Shen Shuai II recipe improves renal hypoxia to attenuate renal injury in 5/6 renal ablation/infarction rats and effect evaluation using blood oxygenation level-dependent functional magnetic resonance imaging.

Background: Renal hypoxia plays a key role in the progression of chronic kidney disease (CKD). Shen Shuai II Recipe (SSR) has shown good results in the treatment of CKD as a common herbal formula. This study aimed to explore the effect of SSR on renal hypoxia and injury in CKD rats. Methods: Twenty-five Wistar rats underwent 5/6 renal ablation/infarction (A/I) surgery were randomly divided into three groups: 5/6 (A/I), 5/6 (A/I) + losartan (LOS), and 5/6 (A/I) + SSR groups. Another eight normal rats were used as the Sham group. After 8-week corresponding interventions, blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) was performed to evaluate renal oxygenation in all rats, and biochemical indicators were used to measure kidney and liver function, hemoglobin, and proteinuria. The expression of fibrosis and hypoxia-related proteins was analyzed using immunoblotting examination. Results: Renal oxygenation, evaluated by BOLD-fMRI as cortical and medullary T2* values (COT2* and MET2*), was decreased in 5/6 (A/I) rats, but increased after SSR treatment. SSR also downregulated the expression of hypoxia-inducible factor-1α (HIF-1α) in 5/6 (A/I) kidneys. With the improvement of renal hypoxia, renal function and fibrosis were improved in 5/6 (A/I) rats, accompanied by reduced proteinuria. Furthermore, the COT2* and MET2* were significantly positively correlated with the levels of creatinine clearance rate (Ccr) and hemoglobin, but negatively associated with the levels of serum creatinine (SCr), blood urea nitrogen (BUN), serum cystatin C (CysC), serum uric acid (UA), 24-h urinary protein (24-h Upr), and urinary albumin:creatinine ratio (UACR). Conclusion: The degree of renal oxygenation reduction is correlated with the severity of renal injury in CKD. SSR can improve renal hypoxia to attenuate renal injury in 5/6 (A/I) rats of CKD.

IL-6/gp130 signaling in CD4+ T cells drives the pathogenesis of pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is characterized by stenosis and occlusions of small pulmonary arteries, leading to elevated pulmonary arterial pressure and right heart failure. Although accumulating evidence shows the importance of interleukin (IL)-6 in the pathogenesis of PAH, the target cells of IL-6 are poorly understood. Using mice harboring the floxed allele of gp130, a subunit of the IL-6 receptor, we found substantial Cre recombination in all hematopoietic cell lineages from the primitive hematopoietic stem cell level in SM22α-Cre mice. We also revealed that a CD4+ cell-specific gp130 deletion ameliorated the phenotype of hypoxia-induced pulmonary hypertension in mice. Disruption of IL-6 signaling via deletion of gp130 in CD4+ T cells inhibited phosphorylation of signal transducer and activator of transcription 3 (STAT3) and suppressed the hypoxia-induced increase in T helper 17 cells. To further examine the role of IL-6/gp130 signaling in more severe PH models, we developed Il6 knockout (KO) rats using the CRISPR/Cas9 system and showed that IL-6 deficiency could improve the pathophysiology in hypoxia-, monocrotaline-, and Sugen5416/hypoxia (SuHx)-induced rat PH models. Phosphorylation of STAT3 in CD4+ cells was also observed around the vascular lesions in the lungs of the SuHx rat model, but not in Il6 KO rats. Blockade of IL-6 signaling had an additive effect on conventional PAH therapeutics, such as endothelin receptor antagonist (macitentan) and soluble guanylyl cyclase stimulator (BAY41-2272). These findings suggest that IL-6/gp130 signaling in CD4+ cells plays a critical role in the pathogenesis of PAH.

Mitophagy mediated by HIF-1α/FUNDC1 signaling in tubular cells protects against renal ischemia/reperfusion injury.

Acute kidney injury (AKI) is associated with a high mortality rate. Pathologically, renal ischemia/reperfusion injury (RIRI) is one of the primary causes of AKI, and hypoxia-inducible factor (HIF)-1α may play a defensive role in RIRI. This study assessed the role of hypoxia-inducible factor 1α (HIF-1α)-mediated mitophagy in protection against RIRI in vitro and in vivo. The human tubular cell line HK-2 was used to assess hypoxia/reoxygenation (H/R)-induced mitophagy through different in vitro assays, including western blotting, immunofluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and reactive oxygen species (ROS) measurement. Additionally, a rat RIRI model was established for evaluation by renal histopathology, renal Doppler ultrasound, and transmission electron microscopy to confirm the in vitro data. The selective HIF-1α inhibitor LW6 reduced H/R-induced mitophagy but increased H/R-induced apoptosis and ROS production. Moreover, H/R treatment enhanced expression of the FUN14 domain-containing 1 (FUNDC1) protein. Additionally, FUNDC1 overexpression reversed the effects of LW6 on the altered expression of light chain 3 (LC3) BII and voltage-dependent anion channels as well as blocked the effects of HIF-1α inhibition in cells. Pretreatment of the rat RIRI model with roxadustat, a novel oral HIF-1α inhibitor, led to decreased renal injury and apoptosis in vivo. In conclusion, the HIF-1α/FUNDC1 signaling pathway mediates H/R-promoted renal tubular cell mitophagy, whereas inhibition of this signaling pathway protects cells from mitophagy, thus aggravating apoptosis, and ROS production. Accordingly, roxadustat may protect against RIRI-related AKI.

Morusin suppresses the stemness characteristics of gastric cancer cells induced by hypoxic microenvironment through inhibition of HIF-1α accumulation.

Gastric cancer (GC) is a common, life-threatening malignancy that contributes to the global burden of cancer-related mortality, as conventional therapeutic modalities show limited effects on GC. Hence, it is critical to develop novel agents for GC therapy. Morusin, a typical prenylated flavonoid, possesses antitumor effects against various cancers. The present study aimed to demonstrate the inhibitory effect and mechanism of morusin on the stemness characteristics of human GC in vitro under hypoxia and to explore the potential molecular mechanisms. The effects of morusin on cell proliferation and cancer stem cell-like properties of the human GC cell lines SNU-1 and AGS were assessed by MTT assay, colony formation test, qRT-PCR, flow cytometry analysis, and sphere formation test under hypoxia or normoxia condition through in vitro assays. The potential molecular mechanisms underlying the effects of morusin on the stem-cell-like properties of human GC cells in vitro were investigated by qRT-PCR, western blotting assay, and immunofluorescence assay by evaluating the nuclear translocation and expression level of hypoxia-inducible factor-1α (HIF-1α). The results showed that morusin exerted growth inhibitory effects on SNU-1 and AGS cells under hypoxia in vitro. Moreover, the proportions of CD44+/CD24- cells and the sphere formation ability of SNU-1 and AGS reduced in a dose-dependent manner following morusin treatment. The expression levels of stem cell-related genes, namely Nanog, OCT4, SOX2, and HIF-1α, gradually decreased, and the nuclear translocation of the HIF-1α protein was apparently attenuated. HIF-1α overexpression partially reversed the abovementioned effects of morusin. Taken together, morusin could restrain stemness characteristics of GC cells by inhibiting HIF-1α accumulation and nuclear translocation and could serve as a promising compound for GC treatment.

Equivalent uniform aerobic dose in radiotherapy for hypoxic tumors.

Objective.Equivalent uniform aerobic dose (EUAD) is proposed for comparison of integrated cell survival in tumors with different distributions of hypoxia and radiation dose.Approach.The EUAD assumes that for any non-uniform distributions of radiation dose and oxygen enhancement ratio (OER) within a tumor, there is a uniform distribution of radiation dose under hypothetical aerobic conditions with OER = 1 that produces equal integrated survival of clonogenic cells. This definition of EUAD has several advantages. First, the EUAD allows one to compare survival of clonogenic cells in tumors with intra-tumor and inter-tumor variation of radio sensitivity due to hypoxia because the cell survival is recomputed under the same benchmark oxygen level (OER = 1). Second, the EUAD for homogeneously oxygenated tumors is equal to the concept of equivalent uniform dose.Main results. We computed the EUAD using radiotherapy dose and the OER derived from the18F-Fluoromisonidazole PET (18F-FMISO PET) images of hypoxia in patients with glioblastoma, the most common and aggressive type of primary malignant brain tumor. The18F-FMISO PET images include a distribution of SUV (Standardized Uptake Value); therefore, the SUV is converted to partial oxygen pressure (pO2) and then to the OER. The prognostic value of EUAD in radiotherapy for hypoxic tumors is demonstrated using correlation between EUAD and overall survival (OS) in radiotherapy for glioblastoma. The correction to the EUAD for the absolute hypoxic volume that traceable to the tumor control probability improves the correlation with OS.Significance. While the analysis proposed in this research is based on the18F-FMISO PET images for glioblastoma, the EUAD is a universal radiobiological concept and is not associated with any specific cancer or any specific PET or MRI biomarker of hypoxia. Therefore, this research can be generalized to other cancers, for example stage III lung cancer, and to other hypoxia biomarkers.

Infertility in Fabry's Disease: role of hypoxia and inflammation in determining testicular damage.

Introduction: Fabry's disease (FD) is a genetic X-linked systemic and progressive rare disease characterized by the accumulation of globotriaosylceramide (GB3) into the lysosomes of many tissues. FD is due to loss-of-function mutations of α-galactosidase, a key-enzyme for lysosomal catabolism of glycosphingolipids, which accumulate as glycolipid bodies (GB). In homozygous males the progressive deposition of GB3 into the cells leads to clinical symptoms in CNS, skin, kidney, etc. In testis GB accumulation causes infertility and alterations of spermatogenesis. However, the precise damaging mechanism is still unknown. Our hypothesis is that GB accumulation reduces blood vessel lumen and increases the distance of vessels from both stromal cells and seminiferous parenchyma; this, in turn, impairs oxygen and nutrients diffusion leading to subcellular degradation of seminiferous epithelium and sterility. Methods: To test this hypothesis, we have studied a 42-year-old patient presenting a severe FD and infertility, with reduced number of spermatozoa, but preserved sexual activity. Testicular biopsies were analyzed by optical (OM) and transmission electron microscopy (TEM). Activation and cellular localization of HIF-1α and NFκB was analyzed by immunofluorescence (IF) and RT-PCR on homogeneous tissue fractions after laser capture microdissection (LCMD). Results: OM and TEM showed that GB were abundant in vessel wall cells and in interstitial cells. By contrast, GB were absent in seminiferous epithelium, Sertoli's and Leydig's cells. However, seminiferous tubular epithelium and Sertoli's cells showed reduced diameter, thickening of basement membrane and tunica propria, and swollen or degenerated spermatogonia. IF showed an accumulation of HIF-1α in stromal cells but not in seminiferous tubules. On the contrary, NFκB fluorescence was evident in tubules, but very low in interstitial cells. Finally, RT-PCR analysis on LCMD fractions showed the expression of pro-inflammatory genes connected to the HIF-1α/NFκB inflammatory-like pathway. Conclusion: Our study demonstrates that infertility in FD may be caused by reduced oxygen and nutrients due to GB accumulation in blood vessels cells. Reduced oxygen and nutrients alter HIF-1α/NFκB expression and localization while activating HIF-1α/NFκB driven-inflammation-like response damaging seminiferous tubular epithelium and Sertoli's cells.

Application of Aquaporins as Markers in Forensic Pathology: A Systematic Review of the Literature.

The study of aquaporins (AQPs) in various forensic fields has offered a promising horizon in response to the need to have reliable elements for the identification of the manner of death and for the individuation of forensic markers for the timing of lesions and vitality of injury. In the literature, various tissues have been studied; the most investigated are the lungs, brain, kidneys, skin, and blood vessels. A systematic literature review on PubMed following PRISMA 2020 guidelines enabled the identification of 96 articles. In all, 34 of these were enrolled to identify Aquaporin-like (AQP-like) forensic markers. The analysis of the literature demonstrated that the most significant markers among the AQPs are as follows: for the brain, AQP4, which is very important in brain trauma and hypoxic damage; AQP3 in the skin lesions caused by various mechanisms; and AQP5 in the diagnosis of drowning. Other applications are in organ damage due to drug abuse and thrombus dating. The focus of this review is to collect all the data present in the literature about the forensic application of AQPs as forensic markers in the most important fields of application. In the current use, the individuation, validation, and application of markers in forensic investigation are very useful in real forensic applications in cases evaluated in court.

WSB1, a Hypoxia-Inducible E3 Ligase, Promotes Myofibroblast Accumulation and Attenuates Alveolar Epithelial Regeneration in Mouse Lung Fibrosis.

Idiopathic pulmonary fibrosis is a progressive interstitial lung disease for which there is no curative therapy available. Repetitive alveolar epithelial injury repair, myofibroblast accumulation, and excessive collagen deposition are key pathologic features of idiopathic pulmonary fibrosis, eventually leading to cellular hypoxia and respiratory failure. The precise mechanism driving this complex maladaptive process remains inadequately understood. WD repeat and suppressor of cytokine signaling box containing 1 (WSB1) is an E3 ubiquitin ligase, the expression of which is associated strongly with hypoxia, and forms a positive feedback loop with hypoxia-inducible factor 1α (HIF-1α) under anoxic condition. This study explored the expression, cellular distribution, and function of WSB1 in bleomycin (BLM)-induced mouse lung injury and fibrosis. WSB1 expression was highly induced by BLM injury and correlated with the progression of lung fibrosis. Significantly, conditional deletion of Wsb1 in adult mice ameliorated BLM-induced pulmonary fibrosis. Phenotypically, Wsb1-deficient mice showed reduced lipofibroblast to myofibroblast transition, but enhanced alveolar type 2 proliferation and differentiation into alveolar type 1 after BLM injury. Proteomic analysis of mouse lung tissues identified caveolin 2 as a potential downstream target of WSB1, contributing to BLM-induced epithelial injury repair and fibrosis. These findings unravel a vital role for WSB1 induction in lung injury repair, thus highlighting it as a potential therapeutic target for pulmonary fibrosis.

Hypoxia-adenosine axis as therapeutic targets for acute respiratory distress syndrome.

The human respiratory and circulatory systems collaborate intricately to ensure oxygen delivery to all cells, which is vital for ATP production and maintaining physiological functions and structures. During limited oxygen availability, hypoxia-inducible factors (HIFs) are stabilized and play a fundamental role in maintaining cellular processes for hypoxia adaptation. First discovered during investigations of erythropoietin production regulation, HIFs influence physiological and pathological processes, including development, inflammation, wound healing, and cancer. HIFs promote extracellular adenosine signaling by enhancing adenosine generation and receptor signaling, representing an endogenous feedback mechanism that curbs excessive inflammation, supports injury resolution, and enhances hypoxia tolerance. This is especially important for conditions that involve tissue hypoxia, such as acute respiratory distress syndrome (ARDS), which globally poses significant health challenges without specific treatment options. Consequently, pharmacological strategies to amplify HIF-mediated adenosine production and receptor signaling are of great importance.

Disruption of the Mouse Blood-Brain Barrier by Small Extracellular Vesicles from Hypoxic Human Placentas.

Cerebrovascular complications, including cerebral edema and ischemic and hemorrhagic stroke, constitute the leading cause of maternal mortality associated with preeclampsia. The underlying mechanisms of these cerebrovascular complications remain unclear. However, they are linked to placental dysfunction and blood-brain barrier (BBB) disruption. Nevertheless, the connection between these two distant organs is still being determined. Increasing evidence suggests that the placenta releases signaling molecules, including extracellular vesicles, into maternal circulation. Extracellular vesicles are categorized according to their size, with small extracellular vesicles (sEVs smaller than 200 nm in diameter) considered critical signaling particles in both physiological and pathological conditions. In preeclampsia, there is an increased number of circulating sEVs in maternal circulation, the signaling function of which is not well understood. Placental sEVs released in preeclampsia or from normal pregnancy placentas exposed to hypoxia induce brain endothelial dysfunction and disruption of the BBB. In this protocol, we assess whether sEVs isolated from placental explants cultured under hypoxic conditions (modeling one aspect of preeclampsia) disrupt the BBB in vivo.

Remodeling of Murine Branch Pulmonary Arteries Under Chronic Hypoxia and Short-Term Normoxic Recovery.

Chronic hypoxia plays a central role in diverse pulmonary pathologies, but its effects on longitudinal changes in the biomechanical behavior of proximal pulmonary arteries remain poorly understood. Similarly, effects of normoxic recovery have not been well studied. Here, we report hypoxia-induced changes in composition, vasoactivity, and passive biaxial mechanics in the main branch pulmonary artery of male C57BL/6J mice exposed to 10% FiO2 for 1, 2, or 3 weeks. We observed significant changes in extracellular matrix, and consequently wall mechanics, as early as 1 week of hypoxia. While circumferential stress and stiffness returned toward normal values by 2-3 weeks of hypoxia, area fractions of cytoplasm and thin collagen fibers did not return toward normal until after 1 week of normoxic recovery. By contrast, elastic energy storage and overall distensibility remained reduced after 3 weeks of hypoxia as well as following 1 week of normoxic recovery. While smooth muscle and endothelial cell responses were attenuated under hypoxia, smooth muscle but not endothelial cell responses recovered following 1 week of subsequent normoxia. Collectively, these data suggest that homeostatic processes were unable to preserve or restore overall function, at least over a brief period of normoxic recovery. Longitudinal changes are critical in understanding large pulmonary artery remodeling under hypoxia, and its reversal, and will inform predictive models of vascular adaptation.

Hypoxia Sensing and Responses in Parkinson's Disease.

Parkinson's disease (PD) is associated with various deficits in sensing and responding to reductions in oxygen availability (hypoxia). Here we summarize the evidence pointing to a central role of hypoxia in PD, discuss the relation of hypoxia and oxygen dependence with pathological hallmarks of PD, including mitochondrial dysfunction, dopaminergic vulnerability, and alpha-synuclein-related pathology, and highlight the link with cellular and systemic oxygen sensing. We describe cases suggesting that hypoxia may trigger Parkinsonian symptoms but also emphasize that the endogenous systems that protect from hypoxia can be harnessed to protect from PD. Finally, we provide examples of preclinical and clinical research substantiating this potential.

Secretome of Hypoxia-Preconditioned Mesenchymal Stem Cells Promotes Liver Regeneration and Anti-Fibrotic Effect in Liver Fibrosis Animal Model.

<b>Background and Objective:</b> Liver fibrosis (LF) is a most common pathological process characterized by the activation of hepatocytes leading to the accumulation of extracellular matrix (ECM). Hypoxia precondition treated in MSCs (H-MSCs) could enhance their immunomodulatory and regeneration capability, through expressing robust anti-inflammatory cytokines and growth factors, known as H-MSCs secretome (SH-MSCs) that are critical for the improvement of liver fibrosis. However, the study regarding the efficacy and mechanism of action of SH-MSCs in ameliorating liver fibrosis is still inconclusive. In this study, the therapeutic potential and underlying mechanism for SH-MSCs in the treatment of liver fibrosis were investigated. <b>Materials and Methods:</b> A rat model with liver fibrosis induced by CCl₄ was created and maintained for 8 weeks. The rats received intravenous doses of SH-MSCs and secretome derived from normoxia MSCs (SN-MSCs), filtered using a tangential flow filtration (TFF) system with different molecular weight cut-off categories, both at a dosage of 0.5 mL. The ELISA assay was employed to examine the cytokines and growth factors present in both SH-MSCs and SN-MSCs. On the ninth day, the rats were euthanized and liver tissues were collected for subsequent histological examination and analysis of mRNA expression. <b>Results:</b> The ELISA test revealed that SH-MSCs exhibited higher levels of VEGF, PDGF, bFGF, IL-10, TGF-ß and IL-6 compared to SN-MSCs. <i>In vivo</i>, administration of SH-MSCs notably decreased mortality rates. It also demonstrated a reduction in liver fibrosis, collagen fiber areas, α-SMA positive staining and relative mRNA expression of TGF-ß. Conversely, SN-MSCs also contributed to liver fibrosis improvement, although SH-MSCs demonstrated more favorable outcomes. <b>Conclusion:</b> Current findings suggested that SH-MSCs could improve CCl₄-induced liver fibrosis and decrease α-SMA and TGF-ß expression.

Acute seizure activity in neonatal inflammation-sensitized hypoxia-ischemia in mice.

OBJECTIVE: To examine acute seizure activity and neuronal damage in a neonatal mouse model of inflammation-sensitized hypoxic-ischemic (IS-HI) brain injury utilizing continuous electroencephalography (cEEG) and neurohistology. METHODS: Neonatal mice were exposed to either IS-HI with Escherichia coli lipopolysaccharide (LPS) or HI alone on postnatal (p) day 10 using unilateral carotid artery ligation followed by global hypoxia (n = 10 [5 female, 5 male] for IS-HI, n = 12 [5 female, 7 male] for HI alone). Video cEEG was recorded for the duration of the experiment and analyzed for acute seizure activity and behavior. Brain tissue was stained and scored based on the degree of neuronal injury in the hippocampus, cortex, and thalamus. RESULTS: There was no significant difference in acute seizure activity among mice exposed to IS-HI compared to HI with regards to seizure duration (mean = 63 ± 6 seconds for HI vs mean 62 ± 5 seconds for IS-HI, p = 0.57) nor EEG background activity. Mice exposed to IS-HI had significantly more severe neural tissue damage at p30 as measured by neuropathologic scores (mean = 8 ± 1 vs 23 ± 3, p < 0.0001). INTERPRETATION: In a neonatal mouse model of IS-HI, there was no significant difference in acute seizure activity among mice exposed to IS-HI compared to HI. Mice exposed to IS-HI did show more severe neuropathologic damage at a later age, which may indicate the presence of chronic inflammatory mechanisms of brain injury distinct from acute seizure activity.

Strategies to Reverse Hypoxic Tumor Microenvironment for Enhanced Sonodynamic Therapy.

Sonodynamic therapy (SDT) has emerged as a highly effective modality for the treatment of malignant tumors owing to its powerful penetration ability, noninvasiveness, site-confined irradiation, and excellent therapeutic efficacy. However, the traditional SDT, which relies on oxygen availability, often fails to generate a satisfactory level of reactive oxygen species because of the widespread issue of hypoxia in the tumor microenvironment of solid tumors. To address this challenge, various approaches are developed to alleviate hypoxia and improve the efficiency of SDT. These strategies aim to either increase oxygen supply or prevent hypoxia exacerbation, thereby enhancing the effectiveness of SDT. In view of this, the current review provides an overview of these strategies and their underlying principles, focusing on the circulation of oxygen from consumption to external supply. The detailed research examples conducted using these strategies in combination with SDT are also discussed. Additionally, this review highlights the future prospects and challenges of the hypoxia-alleviated SDT, along with the key considerations for future clinical applications. These considerations include the development of efficient oxygen delivery systems, the accurate methods for hypoxia detection, and the exploration of combination therapies to optimize SDT outcomes.

Murine Pro-Inflammatory Responses to Acute and Sustained Intermittent Hypoxia: Implications for Obstructive Sleep Apnea Research.

OBJECTIVES: Obstructive sleep apnea (OSA) is characterized by chronic systemic inflammation; however, the mechanisms underlying these pathologic consequences are incompletely understood. Our objective was to determine the effects of short- versus long-term exposure to intermittent hypoxia (IH) on pro-inflammatory mediators within vulnerable organs impacted by OSA. STUDY DESIGN: Experimental animal study. METHODS: A total of 8-10 week old C57BL/6J mice were exposed to normoxic or IH conditions for 7 days (short-term) or 6 weeks (long-term) under 12 h light, 12 h dark cycles. After exposure, multiple tissues were collected over a 24 h period. These tissues were processed and evaluated for gene expression and protein levels of pro-inflammatory mediators from peripheral tissues. RESULTS: We observed a global decrease in immune response pathways in the heart, lung, and liver compared with other peripheral organs after short-term exposure to IH. Although there were tissue-specific alterations in the gene expression of pro-inflammatory mediators, with down-regulation in the lung and up-regulation in the heart, we also observed reduced protein levels of pro-inflammatory mediators in the serum, lung, and heart following short-term exposure to IH. Long-term exposure to IH resulted in an overall increase in the levels of inflammatory mediators in the serum, lung, and heart. CONCLUSIONS: We demonstrated novel, longitudinal changes in the inflammatory cascade in a mouse model of OSA. The duration of exposure to IH led to significant variability of inflammatory responses within blood and cardiopulmonary tissues. Our findings further elucidate how inflammatory responses change over the course of the disease in vulnerable organs. LEVEL OF EVIDENCE: NA Laryngoscope, 134:S1-S11, 2024.

Rectal temperature after hypoxia-ischemia predicts white matter and cortical pathology in the near-term ferret.

BACKGROUND: Neonatal encephalopathy (NE) remains a common cause of infant morbidity and mortality. Neuropathological corollaries of NE associated with acute hypoxia-ischemia include a central injury pattern involving the basal ganglia and thalamus, which may interfere with thermoregulatory circuits. Spontaneous hypothermia (SH) occurs in both preclinical models and clinical hypoxic-ischemic NE and may provide an early biomarker of injury severity. To determine whether SH predicts the degree of injury in a ferret model of hypoxic-ischemic NE, we investigated whether rectal temperature (RT) 1 h after insult correlated with long-term outcomes. METHODS: Postnatal day (P)17 ferrets were presensitized with Escherichia coli lipopolysaccharide before undergoing hypoxia-ischemia/hyperoxia (HIH): bilateral carotid artery ligation, hypoxia-hyperoxia-hypoxia, and right ligation reversal. One hour later, nesting RTs were measured. RESULTS: Animals exposed to HIH were separated into normothermic (NT; ≥34.4 °C) or spontaneously hypothermic (SH; <34.4 °C) groups. At P42, cortical development, ex vivo MRI, and neuropathology were quantitated. Whole-brain volume and fractional anisotropy in SH brains were significantly decreased compared to control and NT animals. SH brains also had significantly altered gyrification, greater cortical pathology, and increased corpus callosum GFAP staining relative to NT and control brains. CONCLUSION: In near-term-equivalent ferrets, nesting RT 1 h after HIH may predict long-term neuropathological outcomes. IMPACT: High-throughput methods to determine injury severity prior to treatment in animal studies of neonatal brain injury are lacking. In a gyrified animal model of neonatal inflammation-sensitized hypoxic-ischemic brain injury in the ferret, rectal temperature 1 h after hypoxia predicts animals who will have increased cortical pathology and white matter changes on MRI. These changes parallel similar responses in rodents and humans but have not previously been correlated with long-term neuropathological outcomes in gyrified animal models. Endogenous thermoregulatory responses to injury may provide a translational marker of injury severity to help stratify animals to treatment groups or predict outcome in preclinical studies.

A New Approach for Exploring Reperfusion Brain Damage in Hypoxic Ischemic Encephalopathy.

Reperfusion is an essential pathological stage in hypoxic ischemic encephalopathy (HIE). Although the Rice-Vannucci model is widely used in HIE research, it remains difficult to replicate HIE-related reperfusion brain injury. The purpose of this study is to establish a rat model of hypoxia ischemia reperfusion brain damage (HIRBD) using a common carotid artery (CCA) muscle bridge in order to investigate the mechanisms of cerebral resistance to hypoxic-ischemic and reperfusion brain damage. Random assignment of Sprague-Dawley (SD) rats to the Sham, HIRBD, and Rice-Vannucci groups. Changes in body weight, mortality rate, spontaneous alternation behavior test (SAB test), and dynamic changes in cerebral blood flow (CBF) were detected. The damaged cerebral cortices were extracted for morphological comparison, transcriptomic analysis, and quantitative real-time PCR. Harvesting the hippocampus for transmission electron microscopy (TEM) detection. As a result, CCA muscle bridge could effectively block CBF, which recovered after the muscle bridge detachment. Pathological comparison, the SAB test, and TEM analysis revealed that brain damage in Rice-Vannucci was more severe than HIRBD. Gpx1, S100a6, Cldn5, Esr1, and Gfap were highly expressed in both HIRBD and Rice-Vannucci. In conclusion, the CCA muscle bridge-established HIRBD model could be used as an innovative and dependable model to simulate pathological process of HIRBD.

TAM-Hijacked Immunoreaction Rescued by Hypoxia-Pathway-Intervened Strategy for Enhanced Metastatic Cancer Immunotherapy.

Immunotherapy is regarded as a prospective strategy against metastatic cancer. However, tumor-associated macrophages (TAMs), which accumulate in hypoxic tumor microenvironment, reduce the effectiveness of immunotherapy by blocking or "hijacking" the initiation of the immune response. Here, a novel tumor-targeted nanoplatform loaded with hypoxia-pathway-intervened docosahexaenoic acid (DHA) and chemotherapeutic drug carfilzomib (CFZ) is developed, which realizes the rescue of TAM-hijacked immune response and effective metastatic cancer immunotherapy. DHA is conjugated to fucoidan (Fuc) via a reduction cleavable selenylsulfide bond (SSe) for micelle preparation, and CFZ is encapsulated in the hydrophobic cores of micelles. The functionalized nanoplatforms (Fuc─SSe─DHA (FSSeD)-CFZs) induce immunogenic cell death, inhibit hypoxia-inducible factor-1α expression, and improve immunosuppression by TAM suppression. FSSeD-CFZs enhance immune response against primary tumor development and metastasis formation. In brief, the novel rescue strategy for TAM-hijacked immunoreaction by inhibiting hypoxia pathway has the potential and clinically translational significance for enhanced metastatic cancer immunotherapy.

Hypoxia-Induced Signaling in Gut and Liver Pathobiology.

Oxygen (O2) is essential for cellular metabolism and biochemical reactions. When the demand for O2 exceeds the supply, hypoxia occurs. Hypoxia-inducible factors (HIFs) are essential to activate adaptive and survival responses following hypoxic stress. In the gut (intestines) and liver, the presence of oxygen gradients or physiologic hypoxia is necessary to maintain normal homeostasis. While physiologic hypoxia is beneficial and aids in normal functions, pathological hypoxia is harmful as it exacerbates inflammatory responses and tissue dysfunction and is a hallmark of many cancers. In this review, we discuss the role of gut and liver hypoxia-induced signaling, primarily focusing on HIFs, in the physiology and pathobiology of gut and liver diseases. Additionally, we examine the function of HIFs in various cell types during gut and liver diseases, beyond intestinal epithelial and hepatocyte HIFs. This review highlights the importance of understanding hypoxia-induced signaling in the pathogenesis of gut and liver diseases and emphasizes the potential of HIFs as therapeutic targets.