Advanced glycation endproducts (AGEs) in saliva of patients with multiple myeloma - a pilot study

Effects of AGEs, sRAGE and HMGB1 on Clinical Outcomes in Multiple Myeloma

Purpose

The receptor for advanced glycation end products (RAGE) upregulated during the onset and progression of cancer and bone-related pathologies. In this study, we aimed to investigate the role of serum advanced glycation end products (AGEs), soluble RAGE (sRAGE) and high mobility group box 1 (HMGB1), in multiple myeloma (MM).

Methods

AGEs, sRAGE and HMGB1 concentrations of 54 newly diagnosed MM patients and 30 healthy volunteers were measured by ELISA. The estimations were done only once at diagnosis. The medical records of the patients were evaluated.

Results

There was no significant difference between the AGEs and sRAGE levels between the patient and control groups (p = 0.273, p = 0.313). In ROC analysis, a HMGB1 cutoff value of > 9170 pg/ml accurately discriminated MM patients (AUC = 0.672, 95% CI 0.561-0.77, p = 0.0034). AGEs level was found to be significantly higher in early-stage disease and HMGB1 in advanced disease (p = 0.022, p = 0.026). High HMGB1 levels were detected in patients whose with better first-line treatment response (p = 0.019). At 36 months, 54% of patients with low AGE were alive, compared to 79% of patients with high AGE (p = 0.055). Patients with high HMGB1 levels tended to have a longer PFS (median 43 mo [95% CI; 20.68-65.31] ) compared to patients with low HMGB1 levels (median 25 mo [95% CI; 12.39-37.6], p = 0.054).

Conclusion

In this study, a significant elevation of serum HMGB1 level was found in MM patients. In addition, the positive effects of RAGE ligands on treatment response and prognosis were determined.

Levels of whole salivary advanced glycation end products and interleukin-17 and peri-implant clinical and radiographic status in patients with osteoporosis at 6-years' follow-up

BACKGROUND

There are no studies that have assessed advanced glycation end products (AGEs) and interleukin 17A (IL-17A) levels in whole saliva (WS) of patients with dental implants. The aim was to compare levels of AGEs and IL-17A in WS and peri-implant clinical and radiographic status of patients with and without osteoporosis at 6-years' follow-up.

METHODS

Osteoporotic (Group-1) and systemically healthy controls (Group-2) having undergone dental implant therapy at least 5 years ago were included. A questionnaire was used to collect information about age, gender, duration and treatment of osteoporosis, number and duration of implants in function, and frequencies of toothbrushing, flossing and hygiene visits. Modified bleeding and plaque indies (mBI and mPI), peri-implant probing depth (PD) and crestal bone loss (CBL) were recorded. WS was collected and levels of AGEs and IL-17A were determined using enzyme linked immunosorbent assay. Sample-size estimation was done and statistical analyses were doing using the independent t- and Wilcoxon rank-sum tests. Statistical significance was marked for P-values that were below 0.01.

RESULTS

In patients with (n = 24) and without (n = 27) osteoporosis, implants were in function for 6.3 ± 0.27 and 6.6 ± 0.5 years, respectively. There was no significant difference in peri-implant mBI, PD, mPI and CBL in both groups. Levels of AGE in patients with (119.6 ± 26.5 μg/ml) and without (91.5 ± 14.6 μg/ml) osteoporosis were comparable. Levels of whole salivary IL-17A in patients without and with osteoporosis were 4.6 ± 0.3 and 5.1 ± 0.8 pg/ml, respectively. Flossing of full mouth interproximal spaces once and twice daily toothbrushing daily was reported by 100% patients with osteoporosis. Among patients with osteoporosis 75% and 25% individuals were receiving professional dental prophylaxis every 4 and 6 months, respectively.

CONCLUSION

Within the limitations of the present study osteoporotic patients are not at an increased risk of peri-implant diseases and can demonstrate salivary AGE and IL-17A levels comparable to non-osteoporotic individuals as long as oral hygiene is stringently maintained.

Clinical Proteomics of Biofluids in Haematological Malignancies

Since the emergence of high-throughput proteomic techniques and advances in clinical technologies, there has been a steady rise in the number of cancer-associated diagnostic, prognostic, and predictive biomarkers being identified and translated into clinical use. The characterisation of biofluids has become a core objective for many proteomic researchers in order to detect disease-associated protein biomarkers in a minimally invasive manner. The proteomes of biofluids, including serum, saliva, cerebrospinal fluid, and urine, are highly dynamic with protein abundance fluctuating depending on the physiological and/or pathophysiological context. Improvements in mass-spectrometric technologies have facilitated the in-depth characterisation of biofluid proteomes which are now considered hosts of a wide array of clinically relevant biomarkers. Promising efforts are being made in the field of biomarker diagnostics for haematologic malignancies. Several serum and urine-based biomarkers such as free light chains, β-microglobulin, and lactate dehydrogenase are quantified as part of the clinical assessment of haematological malignancies. However, novel, minimally invasive proteomic markers are required to aid diagnosis and prognosis and to monitor therapeutic response and minimal residual disease. This review focuses on biofluids as a promising source of proteomic biomarkers in haematologic malignancies and a key component of future diagnostic, prognostic, and disease-monitoring applications.

Protein Carbonylation and Lipid Peroxidation in Hematological Malignancies

Among the different mechanisms involved in oxidative stress, protein carbonylation and lipid peroxidation are both important modifications associated with the pathogenesis of several diseases, including cancer. Hematopoietic cells are particularly vulnerable to oxidative damage, as the excessive production of reactive oxygen species and associated lipid peroxidation suppress self-renewal and induce DNA damage and genomic instability, which can trigger malignancy. A richer understanding of the clinical effects of oxidative stress might improve the prognosis of these diseases and inform therapeutic strategies. The most common protein carbonylation and lipid peroxidation compounds, including hydroxynonenal, malondialdehyde, and advanced oxidation protein products, have been investigated for their potential effect on hematopoietic cells in several studies. In this review, we focus on the most important protein carbonylation and lipid peroxidation biomarkers in hematological malignancies, their role in disease development, and potential treatment implications.

Saliva-omics in plasma cell disorders- Proof of concept and potential as a non-invasive tool for monitoring disease burden

Multiple Myeloma (MM), the second most common lymphoid cancer worldwide, is characterised by the uninhibited proliferation of terminally differentiated B-lymphocytes. Leading to The diagnosis typically requires the presence of a monoclonal protein (M protein) and the demonstration of CRAB features (hypercalcemia, renal impairment, anaemia and bone lesions). MM is considered incurable as, due to serial clonal evolution, the vast majority of patients succumb to treatment-refractory disease. MGUS (Monoclonal Gammopathy of Unknown Uncertain Significance) is the pre-malignant form of MM and, although 93% of MM patients exhibit M protein production associated with MGUS before diagnosis, little is known about the switch from pre-malignant to malignant disease. To explore this disease transition further, LC-MS/MS analysis was carried out to identify potential salivary biomarkers to monitor disease burden. FABP5 was detected in saliva as having a significant increase in abundance when MGUS was compared to symptomatic MM. The levels of FABP5 decreased after treatment indicating correlation with tumour burden. This finding was validated using western blot analysis and ELISA analysis. SIGNIFICANCE: The field of biomarker discovery has focused largely on serum as a biofluid. Saliva is a readily available biofluid that, as a biomarker resource, has been relatively un-explored. The identification of changes in saliva indicating disease progression underlines the utility of saliva as a non-invasive source of informative biomarkers reflecting disease burden and progression.

Evaluation of the AGE/sRAGE Axis in Patients with Multiple Myeloma

Glycative stress influences tumor progression. The aim of the present study was to evaluate the advanced glycation end products/soluble receptor of advanced glycation end products (AGE/sRAGE) axis in patients with multiple myeloma (MM). Blood samples were taken from 19 patients affected by MM and from 16 sex-matched and age-matched healthy subjects. AGE and sRAGE axis were dosed in patients with MM and matched with controls. AGEs were measured by spectrofluorimetric methods. Blood samples for the determination of sRAGE were analyzed by ELISA. AGE levels were significantly reduced in patients with respect to controls. Instead, sRAGE was significantly elevated in patients affected by MM compared to healthy subjects. Moreover, we showed that there was a statistically significant difference in sRAGE according to the heavy and light chain. IgA lambda had significantly higher sRAGE values than IgA kappa, IgG kappa, and IgG Lambda MM patients. From our data emerges the role of the sRAGE/AGE axis in MM. Since AGE is a positive regulator of the activity of RAGE, circulating sRAGE concentrations may reflect RAGE expression and may be raised in parallel with serum AGE concentrations as a counter-system against AGE-caused tissue damage. Serum concentrations of AGE and sRAGE could therefore become potential therapeutic targets.