Tissue Resistance Research Articles

Changes in skin barrier integrity by electrical impedance spectroscopy during dupilumab treatment on a child with severe atopic dermatitis

Background. Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by epidermal skin barrier dysfunction and altered immune response. Electrical impedance spectroscopy (EIS) has been used as a novel tool to detect skin barrier changes in AD. EIS is a non-invasive measure of the electrical impedance of tissue and is sensitive to cellular structure and extracellular environment. Case Presentation. An 8-year-old girl presented with severe AD, starting at 3 years of age. She also had allergic rhinitis, food allergies, and sensitization to mites, eggs, and nuts. Unresponsive to other treatments, she was administered 300 mg of dupilumab, a monoclonal antibody inhibiting IL-4 and IL-13 activity. Patient’s response to the treatment and skin barrier integrity was followed for 6 months: First at the baseline (before dupilumab) and then again at the 1st, 2nd, 3rd, and 5.5th month after dupilumab with SCORing Atopic Dermatitis (SCORAD), as well as measurements of moisture by MoistureMeterSC (Delfin®) and EIS by Nevisense® (SciBase) on the forearm and antecubital fossa of the same arm. At the end of 6 months, her SCORAD improved from 96 to 37. The moisture measurements were variable. The EIS by Z1 score in the forearm increased from 72 to 141 and EIS by MIX scores increased from 2.7 to 6.2. The correlation between SCORAD and forearm EIS by Z1 and MIX scores were significant: r=-0.913, (p=0.03) and r=-0.881, (p=0.049). The correlation between forearm MIX scores with sleeplessness and itching was significant: r=-0.956, (p=0.011), r=-0.942, (p=0.017). Conclusion. As higher EIS scores reflect stronger barrier integrity, the increase in Z1 and MIX obtained from Nevisense® implies an improvement in the skin barrier integrity during dupilumab treatment. This report highlights the potential use of EIS in atopic dermatitis patients to evaluate treatment efficacy. We urge rapid and non-invasive use of EIS in pediatrics to be further investigated in clinical settings.

Adipocyte FGF21 Signaling Defect Aggravated Adipose Tissue Inflammation in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is associated with increased inflammation in adipose tissues. Fibroblast growth factor 21 (FGF21) is an endocrine hormone which signals to multiple tissues to regulate metabolism. However, its role in GDM remains largely unknown. In this study, we found that impaired FGF21 signaling in GDM correlates with worsened inflammation and insulin resistance in white adipose tissues in mice. Mechanistically, the pregnancy-related upregulation of FGF21 signaling in adipocytes promotes the differentiation of regulatory T cells (Tregs), which are critical for reducing pregnancy-induced adipose tissue inflammation. The anti-inflammatory effects of FGF21 may involve linolenic acid-mediated PGE2 synthesis in adipocytes. These findings underscore FGF21’s role in mediating crosstalk between mature adipocytes and immune cells in white adipose tissue and suggest that targeting FGF21 signaling and its downstream metabolites could offer a potential therapeutic approach for GDM in humans.

Identification of the serum metabolomic profile for acute ischemic preconditioning in athletes

PurposeIn recent years, ischemic preconditioning (IPC) has emerged as an effective strategy to increase tissue resistance against long-term ischemic damage and has been increasingly integrated into exercise regimens. However, further research is needed to explore the impact of IPC-mediated metabolic alterations from an exercise standpoint to conduct a comprehensive exploration of metabolic alterations and their exercise-related mechanisms during acute IPC.MethodsNontarget metabolomics was performed on blood samples obtained from 8 male athletes both before and after IPC. The studies included the identification of differentially abundant metabolites, analysis of receiver operating characteristic (ROC) curves, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis for differentially abundant metabolites, and metabolite set enrichment analysis (MSEA).ResultsNineteen differentially abundant metabolites were identified, with increasing levels of five metabolites, such as O-desmethyltramadol and D-gluconate, whereas 14 metabolites, including 9-hydroxy-10e, 12z-octadecadienoic acid (9-HODE), tetradione, 2-hexenal, (2,4-dichlorophenoxy)acetic acid (2,4-D), and phosphatidylserine (PS), decreased. ROC curve analysis revealed an AUC of 0.9375 for D-gluconate. Both KEGG enrichment analysis and MSEA revealed enrichment in the pentose phosphate pathway (PPP).ConclusionThis study revealed that PPP, D-gluconate, O-desmethyltramadol, and D-2-aminobutyric acid could be upregulated within 5 min after acute IPC, whereas 2,4-D, PS, 9-HODE, 2-hexenal, and tetradinone could be downregulated. These identified metabolites show promise for improving physical functional status and could be harnessed to enhance athletic performance.

Critical illness-related corticosteroid insufficiency - an overview of pathogenesis, clinical presentation and management

According to the Society of Critical Care Medicine, critical illness-related corticosteroid insufficiency (CIRCI) characterizes hypothalamic-adrenal axis insufficiency following acute medical conditions of various causes, i.e., sepsis, septic shock, acute respiratory distress syndrome, community-acquired pneumonia, and status after major surgical procedures. Due to highly variable etiology, understanding the pathomechanism and management of CIRCI assumes relevance for all centers providing intensive care. During CIRCI, multiple peripheral adaptations develop, and cortisol distribution volume increases due to hypothalamic-adrenal axis dysregulation, alterations in cortisol metabolism, and tissue resistance to corticosteroids. The proper diagnosis and treatment of CIRCI may be challenging in many cases. Although we have been acquainted with CIRCI since 2008, it remains a difficult condition with widely variable approaches among clinicians due to inconsistent high-quality study results determining the effect of corticosteroids on mortality. Corticosteroids are widely used in acutely ill patients, highlighting the necessity for reliable knowledge to support crucial clinicians’ decisions in daily medical practice. In this review, we provide an overview of the clinical management of patients with CIRCI based on current recommendations and selected studies.

Circulating extracellular vesicle-carried PTP1B and PP2A phosphatases as regulators of insulin resistance.

Metabolic disorders associated with abdominal obesity, dyslipidaemia, arterial hypertension and hyperglycaemia are risk factors for the development of insulin resistance. Extracellular vesicles (EVs) may play an important role in the regulation of metabolic signalling pathways in insulin resistance and associated complications. Circulating large EVs (lEVs) and small EVs (sEVs) from individuals with (IR group) and without insulin resistance (n-IR group) were isolated and characterised. lEVs and sEVs were administered by i.v. injection to mice and systemic, adipose tissue and liver insulin signalling were analysed. The role of phosphatases was analysed in target tissues and cells. Injection of lEVs and sEVs from IR participants impaired systemic, adipose tissue and liver insulin signalling in mice, while EVs from n-IR participants had no effect. Moreover, lEVs and sEVs from IR participants brought about a twofold increase in adipocyte size and adipogenic gene expression. EVs from IR participants expressed two types of phosphatases, phosphotyrosine 1 phosphatase (PTP1B) and protein phosphatase 2 (PP2A), IR lEVs being enriched with the active form of PTP1B while IR sEVs mainly carried active PP2A. Blockade of PTP1B activity in IR lEVs fully restored IRS1 and Akt phosphorylation in adipocytes and blunted insulin-induced Akt phosphorylation by inhibition of the macrophage secretome in hepatocytes. Conversely, blockade of PP2A activity in IR sEVs completely prevented insulin resistance in adipocytes and hepatocytes. These data demonstrate that inhibition of phosphatases carried by EVs from IR participants rescues insulin signalling in adipocytes and hepatocytes and point towards PTP1B and PP2A carried by IR EVs as being novel potential therapeutic targets against insulin resistance in adipose tissue and liver and the development of obesity.

Digitally Controllable Multifrequency Impedance Emulator for Bioimpedance Hardware Validation

ABSTRACTThe accurate emulation of the electrical impedance of biological tissues is crucial for the development and validation of bioimpedance measurement devices and algorithms. This paper describes a digitally controllable impedance emulator capable of reproducing values representative of tissue bioimpedance in user‐specified resistance, reactance, and frequency ranges up to 1 MHz. The presented solution uses a 2R‐1C impedance model to emulate the impedance characteristics of a biological tissue. Specific selection of each element value in this model is achieved using analog multiplexers with low resistance. A MATLAB algorithm was developed for value estimation using target impedance requirements. An example design to emulate impedance from 1 kHz to 1 MHz with 10 to 400 resistance and maximum reactance is provided. The nonideal behavior of this design was evaluated and compared against experimentally collected impedance measurements. Deviations of <1% were observed between experimental and theoretical resistances for values up to 100 kHz (with approximately 5% deviations up to 1 MHz) and reactance deviations were also <1% up to 10 kHz. High frequency deviations are attributed to the parasitic capacitance in the realization of the design. The experimental results validate the design approach and realization for low frequencies. Overall, the innovation of the proposed approach is the control of both resistance and reactance for emulating electrical impedance representative of biological tissues.

Aerobic Exercise Prevents High-Fat-Diet-Induced Adipose Tissue Dysfunction in Male Mice

Background/Objectives: This study aimed to assess the effect of aerobic exercise on capillary density and vascular smooth muscle cell (VSMC) phenotype in the visceral and subcutaneous adipose tissue of high-fat-diet (HFD) mice in order to understand the mechanisms underlying improvements in insulin resistance (IR) and chronic inflammation in adipose tissue (AT). Methods: Male C57BL/6J mice were divided into HFD and normal diet groups for 12 weeks and then further split into sedentary and aerobic exercise subgroups for an additional 8 weeks. Various parameters including body weight, fat weight, blood glucose, lipid profile, insulin levels, glucose tolerance, and inflammatory cytokines were evaluated. Results: Aerobic exercise reduced HFD-induced weight gain, IR, and improved lipid profiles. HFD had a minimal effect on inflammatory cytokines except in visceral adipose tissue (VAT). IR was associated with capillary density in subcutaneous adipose tissue (SAT) and VSMC phenotype in VAT. Aerobic exercise promoted anti-inflammatory responses in VAT, correlating with VSMC phenotype in this tissue. Conclusions: Aerobic exercise can alleviate HFD-induced IR and inflammation through the modulation of VSMC phenotype in AT.

Angiotensin-converting enzyme 2 activation attenuates inflammation and oxidative stress in brain death donor followed by rat lung transplantation

Brain death (BD) provides most of the donor organs destined for lung transplantation (LTx). However, the organs may be affected by inflammatory and oxidative processes. Based on this, we hypothesize that the angiotensin-converting enzyme 2 (ACE2) activation can reduce the lung injury associated with LTx. 3 h after BD induction, rats were injected with saline (BD group) or an ACE2 activator (ACE2a group; 15 mg/kg-1) and kept on mechanical ventilation for additional 3 h. A third group included a control ventilation (Control group) prior to transplant. After BD protocol, left LTx were performed, followed by 2 h-reperfusion. ACE2 activation was associated with better oxygenation after BD management (p = 0.01), attenuating edema (p = 0.05) followed by the reduction in tissue resistance (p = 0.01) and increase of respiratory compliance (p = 0.02). Nrf2 expression was also upregulated in the ACE2a group (p = 0.03). After transplantation, ACE2a group showed lower levels of TNF-α (p = 0.02), IL-6 (p = 0.001), IL-1β (p = 0.01), ROS (p = 0.004) and MDA (p = 0.002), in addition to higher CAT activity (p = 0.04). In conclusion, our study suggests that ACE2 activation improves anti-inflammatory and antioxidant activity in a model of LTx.

Autophagy Alterations in White and Brown Adipose Tissues of Mice Exercised under Different Training Protocols.

Autophagy is a conserved catabolic process that promotes cellular homeostasis and health. Although exercise is a well-established inducer of this pathway, little is known about the effects of different types of training protocols on the autophagy levels of tissues that are tightly linked to age-related metabolic syndromes (like brown adipose tissue) but are not easily accessible in humans. Here, we take advantage of animal models to assess the effects of short- and long-term resistance and endurance training in both white and brown adipose tissue, reporting distinct alterations on autophagy proteins microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B, or LC3B) and sequestosome-1 (SQSTM1/p62). Additionally, we also analyzed the repercussions of these interventions in fat tissues of mice lacking autophagy-related protein 4 homolog B (ATG4B), further assessing the impact of exercise in these dynamic, regulatory organs when autophagy is limited. In wild-type mice, both short-term endurance and resistance training protocols increased the levels of autophagy markers in white adipose tissue before this similarity diverges during long training, while autophagy regulation appears to be far more complex in brown adipose tissue. Meanwhile, in ATG4B-deficient mice, only resistance training could slightly increase the presence of lipidated LC3B, while p62 levels increased in white adipose tissue after short-term training but decreased in brown adipose tissue after long-term training. Altogether, our study suggests an intricated regulation of exercise-induced autophagy in adipose tissues that is dependent on the training protocol and the autophagy competence of the organism.

7492 Fibroblast Growth Factor 21 In The Diagnosis And Treatment Of Metabolic Disorders

Abstract Disclosure: H.M. Heshmati: None. H.S. Abu-Lebdeh: None. Background: Fibroblast growth factor 21 (FGF21), a member of the human FGF superfamily, is a 181 amino acid peptide hormone primarily produced by the liver. The gene of FGF21, located on chromosome 19, was cloned in 2000. FGF21 is involved in the maintenance of metabolic homeostasis. This review presents an update on the relevance of FGF21 in the diagnosis and treatment of metabolic disorders including obesity, nonalcoholic fatty liver disease (NAFLD), dyslipidemia, and type 2 diabetes. Methods: A systematic search of literature was conducted using the search terms fibroblast growth factor 21, obesity, nonalcoholic fatty liver disease, dyslipidemia, and type 2 diabetes. Results: FGF21 is a stress hormone with effects on energy expenditure and metabolism of lipids and glucose. FGF21 exerts its endocrine action in the central nervous system and adipose tissue. The serum FGF21 levels in normal subjects increase with aging. Stressful conditions (e.g., fasting status, protein restriction, exercise, metabolic disorders, kidney diseases, cardiovascular diseases, and sepsis) increase FGF21 secretion. Serum FGF21 levels are increased in obesity, NAFLD, dyslipidemia, and type 2 diabetes. Some of these patients may have a state of FGF21 resistance. The resistance to FGF21 is related, at least in part, to the presence of high circulating levels of fibroblast activation protein, a protease that inactivates FGF21. It has been suggested that the exercise-induced weight loss can be due to increased FGF21 secretion and decreased FGF21 resistance in adipose tissue. Serum FGF21 level has the potential to be used as a biomarker for early diagnosis of metabolic disorders (e.g., NAFLD and type 2 diabetes). Based on different metabolic properties of FGF21, FGF21-based therapy has been considered as an attractive approach for the treatment of metabolic disorders. Since native FGF21 has poor pharmacodynamic properties (e.g., short half-life and proteolytic cleavage by proteases), long-acting FGF21 analogs (e.g., LY2405319, PF-05231023, pegozafermin, AKR-001, and LLF580) have been synthesized and tested in clinical trials for the treatment of obesity, NAFLD, dyslipidemia, and type 2 diabetes. The available results show that FGF21 analogs can reduce body weight, liver fat, blood lipids, and fasting insulin/insulin resistance. Overall, the treatment with these analogs is safe and well tolerated. Conclusion: FGF21 is a predominantly liver-derived peptide hormone regulating energy expenditure and metabolism of lipids and glucose. Serum FGF21 levels are increased in several metabolic disorders including obesity, NAFLD, dyslipidemia, and type 2 diabetes. FGF21 is an attractive target for the treatment of these metabolic disorders. Despite some promising results observed with the use of FGF21 analogs, more clinical studies are needed before recommending FGF21-based therapies in metabolic disorders. Presentation: 6/2/2024

9215 Role Of Insulin/IGF1 Signaling And FoxO Transcription Factors In Satellite Cell And Skeletal Muscle Development And Senescence

Abstract Disclosure: Y. Yu: None. G. Wang: None. B.T. O'Neill: None. C.R. Kahn: None. Aging is associated with loss of skeletal muscle mass, deficiency of satellite cell (SC) function, and increase in intramuscular adipose tissue (IMAT) and insulin resistance posing threats to health and quality of elder life. Insulin / IGF1 signaling and their downstream signaling pathways play crucial roles in muscle function, as well as longevity a broad range of species. To identify the role of Insulin / IGF1 signaling in skeletal muscle homeostasis and aging/senescence, we took advantage of Cre-loxp mouse model using Pax7-Cre or HAS-Cre mice cross with insulin receptor (IR) and IGF1 receptor (IGF1R) double flox mice to create IR/IGF1R double knockout mice in both muscle progenitors (satellite cells) and mature skeletal muscle cells. We refer to the PaxCreIRIGF1RKO as the P7DKO and HSACreIRIGF1RKO as simply the DKO. Both P7DKO and DKO mice show severe loss of skeletal muscle with increased markers of cellular senescence and increased IMAT infiltration. This was indicated by a 60% loss of muscle mass, morphological evidence of skeletal muscle with atrophy and increased adipocyte infiltration, with a >6-fold increase of adipocyte marker Perlipin1. The muscle also exhibited 2- to 10-fold increases of cellular senescence and senescence-associated secretory markers, including Cdkn1a, Cdkn2a, Trp53, CD68, Cxcl14, and Ccr2. Both the whole skeletal muscle and primary satellite cells isolated from P7DKO mouse muscle show a higher level of senescence-associated beta-galactosidase, as compared to the cells from littermate controls. This was accompanied by a deficiency of proliferation and differentiation of the satellite cells. Interestingly, simultaneous knockout of Foxo1/3/4 in the DKO mouse muscle rescued the muscle atrophy, reduced IMAT infiltration and reduced skeletal muscle cell senescence. Thus, insulin/IGF1 signaling in satellite cells and mature muscle cells plays not only an important role in skeletal muscle development, but also skeletal muscle cell senescence, and this is mediated, in large part, through FOXO transcription factors. This pathway and these proteins provide both new insights and potential targets for improving skeletal muscle homeostasis and function in the elderly. Presentation: 6/2/2024

7897 Role Of Insulin/IGF1 Signaling And FoxO Transcription Factors In Satellite Cell And Skeletal Muscle Development And Senescence

Abstract Disclosure: Y. Yu: None. G. Wang: None. B.T. O'Neill: None. C.R. Kahn: None. Aging is associated with loss of skeletal muscle mass, deficiency of satellite cell (SC) function, and increase in intramuscular adipose tissue (IMAT) and insulin resistance posing threats to health and quality of elder life. Insulin / IGF1 signaling and their downstream signaling pathways play crucial roles in muscle function, as well as longevity a broad range of species. To identify the role of Insulin / IGF1 signaling in skeletal muscle homeostasis and aging/senescence, we took advantage of Cre-loxp mouse model using Pax7-Cre or HAS-Cre mice cross with insulin receptor (IR) and IGF1 receptor (IGF1R) double flox mice to create IR/IGF1R double knockout mice in both muscle progenitors (satellite cells) and mature skeletal muscle cells. We refer to the PaxCreIRIGF1RKO as the P7DKO and HSACreIRIGF1RKO as simply the DKO. Both P7DKO and DKO mice show severe loss of skeletal muscle with increased markers of cellular senescence and increased IMAT infiltration. This was indicated by a 60% loss of muscle mass, morphological evidence of skeletal muscle with atrophy and increased adipocyte infiltration, with a >6-fold increase of adipocyte marker Perlipin1. The muscle also exhibited 2- to 10-fold increases of cellular senescence and senescence-associated secretory markers, including Cdkn1a, Cdkn2a, Trp53, CD68, Cxcl14, and Ccr2. Both the whole skeletal muscle and primary satellite cells isolated from P7DKO mouse muscle show a higher level of senescence-associated beta-galactosidase, as compared to the cells from littermate controls. This was accompanied by a deficiency of proliferation and differentiation of the satellite cells. Interestingly, simultaneous knockout of Foxo1/3/4 in the DKO mouse muscle rescued the muscle atrophy, reduced IMAT infiltration and reduced skeletal muscle cell senescence. Thus, insulin/IGF1 signaling in satellite cells and mature muscle cells plays not only an important role in skeletal muscle development, but also skeletal muscle cell senescence, and this is mediated, in large part, through FOXO transcription factors. This pathway and these proteins provide both new insights and potential targets for improving skeletal muscle homeostasis and function in the elderly. Presentation: 6/2/2024

12521 Electrical Impedance Myography And Muscle Health In Older Adults With Type 1 Diabetes

Abstract Disclosure: A. Fremaint: None. G. Jung: None. E. Yu: None. M. Bouxsein: None. Introduction: Recent studies indicate that individuals with Type 1 diabetes mellitus (T1D) develop skeletal muscle health impairments which might contribute to falls and explain their high fracture risk. A novel handheld Electrical Impedance Myography (EIM) device (mScan model 1301, Myolex) has been developed to assess muscle quality by calculating tissue impedance. We hypothesized that mScan could identify individuals with worse strength and body composition outcomes among older adults with and without T1D. Methods: We studied participants of the T1D Bone Health Connection (BEACON) Study who were aged 50+ and who had undergone EIM testing (n=63 T1D, n=50 non-diabetic controls). We analyzed EIM-derived phase angle [Phase = arctan(reactance/resistance)] at 100 kHz in 3 upper extremity muscles (biceps brachii, lateral deltoid, and wrist extensors), where lower phase values indicate poorer muscle quality. Correlations of EIM data were performed with grip strength measured by a handheld dynamometer and appendicular lean mass/height2 (ALM/ht2) and visceral adipose tissue (VAT) from whole-body DXA scans. Pearson’s correlations were used for all statistical analyses. Results: Mean age (63±7 years), sex (54% female), and BMI (26.5 kg/m2) were similar between T1D and control groups. Adults with T1D had a nonsignificant trend towards lower muscle quality at the biceps brachii than controls (8.9±5.4 vs 10.9 ±6.0 degrees, p=0.078). There were no differences between groups in phase angle for lateral deltoid nor wrist extensors. Higher muscle quality at the biceps brachii was associated with higher grip strength (r=0.28, p=0.005) in the full cohort as well as in the T1D group (r=0.40, p <0.001). In the full cohort, greater VAT was associated with lower muscle health at the biceps brachii (r = -0.34, p=0.003) and lateral deltoid (r = -0.23, p<0.014), with similar patterns in both T1D and controls. There were no correlations of muscle quality with ALM/ht2. Conclusion: Our data suggest that mScan holds promise for detection of skeletal muscle health impairments in older adults, including those with T1D, potentially aiding in the diagnosis and prevention of related falls and fractures. Further research is required to investigate the association between VAT and muscle health and to validate the effectiveness of mScan in T1D and other populations. Presentation: 6/3/2024

6874 A Rare Case Of Hereditary 1,25 (OH)2D Resistant Rickets

Abstract Disclosure: G. Umarji: None. F. Thelmo: None. S.A. Jabbour: None. Vitamin D-dependent rickets type 2A (VDDR2A) also known as hereditary 1,25 (OH)2D resistant rickets is due to biallelic loss-of-function mutations in the gene encoding vitamin D receptor on chromosome 12q13.11, thus, it represents a true form of tissue resistance to vitamin D. It is a scarce form of rickets with approximately only 120 cases reported. A 37-year-old male was referred to endocrinology by neurosurgery for evaluation of metabolic bone disease. Seven years ago, he was in a car accident which resulted in a lumbar spine injury causing radiculopathy and severe low back pain leading to lumbar spine decompression/fusion. However, he suffered from nonunion of bones and had to undergo another surgery a year later with recurrent postoperative nonunion of bones. During the operation, the surgeon noticed that his spine seemed demineralized. He had a history of multiple minor fractures in childhood, decreased hearing in left ear for two years, fragile teeth for many years, and some hair loss since age 30. Physical exam showed a height of 1.82 m, weight 89.3 kg with body mass index of 26 kg/m2, broken teeth, no leg bowing and normal stance. Laboratory results showed normal renal function, thyroid function tests and testosterone level, corrected calcium 8.3 mg/dL (8.7-10.2), 25-OH-vitamin D 54 ng/mL (30-100), phosphorus 2.8 mg/dL (2.8-4.1), intact parathyroid hormone 65 pg/mL (15-65), bone-specific alkaline phosphatase 21 mcg/L (4-27), 24-hour urine calcium 156 mg/day (100-300), 24-hour urine phosphorus 1,752 mg/day (390-1,425), FGF-23: 93 RU/mL (44-215) and 1,25 (OH)2D 92 pg/mL (24-81.5). Dual absorptiometry of the lumbar spine and hip showed osteopenia with Z scores of -2.2 and -1.2 respectively. Genetic testing for metabolic bone disease panel showed heterozygous mutation in VDR gene at nucleotide position c.146+9dup associated with autosomal recessive VDDR2A. We present a very rare form of vitamin D resistant rickets. As many patients with VDDR2A are unable to respond to any form of vitamin D, it is suggested that VDDR2 be more appropriately described as hereditary 1,25 (OH)2D resistant rickets (HVDRR), hereditary resistance to 1,25 (OH)2D, or even pseudovitamin D-deficiency type IIA (PDDR IIA). Clinical features include severe rickets, bone pain, hypotonia, dental caries and alopecia. Biochemical features include hypocalcemia, hypophosphatemia, normal to elevated alkaline phosphatase, normal 25(OH)D and importantly, elevated 1,25-(OH)2D levels. Management is with high doses of calcium and vitamin D therapy. While rare, this disease highlights the need for a comprehensive evaluation of metabolic bone diseases and a thorough understanding of calcium and vitamin D metabolism. Presentation: 6/2/2024

Effectiveness of surgical approach in the management of non-traumatic corneal perforations

ABSTRACT Clinical relevance Non-traumatic aetiologies are one of the leading causes of corneal perforations. The management of corneal perforation is quite challenging and complex for anterior segment surgeons. The appropriate surgical approach for each case is usually determined on the basis of a combination of many different parameters. Background The study aimed to evaluate surgical approach options and outcomes in the treatment of non-traumatic corneal perforations. Methods Patient data who underwent surgery for non-traumatic corneal perforation between 2016 and 2023 were retrospectively evaluated. Medical records were assessed in terms of age, gender, perforation aetiology, the first and last examination notes, surgical approach, follow-up time, and additional surgeries and outcomes according to anatomical, therapeutic and functional success. Anterior segment photographs were investigated for thorough explanation of the examinations. Results Forty-five eyes of 45 patients were included (mean age 61.2 ± 22.4 (90-2), female/male ratio 20/25). Surgical approaches applied according to the size and location of the perforation site included fibrin glue application (6), amniotic membrane transplantation (AMT) (9), corneal patch graft application(15), and tectonic keratoplasty (15). The ratio of inflammatory and infectious causes as the two main indications was 29/16. Globe integrity was ensured with the first surgery in 27 eyes. However, 17 eyes required secondary surgical attempts due to failure of the first approach and 1 eye underwent evisceration. AMT was the least successful method among other methods in anatomical, therapeutic, and functional assessment. Conclusion There are various surgical approaches for repairing non-traumatic corneal perforations, each with its own advantages and disadvantages. These include high tissue resistance, the ability to remove necrotic tissue, ease of access, and anti-inflammatory activity. It is possible to successfully repair corneal perforations with single and combined methods, considering the above-mentioned features, especially depending on the size and location of the defect. While AMT is a viable and time-saving choice − especially in the lack of donor tissues − further interventions are necessary in most circumstances.

Oscillatory airflow through the hypopharyngeal and supraglottic airway

Exercise-induced laryngeal obstruction (EILO) is a known cause of exertional dyspnoea, characterised by paradoxical inward collapse of laryngeal tissues. The pathophysiological mechanisms of EILO remain to be fully established, but insufficient mechanical resistance of laryngeal tissues to air-induced loads is hypothesised. It is understood that airflow and anatomic configurations of the airway play a key role in the wall pressure distribution of the larynx. While breathing is a cyclic process with directional changes of airflow, the literature is confined to steady, unidirectional airflow. It is necessary to assess the role of oscillatory airflow on the loads on the laryngeal airway. This study investigates the effect of oscillatory airflow on the laryngeal flow fields and air-induced loads. A computational fluid dynamics model of the upper respiratory tract (URT) is developed using the Reynolds-averaged Navier-Stokes equations. Five oscillatory airflow cases through a single geometry are considered, utilising sinusoidal breathing cycles with different breathing frequencies (24, 32 and 40 breaths per minute) and peak inspiratory flow rates (96, 168 and 240 L/min). Results include the airflow velocity distribution in the URT, and the air-induced pressure and forces. It is demonstrated that inspiratory velocity distribution varies with breathing frequency and intensity. The force acting on the URT walls are in-phase with the airflow rate and therefore exhibit quasi-steady behaviour. These findings are also reflected in the force vectors acting on the aryepiglottic folds and indicate that air-induced closure of the supraglottis in EILO is influenced by the breathing intensity rather than the breathing frequency.

Effect of Clozapine and Olanzapine on the Expression of Selected Genes and Epigenetic Regulators of Insulin Resistance Pathway in Human Preadipocytes – a Preliminary Study

Clozapine and olanzapine, popular second-generation antipsychotics used for various psychiatric disorders, cause significant side effects such as metabolic syndrome, but the exact mechanism remains unclear. The present study aimed to assess clozapine and olanzapine effects on the expression of mRNA insulin pathway genes (IRS-1, PTEN, PIK3CG and PIK3R1), microRNAs (miR-152-3p, miR-214-3p, miR-15b-5p, miR-16-5p, miR-126-3p) and long non-coding RNAs (lncRNAs: XIST, H19, SNHG16, PVT1), in human visceral preadipocytes (HPAd). Expression was examined by real - time PCR. Cell viability was determined by MTT assay. The findings revealed that in HAPd, both clozapine and olanzapine (at doses of 5 µM and 25 µM) decreased IRS-1 gene expression after 24 hours. After 48 hours, IRS-1 expression was reduced by clozapine at both concentrations and olanzapine at 5 µM. In addition, olanzapine (at 25 µM) decreased the expression of PIK3CG, miR-152-3p, miR-214-3p, miR-15b-5p and miR-16-5p after 24 hours, while increasing the expression of miR-126-3p at 5 µM. Clozapine at 25 µM decreased miR-16-5p expression and increased SNHG16 lncRNA expression at 5 µM after 24 hours. After 48 hours, olanzapine (at 25 µM) increased PIK3R1 expression and decreased PIK3CG expression at 5 µM. Both drugs at 5 µM increased the expression of miR-152-3p, miR-214-3p, miR-15b-5p and miR-16-5p after 48 hours, with clozapine further increasing the expression of miR-126-3p at this concentration. The results suggest that clozapine and olanzapine may affect the expression of key genes and epigenetic molecules in the insulin pathway, which is one potential cause leading to insulin resistance in adipose tissue.

Antibiogram development for Australian residential aged care facilities.

Knowledge of local antibiotic resistance data, provided by antibiograms (a cumulative summary of in vitro-antimicrobial-susceptibility-test results), can aid prescribing of appropriate empirical antibiotics. This study aimed to explore the feasibility of antibiogram development for residential aged care facilities (RACFs). Retrospective observational study of culture and sensitivity data. Nine RACFs in Queensland, Australia. Available antimicrobial susceptibility results were collected retrospectively for all residents of recruited RACFs from January 1, 2020, to December 31, 2022. Data were managed and analyzed with WHONET software®, and antibiograms were developed in accordance with the CLSI-M39 guidelines. Antibiogram data beyond the standard 12-months and pooling of data from geographically similar RACFs were explored as options to improve feasibility and validity of the antibiograms. The most prevalent bacteria in the RACFs were Escherichia coli and Staphylococcus aureus. Due to the low number of positive cultures (less than 30) for individual RACFs, an annual antibiogram was not feasible. Extending the time-period to three years improved feasibility of antibiograms for E.coli in seven RACFs and S.aureus in five RACFs. Combining the data from closely located RACFs allowed for sufficient urinary and skin swab isolates to produce annual pooled antibiograms for all three years. Use of extended time period antibiograms can provide RACF specific urinary and skin/soft tissue resistance data without the necessity of private pathology provider input. However, pooled syndromic antibiograms can be made available on an annual basis, which may be the preferred option.

Advancing Boiling Histotripsy Dose in Ex Vivo And In Vivo Renal Tissues Via Quantitative Histological Analysis and Shear Wave Elastography

ObjectiveIn the context of developing boiling histotripsy (BH) as a potential clinical approach for non-invasive mechanical ablation of kidney tumors, the concept of BH dose (BHD) was quantitatively investigated in porcine and canine kidney models in vivo and ex vivo. MethodsVolumetric lesions were produced in renal tissue using a 1.5-MHz 256-element HIFU-array with various pulsing protocols: pulse duration tp = 1–10 ms, number of pulses per point ppp = 1–15. Two BHD metrics were evaluated: BHD1 = ppp, BHD2 = tp × ppp. Quantitative assessment of lesion completeness was performed by their histological analysis and assignment of damage score to different renal compartments (i.e., cortex, medulla, and sinus). Shear wave elastography (SWE) was used to measure the Young's modulus of renal compartments in vivo vs ex vivo, and before vs after BH treatments. ResultsIn vivo tissue required lower BH doses to achieve identical degree of fractionation as compared to ex vivo. Renal cortex (homogeneous, low in collagen) was equal or higher in stiffness than medulla (anisotropic, collagenous), 5.8–12.2 kPa vs 4.7–9.6 kPa, but required lower BH doses to be fully fractionated. Renal sinus (fatty, irregular, with abundant collagenous structures) was significantly softer ex vivo vs in vivo, 4.9–5.1 kPa vs 9.7–15.2 kPa, but was barely damaged in either case with any tested BH protocols. BHD1 was shown to be relevant for planning the treatment of renal cortex (sufficient BHD1 = 5 pulses in vivo and 10 pulses ex vivo), while none of the tested doses resulted in complete fractionation of medulla or sinus. Post-treatment SWE imaging revealed reduction of tissue stiffness ex vivo by 27–58%, increasing with the applied dose, and complete absence of shear waves within in vivo lesions, both indicative of tissue liquefaction. ConclusionThe results imply that tissue resistance to mechanical fractionation, and hence required BH dose, are not solely determined by tissue stiffness but also depend on its composition and structural arrangement, as well as presence of perfusion. The SWE-derived reduction of tissue stiffness with increasing BH doses correlated with tissue damage score, indicating potential of SWE for post-treatment confirmation of BH lesion completeness.

Isongifolene Improves Crohn's Disease-Like Colitis in Mice by Reducing Apoptosis of Intestinal Epithelial Cells

To investigate the effect and molecular mechanism of isolongifolene (ISO) on the apoptosis of intestinal epithelial cells and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced Crohn's disease (CD)-like colitis in mice. In the animal experiments, mice were randomly assigned to the wild type (WT) group, TNBS group and TNBS+ISO group, with 8 mice in each group. Colitis models of mice were established in the TNBS group and the TNBS+ISO group by rectal injection of TNBS. After modeling, the mice in the TNBS+ISO group were given ISO intervention via intragastric gavage (10 mg/kg), and the other two groups were given the same amount of normal saline via intragastric gavage. The mice were sacrificed on the 7th day. The changes in body mass, disease activity scores (DAI), and the colon length of mice were measured, and transepithelial electrical resistance (TEER) of the colon tissues was determined. The score of colon inflammation was calculated according to HE staining. The levels of intestinal mucosal inflammatory factors, including tumor necrosis factor alpha (TNF-α), interferon (IFN)-γ, interleukin (IL)-1β, and IL-6, were measured by RT-PCR and ELISA. The apoptosis of colon tissue cells was determined by TUNEL assay. The expressions of apoptotic proteins (cleaved caspase-3/caspase-3 and Bax), an anti-apoptotic protein (Bcl-2), and tight junction proteins (ZO-1 and claudin-1) were detected by Western blot and immunofluorescence. In the cell experiment, TNF-α was used to induce intestinal epithelial cell Caco-2 apoptosis model, which was treated with ISO. Then, intervention with the AMPK inhibitor Compound C was given. TUNEL assay, Western blot assay, and immunofluorescence assay were performed to measure apoptosis and the expression of apoptosis proteins in the Caco-2 cells. Gene Ontology (GO) enrichment analysis was performed to predict the biological function of ISO. Then, the mechanism involved was verified by examination of the mice and Caco-2 cells. Western blot was performed to determine the expression levels of p-AMPK/AMPK and p-PGC1α in the colon tissues from the mice of different groups and Caco-2 cells. The apoptosis of the cells was determined by TUNEL assay. According to the results of the animal experiment, ISO could alleviate experimental colitis and intestinal barrier dysfunction, leading to improvements in body mass loss, colon length shortening, DAI score, inflammatory rating, and TEER values (all P<0.05) in mice. Furthermore, ISO decreased the expression of pro-inflammatory factors TNF-α, IFN-γ, IL-1β, and IL-6 and increased the expression of the tight junction proteins ZO-1 and claudin-1 (all P<0.05). In the cell experiment, in a TNF-α-induced intestinal epithelial cell model, ISO was also found to protect intestinal barrier against damage. ISO reduced the proportion of apoptotic intestinal epithelial cells, reduced the expression of cleaved-caspase-3/caspase-3 and Bax, and upregulated the level of Bcl-2 (all P<0.05). GO enrichment predictive analysis showed that the role of ISO in improving CD-like enteritis might be associated with the negative regulation of apoptosis. Verification of the mechanism showed that the expression of p-AMPK and p-PGC1α in the mice colon tissue was significantly upregulated after ISO intervention (P<0.05). In contrast, the AMPK inhibitor Compound C increased the apoptosis rate of ISO-treated Caco-2 cells and decreased the relative expression levels of ZO-1 and claudin-1 (P<0.05). ISO reduces intestinal epithelial cell apoptosis at least in part by activating AMPK/PGC1α signaling pathway, thereby alleviating TNBS-induced intestinal barrier dysfunction and CD-like colitis in mice.