Cell Connection of Immunity Associated with Obesity and Concomitant Pathologies

Subclinical inflammation in morbid obesity is associated with immune activation and the development of concomitant diseases. Impaired immune homeostasis and immune cell dysregulation in adipose tissue are associated with phenotypic and functional changes in the pool of T lymphocytes and the development of chronic hypovitaminosis D. Low vitamin D levels in obesity lead to the activation, proliferation and production of pro-inflammatory mediators by T cells. Hypovitaminosis D is the cause of a decrease in the functional potential of regulatory and anti-inflammatory lymphocytes and the maintenance of the inflammatory response. The exact molecular genetic mechanisms of the effect of vitamin D on T lymphocytes have not been fully elucidated. Therefore, uncovering the functional role of T cells and their relationship to vitamin D homeostasis in the context of obesity development may contribute to the development of new pathogenetic methods for clinical prediction of the risk of metabolic, oncologic, autoimmune and infectious complications. The review presents the molecular genetic mechanisms of the effect of vitamin D on adipose tissue resident T lymphocytes and the characteristics of vitamin D receptor expression, and analyzes the phenotypic and functional characteristics of potentially pathogenic T lymphocytes in relation to the development of obesity and its associated complications.

Impact of vitamin D level at diagnosis and transplantation on the prognosis of hematological malignancy: a meta-analysis

Vitamin D deficiency impairs prognosis in many types of cancer; however, its significance in each subtype of hematological malignancies is unclear. In addition, data on the association between pretransplant vitamin D levels and outcomes of hematopoietic stem cell transplantation (HSCT) are inconsistent. This systematic review and meta-analysis aimed to elucidate the impact of vitamin D levels at diagnosis or pre-HSCT on the prognosis of hematological malignancies. Thirty articles and abstracts were extracted from PubMed, Embase, and Cochrane Library databases and conference proceedings. Fixed and random effect models were used to analyze primary outcomes: overall survival (OS) and progression-free survival (PFS). Lower vitamin D level was significantly associated with poorer OS and PFS in myeloid malignancies (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.06-1.82 and HR, 2.03; 95% CI, 1.23-3.32, respectively) and lymphoid malignancies (HR, 2.07; 95% CI, 1.79-2.40 and HR, 1.91; 95% CI, 1.61-2.25, respectively), as well as outcomes for several lymphoma subtypes individually. Furthermore, a lower pretransplant vitamin D level was associated with poorer OS in autologous and allogeneic HSCT (HR, 1.65; 95% CI, 1.04-2.61 and HR, 1.50; 95% CI, 1.03-2.18, respectively). Despite the relatively small number of studies evaluated, these data suggest the importance of vitamin D status in outcomes of hematological malignancies (PROSPERO registration number: CRD42020205821).

Pre-transplantation plasma vitamin D levels and acute graft-versus-host disease after myeloablative hematopoietic cell transplantation in adults

BACKGROUND

The association between vitamin D and acute graft-versus-host disease (GvHD) remains controversial, especially for patients receiving myeloablative conditioning.

METHODS

We measured pre-transplantation plasma vitamin D (25-hydroxyvitamin D₃ + D₂) levels by competitive electrochemiluminescence in plasma samples from 116 adult patients who underwent a myeloablative allogeneic transplantation at Rigshospitalet, Copenhagen between July 2015 and August 2018.

RESULTS

The median (Q1, Q3) pre-transplantation plasma vitamin D level was 64 (47, 85) nmol/L (normal range: 50-160 nmol/L). Vitamin D insufficiency (<50 nmol/L) and moderate deficiency (<25 nmol/L) were observed in 29% and 8% of patients, respectively. No patients had a severe deficiency (<12 nmol/L). Pre-transplantation vitamin D levels were slightly higher in patients who later developed grade II-IV acute GvHD (mean difference: 8.1 nmol/L), but the 95% confidence interval [CI] encompassed clinically insignificant differences (CI: -2.2, 19.2 nmol/L). From multivariable logistic regression, we found that a patient with a pre-transplantation vitamin D level of 85 nmol/L (Q3) had 1.5 times higher odds of grade II-IV acute GvHD than a patient with a level of 47 nmol/L (Q1; CI of odds ratio: 0.84, 2.7; adjusted for patient age, donor type, use of anti-thymocyte globulin, and use of 12 Gy total-body irradiation). Patients with pre-transplantation vitamin D insufficiency (N = 34) had a cumulative incidence of grade II-IV acute GvHD similar to that of patients with vitamin D sufficiency (26% [CI: 11%, 42%] versus 35% [CI: 25%, 46%], respectively).

CONCLUSIONS

Our data did not support an association between pre-transplantation vitamin D levels or vitamin D insufficiency and acute GvHD in adult patients receiving myeloablative conditioning.

The Crossroads between Infection and Bone Loss

Bone homeostasis, based on a tight balance between bone formation and bone degradation, is affected by infection. On one hand, some invading pathogens are capable of directly colonizing the bone, leading to its destruction. On the other hand, immune mediators produced in response to infection may dysregulate the deposition of mineral matrix by osteoblasts and/or the resorption of bone by osteoclasts. Therefore, bone loss pathologies may develop in response to infection, and their detection and treatment are challenging. Possible biomarkers of impaired bone metabolism during chronic infection need to be identified to improve the diagnosis and management of infection-associated osteopenia. Further understanding of the impact of infections on bone metabolism is imperative for the early detection, prevention, and/or reversion of bone loss. Here, we review the mechanisms responsible for bone loss as a direct and/or indirect consequence of infection.