Factors to take into account when interpreting 25-hydroxy-vitamin D serum levels

BACKGROUND

Assessing vitamin D status, typically evaluated using serum or plasma 25-hydroxy vitamin D [25(OH)D] concentration, is complex because of various influencing factors.

METHODS

Seasonality significantly affects intra-individual variability in 25(OH)D levels. This variation can be addressed by employing cosinor functions that are tailored to the geographical location of the patient to correct for seasonal effects. In addition to seasonality, genetic factors, such as DBP polymorphism and body composition, particularly adiposity, play crucial roles. Dialysis patients with DBP 2-2 phenotype exhibit higher vitamin D requirements. Genotyping/phenotyping of DBP allows for better tailored vitamin D supplementation. The lipid-soluble nature of vitamin D also interacts with plasma components such as serum triglycerides, which can influence vitamin D measurements. Adiposity, which is negatively correlated with vitamin D concentration, necessitates body mass-based mathematical adjustments for accurate vitamin D assessment in subjects with extreme BMI values.

CONCLUSIONS

Accordingly, vitamin D replacement therapy must be personalized, taking into account factors such as body size and seasonal variations, to effectively reach the target serum 25(OH)D concentrations.

The potential role of vitamin D binding protein in kidney disease: a comprehensive review

Chronic kidney disease (CKD) is a growing health concern with a complex etiological landscape. Among the numerous factors implicated, vitamin D binding protein (VDBP) has emerged as a focal point of scientific studies because of its critical role in vitamin D metabolism and immune modulation. The relationship between VDBP and CKD reveals a complex web of molecular and biochemical details that have great potential for improving diagnostic understanding and treatment strategies for CKD. This review summarizes the multifaceted roles of VDBP, including its molecular dynamics, interactions with vitamin D, and subsequent implications for kidney function. The main focus of the discussion is how VDBP affects bone mineral homeostasis, highlighted by the dysregulation of calcium and phosphorus metabolism, which is a part of the pathophysiology of CKD. The discussion also touches on the immunomodulatory scope of VDBP and how it may reduce the chronic inflammatory environment that accompanies CKD. The diagnostic potential of VDBP as a biomarker for CKD has been rigorously examined, highlighting its capacity to improve early detection and prognostic assessment. Modification of VDBP activity has the potential to slow the course of CKD and improve patient outcomes. Furthermore, a detailed examination of the genetic polymorphisms of VDBP and their implications for CKD susceptibility and treatment responsiveness provides a perspective for personalized medical methods. Prospects for the future depend on the expansion of studies that try to understand the molecular mechanisms underlying the VDBP-CKD interaction, in addition to clinical trials that evaluate the effectiveness of VDBP-focused treatment approaches.

A meta-analysis of the placebo response in vitiligo: Causes and consequences for the interpretation of clinical trials

The current understanding of the placebo response in vitiligo is limited. Nonetheless, it is difficult to compare the outcomes of vitiligo trials if the repigmentation rates in placebo patients vary significantly. We conducted a meta-analysis of the placebo response in vitiligo trials. Overall, repigmentation rates in patients receiving placebo were 22%, ranging substantially from 0 to 60%. Repigmentation (>25%) was still relatively common for placebo (9.35%), but fell to 5% when >50% improvement was analyzed. Higher frequencies of placebo responses correlated with more repigmentation in the intervention groups. Facial vitiligo and sunlight exposure was linked to higher placebo responses. Roughly estimating the amount of improvement using quartiles (0-25, 25%-50%, 50%-75%, 75%-100% repigmentation) resulted in higher placebo rates compared to other assessment methods. In clinical studies with older patients, the ratio of placebo reactions to treatment responses was higher. This is likely because clinical trials with older patients reported less repigmentation after treatment than studies with younger patients. The percentual difference in affected body surface area during the study period ranged from 6.2% worsening to 17.6% improvement in the placebo groups. This high variability in placebo responses illustrates the need for standardized outcome measures and more head-to-head trials in vitiligo.

The Impact of Antioxidants on Vitiligo and Melasma: A Scoping Review and Meta-Analysis

Reactive oxygen species (ROS) generated during melanogenesis make melanocytes particularly vulnerable to oxidative stress, influencing their survival and melanin synthesis. Oxidative stress, significantly present in vitiligo and recently also detected in melasma, triggers inflammatory cascades and melanogenesis, making antioxidants a promising therapeutic avenue. A systematic search was conducted on Embase and Pubmed to study the efficacy of antioxidants for treating vitiligo and/or melasma. Meta-analysis was performed to assess the difference in Melasma Severity Index (MASI) scores between baseline and follow-up. Various antioxidants like polypodium leucotomos, ginkgo biloba, catalase/superoxide dismutase, and vitamin E have potential in vitiligo. For melasma, vitamin C, silymarin, and niacinamide were among those showing promise in reducing pigmentation, with vitamin C displaying significant effects in meta-analysis. Different antioxidants improve both vitiligo and melasma, with an increased minimal erythema dose (MED) following UV exposure being significant for vitiligo and tyrosinase inhibition being crucial for melasma. However, the efficacy of individual antioxidants varies, and their exact mechanisms, especially in stimulating melanocyte proliferation and anti-inflammatory pathways, require further investigation to understand better and optimize their use.

Infrared Spectroscopy: A New Frontier in Hematological Disease Diagnosis

Hematological diseases, due to their complex nature and diverse manifestations, pose significant diagnostic challenges in healthcare. The pressing need for early and accurate diagnosis has driven the exploration of novel diagnostic techniques. Infrared (IR) spectroscopy, renowned for its noninvasive, rapid, and cost-effective characteristics, has emerged as a promising adjunct in hematological diagnostics. This review delves into the transformative role of IR spectroscopy and highlights its applications in detecting and diagnosing various blood-related ailments. We discuss groundbreaking research findings and real-world applications while providing a balanced view of the potential and limitations of the technique. By integrating advanced technology with clinical needs, we offer insights into how IR spectroscopy may herald a new era of hematological disease diagnosis.

Unlocking the link between haptoglobin polymorphism and noninfectious human diseases: insights and implications

Haptoglobin (Hp) is a polymorphic protein that was initially described as a hemoglobin (Hb)-binding protein. The major functions of Hp are to scavenge Hb, prevent iron loss, and prevent heme-based oxidation. Hp regulates angiogenesis, nitric oxide homeostasis, immune responses, and prostaglandin synthesis. Genetic polymorphisms in the Hp gene give rise to different phenotypes, including Hp 1-1, Hp 2-1, and Hp 2-2. Extensive research has been conducted to investigate the association between Hp polymorphisms and several medical conditions including cardiovascular disease, inflammatory bowel disease, cancer, transplantation, and hemoglobinopathies. Generally, the Hp 2-2 phenotype is associated with increased disease risk and poor outcomes. Over the years, the Hp 2 allele has spread under genetic pressures. Individuals with the Hp 2-2 phenotype generally exhibit lower levels of CD163 expression in macrophages. The decreased expression of CD163 may be associated with the poor antioxidant capacity in the serum of subjects carrying the Hp 2-2 phenotype. However, the Hp 1-1 phenotype may confer protection in some cases. The Hp1 allele has strong antioxidant, anti-inflammatory, and immunomodulatory properties. It is important to note that the benefits of the Hp1 allele may vary depending on genetic and environmental factors as well as the specific disease or condition under consideration. Therefore, the Hp1 allele may not necessarily confer advantages in all situations, and its effects may be context-dependent. This review highlights the current understanding of the role of Hp polymorphisms in cardiovascular disease, inflammatory bowel disease, cancer, transplantation, hemoglobinopathies, and polyuria.

Chronic Kidney Disease: Early Detection, Mechanisms, and Therapeutic Implications

Chronic Kidney Disease (CKD) constitutes a global health crisis, silently affecting millions worldwide [...].

Unveiling the Hidden Power of Uromodulin: A Promising Potential Biomarker for Kidney Diseases

Uromodulin, also known as Tamm-Horsfall protein, represents the predominant urinary protein in healthy individuals. Over the years, studies have revealed compelling associations between urinary and serum concentrations of uromodulin and various parameters, encompassing kidney function, graft survival, cardiovascular disease, glucose metabolism, and overall mortality. Consequently, there has been a growing interest in uromodulin as a novel and effective biomarker with potential applications in diverse clinical settings. Reduced urinary uromodulin levels have been linked to an elevated risk of acute kidney injury (AKI) following cardiac surgery. In the context of chronic kidney disease (CKD) of different etiologies, urinary uromodulin levels tend to decrease significantly and are strongly correlated with variations in estimated glomerular filtration rate. The presence of uromodulin in the serum, attributable to basolateral epithelial cell leakage in the thick ascending limb, has been observed. This serum uromodulin level is closely associated with kidney function and histological severity, suggesting its potential as a biomarker capable of reflecting disease severity across a spectrum of kidney disorders. The UMOD gene has emerged as a prominent locus linked to kidney function parameters and CKD risk within the general population. Extensive research in multiple disciplines has underscored the biological significance of the top UMOD gene variants, which have also been associated with hypertension and kidney stones, thus highlighting the diverse and significant impact of uromodulin on kidney-related conditions. UMOD gene mutations are implicated in uromodulin-associated kidney disease, while polymorphisms in the UMOD gene show a significant association with CKD. In conclusion, uromodulin holds great promise as an informative biomarker, providing valuable insights into kidney function and disease progression in various clinical scenarios. The identification of UMOD gene variants further strengthens its relevance as a potential target for better understanding kidney-related pathologies and devising novel therapeutic strategies. Future investigations into the roles of uromodulin and regulatory mechanisms are likely to yield even more profound implications for kidney disease diagnosis, risk assessment, and management.

The role of sRAGE in cardiovascular diseases

Advanced glycation end products (AGEs), by-products of glucose metabolism, have been linked to the emergence of cardiovascular disorders (CVD). AGEs can cause tissue damage in four different ways: (1) by altering protein function, (2) by crosslinking proteins, which makes tissue stiffer, (3) by causing the generation of free radicals, and (4) by activating an inflammatory response after binding particular AGE receptors, such as the receptor for advanced glycation end products (RAGE). It is suggested that the soluble form of RAGE (sRAGE) blocks ligand-mediated pro-inflammatory and oxidant activities by serving as a decoy. Therefore, several studies have investigated the possible anti-inflammatory and anti-oxidant characteristics of sRAGE, which may help lower the risk of CVD. According to the results of various studies, the relationship between circulating sRAGE, cRAGE, and esRAGE and CVD is inconsistent. To establish the potential function of sRAGE as a therapeutic target in the treatment of cardiovascular illnesses, additional studies are required to better understand the relationship between sRAGE and CVD. In this review, we explored the potential function of sRAGE in different CVD, highlighting unanswered concerns and outlining the possibilities for further investigation.

Vitamin D and Vitamin D Binding Protein in Health and Disease 2.0

Vitamin D, often referred to as the "sunshine nutrient", has gained considerable attention in recent years due to its multifaceted impact on health and disease [...].

Unlocking the Diagnostic Potential of Saliva: A Comprehensive Review of Infrared Spectroscopy and Its Applications in Salivary Analysis

Infrared (IR) spectroscopy is a noninvasive and rapid analytical technique that provides information on the chemical composition, structure, and conformation of biomolecules in saliva. This technique has been widely used to analyze salivary biomolecules, owing to its label-free advantages. Saliva contains a complex mixture of biomolecules including water, electrolytes, lipids, carbohydrates, proteins, and nucleic acids which are potential biomarkers for several diseases. IR spectroscopy has shown great promise for the diagnosis and monitoring of diseases such as dental caries, periodontitis, infectious diseases, cancer, diabetes mellitus, and chronic kidney disease, as well as for drug monitoring. Recent advancements in IR spectroscopy, such as Fourier-transform infrared (FTIR) spectroscopy and attenuated total reflectance (ATR) spectroscopy, have further enhanced its utility in salivary analysis. FTIR spectroscopy enables the collection of a complete IR spectrum of the sample, whereas ATR spectroscopy enables the analysis of samples in their native form, without the need for sample preparation. With the development of standardized protocols for sample collection and analysis and further advancements in IR spectroscopy, the potential for salivary diagnostics using IR spectroscopy is vast.

Enzymatic Deglycation of Damaged Skin by Means of Combined Treatment of Fructosamine-3-Kinase and Fructosyl-Amino Acid Oxidase

The consensus in aging is that inflammation, cellular senescence, free radicals, and epigenetics are contributing factors. Skin glycation through advanced glycation end products (AGEs) has a crucial role in aging. Additionally, it has been suggested that their presence in scars leads to elasticity loss. This manuscript reports fructosamine-3-kinase (FN3K) and fructosyl-amino acid oxidase (FAOD) in counteracting skin glycation by AGEs. Skin specimens were obtained (n = 19) and incubated with glycolaldehyde (GA) for AGE induction. FN3K and FAOD were used as monotherapy or combination therapy. Negative and positive controls were treated with phosphate-buffered saline and aminoguanidine, respectively. Autofluorescence (AF) was used to measure deglycation. An excised hypertrophic scar tissue (HTS) (n = 1) was treated. Changes in chemical bonds and elasticity were evaluated using mid-infrared spectroscopy (MIR) and skin elongation, respectively. Specimens treated with FN3K and FAOD in monotherapy achieved an average decrease of 31% and 33% in AF values, respectively. When treatments were combined, a decrease of 43% was achieved. The positive control decreased by 28%, whilst the negative control showed no difference. Elongation testing of HTS showed a significant elasticity improvement after FN3K treatment. ATR-IR spectra demonstrated differences in chemical bounds pre- versus post-treatment. FN3K and FAOD can achieve deglycation and the effects are most optimal when combined in one treatment.

Topical Application of Deglycating Enzymes as an Alternative Non-Invasive Treatment for Presbyopia

Presbyopia is an age-related vision disorder that is a global public health problem. Up to 85% of people aged ≥40 years develop presbyopia. In 2015, 1.8 billion people globally had presbyopia. Of those with significant near vision disabilities due to uncorrected presbyopia, 94% live in developing countries. Presbyopia is undercorrected in many countries, with reading glasses available for only 6-45% of patients living in developing countries. The high prevalence of uncorrected presbyopia in these parts of the world is due to the lack of adequate diagnosis and affordable treatment. The formation of advanced glycation end products (AGEs) is a non-enzymatic process known as the Maillard reaction. The accumulation of AGEs in the lens contributes to lens aging (leading to presbyopia and cataract formation). Non-enzymatic lens protein glycation induces the gradual accumulation of AGEs in aging lenses. AGE-reducing compounds may be effective at preventing and treating AGE-related processes. Fructosyl-amino acid oxidase (FAOD) is active on both fructosyl lysine and fructosyl valine. As the crosslinks encountered in presbyopia are mainly non-disulfide bridges, and based on the positive results of deglycating enzymes in cataracts (another disease caused by glycation of lens proteins), we studied the ex vivo effects of topical FAOD treatment on the power of human lenses as a new potential non-invasive treatment for presbyopia. This study demonstrated that topical FAOD treatment resulted in an increase in lens power, which is approximately equivalent to the correction obtained by most reading glasses. The best results were obtained for the newer lenses. Simultaneously, a decrease in lens opacity was observed, which improved lens quality. We also demonstrated that topical FAOD treatment results in a breakdown of AGEs, as evidenced by gel permeation chromatography and a marked reduction in autofluorescence. This study demonstrated the therapeutic potential of topical FAOD treatment in presbyopia.

The Potential Use of Near- and Mid-Infrared Spectroscopy in Kidney Diseases

Traditional renal biomarkers such as serum creatinine and albuminuria/proteinuria are rather insensitive since they change later in the course of the disease. In order to determine the extent and type of kidney injury, as well as to administer the proper therapy and enhance patient management, new techniques for the detection of deterioration of the kidney function are urgently needed. Infrared spectroscopy is a label-free and non-destructive technique having the potential to be a vital tool for quick and inexpensive routine clinical diagnosis of kidney disorders. The aim of this review is to provide an overview of near- and mid-infrared spectroscopy applications in patients with acute kidney injury and chronic kidney disease (e.g., diabetic nephropathy and glomerulonephritis).

Pressure therapy for scars: Myth or reality? A systematic review

BACKGROUND

Hypertrophic scarring is a deviate occurrence after wound closure and is a common burn sequela. The mainstay of scar treatment consists of a trifold approach: hydration, UV-protection and the use of pressure garments with or without extra paddings or inlays to provide additional pressure. Pressure therapy has been reported to induce a state of hypoxia and to reduce the expression pattern of transforming growth factor-β1 (TGF-β1), therefore limiting the activity of fibroblasts. However, pressure therapy is said to be largely based on empirical evidence and a lot of controversy concerning the effectiveness still prevails. Many variables influencing its effectivity, such as adherence to treatment, wear time, wash frequency, number of available pressure garment sets and amount of pressure remain only partially understood. This systematic review aims to give a complete and comprehensive overview of the currently available clinical evidence of pressure therapy.

METHODS

A systematic search for articles concerning the use of pressure therapy in the treatment and prevention of scars was performed in 3 different databases (Pubmed, Embase, and Cochrane library) according to the PRISMA statement. Only case series, case-control studies, cohort studies, and RCTs were included. The qualitative assessment was done by 2 separate reviewers with the appropriate quality assessment tools.

RESULTS

The search yielded 1458 articles. After deduplication and removal of ineligible records, 1280 records were screened on title and abstract. Full text screening was done for 23 articles and ultimately 17 articles were included. Comparisons between pressure or no pressure, low vs high pressure, short vs long duration and early vs late start of treatment were investigated.

CONCLUSION

There is sufficient evidence that indicates the value of prophylactic and curative use of pressure therapy for scar management. The evidence suggests that pressure therapy is capable of improving scar color, thickness, pain, and scar quality in general. Evidence also recommends commencing pressure therapy prior to 2 months after injury, and using a minimal pressure of 20-25 mmHg. To be effective, treatment duration should be at least 12 months and even preferably up to 18-24 months. These findings were in line with the best evidence statement by Sharp et al. (2016).

Occlusion and hydration of scars: moisturizers versus silicone gels

BACKGROUND

The mainstay of non-invasive scar management, consists of pressure therapy with customized pressure garments often combined with inlays, hydration by means of silicones and/or moisturizers as well as UV protection. It is generally accepted that scar dehydration resulting from impaired barrier function of the stratum corneum and expressed by raised trans epidermal water loss (TEWL) values, can lead to increased fibroblast activity and thereby hypertrophic scar formation. However, we have reached no consensus on exactly what optimal scar hydration is nor on barrier function repair: by means of silicone sheets, liquid silicone gels or moisturizers. Occlusive silicone sheets almost completely prevent TEWL and have been shown to be effective. Nevertheless, many important disadvantages due to excessive occlusion such as difficulties in applying the sheets exceeding 10-12 h, pruritus, irritation, and maceration of the skin are limiting factors for its use. To avoid these complications and to facilitate the application, liquid silicone gels were developed. Despite a reduced occlusion, various studies have shown that the effects are comparable to these of the silicone sheets. However, major limiting factors for general use are the long drying time, the shiny aspect after application, and the high cost especially when used for larger scars. Based on excellent clinical results after using three specific moisturizers for scar treatment in our patients, we wanted to investigate whether these moisturizers induce comparable occlusion and hydration compared to both each other and the widely recognized liquid silicone gels. We wanted to provide a more scientific basis for the kind of moisturizers that can be used as a full-fledged and cost-effective alternative to silicone gel.

METHODS

A total of 36 healthy volunteers participated in this study. Increased TEWL was created by inducing superficial abrasions by rigorous (20x) skin stripping with Corneofix® adhesive tape in squares of 4 cm². Three moisturizers and a fluid silicone gel were tested: DermaCress, Alhydran, Lipikar and BAP Scar Care silicone gel respectively. TEWL reducing capacities and both absolute (AAH) and cumulative (CAAH) absolute added hydration were assessed using a Tewameter® TM300 and a Corneometer® CM825 at different time points for up to 4 h after application.

RESULTS

We found an immediate TEWL increase in all the zones that underwent superficial abrasions by stripping. Controls remained stable over time, relative to the ambient condition. The mean percentage reduction (MPR) in TEWL kept increasing over time with Alhydran and DermaCress, reaching a maximum effect 4 h after application. Silicone gel reached maximal MPR almost immediately after application and only declined thereafter. The silicone gel never reached the minimal MPR of Alhydran or DermaCress. Hydration capacity assessed through CAAH as measured by the Corneometer was significantly less with silicone gel compared to the moisturizers. Compared to silicone gel Lipikar provided similar occlusion and the improvement in hydration was highly significant 4 h after application.

CONCLUSION

Based on the results of both our previous research and this study it is clearly demonstrated that the occlusive and hydrative effect of fluid silicone gel is inferior to the moisturizers used in our center. Lipikar hydrates well but is less suitable for scar treatment due to the lack of occlusion. A well-balanced occlusion and hydration, in this study only provided by Alhydran and DermaCress, suggests that moisturizers can be used as a scar hydration therapy that replaces silicone products, is more cost-effective and has a more patient-friendly application.

Vitamin D and Vitamin D-Binding Protein in Health and Disease

Vitamin D is a fat-soluble secosteroid that exists in two forms: vitamin D₂ and vitamin D₃ [...].

Dissolving microneedles for effective and painless intradermal drug delivery in various skin conditions: A systematic review

Intra- and transdermal administration of substances via percutaneous injection is effective but considered painful, and inconvenient in addition to bringing forth biohazardous waste material. In contrast to injection, topical drug application, which includes ointments, creams and lotions, increases the local drug load. Moreover, it has reduced side effects compared to systemic administration. However, the epidermis poses a barrier to high molecular weight substances, limiting the delivery efficiency. Dissolving microneedles (DMN) are hydrophilic, mostly polymer-based constructs that are capable of skin penetration and were developed to provide painless and direct dermal drug delivery. This systematic review provides a comprehensive overview of the available clinical evidence for the use of DMN to treat various skin conditions. According to the PRISMA statement, a systematic search for articles on the use of DMN for dermatological indications was conducted on three different databases (Pubmed, Embase, and the Cochrane library). Only human clinical trials were considered. Qualitative assessment was done by two separate reviewers using the Cochrane risk of bias (RoB 2) and Chambers' criteria assessment tools. The search yielded 1090 articles. After deduplication and removal of ineligible records, 889 records were screened on title and abstract. Full text screening was done for 18 articles and ultimately 17 articles were included of which 15 were randomized controlled trials and two were case series. The quality assessment showed that the majority of included studies had low to no risk of bias. Clinical data supports that DMN are an excellent, effective, and pain free drug delivery method for multiple dermatological disorders including skin aging, hyperpigmentation, psoriasis, warts, and keloids by supplying a painless and effective vehicle for intradermal/intralesional drug administration. Microneedle technology provides a promising non- to minimally-invasive alternative to percutaneous injection.

C-reactive protein interacts with amphotericin B liposomes and its potential clinical consequences

OBJECTIVES

Amphotericin B (AmB) is the gold standard for treating invasive fungal infections. New liposomal-containing AmB formulations have been developed to improve efficacy and tolerability. Serum/plasma C-reactive protein (CRP) values are widely used for monitoring infections and inflammation. CRP shows a high affinity to phosphocholine and it aggregates structures bearing this ligand, e.g. phosphocholine-containing liposomes. Therefore, we studied the interaction between CRP and phosphocholine-containing liposomal AmB preparations in vivo and in vitro.

METHODS

CRP was prepared by affinity chromatography. Liposomal AmB (L-AmB, AmBisome^®) was spiked (final concentrations of L-AmB: 150 mg/L) to CRP-containing serum (final CRP concentration: 300 mg/L). Following the addition of L-AmB, complex formation was monitored turbidimetrically. The size of CRP-L-AmB complexes was assessed using gel filtration. CRP was monitored in patients receiving either L-Amb or AmB lipid complex (ABLC).

RESULTS

Following addition of L-AmB to CRP-containing plasma, turbidimetry showed an increase in absorbance. These results were confirmed by gel permeation chromatography. Similarly, in vivo effects were observed following intravenous administration of AmBisome^®: a decline in CRP values was observed. In patients receiving L-Amb, decline of CRP concentration was faster than in patients receiving ABLC.

CONCLUSIONS

In vitro experiments are suggestive of a complexation between CRP and liposomes in plasma. Interpretation of CRP values following administration of AmBisome^® might be impaired due to this complexation. In vivo formation of complexes between liposomes and CRP might contribute, or even lead, to intravascular microembolisation. Similar effects have been described following the administration of Intralipid^® and other phosphocholine-containing liposomes.

A meta-analysis of chemokines in vitiligo: Recruiting immune cells towards melanocytes

Chemokine research offers insightful information on the pathogenesis of cutaneous immune disorders, such as vitiligo. Compared to cytokines, the higher detectable levels of chemokines display promising potential as future disease biomarkers. Nonetheless, some published study results are contradictory, which can be attributed to patient characteristics and methodological differences. In this study, a meta-analysis was performed to compare chemokine expression in blood and skin samples from vitiligo patients versus healthy controls. Furthermore, the relationship between chemokine expression and disease activity was evaluated. Chemokine levels were investigated in 15 articles in the circulation and in 9 articles in vitiligo skin. Overall, some clear trends were observed. CXCR3 signaling by CXCL10 and CXCL9 has been confirmed by several reports, although CXCL10 showed more robust findings in blood samples. In this meta-analysis, CCL5, CXCL8, CXCL12, and CXCL16 levels were also significantly elevated. This indicates a complex immune pathway activation in vitiligo that overall supports a Th1-dominant response. Chemokines linked to the Th2 and Th17 pathways were less prevalent. Despite these findings, study protocols that examine a broader range of chemokines are encouraged, because current research is mostly focused on a small number of chemokines that were differentially expressed in previous studies.

Immune Complex Glomerulonephritis in a Patient with Myelodysplastic Syndrome with Ring Sideroblasts Treated with Luspatercept

Myelodysplastic syndromes (MDS) are a group of clonal myeloid disorders distinguished by dysplastic bone marrow and peripheral blood cells, ineffective hematopoiesis, and an increased risk of developing acute myeloid leukemia (AML). MDS with ring sideroblasts (MDS-RS) is a favorable outcome subtype with a lower frequency of AML transformation. The FDA recently approved luspatercept for the treatment of patients with very-low-, low-, and intermediate-risk MDS-RS who have failed to correct anemia with an erythropoiesis-stimulating agent (ESA) and require two units of red blood cells over an eight-week period. This drug's pharmacology is based on the critical role of the transforming growth factor-beta (TGF-β) pathway in regulating erythropoiesis. In this case report, we describe for the first time an acute kidney injury caused by membranoproliferative glomerulonephritis (MPGN) in a patient with MDS-RS who was treated with luspatercept. We propose that a multi-hit hypothesis could explain the immunopathogenesis. A first unknown hit may stimulate IgA immune complex production, whereas luspatercept administration acts as a second hit, causing Smad1-5-8 phosphorylation. This intriguing case report on immune-complex-mediated proliferative glomerulonephritis following luspatercept treatment generates hypotheses and stimulates further research in this area.

The Potential Applications of Raman Spectroscopy in Kidney Diseases

Raman spectroscopy (RS) is a spectroscopic technique based on the inelastic interaction of incident electromagnetic radiation (from a laser beam) with a polarizable molecule, which, when scattered, carries information from molecular vibrational energy (the Raman effect). RS detects biochemical changes in biological samples at the molecular level, making it an effective analytical technique for disease diagnosis and prognosis. It outperforms conventional sample preservation techniques by requiring no chemical reagents, reducing analysis time even at low concentrations, and working in the presence of interfering agents or solvents. Because routinely utilized biomarkers for kidney disease have limitations, there is considerable interest in the potential use of RS. RS may identify and quantify urinary and blood biochemical components, with results comparable to reference methods in nephrology.

The Meaning and Reliability of Minimal Important Differences (MIDs) for Clinician-Reported Outcome Measures (ClinROMs) in Dermatology-A Scoping Review

Background: Clinician-reported outcome measures (ClinROMs) are frequently used in clinical trials and daily practice to evaluate the disease status and evolution of skin disorders. The minimal important difference (MID) represents the smallest difference that decreases the disease impact enough to make a treatment change worthwhile for patients. As no clear guidance exists on the preferred method to calculate MIDs for ClinROMs, we evaluated how the published values for different skin disorders should be interpreted. Methods: A systematic search was performed for MIDs of ClinROMs that focus on skin disorders and/or symptoms. The results of the questions in the credibility instrument for MIDs of Devji et al., 2020 were analyzed to gain insights into the meaning of these MIDs. Results: 29 MIDs were identified. The most common skin diseases were atopic dermatitis/eczema, followed by bullous disorders and psoriasis. A minimal important difference from the patients’ perspective was determined in 31% of the cases. However, in 41.4% of the cases, it concerned a substantial rather than a minimal difference in disease severity rated by physicians. Over half (55.1%) of the studies contained an inadequate number of patients (n < 150). MID values increased substantially in patients with severe compared to mild disease. Conclusions: MIDs of ClinROMs for skin disorders should be carefully interpreted due to the substantial differences in methodology between the studies. There is an urgent need for a consensus method to report reliable MIDs. Otherwise, this lack of uniformity could not only affect the design and conclusion of clinical trials but also skew treatment decisions.

Shunt Nephritis: A Case of Mistaken Identity

BACKGROUND

Membranoproliferative glomerulonephritis is a histological pattern of glomerular injury due to the deposition of immune complexes and complement factors. It is associated with bacterial and viral infections, auto-immune diseases such as systemic lupus erythematosus and Sjögren's syndrome, monoclonal gammopathy, and complement disorders (dense deposit disease and C3 glomerulopathy).  Case presentation: This is the report of a 25-year-old male with membranoproliferative glomerulonephritis who was initially treated for systemic lupus erythematosus, but who was later diagnosed with nephritis due to a chronic infection of a central nervous system shunt, last revised at the age of 3 years old.

DISCUSSION

We highlight the challenges in making an early diagnosis of shunt nephritis, and succinctly discuss the clinical, biochemical, histopathological findings, and differential diagnosis of this type of infection-related glomerulonephritis.

Hypergastrinemia, a clue leading to the identification of an atypical form of diabetes mellitus type 2

BACKGROUND

A hitherto undescribed form of diabetes mellitus type 2 is reported in a Flemish family. In these patients, markedly elevated gastrin levels were observed, which could not be linked to gastrointestinal symptoms.

MATERIALS AND METHODS

Gel permeation chromatography was performed for gastrin, insulin, and proinsulin. Proprotein convertase subtilisin/kexin type (PCSK1 and PCSK2)] were sequenced. Whole-exome sequencing was performed on the genomic DNA extracted from leukocytes of the proband of the family.

RESULTS

Gel permeation chromatography revealed that the apparent hypergastrinemia was caused by the accumulation of biologically inactive progastrin. Besides, high serum concentrations of proinsulin and intact fibroblast growth factor 23 (FGF23) were also detected. Sequencing of PCSK1 and PCSK2 genes did not reveal any mutations in these genes. Whole exome sequencing revealed a c.1150C>T (p.Pro384Ser) mutation in G protein-coupled receptor kinase 6 (GRK6), which cosegregated with the disease. Expression of the mutant enzyme in mammalian cells revealed that it was mislocalized compared to the wild-type GRK6.

CONCLUSIONS

In the affected patients, prohormone processing is impaired likely due to the altered function of mutant GRK6. Delayed pro-insulin processing causes hypoglycaemia episodes a couple of hours following meals. In addition, increased plasma concentrations of progastrin and intact FGF23 in the affected individuals can be explained by incomplete processing of the precursor hormones.

Urinary Epidermal Growth Factor: A Promising "Next Generation" Biomarker in Kidney Disease

BACKGROUND

The epidermal growth factor (EGF) is a globular protein that is generated in the kidney, especially in the loop of Henle and the distal convoluted tubule. While EGF is nonexistent or hardly detectable in plasma, it is present in normal people's urine. Until now, risk stratification and chronic kidney disease (CKD) diagnosis have relied on estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (uACR), both of which reflect glomerular function or impairment. Tubular dysfunction, on the other hand, may also be associated with renal failure.

SUMMARY

Because decreased urine EGF (uEGF) indicates tubular atrophy and interstitial fibrosis, this biomarker, together with eGFR and uACR, may be employed in the general population for risk assessment and diagnosis of CKD. uEGF levels have been shown to correlate with intrarenal EGF mRNA expression and have been found to decrease in a variety of glomerular and non-glomerular kidney disorders.

KEY MESSAGE

uEGF, uEGF/creatinine, or uEGF/monocyte chemotactic peptide-1 are possible "new generation" biomarkers linked to a variety of kidney diseases that deserve further investigation as a single biomarker or as part of a multi-biomarker panel.

The use of fluid silicone gels in the prevention and treatment of hypertrophic scars: a systematic review and meta-analysis

BACKGROUND

Silicone products, either as a sheet or in fluid form, are universally considered as the first line therapy in the prevention and treatment of hypertrophic scars and keloids. However, the study results have been questioned by different authors and there has never been a large systematic synopsis published on the efficacy of fluid silicone gels. This systematic review aims to elucidate the available evidence of the results obtained by fluid silicone gels and present a complete and comprehensive overview of the available literature as well as a meta-analysis of the pooled data.

METHODS

A systematic search for articles concerning the use of silicone gel in the treatment and prevention of scars was performed on 3 different databases (Pubmed, Embase and Cochrane library) according to the PRISMA statement. Only RCT's were included. Qualitative assessment was done by 2 separate reviewers using the Cochrane risk of bias (RoB 2) assessment tool. Revman 5.4.1 software was used for meta-analysis.

RESULTS

The search yielded 507 articles. Two articles were identified through other sources. After deduplication and removal of ineligible records, 340 records were screened on title and abstract. Full text screening was done for 23 articles and ultimately 18 articles were included. A meta-analysis comparing fluid silicone gel to no treatment or placebo gels was conducted.

CONCLUSION

Studies on the effects of liquid silicone gels on hypertrophic scars are numerous and this systematic review shows that the use of liquid silicone gels is associated with both a prophylactic and a curative effect on scars. However, a considerable amount of the available 'high evidence' trials are at a high risk for bias and it is uncertain whether or not the effects of silicone gels are comparable to silicone sheets and if the additional components present in many silicone gels are partially responsible for their scar improving capacity.

Host polymorphisms and COVID-19 infection

Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). There is growing evidence that host genetics play an important role in COVID-19 severity. Based on current knowledge about the human protein machinery for SARS-CoV-2 entry, the host innate immune response, and virus-host interactions, the potential effects of human genetic polymorphisms, which may contribute to clinical differences in SARS-CoV-2 pathogenesis, may help to determine the individual risk for COVID-19 infection and outcome.

The Role of Advanced Glycation End Products and Its Soluble Receptor in Kidney Diseases

Patients with chronic kidney disease (CKD) are more prone to oxidative stress and chronic inflammation, which may lead to an increase in the synthesis of advanced glycation end products (AGEs). Because AGEs are mostly removed by healthy kidneys, AGE accumulation is a result of both increased production and decreased kidney clearance. On the other hand, AGEs may potentially hasten decreasing kidney function in CKD patients, and are independently related to all-cause mortality. They are one of the non-traditional risk factors that play a significant role in the underlying processes that lead to excessive cardiovascular disease in CKD patients. When AGEs interact with their cell-bound receptor (RAGE), cell dysfunction is initiated by activating nuclear factor kappa-B (NF-κB), increasing the production and release of inflammatory cytokines. Alterations in the AGE-RAGE system have been related to the development of several chronic kidney diseases. Soluble RAGE (sRAGE) is a decoy receptor that suppresses membrane-bound RAGE activation and AGE-RAGE-related toxicity. sRAGE, and more specifically, the AGE/sRAGE ratio, may be promising tools for predicting the prognosis of kidney diseases. In the present review, we discuss the potential role of AGEs and sRAGE as biomarkers in different kidney pathologies.

Labile glycated hemoglobin: an underestimated laboratory marker of short term glycemia

OBJECTIVES

Diabetes mellitus is a major public health problem. Hemoglobin A_1c (HbA_1c) is a key laboratory parameter in the management of diabetes patients. However, in diabetes monitoring, interpretation of HbA_1c results is hampered by the important interindividual variation in red blood cell (RBC) life span. Furthermore, HbA_1c only slowly responds to changes in glucose metabolism. Besides HbA_1c, there exists a labile HbA_1c fraction (l-HbA_1c), exhibiting much faster kinetics. As both HbA_1c and l-HbA_1c are measured by modern standard chromatography, we explored the possibilities of using the l-HbA_1c fraction for monitoring glycemia.

METHODS

l-HbA_1c and HbA_1c fractions were simultaneously assayed on a Tosoh G8 analyzer and expressed as %. l-HbA_1c results were compared with serum glucose and HbA_1c. Concomitantly, RBC distribution width (RDW) was determined on a Sysmex SN analyzer as a marker for erythrocyte life span.

RESULTS

l-HbA_1c could be measured with between-run coefficient of variations (CVs) between 2.2 and 2.3%. l-HbA_1c correlated with both glycemia (r=0.80) and HbA_1c results (r=0.73). In a multiple regression model (r²=0.752), glycemia and HbA_1c were the most determining factors. To a lesser extent, RDW correlated with l-HbA_1c (r=0.158). Furthermore, the l-HbA_1c/HbA_1c ratio weakly positively correlated with RDW (r=0.247).

CONCLUSIONS

L-HBA_1c represents an additional marker for monitoring the rapid occurrence of glycemic disorders that escape detection when using only HbA_1c and blood glucose. RDW can be used as an indicator of atypical RBCs life span, in which the l-HbA_1c fraction may be helpful.

A rare presentation of kidney failure in a patient with giant cell arteritis: case report and review of literature

Although giant cell arteritis, also called temporal arteritis, is the most common primary vasculitis in the elderly, an association with AA amyloidosis has rarely been reported. AA amyloidosis is a disorder that results from the extracellular deposition of proteolytic cleavage products of serum amyloid A, which occurs in the setting of long-standing inflammation. We present a case of a patient with giant cell arteritis who developed a rapidly deteriorating kidney function, due to AA amyloidosis. Early recognition of this rare phenomenon is crucial as prompt treatment may be beneficial in the salvage of renal function.

Gut Microbiota and Their Derived Metabolites, a Search for Potential Targets to Limit Accumulation of Protein-Bound Uremic Toxins in Chronic Kidney Disease

Chronic kidney disease (CKD) is characterized by gut dysbiosis with a decrease in short-chain fatty acid (SCFA)-producing bacteria. Levels of protein-bound uremic toxins (PBUTs) and post-translational modifications (PTMs) of albumin increase with CKD, both risk factors for cardiovascular morbidity and mortality. The relationship between fecal metabolites and plasma concentrations of PBUTs in different stages of CKD (n = 103) was explored. Estimated GFR tends to correlate with fecal butyric acid (BA) concentrations (r_s = 0.212; p = 0.032), which, in its turn, correlates with the abundance of SCFA-producing bacteria. Specific SCFAs correlate with concentrations of PBUT precursors in feces. Fecal levels of p-cresol correlate with its derived plasma UTs (p-cresyl sulfate: r_s = 0.342, p < 0.001; p-cresyl glucuronide: r_s = 0.268, p = 0.006), whereas an association was found between fecal and plasma levels of indole acetic acid (r_s = 0.306; p = 0.002). Finally, the albumin symmetry factor correlates positively with eGFR (r_s = 0.274; p = 0.005). The decreased abundance of SCFA-producing gut bacteria in parallel with the fecal concentration of BA and indole could compromise the intestinal barrier function in CKD. It is currently not known if this contributes to increased plasma levels of PBUTs, potentially playing a role in the PTMs of albumin. Further evaluation of SCFA-producing bacteria and SCFAs as potential targets to restore both gut dysbiosis and uremia is needed.

On the protein content of kidney stones: an explorative study

OBJECTIVES

Kidney stone formation is complex; urinary protein inhibitors play a major role in natural defense against stone formation. Using attenuated total-reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy of kidney stones, proteins are usually not quantified and often reported as 'organic matrix', for which there is little attention: treatment of urolithiasis is based on the nature of the major organic/inorganic stone compound. Literature no longer regards urinary proteins as innocent bystander, but highlights the role of proteins as urolithiasis modulators. We explored the potential significance of the protein content of kidney stones.

METHODS

800 stones were analyzed using ATR-FTIR spectroscopy; spectra were corrected for protein content. The ratio of the amide I peak (1655 cm^-1) divided by the maximum peak was calculated. A subgroup of stones (n = 43) was weighed; protein concentration was assayed. Kidney stone composition was taken into account when calculating protein concentration. Electrophoresis was implemented to investigate the protein bands. Multiple regression analysis was carried out to study the influence of various demographic variables (age, gender, stone type) on protein concentration.

RESULTS

Protein concentration showed a marked variation according to the stone composition. High relative protein content (>0.4% stone mass) was found in mixed calcium apatite/calcium oxalate dihydrate stones, mixed calcium oxalate dihydrate/calcium oxalate monohydrate/calcium apatite stones, and mixed calcium oxalate monohydrate/brushite stones, whereas lower protein percentages were found in cystine, urate, and calcium oxalate monohydrate stones. Protein concentration was dependent of the patient's age.

CONCLUSION

ATR-FTIR is a practical way for assessing protein concentration in kidney stones.

LIST OF ABBREVIATIONS

A: absorbance; as, asymmetric vibrations; ATR-FTIR, attenuated total-reflectance Fourier-transform infrared; β, standardized regression coefficient; CAP, calcium apatite; COD, calcium oxalate dihydrate; COM, calcium oxalate monohydrate; CV, coefficient of variation; δ, bending vibrations; ELISA, enzyme-linked immunosorbent assay; IQR, interquartile range; IR, infrared; LOD, limit of detection; LOQ, limit of quantification; MIR, mid-infrared; N or n, amount; r, correlation; r², coefficient of determination; s, symmetric vibrations; SD, standard deviation; SE, standard error; THP, Tamm-Horsfall protein; UA, uric acid; V, stretching vibrations; VIF: variance inflation factor; ZnSe, zinc selenide.

Measured Glomerular Filtration Rate: The Query for a Workable Golden Standard Technique

Inulin clearance has, for a long time, been considered as the reference method to determine measured glomerular filtration rates (mGFRs). However, given the known limitations of the standard marker, serum creatinine, and of inulin itself, and the frequent need for accurate GFR estimations, several other non-radioactive (iohexol and iothalamate) and radioactive (51Cr-EDTA, 99mTc-DTPA, 125I iothalamate) exogenous mGFR filtration markers are nowadays considered the most accurate options to evaluate GFR. The availability of 51Cr-EDTA is limited, and all methods using radioactive tracers necessitate specific safety precautions. Serum- or plasma-based certified reference materials for iohexol and iothalamate and evidence-based protocols to accurately and robustly measure GFR (plasma vs. urinary clearance, single-sample vs. multiple-sample strategy, effect of sampling time delay) are lacking. This leads to substantial variation in reported mGFR results across studies and questions the scientific reliability of the alternative mGFR methods as the gold standard to evaluate kidney function. On top of the scientific discussion, regulatory issues are further narrowing the clinical use of mGFR methods. Therefore, this review is a call for standardization of mGFR in terms of three aspects: the marker, the analytical method to assess concentrations of that marker, and the procedure to determine GFR in practice. Moreover, there is also a need for an endogenous filtration marker or a panel of filtration markers from a single blood draw that would allow estimation of GFR as accurately as mGFR, and without the need for application of anthropometric, clinical, and demographic characteristics.