Comparative study of arterial and venous grafting for pedicle lengthening in head and neck microvascular reconstruction.

BACKGROUND: In the field of head and neck microvascular reconstruction, no previous study has compared arterial and venous grafting as methods of anterolateral thigh (ALT) pedicle lengthening. Therefore, we conducted this comparative study to compare the outcomes between the two pedicle lengthening techniques. METHODS: We performed comparative effectiveness research by conducting a retrospective chart review from January 2012 to December 2021 to identify patients who underwent head and neck reconstruction with non-descending branch ALT perforator flaps using either the in situ pedicle lengthening (ISPL) technique or the vein graft (VG) technique. A total of 26 patients were analyzed, including 14 who underwent ISPL, and 12 who underwent VG. The collected data, including patient demographics, surgical indications, history of prior free flap, prior neck dissection, radiation therapy, chemotherapy, graft length, and flap outcomes, were analyzed. The flap outcomes were categorized as total flap loss, partial flap loss, flap compromise that required operating room visits, or minor issues, including infection or dehiscence. The flap characteristics and postoperative outcomes were compared between the two groups. RESULTS: The VG group had two flap losses, whereas the ISPL group had none. Although the failure rate was higher in the VG group than that in the ISPL group, the difference was not statistically significant (0% vs. 16.7%, p = 0.203). Additionally, there were no significant differences in flap take-back (14.3% vs. 16.7%, p = 1) and minor complications between the two groups (35.7% vs. 33.3%, p = 1). CONCLUSIONS: If pedicle lengthening with vessel graft is inevitable in head and neck reconstruction, arterial graft may provide a reliable outcome and may be considered an effective alternative when compared to vein grafts.

Caenorhabditis elegans as a Convenient Animal Model for Microbiome Studies.

Microbes constitute the most prevalent life form on Earth, yet their remarkable diversity remains mostly unrecognized. Microbial diversity in vertebrate models presents a significant challenge for investigating host-microbiome interactions. The model organism Caenorhabditis elegans has many advantages for delineating the effects of host genetics on microbial composition. In the wild, the C. elegans gut contains various microbial species, while in the laboratory it is usually a host for a single bacterial species. There is a potential host-microbe interaction between microbial metabolites, drugs, and C. elegans phenotypes. This mini-review aims to summarize the current understanding regarding the microbiome in C. elegans. Examples using C. elegans to study host-microbe-metabolite interactions are discussed.

In situ pedicle lengthening and perforator shifting technique for overcoming the perforator variation of the anterolateral thigh free flap during head and neck reconstruction.

BACKGROUND: Anterolateral thigh (ALT) free flap is one of the most popular options for surgeons when reconstructing head and neck defects. When the recipient vessels are located in a remote site, a flap with adequate pedicle length is essential. The conventional methods of either pedicle elongation or fabricating combined flap increase the total surgical time. We present the experience on the use of what in situ pedicle lengthening and perforator shifting technique to overcome these problems. METHODS: Fifteen patients with an age range of 38-65 years underwent in situ vascular transposition microsurgery of the ALT free flap harvest during head and neck reconstruction. Fourteen patients were male and one was female. Indications for reconstruction were malignant neoplasm in 14 patients and osteoradionecrosis in one patient. In this series, the descending branch of the lateral circumflex femoral vessels was used for interposition grafts. If the pedicle length was insufficient, the interposition grafts were used to lengthen the pedicle. The interposition grafts could also bridge different perforasomes in the thigh region in complex head and neck reconstruction. RESULTS: Of the 15 patients, 11 received the in situ pedicle lengthening technique, while four patients received in situ fabricated combined techniques. After surgery, all of the patients were followed up for at least 3 months. Two partial wounds involving poor healing occurred but finally healed after debridement. There were two major complications: one case involved venous thrombosis of the anastomosis and the other suffered from hematoma. Both cases were salvaged. All of the 15 free ALT flaps were successful. CONCLUSIONS: The alternative method employed in this series was able to solve the ALT flap perforator variation. Although the enrolled cases were confined to only head and neck reconstruction in the series, the in situ technique of the ALT flaps could be administered during reconstruction in other regions.

Recipient vessel selection for multiple free flap transfers in head and neck reconstruction at different periods.

BACKGROUND: Treatment decisions can be challenging in patients undergoing multiple oropharyngeal microsurgical reconstructions at different periods by various causes. We, retrospectively, reviewed patients with at least three consecutive free flap reconstructions to determine the optimal strategy for selecting recipient vessels. METHODS: Then, 36 patients (33 men and 3 women) who underwent at least 3 microsurgical reconstructions with a total of 51 free flap transfers for head and neck defects were included in this report. The most common reason for multiple microsurgical reconstructions was recurrent disease. For reconstructions, recipient vessel candidates on the same side of the head and neck were prioritized; if ipsilateral vessels were unavailable, contralateral recipient vessels, which might necessitate vein grafts, were used. RESULTS: The most common reconstructions were anterolateral thigh flaps (19 cases). The most commonly used contralateral recipient vessels were the superior thyroid artery, facial artery, and external jugular vein. All vessel anastomoses were performed using the end-to-end method. Postoperative complications occurred at the sites of 26 free flap reconstructions. The overall flap reconstruction success rate in patients with at least three surgeries was 90.2%. The median follow-up duration was 25.8 months. During follow-up, 26 patients survived until the end of follow-up. CONCLUSIONS: In patients undergoing multiple free flap reconstructions, recipient vessels on the ipsilateral side that have not been subjected to radiation should be selected first. Recipient vessels contralateral to the reconstruction side can then be selected; however, they may require vein grafts. Finally, distant healthy recipient vessels can be selected through vein grafting.

Emerging use of senolytics and senomorphics against aging and chronic diseases.

Senescence is a state of cell cycle arrest that plays an important role in embryogenesis, wound healing and protection against cancer. Senescent cells also accumulate during aging and contribute to the development of age-related disorders and chronic diseases, such as atherosclerosis, type 2 diabetes, osteoarthritis, idiopathic pulmonary fibrosis, and liver disease. Molecules that induce apoptosis of senescent cells, such as dasatinib, quercetin, and fisetin, produce health benefits and extend lifespan in animal models. We describe here the mechanism of action of senolytics and senomorphics, many of which are derived from plants and fungi. We also discuss the possibility of using such compounds to delay aging and treat chronic diseases in humans.

Membrane vesicles nucleate mineralo-organic nanoparticles and induce carbonate apatite precipitation in human body fluids.

Recent studies indicate that membrane vesicles (MVs) secreted by various cells are associated with human diseases, including arthritis, atherosclerosis, cancer, and chronic kidney disease. The possibility that MVs may induce the formation of mineralo-organic nanoparticles (NPs) and ectopic calcification has not been investigated so far. Here, we isolated MVs ranging in size between 20 and 400 nm from human serum and FBS using ultracentrifugation and sucrose gradient centrifugation. The MV preparations consisted of phospholipid-bound vesicles containing the serum proteins albumin, fetuin-A, and apolipoprotein A1; the mineralization-associated enzyme alkaline phosphatase; and the exosome proteins TNFR1 and CD63. Notably, we observed that MVs induced mineral precipitation following inoculation and incubation in cell culture medium. The mineral precipitates consisted of round, mineralo-organic NPs containing carbonate hydroxyapatite, similar to previous descriptions of the so-called nanobacteria. Annexin V-immunogold staining revealed that the calcium-binding lipid phosphatidylserine (PS) was exposed on the external surface of serum MVs. Treatment of MVs with an anti-PS antibody significantly decreased their mineral seeding activity, suggesting that PS may provide nucleating sites for calcium phosphate deposition on the vesicles. These results indicate that MVs may represent nucleating agents that induce the formation of mineral NPs in body fluids. Given that mineralo-organic NPs represent precursors of calcification in vivo, our results suggest that MVs may initiate ectopic calcification in the human body.

Hirsutella sinensis polysaccharides and Parabacteroides goldsteinii reduce lupus severity in imiquimod-treated mice.

BACKGROUND: The incidence of autoimmune diseases is increasing in developed countries, possibly due to the modern Western diet and lifestyle. We showed earlier that polysaccharides derived from the medicinal fungus Hirsutella sinensis produced anti-inflammatory, anti-diabetic and anti-obesity effects by modulating the gut microbiota and increasing the abundance of the commensal Parabacteroides goldsteinii in mice fed with a high-fat diet. METHODS: We examined the effects of the prebiotics, H. sinensis polysaccharides, and probiotic, P. goldsteinii, in a mouse model of imiquimod-induced systemic lupus erythematosus. RESULTS: The fungal polysaccharides and P. goldsteinii reduced markers of lupus severity, including the increase of spleen weight, proteinuria, and serum levels of anti-DNA auto-antibodies and signal transducer and activator of transcription 4 (STAT4). Moreover, the polysaccharides and P. goldsteinii improved markers of kidney and liver functions such as creatinine, blood urea nitrogen, glomerulus damage and fibrosis, and serum liver enzymes. However, the prebiotics and probiotics did not influence gut microbiota composition, colonic histology, or expression of tight junction proteins in colon tissues. CONCLUSIONS: Our results indicate that H. sinensis polysaccharides and the probiotic P. goldsteinii can reduce lupus markers in imiquimod-treated mice. These prebiotics and probiotics may therefore be added to other interventions conducive of a healthy lifestyle in order to counter autoimmune diseases.

Physicochemical and biological properties of biomimetic mineralo-protein nanoparticles formed spontaneously in biological fluids.

Recent studies indicate that mineral nanoparticles (NPs) form spontaneously in human body fluids. These biological NPs represent mineral precursors that are associated with ectopic calcifications seen in various human diseases. However, the parameters that control the formation of mineral NPs and their possible effects on human cells remain poorly understood. Here a nanomaterial approach to study the formation of biomimetic calcium phosphate NPs comparable to their physiological counterparts is described. Particle sizing using dynamic light scattering reveals that serum and ion concentrations within the physiological range yield NPs below 100 nm in diameter. While the particles are phagocytosed by macrophages in a size-independent manner, only large particles or NP aggregates in the micrometer range induce cellular responses that include production of mitochondrial reactive oxygen species, caspase-1 activation, and secretion of interleukin-1ß (IL-1ß). A comprehensive proteomic analysis reveals that the particle-bound proteins are similar in terms of their identity and number, regardless of particle size, suggesting that protein adsorption is independent of particle size and curvature. In conclusion, the conditions underlying the formation of mineralo-protein particles are similar to the ones that form in vivo. While mineral NPs do not activate immune cells, they may become pro-inflammatory and contribute to pathological processes once they aggregate and form larger mineral particles.

Clinical predictors of early surgical intervention in patients with venomous snakebites.

BACKGROUND: Venomous snakebites induce tissue destruction and secondary infection; however, the optimal timing of surgical intervention for these complications remains unknown. This study assessed the clinical predictors of early surgical intervention in patients with snakebites. METHODS: This retrospective study included 63 patients (45 men and 18 women) with venomous snakebites. In addition to the snake species, the demographics, affected body parts, clinical characteristics, and ultrasound findings of the patients in the surgical (32 patients) and nonsurgical (31 patients) groups were analyzed and compared. RESULTS: A higher incidence of acute compartment syndrome, local ecchymosis, skin necrosis, bullae, blisters, and fever was found in the surgical group than in the nonsurgical group, and ultrasound findings of the absence of Doppler flow were more frequently noted in the surgical group than in the nonsurgical group. After adjustment using a multivariate logistic regression model, only advanced age, Naja atra bite, local ecchymosis, and bulla or blister formation remained significant factors for surgical intervention. Furthermore, comparison of the outcomes of patients who received early (≤ 24 h) and late (> 24 h) surgical intervention revealed that the duration of continuous negative pressure wound therapy (6 vs. 15 days; P = 0.006), duration of hospital stay (13 vs. 26 days; P = 0.002), and duration of outpatient follow-up (15 vs. 36 days; P < 0.001) were significantly lower in patients who received early surgical intervention. The final reconstructive surgery was simple among the patients who received surgical intervention within 24 h of being bitten (P = 0.028). CONCLUSION: In patients with snakebites, advanced age, high-risk clinical manifestations (e.g., local ecchymosis and bulla or blister formation), and Naja atra envenomation are predictors of surgical intervention within 24 h.

3200 ppi Matrix-Addressable Blue MicroLED Display.

In this article, an active matrix (AM) micro light-emitting diode (MicroLED) display with a resolution of 1920 × 1080 and a high pixel density of 3200 pixels per inch (ppi) is reported. The single pixel with a diameter of 5 µm on the MicroLED array exhibits excellent characteristics, including a forward voltage of 2.8 V at 4.4 µA, an ideality factor of 1.7 in the forward bias of 2-3 V, an extremely low leakage current of 131 fA at -10 V, an external quantum efficiency of 6.5%, and a wall-plug efficiency of 6.6% at 10.2 A/cm2, a light output power of 28.3 µW and brightness of 1.6 × 105 cd/m2 (nits) at 1 mA. The observed blue shift in the electroluminent peak wavelength is only 6.6 nm from 441.2 nm to 434.6 nm with increasing the current from 5 µA to 1 mA (from 10 to 5 × 103 A/cm2). Through flip-chip bonding technology, the 1920 × 1080 bottom-emitting MicroLED display through the backside of a sapphire substrate can demonstrate high-resolution graphic images.

Effect of Total Intravenous Anesthesia on Postoperative Pulmonary Complications in Patients Undergoing Microvascular Reconstruction for Head and Neck Cancer: A Randomized Clinical Trial.

Importance: Free flap surgery is a lengthy procedure with massive tissue destruction and reconstruction, which makes postoperative pulmonary complications (PPCs) a noticeable issue among patients with head and neck cancer. Propofol-based total intravenous anesthesia (TIVA) has better survival outcomes than inhalational anesthesia (INH) in several types of cancer surgery. A previous retrospective study found that patients in the TIVA group had a lower PPC rate, which may be correlated with a lower intraoperative fluid requirement. We hypothesize that the protective effect remains among patients undergoing free flap surgery for head and neck cancer in a prospective and goal-directed fluid therapy setting. Objective: To assess the effect of TIVA vs INH on PPCs in patients undergoing microvascular reconstruction for head and neck cancer. Design, Setting, and Participants: This prospective, 2-arm, randomized clinical trial was conducted at a tertiary hospital in Taiwan; a total of 78 patients 18 years and older with American Society of Anesthesiologists physical status classification 1 to 3 who were scheduled for elective free flap surgery under general anesthesia were included. The trial started in October 2017, completed in October 2019, and finished analysis in January 2022. Interventions: Patients were enrolled and randomized to the TIVA or INH group. All patients received goal-directed fluid therapy and hemodynamic management if they had a mean arterial pressure (MAP) below 75 mm Hg or a reduction of 10% from baseline MAP. Main Outcomes and Measures: The primary outcome was a composite of PPCs. The secondary outcomes were the differences in intraoperative hemodynamic values (mean arterial pressure, MAP; cardiac index, CI; systemic vascular resistance index, SVRI; and stroke volume variation, SVV). Results: A total of 70 patients (65 men [93%]; 5 women [7%]) completed the trial; median (IQR) age was 52.0 (48-59) years in the TIVA group and 57.0 (46-64) years in the INH group. The demographic characteristics were similar between the 2 groups, except that patients in the TIVA group had a slightly lower body mass index. Patients in the TIVA group had a lower risk of developing PPCs (unadjusted odds ratio, 0.25; 95% CI, 0.08-0.80). The TIVA group had significantly higher MAP, lower CI, and higher SVRI than the INH group after the third hour of monitoring. The TIVA group showed a relatively stable hourly MAP, CI, SVRI, and SVV across time points, while the INH group showed a more varying pattern. The generalized estimating equation showed no clinical differences in the trend of hemodynamic parameters across time between groups. Conclusions and Relevance: In this randomized clinical trial, using propofol-based TIVA reduced the incidence of PPCs in free flap surgery. This finding may be related to more stable hemodynamic manifestations and a lower total balance of fluid throughout the surgery. Trial Registration: ClinicalTrials.gov Identifier: NCT03263078.

Invasive Candidiasis in Hospitalized Patients with Major Burns.

BACKGROUND: Invasive candidiasis (IC) is a major cause of morbidities and mortality in patients hospitalized with major burns. This study investigated the incidence of IC in this specific population and analyzed the possible risk factors. MATERIALS AND METHODS: We retrospectively analyzed data from the National Health Insurance Research Database (NHIRD) of Taiwan. We identified 3582 patients hospitalized with major burns on over 20% of their total body surface area (TBSA) during 2000-2013; we further analyzed possible risk factors. RESULT: IC was diagnosed in 452 hospitalized patients (12.6%) with major burns. In the multivariate analysis, patients older than 50 years (adjusted odds ratio (OR) = 1.96, 95% confidence interval (CI) 1.36-2.82), those of female sex (adjusted OR = 1.33, 95% CI 1.03-1.72), those with burns on the head (adjusted OR = 1.33, 95% CI 1.02-1.73), and those with burns over a greater TBSA had higher risks of IC. CONCLUSION: Treating IC is crucial in healthcare for major burns. Our study suggests that several risk factors are associated with IC in patients hospitalized with major burns, providing reliable reference value for clinical decisions.

Comprehensive proteomic analysis of mineral nanoparticles derived from human body fluids and analyzed by liquid chromatography-tandem mass spectrometry.

Mineralo-protein nanoparticles (NPs) formed spontaneously in the body have been associated with ectopic calcifications seen in atherosclerosis, chronic degenerative diseases, and kidney stone formation. Synthetic NPs are also known to become coated with proteins when they come in contact with body fluids. Identifying the proteins found in NPs should help unravel how NPs are formed in the body and how NPs in general, be they synthetic or naturally formed, interact within the body. Here, we developed a proteomic approach based on liquid chromatography (LC) and tandem mass spectrometry (MS/MS) to determine the protein composition of carbonate-apatite NPs derived from human body fluids (serum, urine, cerebrospinal fluid, ascites, pleural effusion, and synovial fluid). LC-MS/MS provided not only an efficient and comprehensive determination of the protein constituents, but also a semiquantitative ranking of the identified proteins. Notably, the identified NP proteins mirrored the protein composition of the contacting body fluids, with albumin, fetuin-A, complement C3, α-1-antitrypsin, prothrombin, and apolipoproteins A1 and B-100 being consistently associated with the particles. Since several coagulation factors, calcification inhibitors, complement proteins, immune regulators, protease inhibitors, and lipid/molecule carriers can all become NP constituents, our results suggest that mineralo-protein complexes may interface with distinct biochemical pathways in the body depending on their protein composition. We propose that LC-MS/MS be used to characterize proteins found in both synthetic and natural NPs.

Exposure to Dengue Envelope Protein Domain III Induces Nlrp3 Inflammasome-Dependent Endothelial Dysfunction and Hemorrhage in Mice.

Typically occurring during secondary dengue virus (DENV) infections, dengue hemorrhagic fever (DHF) causes abnormal immune responses, as well as endothelial vascular dysfunction, for which the responsible viral factor remains unclear. During peak viremia, the plasma levels of virion-associated envelope protein domain III (EIII) increases to a point at which cell death is sufficiently induced in megakaryocytes in vitro. Thus, EIII may constitute a virulence factor for endothelial damage. In this study, we examined endothelial cell death induced by treatment with DENV and EIII in vitro. Notably, pyroptosis, the major type of endothelial cell death observed, was attenuated through treatment with Nlrp3 inflammasome inhibitors. EIII injection effectively induced endothelial abnormalities, and sequential injection of EIII and DENV-NS1 autoantibodies induced further vascular damage, liver dysfunction, thrombocytopenia, and hemorrhage, which are typical manifestations in DHF. Under the same treatments, pathophysiological changes in the Nlrp3 inflammasome-deficient mice were notably reduced compared with those in the wild-type mice. These results suggest that the Nlrp3 inflammasome constitutes a potential therapeutic target for treating DENV-induced hemorrhage in DHF.

Recent advances in the field of caloric restriction mimetics and anti-aging molecules.

Caloric restriction (CR) mimetics are molecules that produce beneficial effects on health and longevity in model organisms and humans, without the challenges of maintaining a CR diet. Conventional CR mimetics such as metformin, rapamycin and spermidine activate autophagy, leading to recycling of cellular components and improvement of physiological function. We review here novel CR mimetics and anti-aging compounds, such as 4,4'-dimethoxychalcone, fungal polysaccharides, inorganic nitrate, and trientine, highlighting their possible molecular targets and mechanisms of action. The activity of these compounds can be understood within the context of hormesis, a biphasic dose response that involves beneficial effects at low or moderate doses and toxic effects at high doses. The concept of hormesis has widespread implications for the identification of CR mimetics in experimental assays, testing in clinical trials, and use in healthy humans. We also discuss the promises and limitations of CR mimetics and anti-aging molecules for delaying aging and treating chronic diseases.

Ganoderma lucidum stimulates autophagy-dependent longevity pathways in Caenorhabditis elegans and human cells.

The medicinal fungus Ganoderma lucidum is used as a dietary supplement and health tonic, but whether it affects longevity remains unclear. We show here that a water extract of G. lucidum mycelium extends lifespan of the nematode Caenorhabditis elegans. The G. lucidum extract reduces the level of fibrillarin (FIB-1), a nucleolar protein that correlates inversely with longevity in various organisms. Furthermore, G. lucidum treatment increases expression of the autophagosomal protein marker LGG-1, and lifespan extension is abrogated in mutant C. elegans strains that lack atg-18, daf-16, or sir-2.1, indicating that autophagy and stress resistance pathways are required to extend lifespan. In cultured human cells, G. lucidum increases concentrations of the LGG-1 ortholog LC3 and reduces levels of phosphorylated mTOR, a known inhibitor of autophagy. Notably, low molecular weight compounds (<10 kDa) isolated from the G. lucidum water extract prolong lifespan of C. elegans and the same compounds induce autophagy in human cells. These results suggest that G. lucidum can increase longevity by inducing autophagy and stress resistance.

Ectopic calcification and formation of mineralo-organic particles in arteries of diabetic subjects.

Vascular calcification occurs in various diseases including atherosclerosis, chronic kidney disease and type 2 diabetes but the mechanism underlying mineral deposition remains incompletely understood. Here we examined lower limb arteries of type 2 diabetes subjects for the presence of ectopic calcification and mineral particles using histology, electron microscopy and spectroscopy analyses. While arteries of healthy controls showed no calcification following von Kossa staining, arteries from 83% of diabetic individuals examined (19/23) revealed microscopic mineral deposits, mainly within the tunica media. Mineralo-organic particles containing calcium phosphate and proteins such as albumin, fetuin-A and apolipoprotein-A1 were detected in calcified arteries. Ectopic calcification and mineralo-organic particles were observed in a majority of diabetic patients and predominantly in arteries showing hyperplasia. While a low number of subjects was examined and information about disease severity and patient characteristics is lacking, these calcifications and mineralo-organic particles may represent signs of tissue dysfunction.

Plant and fungal products that extend lifespan in Caenorhabditis elegans.

The nematode Caenorhabditis elegans is a useful model to study aging due to its short lifespan, ease of manipulation, and available genetic tools. Several molecules and extracts derived from plants and fungi extend the lifespan of C. elegans by modulating aging-related pathways that are conserved in more complex organisms. Modulation of aging pathways leads to activation of autophagy, mitochondrial biogenesis and expression of antioxidant and detoxifying enzymes in a manner similar to caloric restriction. Low and moderate concentrations of plant and fungal molecules usually extend lifespan, while high concentrations are detrimental, consistent with a lifespan-modulating mechanism involving hormesis. We review here molecules and extracts derived from plants and fungi that extend the lifespan of C. elegans, and explore the possibility that these natural substances may produce health benefits in humans.

Hormetic Effects of Phytochemicals on Health and Longevity.

Caloric restriction, intermittent fasting, and exercise activate defensive cellular responses such as autophagy, DNA repair, and the induction of antioxidant enzymes. These processes improve health and longevity by protecting cells and organs against damage, mutations, and reactive oxygen species. Consuming a diet rich in vegetables, fruits, and mushrooms can also improve health and longevity. Phytochemicals such as alkaloids, polyphenols, and terpenoids found in plants and fungi activate the same cellular processes as caloric restriction, fasting, and exercise. Many of the beneficial effects of fruits and vegetables may thus be due to activation of stress resistance pathways by phytochemicals. A better understanding of the mechanisms of action of phytochemicals may provide important insights to delay aging and prevent chronic diseases.

Corrigendum: The ATP-P2X7 Signaling Axis Is an Essential Sentinel for Intracellular Clostridium difficile Pathogen-Induced Inflammasome Activation.

[This corrects the article DOI: 10.3389/fcimb.2018.00084.].