Hyperhomocysteinaemia is associated with osteoporosis in patients with Crohn's disease

Does Magnesium Provide a Protective Effect in Crohn's Disease Remission? A Systematic Review of the Literature

This systematic review evaluates the hypothesis that optimal serum magnesium levels may enhance remission rates in Crohn's disease (CD) and considers whether magnesium supplementation could be beneficial in CD management. This review aims to synthesize available evidence concerning the impact of serum magnesium on disease remission in CD, and to analyze the effectiveness and mechanistic roles of magnesium supplementation. Adhering to the PRISMA guidelines, we searched PubMed, Web of Science, and Scopus up to January 2024 using MeSH terms and free-text queries related to CD and magnesium. The inclusion criteria were studies that investigated serum magnesium levels, effects of supplementation, and the inflammatory mechanisms in CD remission. From the 525 records identified, eight studies met the inclusion criteria after the removal of duplicates and irrelevant records. These studies, conducted between 1998 and 2023, involved a cumulative sample of 453 patients and 292 controls. Key findings include significantly lower serum magnesium levels in CD patients (0.79 ± 0.09 mmol/L) compared to controls (0.82 ± 0.06 mmol/L), with up to 50% prevalence of hypomagnesemia in CD patients observed in one study. Notably, CD patients, particularly men, exhibited lower magnesium intake (men: 276.4 mg/day; women: 198.2 mg/day). Additionally, low magnesium levels correlated with increased sleep latency (95% CI -0.65 to -0.102; p = 0.011) and decreased sleep duration (95% CI -0.613 to -0.041; p = 0.028). Another key finding was the significant association between low serum magnesium levels and elevated CRP levels as an indicator of CD disease activity. The findings support the hypothesis that serum magnesium levels are significantly lower in CD patients compared to healthy controls and suggest that magnesium supplementation could improve CD management by enhancing remission rates and sleep quality. However, more rigorous, evidence-based research is necessary to define specific supplementation protocols and to fully elucidate the role of magnesium in CD pathophysiology.

Micronutrient Status in Adult Crohn's Disease during Clinical Remission: A Systematic Review

Adults with Crohn's disease (CD) may be at risk of micronutrient insufficiency in clinical remission through restrictive eating, malabsorption, abnormal losses or inflammation. This systematic review synthesises the literature on micronutrient insufficiency in CD in clinical remission in terms of the prevalence of low circulating micronutrient concentrations and as a comparison against a healthy control (HC). Studies were included if the population was predominantly in remission. A total of 42 studies met the inclusion criteria; 12 were rated as low quality, leaving 30 studies covering 21 micronutrients of medium/high quality that were included in the synthesis. Vitamins D and B12 were the most frequently reported nutrients (8 and 11); there were few eligible studies for the remaining micronutrients. The prevalence studies were consistent in reporting individuals with low Vitamins A, B6, B12 and C, β-carotene, D, Magnesium, Selenium and Zinc. The comparator studies were inconsistent in finding differences with CD populations; Vitamin D, the most reported nutrient, was only lower than the HC in one-quarter of the studies. Adult CD populations are likely to contain individuals with low levels of one or more micronutrients, with the most substantial evidence for Vitamins D and B12. The studies on other micronutrients are of insufficient number, standardisation and quality to inform practice.

The Role of Methyl Donors of the Methionine Cycle in Gastrointestinal Infection and Inflammation

Vitamin deficiency is well known to contribute to disease development in both humans and other animals. Nonetheless, truly understanding the role of vitamins in human biology requires more than identifying their deficiencies. Discerning the mechanisms by which vitamins participate in health is necessary to assess risk factors, diagnostics, and treatment options for deficiency in a clinical setting. For researchers, the absence of a vitamin may be used as a tool to understand the importance of the metabolic pathways in which it participates. This review aims to explore the current understanding of the complex relationship between the methyl donating vitamins folate and cobalamin (B12), the universal methyl donor S-adenosyl-L-methionine (SAM), and inflammatory processes in human disease. First, it outlines the process of single-carbon metabolism in the generation of first methionine and subsequently SAM. Following this, established relationships between folate, B12, and SAM in varying bodily tissues are discussed, with special attention given to their effects on gut inflammation.

Osteoporosis Complications in Crohn's Disease Patients: Factors, Pathogenesis, and Treatment Outlines

The causes of osteoporosis in Crohn’s disease (CD) are multifactorial; cytokines, steroids, and vitamin deficiency all have an essential role. It is imperative to distinguish the factors that contribute to bone resorption, potentially increasing the risk of low bone mineral density (BMD), osteoporosis, and fracture. However, the pathogenicity of osteoporosis associated with CD remains unclear. Although osteoporosis treatment may vary between bisphosphonate and corticosteroid, infliximab's efficacy, when combined with immune modulators, suppresses both CD symptoms and osteoporosis progression. In this review, we aim to understand the present pathogenicity of osteoporosis, including the factors pro-inflammatory cytokines, chronic steroid use, and malnutrition, developing osteoporosis in a different pathological way, and to assist the treatment lines implying a positive outcome of osteoporosis in CD patients.

Osteoporosis is considered to be one of the early complications of CD where early detection can prevent osteoporosis progression. This can be done by utilizing dual-energy X-ray-absorptiometry (DEXA) to evaluate the Z-score and treat the existing factors that have a role in the progression of osteoporosis in CD patients.

Nutrients in the Prevention of Osteoporosis in Patients with Inflammatory Bowel Diseases

The chronic character of inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis, results in various complications. One of them is osteoporosis, manifested by low bone mineral density, which leads to an increased risk of fractures. The aetiology of low bone mineral density is multifactorial and includes both diet and nutritional status. Calcium and vitamin D are the most often discussed nutrients with regard to bone mineral density. Moreover, vitamins A, K, C, B12; folic acid; calcium; phosphorus; magnesium; sodium; zinc; copper; and selenium are also involved in the formation of bone mass. Patients suffering from inflammatory bowel diseases frequently consume inadequate amounts of the aforementioned minerals and vitamins or their absorption is disturbed, resulting innutritional deficiency and an increased risk of osteoporosis. Thus, nutritional guidelines for inflammatory bowel disease patients should comprise information concerning the prevention of osteoporosis.

Vitamin B12 deficiency in inflammatory bowel disease: prevalence, risk factors, evaluation, and management

BACKGROUND

Management of vitamin B(12) (cobalamin, Cbl) deficiency in inflammatory bowel disease (IBD) is often not evidenced-based because of uncertainty on whether it causes enough malabsorption to result in clinical disease. This systematic review examines whether IBD predisposes to Cbl deficiency. We provide an approach to the management of abnormal Cbl values in IBD based on current literature and consensus-based guidelines.

METHODS

An extensive search of the Ovid MEDLINE and EMBASE databases by independent reviewers identified 42 articles with a total of 3732 patients evaluating Cbl deficiency in IBD.

RESULTS

Crohn's disease without ileal resection, regardless of disease location in the ileum, did not increase the risk for Cbl deficiency. Ileal resections greater than 30 cm were associated with Cbl deficiency in Crohn's disease, whereas those less than 20 cm were not. The effects of 20 to 30 cm resections were inconsistent. Ulcerative colitis did not predispose to deficiency. All studies failed to use confirmatory biomarker testing as stipulated by diagnostic guidelines for Cbl deficiency.

CONCLUSIONS

This literature does not support an association of Crohn's disease in general, regardless of ileal involvement, with Cbl deficiency. Only ileal resections greater than 20 cm in Crohn's disease predispose to deficiency and warrant treatment. Based on these findings, we suggest a diagnostic and therapeutic algorithm. All findings and recommendations require verification in further studies using confirmatory biomarkers as per diagnostic guidelines for Cbl deficiency. Serum Cbl levels alone are likely insufficient to diagnose deficiency in asymptomatic patients.

The role of homocysteine in bone remodeling

Bone remodeling is a very complex process. Homocysteine (Hcy) is known to modulate this process via several known mechanisms such as increase in osteoclast activity, decrease in osteoblast activity and direct action of Hcy on bone matrix. Evidence from previous studies further support a detrimental effect on bone via decrease in bone blood flow and an increase in matrix metalloproteinases (MMPs) that degrade extracellular bone matrix. Hcy binds directly to extracellular matrix and reduces bone strength. There are several bone markers that can be used as parameters to determine how high levels of plasma Hcy (hyperhomocysteinemia, HHcy) affect bone such as: hydroxyproline, N-terminal collagen 1 telopeptides. Mitochondrion serves an important role in generating reactive oxygen species (ROS). Mitochondrial abnormalities have been identified during HHcy. The mechanism of Hcy-induced bone remodeling via the mitochondrial pathway is largely unknown. Therefore, we propose a mitochondrial mechanism by which Hcy can contribute to alter bone properties. This may occur both through generations of ROS that activate MMPs and could be extruded into matrix to degrade bone matrix. However, there are contrasting reports on whether Hcy affects bone density, with some reports in favour and others not. Earlier studies also found an alteration in bone biomechanical properties with deficiencies of vitamin B12, folate and HHcy conditions. Moreover, existing data opens speculation that folate and vitamin therapy act not only via Hcy-dependent pathways but also via Hcy-independent pathways. However, more studies are needed to clarify the mechanistic role of Hcy during bone diseases.

Protective effect of folic acid on cyclosporine-induced bone loss in rats

Hyperhomocysteinemia is seen in patients with decreased bone mineral density. Cyclosporine can cause alveolar bone loss and osteopenia. It is also associated with elevated serum homocysteine levels. We aimed to investigate the effect of cyclosporine on serum homocysteine level, bone volume, and bone density, and determine whether folic acid had a protective effect against bone loss. In an experimental study, 40 male Sprague-Dawley rats were randomly assigned to five groups and received dietary supplementation for 6 weeks with olive oil (Group A), cyclosporine (Group B), folic acid (Group C), and cyclosporine plus folic acid (Group D), or no supplementation (Group F, control). Serum homocysteine, calcium, alkaline phosphatase, total bone volume, periodontal ligament volume, and volume density of bone were compared between groups. Mean serum homocysteine level (10.84 ± 0.93 μmol/l) was significantly higher in group B (cyclosporine supplementation) compared with the other groups (P = 0.001). Mean total mandibular volume was 46.3 ± 13.6 mm(3) in rats treated with cyclosporine, 80.4 ± 15.70 mm(3) in rats treated with folic acid (P = 0.004), and 73.9 ± 21.3 mm(3) in rats treated with cyclosporine plus folic acid (P = 0.028). In our experimental model, cyclosporine increased serum homocysteine levels and decreased bone volume and density. Folic acid may have a preventive role against bone loss in rats treated with cyclosporine.

Proton pump inhibitors and fracture risk: true effect or residual confounding?

Fracture is a major contributor to human morbidity and mortality, especially in the elderly. It has been discussed in the literature that conditions associated with decreased stomach acidity may lead to a decrease in intestinal calcium absorption and, consequently, to an increased fracture risk. In recent years, several observational studies reported a slightly increased fracture risk in association with the use of proton pump inhibitors (PPIs) and/or histamine H(2) receptor antagonists. It was the objective of this review to critically assess the available evidence linking PPI use to an increased fracture risk. A MEDLINE and EMBASE search from 1960 to June 2010 was performed to identify the relevant articles using predefined search terms. Because (i) there is no proven mechanism, (ii) the reported magnitude of the risk elevation associated with the use of PPIs was only weak, and (iii) the likelihood of residual confounding despite adjustment for known co-morbidities and drug use cannot be ruled out, we conclude that the currently available literature does not support the notion that the use of PPIs is causally related to a materially increased fracture risk in humans.

The relationship between plasma homocysteine levels and bone mineral density in post-menopausal women

BACKGROUND

Whether or not mild hyperhomocysteinemia and low serum levels of folates or vitamin B12 are risk factors for osteoporosis in the elderly is controversial.

AIMS AND METHODS

To investigate whether or not plasma levels of total homocysteine (tHcy) and serum levels of folates and vitamin B12 are associated with bone mineral density (BMD), we carried out a cross-sectional study on 446 post-menopausal women (mean age: 65.1+/-9.4 years), consecutively seen at the Siena Unit (Tuscany region, Central Italy) for BMD evaluation over a two-year period. BMD of the total femur, femoral neck and lumbar spine was detected by dual-energy X-ray absorptiometry.

RESULTS

The age-adjusted geometric mean of plasma tHcy levels (micromol/L) was 9.96+/-1.29 in women with normal BMD, 11.06+/-1.32 in those with osteopenia and 11.88+/-1.35 in those with osteoporosis (p<0.0001). On multiple linear regression analysis, adjusting for age, body mass index, folates, vitamin B12, creatinine clearance, smoking habit and alcohol intake, tHcy was negatively related to BMD of the total femur [beta estimate for log-homocysteine: -0.050 (95% CI: -0.100 to -0.001, p=0.048; R(2)=0.02)], but not of femoral neck or lumbar spine. There was no significant association between BMD and serum levels of folates and vitamin B12.

CONCLUSIONS

tHcy is negatively associated with BMD of the total femur. The contribution of tHcy to explain the variance of BMD is small (2% of the total variance) but clinically relevant, considering the high prevalence of osteoporosis among post-menopausal women and the possibility to lower tHcy by vitamin supplementation.

Differential effects of homocysteine and beta aminopropionitrile on preosteoblastic MC3T3-E1 cells

Compounds, like beta-aminopropionitrile (bAPN) and homocysteine (hcys), are known to inhibit a stable matrix formation. Osteoblast-synthesized collagen matrix regulates the differentiation of precursor cells into mature osteoblasts. They express lysyl oxidase, an enzyme involved in the collagen cross-linking process. Lately, plasma hcys levels have recently been strongly correlated with fracture in humans. We have previously shown that bAPN not only disturbs collagen cross-links but also affects osteoblastic differentiation in a cell culture system. The aim of the present study was to investigate the effects of bAPN and hcys on collagen cross-links and gene expression at the mRNA level by FTIR and quantitative RT-PCR, respectively. We found that bAPN and hcys down-regulated cell multiplication. While bAPN also down-regulated the metabolic activity of MC3T3-E1 cells, hcys down-regulated it by lower concentrations but up-regulated it by higher; both substances up-regulated alkaline phosphatase activity. The substances increased the ratio of pyr/divalent cross-links of collagen, and down-regulated mRNA expression of lysyl hydroxylase (Plod2) and lysyl oxidase (Lox), genes which play an important role in the formation of a stable matrix. Furthermore, we demonstrate that both substances stimulated the expression of Runx2, an indispensable regulator of osteoblastic differentiation. However, analysis of genome wide mRNA expression suggests that hcys and bAPN have differential effects on genes involved in osteoblastic differentiation and phenotype regulation. The results indicate that although both bAPN and hcys affect collagen cross-link post-translational modifications in a similar manner as far as pyr and divalent cross-links are concerned, they have differential effects on the monitored genes expression at the mRNA level, with hcys exerting a broader effect on the genome wide mRNA expression.

Bone tissue and hyperhomocysteinemia

Bone tissue quality is determined not only by multiple architectural variables, but also by the mechanical properties of collagen type 1. Homocysteinuria is a genetic disease whose manifestations include severe hyperhomocysteinemia and decreased bone strength. The effects of smaller homocysteine elevations on bone tissue are difficult to demonstrate in clinical studies. Studies in animals and in humans suggest that homocysteine may weaken collagen crosslinks and, if present in large amounts, interfere with bone remodeling. Whether routine homocysteine assays should be performed to detect bone frailty remains unclear. In clinical practice, the focus should be on identifying patients with potential causes of homocysteine elevation (e.g., medications), who should then be given vitamin D and folic acid supplementation if needed. This approach may improve not only bone health, but also vascular and general health.

Sarcopenia is prevalent in patients with Crohn's disease in clinical remission

BACKGROUND

Patients with Crohn's disease (CD) are prone to osteoporosis. A loss of muscle mass, called sarcopenia, is responsible for an increased risk of disability. Many factors associated with osteopenia also decrease muscle mass. The aim of the present study was to measure the prevalence of sarcopenia in CD patients in remission and uncover its relationship with osteopenia.

METHODS

In all, 82 CD patients (43 female/39 male; 36 +/- 14 years; body mass index [BMI] 21.1 +/- 3.4) and 50 healthy volunteers (30F/20M; 39 +/- 13 years; BMI 22.2 +/- 2.5) were studied. Body composition was assessed using dual-energy x-ray absorptiometry. Sarcopenia was defined as an appendicular skeletal muscle index (ASMI) below 5.45 kg/m(2) for women and 7.26 for men. Osteopenia was defined as a T-score for bone mineral density (BMD) (g/cm(2)) below -1.0.

RESULTS

In all, 60% of CD patients were found to be sarcopenic and 30% osteopenic, compared to 16% and 4% of controls, respectively (P < 0.01). ASMI was significantly lower in patients than in controls (6.0 +/- 1.1 versus 6.5 +/- 1.2; P < 0.05). Sarcopenic patients had significantly (P < 0.01) lower BMI (20.0 +/- 3.5 versus 22.7 +/- 2.8 kg/m(2)), lean mass (41.5 +/- 9.1 versus 48.1 +/- 9.1 kg), and BMD (1.09 +/- 0.12 versus 1.15 +/- 0.08 g/cm(2)) than nonsarcopenic patients; 91% of sarcopenic patients were also osteopenic. ASMI correlated with BMD (r = 0.46; P < 0.01) and BMI (r = 0.38; P < 0.01).

CONCLUSIONS

The prevalence of sarcopenia is high in young CD patients and strongly related to osteopenia. These 2 phenomena may share similar mechanisms. Simultaneous screening for sarcopenia and osteopenia may be useful in CD patients.

Collagen cross-linking influences osteoblastic differentiation

Osteoblasts synthesize collagen matrix, which itself regulates the differentiation of precursor cells into mature osteoblasts. They express lysyl oxidase (LOX), which is involved in the collagen cross-linking process. Lathyrogens, like ss-aminopropionitrile (ssAPN), inhibit the formation of a stable matrix. The aim of the present study was to investigate the influence of cross-linking on osteoblastic differentiation. MC3T3-E1 cells were seeded and treated with or without 400 muM ssAPN for 1 week. Thereafter, living cells were removed and, on this extracellular matrix, new MC3T3-E1 cells were seeded and cultured for 1 week without ssAPN. RNA was isolated, and expression of specific marker genes was determined by quantitative reverse transcription-polymerase chain reaction. Changes in specific cross-links after ssAPN treatment were measured with Fourier-transform infrared spectroscopy. The collagen matrix that formed showed a significant reduction of two major cross-links of bone collagen, deH-DHLNL and pyr, compared to control cultures. Gene expression studies showed an increase of collagen alpha1 (I) (COL1A1) to 150%. Expression of LOX and osteocalcin (OCN) mRNA was significantly downregulated to about 75%. When fresh MC3T3-E1 cells were seeded on this altered matrix without ssAPN, COL1A1 mRNA expression was upregulated (140%), OCN was downregulated (60%), and LOX mRNA expression remained unaffected. These results indicate that ssAPN treatment not only disrupts collagen cross-link formation but also affects osteoblastic activity and expression. In conclusion, the disrupted matrix produced in the presence of lathyrogen influences, even in its absence, the expression of osteoblastic genes.