1
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Qu S, Tang Y, Ning Z, Zhou Y, Wu H. Desired properties of polymeric hydrogel vitreous substitute. Biomed Pharmacother 2024; 172:116154. [PMID: 38306844 DOI: 10.1016/j.biopha.2024.116154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 02/04/2024] Open
Abstract
Vitreous replacement is a commonly employed method for treating a range of ocular diseases, including posterior vitreous detachment, complex retinal detachment, diabetic retinopathy, macular hole, and ocular trauma. Various clinical substitutes for vitreous include air, expandable gas, silicone oil, heavy silicone oil, and balanced salt solution. However, these substitutes have drawbacks such as short retention time, cytotoxicity, high intraocular pressure, and the formation of cataracts, rendering them unsuitable for long-term treatment. Polymeric hydrogels possess the potential to serve as ideal vitreous substitutes due to their structure-mimicking to natural vitreous and adjustable mechanical properties. Replacement with hydrogels as the tamponade can help maintain the shape of the eyeball, apply pressure to the detached retina, and ensure the metabolic transport of substances without impairing vision. This literature review examines the required properties of artificial vitreous, including the optical properties, rheological properties, expansive force action, and physiological and biochemical functions of chemically and physically crosslinked hydrogels. The strategies for enhancing the biocompatibility and injectability of hydrogels are also summarized and discussed. From a clinical ophthalmology perspective, this paper presents the latest developments in vitreous replacement, providing clinicians with a comprehensive understanding of hydrogel clinical applications, which offers guidance for future design directions and methodologies for hydrogel development.
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Affiliation(s)
- Sheng Qu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Yi Tang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Zichao Ning
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Yanjie Zhou
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Hong Wu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China.
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2
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Kamaha Tchekep AG, Suryanarayanan V, Pattanayak DK. New insight into interference-free and highly sensitive dopamine electroanalysis. Anal Chim Acta 2024; 1291:342234. [PMID: 38280788 DOI: 10.1016/j.aca.2024.342234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/12/2023] [Accepted: 01/09/2024] [Indexed: 01/29/2024]
Abstract
Early diagnosis of Parkinson's disease and hyperprolactinemia based on electrochemical dopamine (DA) sensing appears as an efficient and promising practical diagnostic method. However, the coexistence of DA in real samples with ascorbic acid (AA) and uric acid (UA), which oxidize at potentials close to its own, prevents the accurate electrochemical DA sensing and therefore, hinders the effective diagnosis of these diseases. In this work, we successfully combined the electrostatic proprieties of GO, the electron transfer properties of an AuNPs@MWCNTs nanocomposite and the ability of thiol group of the amino acid l-cysteine to react chemically with carbonyl groups of UA, to develop a novel approach that enabled complete suppression of interference from AA and UA and hence, accurate DA electroanalysis in the conditions close to those of human blood serum. The chemical reaction between l-cysteine and UA was evidenced by monitoring the DPV responses of UA under different conditions. XRD, Raman spectroscopy, XPS and FE-SEM revealed the successful synthesis of GO and AuNPs@MWCNTs. The study of the electrode material (GO-AuNPs@MWCNTs) morphology via FE-SEM and HR-TEM showed that AuNPs@MWCNTs are distributed throughout the exfoliated GO layers. The fabricated sensor was calibrated in the concentration range of 0.5-5 μM, in the presence of the highest blood concentrations of AA and UA for healthy individuals. A linear relationship was observed and the LOD was found to be 1.31 nM (S/N = 3). Furthermore, the sensor showed good electron transfer kinetics, good repeatability and reproducibility, satisfactory long-term stability, and recoveries in human blood serum.
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Affiliation(s)
- A G Kamaha Tchekep
- Electrochemical Process Engineering Division, CSIR-Central Electrochemical Research Institute, Karaikudi, 630003, Tamil Nadu, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - V Suryanarayanan
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India; Electro Organic & Materials Electrochemistry Division, CSIR-Central Electrochemical Research Institute, Karaikudi, 630003, Tamil Nadu, India
| | - Deepak K Pattanayak
- Electrochemical Process Engineering Division, CSIR-Central Electrochemical Research Institute, Karaikudi, 630003, Tamil Nadu, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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3
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Gregory A, Yumnamcha T, Shawky M, Eltanani S, Naghdi A, Ross BX, Lin X, Ibrahim AS. The Warburg effect alters amino acid homeostasis in human retinal endothelial cells: implication for proliferative diabetic retinopathy. Sci Rep 2023; 13:15973. [PMID: 37749155 PMCID: PMC10520048 DOI: 10.1038/s41598-023-43022-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/18/2023] [Indexed: 09/27/2023] Open
Abstract
Proliferative diabetic retinopathy (PDR) remains a leading cause of blindness despite progress in screening and treatment. Recently, the Warburg effect, a metabolic alteration affecting amino acid (AA) metabolism in proliferating cells, has drawn attention regarding its role in PDR. This study aimed to investigate the impact of the Warburg effect on AA metabolism in human retinal endothelial cells (HRECs) subjected to PDR-associated risk factors and validate the findings in patients with PDR. In vitro experiments exposed HRECs to high glucose (HG) and/or hypoxia (Hyp), known inducers of the Warburg effect. The HG + Hyp group of HRECs exhibited significant differences in non-essential AAs with aliphatic non-polar side chains, mainly driven by elevated glycine concentrations. Pathway enrichment analysis revealed several glycine metabolism-related pathways significantly altered due to the Warburg effect induced by HG + Hyp. Crucially, vitreous humor samples from PDR patients displayed higher glycine levels compared to non-diabetic and diabetic patients without PDR. The odds ratio for PDR patients with glycine levels above the cut-off of 0.0836 µM was 28 (p = 0.03) compared to non-PDR controls. In conclusion, this study provides mechanistic insights into how a specific Warburg effect subtype contributes to glycine accumulation in PDR and supports glycine's potential as a biomarker for PDR pathogenesis.
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Affiliation(s)
- Andrew Gregory
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Thangal Yumnamcha
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Mohamed Shawky
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
- Department of Biochemistry, Faculty of Pharmacy, Horus University, Damietta, Egypt
| | - Shaimaa Eltanani
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Armaan Naghdi
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Bing X Ross
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Xihui Lin
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA
| | - Ahmed S Ibrahim
- Department of Ophthalmology, Visual, and Anatomical Sciences, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA.
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
- Department of Pharmacology, School of Medicine, Wayne State University, 540 East Canfield, Gordon Scott Hall (room 7133), Detroit, MI, 48201, USA.
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4
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Wang W, Shi D, Zhang Y, Li W, Li F, Feng H, Ma L, Yang C, Peng Z, Song G, Zeng H, Xie L. An injectable hydrogel based on hyaluronic acid prepared by Schiff base for long-term controlled drug release. Int J Biol Macromol 2023:125341. [PMID: 37327929 DOI: 10.1016/j.ijbiomac.2023.125341] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/28/2023] [Accepted: 06/10/2023] [Indexed: 06/18/2023]
Abstract
Drug-loaded injectable hydrogels have been studied widely in biomedical technology while the stable long-term controlled drug release and cytotoxicity are challenges. In this work, an injectable hydrogel with good swelling resistance was in situ synthetized using aminated hyaluronic acid (NHA) and aldehyde β-cyclodextrin (ACD) via Schiff-base reaction. The composition, morphology and mechanical property were characterized with FTIR, 13C NMR, SEM and rheology test, respectively. Voriconazole (VCZ) and Endophthalmitis was selected as a model drug and disease, respectively. The drug release, cytotoxicity and antifungal properties were detected in vitro. The results showed a long-term (> 60 days) drug release was realized, the NHA/ACD2/VCZ presented a zero-order release in the later stage. The cytotoxicity of NHA/ACD was detected by live/dead staining assay and Cell Counting Kit-8 (CCK-8). The survival rate of adult retina pigment epithelial cell line-19 (ARPE-19) was over 100 % after 3 d, it indicated a good cytocompatibility. The antifungal experiment presented samples had antifungal property. Biocompatibility in vivo proved NHA/ACD2 had no adverse effects on ocular tissues. Consequently, the injectable hydrogel based on hyaluronic acid prepared by Schiff base reaction provides a new option for long-term controlled drug release in the course of disease treatment from a material perspective.
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Affiliation(s)
- Wenqian Wang
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Depeng Shi
- Medical College of Qingdao University, Qingdao University, Qingdao, Shandong 266071, China; Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong 266071, China
| | - Yongfei Zhang
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Wenhui Li
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Feng Li
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Hui Feng
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Lichun Ma
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Chao Yang
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China.
| | - Zhi Peng
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Guojun Song
- College of Materials Science and Engineering, Qingdao University, Qingdao, Shandong 266071, China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Lixin Xie
- Eye Institute of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong 266071, China.
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Yoon ES, Park HJ, Kil MS, Kim J, Lee KG, Choi BG. Preparation of nanopillar array electrode of iridium oxide for high performance of
pH
sensor and its real‐time sweat monitoring. B KOREAN CHEM SOC 2023. [DOI: 10.1002/bkcs.12689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- Eun Seop Yoon
- Department of Chemical Engineering Kangwon National University Samcheok South Korea
| | - Hong Jun Park
- Department of Chemical Engineering Kangwon National University Samcheok South Korea
| | - Min Sik Kil
- Department of Chemical Engineering Kangwon National University Samcheok South Korea
| | - Jueun Kim
- Center for Nano Bio Development National NanoFab Center Daejeon South Korea
| | - Kyoung G. Lee
- Center for Nano Bio Development National NanoFab Center Daejeon South Korea
| | - Bong Gill Choi
- Center for Nano Bio Development National NanoFab Center Daejeon South Korea
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Wang Y, Hu LF, Cui PF, Qi LY, Xing L, Jiang HL. Pathologically Responsive Mitochondrial Gene Therapy in an Allotopic Expression-Independent Manner Cures Leber's Hereditary Optic Neuropathy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103307. [PMID: 34431574 DOI: 10.1002/adma.202103307] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) is a rare inherited blindness caused by mutations in the mitochondrial DNA (mtDNA). The disorder is untreatable and tricky, as the existing chemotherapeutic agent Idebenone alleviates symptoms rather than overcoming the underlying cause. Although some studies have made progress on allotopic expression for LHON, in situ mitochondrial gene therapy remains challenging, which may simplify delivery procedures to be a promising therapeutic for LHON. LHON becomes more difficult to manage in the changed mitochondrial microenvironment, including increasing reactive oxygen species (ROS) and decreasing mitochondrial membrane potential (MMP). Herein, a pathologically responsive mitochondrial gene delivery vector named [triphenylphosphine-terminated poly(sulfur-containing thioketal undecafluorohexylamine histamine) and Ide-terminated poly(sulfur-containing thioketal undecafluorohexylamine histamine)] (TISUH) is reported to facilitate commendable in situ mitochondrial gene therapy for LHON. TISUH directly targets diseased mitochondria via triphenylphosphine and fluorination addressing the decreasing MMP. In addition, TISUH can be disassembled by high mitochondrial ROS levels to release functional genes for enhancing gene transfection efficiency and fundamentally correcting genetic abnormalities. In both traditional and gene-mutation-induced LHON mouse models, TISUH-mediated gene therapy shows satisfactory curative effect through the sustained therapeutic protein expression in vivo. This work proposes a novel pathologically responsive in situ mitochondrial delivery platform and provides a promising approach for refractory LHON as well as other mtDNA mutated diseases treatments.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Li-Fan Hu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Peng-Fei Cui
- School of Pharmacy, Changzhou University, Changzhou, 213164, China
| | - Lian-Yu Qi
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Lei Xing
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
| | - Hu-Lin Jiang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
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7
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Ye P, Zhang X, Xu Y, Xu J, Song X, Yao K. Alterations of the Gut Microbiome and Metabolome in Patients With Proliferative Diabetic Retinopathy. Front Microbiol 2021; 12:667632. [PMID: 34566901 PMCID: PMC8457552 DOI: 10.3389/fmicb.2021.667632] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 08/10/2021] [Indexed: 12/05/2022] Open
Abstract
Diabetic retinopathy (DR) has been reported to associate with gut microbiota alterations in murine models and thus “gut-retina-axis” has been proposed. However, the role of gut microbiome and the associated metabolism in DR patients still need to be elucidated. In this study, we collected fecal samples from 45 patients with proliferative diabetic retinopathy (PDR) and 90 matched diabetic patients (1:2 according to age, sex, and duration of diabetes) without DR (NDR) and performed 16S rRNA gene sequencing and untargeted metabolomics. We observed significantly lower bacterial diversity in the PDR group than that in the NDR group. Differential gut bacterial composition was also found, with significant depletion of 22 families (e.g., Coriobacteriaceae, Veillonellaceae, and Streptococcaceae) and enrichment of two families (Burkholderiaceae and Burkholderiales_unclassified) in the PDR group as compared with the NDR group. There were significantly different fecal metabolic features, which were enriched in metabolic pathways such as arachidonic acid and microbial metabolism, between the two groups. Among 36 coabundance metabolite clusters, 11 were positively/negatively contributed to PDR using logistic regression analysis. Fifteen gut microbial families were significantly correlated with the 11 metabolite clusters. Furthermore, a fecal metabolite-based classifier was constructed to distinguish PDR patients from NDR patients accurately. In conclusion, PDR is associated with reduced diversity and altered composition of gut microbiota and specific microbe-metabolite interplay. Our findings help to better understand the disease pathogenesis and provide novel diagnostic and therapeutic targets for PDR.
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Affiliation(s)
- Panpan Ye
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Eye Hospital, Zhejiang University, Hangzhou, China
| | - Xueyou Zhang
- Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yufeng Xu
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Eye Hospital, Zhejiang University, Hangzhou, China
| | - Jia Xu
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Eye Hospital, Zhejiang University, Hangzhou, China
| | - Xiaoxiao Song
- Department of Endocrinology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ke Yao
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,Eye Hospital, Zhejiang University, Hangzhou, China
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Hostiuc S, Negoi I, Hostiuc M. Markers of hyperglycemia in the vitreous humor. A systematic review and meta-analysis. J Forensic Leg Med 2021; 83:102250. [PMID: 34488176 DOI: 10.1016/j.jflm.2021.102250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/23/2021] [Accepted: 08/27/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Vitreous humor has been extensively used in forensic practice to assess hyperglycemia after death. The results from different articles, for various hyperglycemia markers are highly variable, and a systematic analysis of the results from studies currently used in forensic practice as landmarks has not yet been performed. Therefore, we aimed to evaluate to usefulness and limits of using the values of vitreous glucose, lactic acid, beta-hydroxybutyrate, and 1,5 Anhydro-d-glucitol to detect postmortem hyperglycemia. MATERIALS AND METHODS For this purpose, we performed a systematic review and a meta-analysis using the random-effects model to identify the threshold values and average differences for the markers mentioned above in the vitreous humor of diabetic versus nondiabetic subjects. RESULTS We included eleven studies in the meta-analysis and found the following mean differences between the diabetic and nondiabetic groups: for glucose - 91.4 mg/dl, for lactate - 34.17 mg/dl, for the Traub formula - 111 mg/dl, for fructosamine - 0.71 mmol/L, for beta-hydroxybutyrate - 36.55 mg/dl and 1,5 Anhydro-d-glucitol - -15.2 mg/dl. We also gave practical recommendations, based on the range of values and 95% confidence intervals in normal subjects and controls to identify antemortem hyperglycemia and evaluated, whenever possible, threshold values for fatal diabetes. CONCLUSIONS Glucose, Traub formula, fructosamine, and beta-hydroxy-butyrate can be used to detect postmortem hyperglycemia with some limitations; 1,5 Anhydro-d-glucitol can only be used to suggest the absence of a hyperglycemic status before death.
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Affiliation(s)
- Sorin Hostiuc
- Prof, Carol Davila University of Medicine and Pharmacy, Faculty of Dental Medicine, Dept. of Legal Medicine and Bioethics, 042122, Bucharest, Romania.
| | - Ionut Negoi
- Assoc.Prof, Carol Davila University of Medicine and Pharmacy, Faculty of Medicine, Dept. of Surgery, 020021, Bucharest, Romania.
| | - Mihaela Hostiuc
- Lecturer Carol Davila University of Medicine and Pharmacy, 020021, Faculty of Medicine, Dept. of Internal Medicine, Bucharest, Romania.
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9
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Roles of interstitial fluid pH and weak organic acids in development and amelioration of insulin resistance. Biochem Soc Trans 2021; 49:715-726. [PMID: 33769491 DOI: 10.1042/bst20200667] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/20/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is one of the most common lifestyle-related diseases (metabolic disorders) due to hyperphagia and/or hypokinesia. Hyperglycemia is the most well-known symptom occurring in T2DM patients. Insulin resistance is also one of the most important symptoms, however, it is still unclear how insulin resistance develops in T2DM. Detailed understanding of the pathogenesis primarily causing insulin resistance is essential for developing new therapies for T2DM. Insulin receptors are located at the plasma membrane of the insulin-targeted cells such as myocytes, adipocytes, etc., and insulin binds to the extracellular site of its receptor facing the interstitial fluid. Thus, changes in interstitial fluid microenvironments, specially pH, affect the insulin-binding affinity to its receptor. The most well-known clinical condition regarding pH is systemic acidosis (arterial blood pH < 7.35) frequently observed in severe T2DM associated with insulin resistance. Because the insulin-binding site of its receptor faces the interstitial fluid, we should recognize the interstitial fluid pH value, one of the most important factors influencing the insulin-binding affinity. It is notable that the interstitial fluid pH is unstable compared with the arterial blood pH even under conditions that the arterial blood pH stays within the normal range, 7.35-7.45. This review article introduces molecular mechanisms on unstable interstitial fluid pH value influencing the insulin action via changes in insulin-binding affinity and ameliorating actions of weak organic acids on insulin resistance via their characteristics as bases after absorption into the body even with sour taste at the tongue.
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Tassew NG, Laing ST, Aaronson J, de Jong I, Schuetz C, Lorget F. Tolerability Assessment of Formulation pH in New Zealand White Rabbits Following Intravitreal Administration. Toxicol Pathol 2020; 49:605-609. [PMID: 33252028 DOI: 10.1177/0192623320969667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Development of intravitreal drugs presents several challenges due to the delicate ocular environment and volume constraints of what can be safely administered in the eye. Formulation development of intravitreally administered drugs may necessitate the use of nonphysiological pH in order to accommodate manufacturing processes or achieve favorable drug properties. Clinical and nonclinical data show that intravitreal drugs formulated in the pH 5.5 to 7.4 range are well tolerated. The aim of this study was to provide ocular toxicity data for formulations in the pH 4.0 to 5.5 range following intravitreal administration in New Zealand White rabbits. This range was evaluated as part of formulation development for an intravitreal drug that necessitated the use of pH outside the available tolerability data for formulations. Toxicity was assessed by ophthalmic examinations, intraocular pressure (IOP) measurement, clinical observations, body weights, and microscopic analysis of ocular tissue. Histidine chloride pH 5.0 to 5.5 and acetate chloride pH 4.0 to 5.0 solutions were well tolerated, and no test article-related ocular inflammation, IOP changes, or gross or microscopic findings were observed in any eye. The data presented here add to the knowledge of pH ranges that can be explored for intravitreal drug formulation development.
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Affiliation(s)
- Nardos G Tassew
- Safety Assessment, 7412Genentech, South San Francisco, CA, USA
| | - Steven T Laing
- Safety Assessment, 7412Genentech, South San Francisco, CA, USA
| | | | - Isabella de Jong
- Pharm Dev, Genentech, South San Francisco, CA, USA. Lorget is now with Sangamo Therapeutics, Brisbane, CA, USA. Aaronson is now with 99373Ascendis Pharma A/S, Palo Alto, CA, USA
| | - Chris Schuetz
- Safety Assessment, 7412Genentech, South San Francisco, CA, USA
| | - Florence Lorget
- Safety Assessment, 7412Genentech, South San Francisco, CA, USA
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