Protein Loading Research Articles

Bioconversion of mustard oil cake for production of lipase, optimization and direct immobilization from solid-state fermentation extract

Fungal lipases are the leading industrial biocatalyst due to their broad applications, but high cost limits their commercial usage. The low-cost agri-residues substrates can reduce the cost of lipase production. However, the compatibility of agri-residue with fungal species, recovery process of lipase and stability of the enzyme are crucial steps. The aim of the present work was optimization of lipase production from a suitable combination of fungal culture with a locally available vegetable oilseed cake (mustard/groundnut/almond/cottonseed) in solid-state fermentation process and its direct immobilization. The enzyme produced using selected combination of Rhizopus oryzae and mustard oilseed cake was optimized by Plackett–Burman design, one-factor-at-a-time and central composite design (CCD). The highest enzyme activity of 25.08 U/gds was obtained by CCD at urea 2.11% w/w, inoculum size 1.18% v/w, and moisture content 69.99% w/w. The crude enzyme from the extract was immobilized on functionalized magnetic nanoparticles with the results of protein loading 68.88 ± 3.54 µg/mg of MNPs and activity recovery of 60.33 ± 3.03%. This study can be helpful to explore the suitability of locally available agri-residue for production of lipase and utilization of enzyme in different industrial applications.

Rapid screening of acetylcholinesterase inhibitors in Qi-Fu-Yin using magnetic metal-organic frameworks immobilized with acetylcholinesterase.

Current immobilization approaches for ligand fishing often experience challenges such as limited protein loading capacity and difficulties in the recycling process. To overcome these challenges, we synthesized a magnetic metal-organic frameworks (MMOFs) composite, which can be rapidly separated and has a large specific surface area, and employed it to immobilize acetylcholinesterase (AChE). The synthesized MMOFs@AChE composite exhibited a high immobilization yield (129.7mg/g) and excellent relative activity recovery (88.1%). Furthermore, immobilized AChE can improve its resistance to alkaline environments and high temperatures. After being stored at 4°C for a month, the immobilized enzyme maintained 91.4% of its original activity, significantly higher than the free enzyme (77.6%). Furthermore, it preserved more than 80% of its initial activity after five cycles and 68.7% after eight cycles. The composite MMOFs@AChE was then incubated with Qi-Fu-Yin extract to fish for ligands binding to AChE. Notably, Qi-Fu-Yin can alleviate Alzheimer's disease (AD) symptoms by modulating the AChE pathway, while active compounds remain unclear. Sixteen potential AChE inhibitors were identified through UHPLC-Q-Exactive-Orbitrap-MS/MS. The results of ligand fishing were validated through molecular docking studies, molecular dynamics simulation, surface plasmon resonance and AChE inhibitory activity assays. The screened compounds may exert inhibitory effects on AChE by altering the spatial configuration of the catalytic site or by influencing the binding of the substrate to the catalytic site, catalytic anionic site and peripheral anionic site regions. The MMOFs@AChE-based ligand fishing platform offers an efficient, effective, and convenient approach for enzymatic inhibitors discovery from natural products.

Insights into the Mechanism of Protein Loading by Chain-Length Asymmetric Complex Coacervates.

The study of the phase behavior of polyelectrolyte complex coacervates has attracted significant attention in recent years due to their potential use as membrane-less organelles, microreactors, and drug delivery platforms. In this work, we investigate the mechanism of protein loading in chain-length asymmetric complex coacervates composed of a polyelectrolyte and an oppositely charged multivalent ion. Unlike the symmetric case (polycation + polyanion), we show that protein loading is highly selective based on the protein's net charge: only proteins with charges opposite to the polyelectrolyte can be loaded. Through a series of systematic experiments, we identified that the protein loading process relies on the formation of a neutral three-component coacervate in which both the protein and the multivalent ion serve as complexing agents for the polyelectrolyte. Lastly, we demonstrated that this mechanism extends to the sequestration of other charged small molecules, offering valuable insights into designing functional multicomponent coacervates.

Immobilized Candida antarctica lipase B (CALB) for biodiesel production from rapeseed oil; evaluation of the effect of immobilization protocol.

The catalytic performance of Candida antarctica lipase B (CALB) immobilized on silica-coated magnetic nanoparticles was evaluated for biodiesel production via methanolysis of rapeseed oil. Two different covalent immobilization approaches were compared to assess the effect of immobilization protocols on lipase efficiency. The first approach involved immobilization of CALB on amine-functionalized magnetic nanoparticles (MNPs), which targeted the Lys-rich regions of the enzyme. The second used epoxy-functionalized MNPs, enabling broader nucleophilic groups on the enzyme surface to participate in the coupling reaction. Immobilization of 20 mg of CALB on 1 g of each support resulted in 82 % and 86 % protein loading on the amine- and epoxy-functionalized MNPs, respectively, after 24 h of incubation. Response surface methodology (RSM) was applied to optimize biodiesel production by analyzing the effects of parameters such as reaction temperature, time, t-butanol concentration, biocatalyst loading, and molecular sieve quantity on the yield of fatty acid methyl esters (FAME). Out of 45 designed experiments, the maximum FAME yields were 92 % and 84 % for the epoxy- and amine-functionalized MNPs, respectively.

Impact of high-intensity ultrasound on interfacial protein adsorption of non-dairy whipping cream: Whipping properties and foam stabilization model

In this paper, the competitive adsorption and practical application characteristics of ultrasound treatment on the oil-water interface in non-dairy whipping cream were explored. The results showed that ultrasound treatment promoted the competitive adsorption of casein, resulting in an increase of interfacial protein loading in the system by 4.82 mg/m2 and a decrease in oil droplet size by 0.20 μm. In addition, due to the increase of interfacial protein in the system, the partial coalescence of the fat globule of systems decreased, which led to a rapid collapse of the foam after 2 days of storage. Ultrasound weakened the strength of the gel network inside emulsions, which weakened the anti-deformation ability of emulsions. Although the LVR of the ultrasonically treated samples narrowed after churning, the G′ value increased. In addition, the stress yield point of the foams shifted to higher strains as the ultrasonic power increased, implying better resistance to deformation.

GLP-1 enhances β-cell response to protein ingestion and bariatric surgery amplifies it.

The glycemic-independent actions of glucagon-like peptide-1 (GLP-1) in the prandial state in humans are unknown. We examined the contribution of GLP-1 to β-cell secretory response (primary endpoint) and glucose metabolism during protein ingestion under basal glycemia, as well as whether these responses are affected by rerouted gut after gastric bypass (GB) or sleeve gastrectomy (SG). Insulin secretion rate (ISR) and glucose fluxes during a 50-g oral protein load were compared among 10 nondiabetic individuals with GB, 9 with SG, and 7 non-operated controls (CN), with and without intravenous infusion of exendin(9-39) (Ex-9), a GLP-1 receptor (GLP-1R) antagonist. Blocking GLP-1R increased glucose before and after protein ingestion and decreased β-cell sensitivity to glucose in the first 30 min of protein ingestion in all three groups (p < 0.05). Reduction in the premeal ISR by Ex-9 infusion was only observed in CN, whereas diminished prandial ISR3h by GLP-1R blockade was only observed in GB and SG (p < 0.05 for interaction). GLP-1R blockade enhanced post-protein insulin action in GB and SG, but not in CN, and exaggerated endogenous glucose production only GB (p < 0.05 for interaction). These findings are consistent with both pancreatic and extra-pancreatic roles for GLP-1 during protein ingestion in humans that are exaggerated by bariatric surgery.

Immobilization of lipase on mesoporous silica nanocarriers for efficient preparation of phytosterol esters

Phytosterol esters (PEs) are favored for their good solubility, high bioavailability, and various health benefits. Mesoporous silica (MS) nanocarriers were synthesized and utilized to immobilize free lipase AYS “Amano” (from Candida rugosa) for further preparing PEs. The optimal immobilization conditions were an initial enzyme content of 160 mg/mL, pH of 7.0, temperature of 30 °C, and adsorption time of 6 h, resulting in a protein loading of 42.3 mg/g and an immobilization efficiency of 73.4 %. Compared to commercial carriers, MS carriers demonstrated superior immobilization efficiency and phytosterol conversion rates when soybean oil was used as the PEs source for the transesterification. The phytosterol conversion rate reached 97.7 % in a solvent system with optimal reaction conditions. After 30 days of storage, the immobilized lipase retained 55.7 % of its activity, and it had 63.0 % retention activity after 10 reuse cycles. This study significantly enhanced the lipase's phytosterols conversion and reusability, supporting sustainable and efficient industrial production of PEs.

Chemical and bacteriological quality of newly Trade Ostrich’s Meat Cuts

In Egypt, ostrich meat as a production animal is relatively under-researched compared to other farmed animals, especially regarding its meat quality. Despite ostrich farming being prominent for feather production in the early 20th century, its meat is gaining popularity among Egyptian consumers. Ostriches provide multiple products, including feathers, leather, and low-fat red meat. However, there is a lack of comprehensive data on ostrich meat's chemical and microbial quality, which is essential for ensuring food safety and quality. This study aims to analyze the proximate chemical and bacteriological properties of ostrich meat cuts sold in Egyptian markets. Thirty frozen ostrich meat samples (inside leg, outside leg, wings, and trim) were randomly collected from an ostrich abattoir and analyzed for moisture, protein, fat, ash content, and microbial load. The results showed that ostrich’s meat had favorable nutritional characteristics, as high protein and low-fat content, with moisture levels ranging from 73.86% to 76.39%. The protein content in ostrich’s meat ranged from 17.22 % to 21%, while the fat content varied from 1.82% to 5.11%. Microbiological analysis revealed that the total bacterial counts ranging in ostrich’s meat from 4.1x103 to 3.2x104 CFU/g. Escherichia coli and Staphylococcus aureus were detected in some in ostrich’s meat samples under the potential food safety concerns. The findings suggested the need for stricter hygiene practices during processing and storage to maintain meat quality and ensure consumer safety. This research underscores the importance of improving the scientific knowledge surrounding ostrich’s meat in Egypt, particularly regarding its chemical and microbiological quality to enhance consumer confidence and promote its broader use.

Relationship between Fertility Diet Score Index Items and Ovulation in Women with Polycystic Ovary Syndrome: A Narrative Review

Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder affecting women of reproductive age, characterized by ovarian dysfunction and a leading cause of infertility due to ovulatory issues. Lifestyle interventions, including dietary modifications, exercise, and weight management, are considered first-line therapies for women with PCOS; however, the optimal treatment remains unidentified. The Fertility Diet (FD), introduced in 2007, represents a dietary approach that may positively impact fertility by emphasizing specific micronutrients, dietary composition modifications, weight management, and increased physical activity. This narrative review aims to evaluate how various components of the Fertility Diet influence ovulation and overall fertility, assessed through a fertility diet score. The findings of this study suggest that adherence to the Fertility Diet, particularly higher intake of the monounsaturated to trans-fat ratio, and increased vegetable protein intake, may positively influence fertility outcomes in individuals with PCOS. In contrast, high consumption of animal protein and high glycemic load food may have adverse effects. However, the current evidence remains insufficient for definitive conclusions, warranting further interventional studies to explore this relationship.

How long do bacteria, fungi, protozoa, and viruses retain their replication capacity on inanimate surfaces? A systematic review examining environmental resilience versus healthcare-associated infection risk by "fomite-borne risk assessment".

SUMMARYIn healthcare settings, contaminated surfaces play an important role in the transmission of nosocomial pathogens potentially resulting in healthcare-associated infections (HAI). Pathogens can be transmitted directly from frequent hand-touch surfaces close to patients or indirectly by staff and visitors. HAI risk depends on exposure, extent of contamination, infectious dose (ID), virulence, hygiene practices, and patient vulnerability. This review attempts to close a gap in previous reviews on persistence/tenacity by only including articles (n = 171) providing quantitative data on re-cultivable pathogens from fomites for a better translation into clinical settings. We have therefore introduced the new term "replication capacity" (RC). The RC is affected by the degree of contamination, surface material, temperature, relative humidity, protein load, organic soil, UV-light (sunlight) exposure, and pH value. In general, investigations into surface RC are mainly performed in vitro using reference strains with high inocula. In vitro data from studies on 14 Gram-positive, 26 Gram-negative bacteria, 18 fungi, 4 protozoa, and 37 viruses. It should be regarded as a worst-case scenario indicating the upper bounds of risks when using such data for clinical decision-making. Information on RC after surface contamination could be seen as an opportunity to choose the most appropriate infection prevention and control (IPC) strategies. To help with decision-making, pathogens characterized by an increased nosocomial risk for transmission from inanimate surfaces ("fomite-borne") are presented and discussed in this systematic review. Thus, the review offers a theoretical basis to support local risk assessments and IPC recommendations.

Fluorescent Reporter-Based Fiber Optic Probe for Continuous Detection of Antibodies.

Measurement of antibody and antibody fusion protein concentration is vital for process development and manufacturing. Continuous, in-line monitoring of antibody concentration could be useful in a variety of applications, such as controlling the loading of protein A columns to prevent breakthrough, monitoring bioreactor titer, and detecting leaks past ultrafiltration/diafiltration membranes. Molecule-specific monitoring techniques are advantageous for antibody detection in cell culture fluid in the presence of complex process impurities. Here we report a continuous in-line, real-time IgG monitoring platform using a fiber-optic biosensor with a replaceable sensor tip covalently functionalized with a fluor-labeled protein consisting of a pentamer of the Z domain (a more stable form of the B domain) of protein A. The sensor demonstrates concentration-dependent fluorescence enhancement in the presence of human IgG (0.01-0.75 g/L), with consistent signals during five runs each with 1 and 0.1 g/L IgG, and maintains its specificity in the presence of Chinese hamster ovary (CHO) cell culture fluid. A 5% breakthrough of a typical 10 g/L load would be detected in less than 20 s in a flowing stream emerging from a protein A column without prior sample preparation. This sensor platform may be suitable for monitoring IgG and fragment, crystallizable (Fc) fusion proteins in diverse upstream and downstream bioprocess applications.

Establishment of an Early Prediction Model for Severe Fever With Thrombocytopenia Syndrome-Associated Encephalitis.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease primarily transmitted by ticks. The development of encephalitis in SFTS patients significantly increases the risk of adverse outcomes. However, the understanding of SFTS-associated encephalitis (SFTSAE) is still limited. This study aimed to identify the clinical characteristics of SFTSAE and develop a predictive model for early detection. We retrospectively collected data from 220 SFTS patients admitted to Nanjing Drum Tower Hospital between May 2019 and January 2024. The patients were first randomly divided into a training set (154 people, 70%) and a validation set (66 people, 30%). The patients in the training set were divided into SFTSAE and non-SFTSAE groups according to the presence of encephalitis. A prediction model was constructed using the training set: important clinical parameters were selected using univariate logistic regression, and then multivariate logistic regression was performed to determine the independent risk factors for SFTSAE. A prediction model was constructed using these independent risk factors. Finally, the validation set was used to verify the predictive ability of the model. Age, C-reactive protein, d-dimer, and viral load were independent risk factors for SFTSAE (p < 0.05). A nomogram containing these four indicators was constructed, and the predictive performance of the nomogram was evaluated using the ROC curve. The AUC of the model was 0.846 (95% confidence interval [CI]: 0.770-0.921), which had good predictive ability for SFTSAE. Conclusion: The overall mortality rate of SFTS patients was 17.53%, and the mortality rate of encephalitis patients was 50%. Old age, high C-reactive protein, elevated d-dimer, and high viral load were independent risk factors for SFTSAE. The nomogram constructed based on these four indicators had good predictive ability and could be used as an evaluation tool for clinical treatment.

Effect of Protein Loading Density on the Structure and Biopreservation Efficacy of Metal-Organic Frameworks

Article Effect of Protein Loading Density on the Structure and Biopreservation Efficacy of Metal-Organic Frameworks Yixuan Wang 1,2, Sirimuvva Tadepalli 3,†, Harsh Baldi 1,2, Jeremiah J. Morrissey 1,4 and Srikanth Singamaneni 1,2,4,* 1 Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA 2 Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA 3 Radiation Oncology-Radiation Physics, Stanford School of Medicine, Stanford, CA 94305, USA 4 Siteman Cancer Center, Barnes-Jewish Hospital, and Washington University School of Medicine in St. Louis, St. Louis, MO 63130, USA * Correspondence: singamaneni@wustl.edu † Present Affiliation: Department of Immunology, School of Medicine, Stanford University, Stanford, CA 94305, USA Received: 9 September 2024; Revised: 31 October 2024; Accepted: 5 November 2024; Published: 20 November 2024 Abstract: Metal-organic frameworks (MOFs) have emerged as attractive bioencapsulants for preserving the structure and function of various biomolecules against harsh environmental conditions. However, the effect of the loading density of the biomolecules on the structure, physical properties, and biopreservation efficacy of MOF crystals remains elusive. We investigated the structure and properties of zeolitic imidazolate framework (ZIF)-90 crystals as a function of the loading density of a model protein, bovine/human serum albumin (BSA/HSA). We show that the total protein concentration in the MOF growth reaction solution significantly affects the morphology, degree of crystallinity, and biopreservation efficacy of the MOF crystals. The structure integrity and immunologic functionality of albumin remained well-preserved within an optimal protein concentration range of 0.1–1 mg/mL. The proposed optimal range of biomolecule concentration during in situ MOF growth is critical for guiding future research and design endeavors within the rapidly evolving field of MOF-biomedical applications, offering exciting possibilities for biopreservation, drug delivery, and diagnostics.

The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications.

Among eukaryotes, there are many examples of partial genome elimination during ontogenesis. A striking example of this phenomenon is the loss of entire avian chromosomes during meiosis, called a germline-restricted chromosome (GRC). The GRC is absent in somatic tissues but present in germ cells. It has been established that a prophase I male GRC is usually represented by a univalent surrounded by heterochromatin. In the present study, an immunocytochemical analysis of zebra finch spermatocytes was performed to focus on some details of this chromosome's organization. For the first time, it was shown that a prophase I GRC contains the HORMAD1 protein, which participates in the formation of a full axial element. This GRC axial element has signs of a delay of core protein loading, probably owing to peculiarities of meiotic silencing of chromatin. The presence of repressive marks (H3K9me3 and H3K27me3) and the lack of RNA polymerase II, typically associated with active transcription, indicate transcriptional inactivation in the GRC body, despite the known activity of some genes of the GRC. Nevertheless, RPA and RAD51 proteins were found at some GRC sites, indicating the formation and repair of double-strand breaks on this chromosome. Our results provide new insights into the meiotic behavior and structure of a GRC.

Synthesis and application of electrospun polyvinylidene fluoride/polyvinylidene glycol nanofibrous membrane for enhanced biomarker detection in immunochromatography assay

Immunochromatography assay (ICA) stands as a pioneering point-of-care testing (POCT) method, leveraging the simplicity, portability, and versatility of dry-strip testing method, chromatographic and antigen-antibody immunological reaction. Despite its numerous advantages, the shortcomings like low sensitivity, limited matrix, restricted matrix compatibility, and uncontrollable chromatographic rates, have hindered the ICA application. To overcome the aforementioned challenges, we proposed constructing a novel ICA strip based on homemade hydrophilic, flexible membranes to replace the commercially available nitrocellulose (NC). The key to the innovation lies in the spinning solution of a blend of poly (vinylidene fluoride) (PVDF) and polyethylene glycol (PEG), which is made into a nanofibrous membrane named EPVDF/PEG membrane by electrostatic spinning technique. This membrane, due to its high specific surface area and high porosity, can be loaded with more detection reagents than normal substrates, increasing the reaction time and achieving improved detection sensitivity. This membrane also has adjustable chromatographic rate, high protein loading capacity, good biocompatibility and excellent colouring ability. As a result, the established EPVDF/PEG-based ICA strips demonstrate an ultralow detection limit, as low as 0.5 mIU∙mL−1 when human chorionic gonadotropin (HCG) serves as the biomarker model, which is a 50-fold increase in detection sensitivity compared to commercial strips. Furthermore, EPVDF/PEG-based ICA strips can be produced on a large scale for the availability of efficient and mature electrospinning technologies. In summary, this work offers a transformative advancement in ICA development, potentially opening new horizons for sensitive biomarker detection.

Virus-like particle encapsulation of functional proteins: advances and applications.

Proteins face several challenges in biomedicine, including issues with antibody production, degradation by proteases, rapid clearance by the kidneys, and short half-lives. To address these problems, various nano delivery systems have been developed, with virus-like particles (VLPs) emerging as a leading solution. VLPs, which are self-assembled protein complexes, offer effective encapsulation and transport of proteins. They provide enhanced stability, extended circulation time, preserved biological activity, improved targeting for therapies or imaging, and reduced side effects due to minimized systemic exposure. This review explores various methods for encapsulating proteins within VLPs. It assesses the benefits and limitations of each method and their applications in imaging, therapeutic enzyme delivery, vaccines, immunotherapy, nanoreactors, and biosensors. Future advancements in VLPs will depend on improving packaging methods, controlling protein loading, optimizing assembly techniques, and enhancing capsid design. The review also discusses current challenges and proposes solutions to advance the use of VLPs in various applications.

The critical role of endoplasmic reticulum stress and the stimulator of interferon genes (STING) pathway in kidney fibrosis

Endoplasmic reticulum (ER) stress is a condition in which the ER is overwhelmed and unable to manage its protein load properly. The precise activation mechanisms and role of ER stress in kidney disease remain unclear. To study this, we performed unbiased transcriptomics analysis to demonstrate ER stress in kidneys of patients with chronic kidney disease and in mouse models of acute and chronic kidney injury (cisplatin and unilateral ureteral obstruction and reanalyzed previously published data on folic acid and mitochondrial transcription factor A(TFAM) knockout mice). Inhibiting the protein kinase RNA-like ER kinase (PERK) arm of ER stress but not activating transcription factor 6 or inositol-requiring enzyme 1, protected mice from kidney fibrosis. The stimulator of interferon genes (STING) was identified as an important upstream activator of ER stress in kidney tubule cells. STING and PERK were found to physically interact, and STING agonists induced PERK activation in kidney tubule cells. Mice with a STING activating mutation presented with ER stress and kidney fibroinflammation. We also generated mice with a tubule specific STING deletion that were resistant to ER stress and kidney fibrosis. Human kidney spatial transcriptomics highlighted a spatial correlation between STING, ER stress and fibrotic gene expression. Thus, our results indicate that STING is an important upstream regulator of PERK and ER stress in tubule cells during kidney fibrosis development.

Functionalized α-Cyanostilbene Derivatives for Detection of Hypoxia or Proteostasis Imbalance in Live Cells.

α-Cyanostilbene represents one of the easily functionalized aggregation-induced emission (AIE) scaffolds. It has been widely adopted for the construction of fluorescent materials for broad applications. Here, we further expanded the utilization of α-cyanostilbene derivatives for the detection of hypoxia or proteostasis imbalance in live cells. Four different amine containing donors were introduced to construct α-cyanostilbene derivatives (R-ASC) with donor-acceptor scaffolds. Equipped with the cysteine (Cys) reactive group, maleimide (MI), R-ASC-MI shows fluorescence turn-on property upon binding with unfolded proteins in vitro and in live cells under proteostatic stress. By virtue of R-ASC-MI, the level of unfolded protein loads in cells can be quantified by flow cytometry, or visualized under microscope. Furthermore, we also characterized the performance of R-ASC-NO2, synthetic precursors of R-ASC-MI, in cellular hypoxia. R-ASC-NO2 revealed upregulated activities of nitroreductase, as well as increased hydrophobicity in live cells, under either chemical (NaN3) induced or atmospheric (1 % O2) hypoxia. Together, the advantages of easy modification and high signal-to-noise ratio of new α-cyanostilbene derivatives reported in this work highlight the great potential of α-cyanostilbene in constructing functional biosensors and many other domains.

Tubulointerstitial injury in proteinuric chronic kidney diseases.

Proteinuria is an independent risk factor for chronic kidney disease progression and cardiovascular diseases. Apart from its prognostic role, the load of proteins that pass across the disrupted glomerular capillary wall trigger multiple pathophysiologic processes. These include, among others, intratubular complement activation and excessive proximal tubular reabsorption of filtered proteins, especially albumin and albumin-bound free fatty acids, which can set off several pathways of cellular damage. The activation of these pathways can cause apoptosis of proximal tubular cells and paracrine effects that incite the development of interstitial inflammation and fibrosis, ultimately leading to irreversible kidney injury. In this review, we provide a comprehensive overview of the current understanding on the mechanisms underlying the tubular toxicity of ultrafiltered proteins in the setting of proteinuric chronic kidney diseases. The acquired knowledge is expected to be instrumental for the development of novel therapeutic classes of medications to be tested on top of standard of care with optimized renin-angiotensin-aldosterone blockade and sodium-glucose cotransporter-2 inhibition, in order to further improve the clinical outcomes of patients with proteinuric chronic kidney diseases.

Evaluation of renal functional reserve in patients with preserved renal function and coronary microvascular disease

Abstract Background/introduction Renal Functional Reserve (RFR) stands as a subject of significant scientific discussion,holding promise as a diagnostic tool for early detection of subclinical renal disorders. Literature establishes a link between chronic kidney disease &amp; cardiovascular disease (CVD). Purpose This study aims to assess RFR in patients with coronary microvascular dysfunction (CMD), while maintaining preserved renal function (eGFR≥60ml/min/1.73m2 by CKD-EPI criteria)&amp;proteinuria&amp;lt;400mg/24hr. The investigation seeks to provide insights into the nuanced relationship between renal function&amp;CMD, offering potential early indicators of CVD. Methods This is a single-center, prospective study enrolling patients with CMD. In the absence of significant coronary artery disease, functional coronary circulation assessment was performed. Coronary flow reserve (CFR) &amp; index of microvascular resistance (IMR) were measured invasively with bolus thermodilution technique. In all participants, RFR was estimated by endogenous creatinine clearance after oral protein load (cooked meal, 1.2gr/kg). Normal RFR was defined as≥30 ml/min/1.73m2. Also, patients with CMD were offered 24-hour Ambulatory Blood Pressure Monitoring (ABPM). Results A total of 25 participants have been enrolled so far in study: 11 without CMD - control group [7 female, 64%, mean age: 52.9±8.8 years) &amp; 14 with CMD – CMD group (11 female, 79%, mean age: 53.5±10,3 years). CMD patients were classified into 2 groups, structural &amp; functional endotype (CFR&amp;lt;2.5 &amp; IMR≥25 were considered abnormal). The RFR value for CMD &amp; control group is 7.4±6.3 vs 36.3±5.8 ml/min/1.73m2 respectively (p&amp;lt;0.05). This difference between groups remained statistically significant after controlling for confounding factors. It was found that RFR value for functional &amp; structural CMD endotype was 3.8±2.6 &amp; 9.6±7,2 ml/min/1.73m2 respectively (p=0.06). Furthermore, no statistical significance was found between RFR and IMR, CFR indices. According to data from ABPM, there were no significant differences in ambulatory blood pressure (both systolic and diastolic) between the two endotypes of CMD, as well as no relationship with RFR was observed. However, the proportion of non-dipping BP pattern was significantly higher in functional CMD endotype (p&amp;lt;0.05). It was not found correlation between RFR &amp; non-dipping phenotype. Conclusions Impaired RFR is evident across all individuals experiencing microvascular angina. Furthermore, those with functional CMD exhibit a diminished RFR when compared with their counterparts with structural CMD. RFR does not exhibit a correlation with blood pressure levels or the absence of a nocturnal dipping pattern. In light of the hypothesis asserting that appraising renal functional reserve serves as an early diagnostic measure for subclinical renal disorders, promptly recognizing individuals with distinct phenotypes could facilitate tailoring therapeutic interventions on an individual basis.Functional Coronary AngiogramCMD group baseline characteristics