Essentially all bacteria secrete nano-sized (~20-200 nm) bacterial extracellular vesicles (bEVs) loaded with proteins, lipids, glycans, and nucleic acids. bEVs facilitate interactions among cells of the same species, different microbial species, and even with cells of multicellular organisms in the context of colonization or infection. Their interactions with host organism immune cell receptors vary depending on the producing bacterial species and are now being harnessed for the development of bEVs as a potential immunotherapeutic platform. Both basic/mechanistic and preclinical therapeutic development studies are thus increasing in number and require implementation of methods for multiparametric analytical characterization as well as in vivo administration in preclinical animal models of disease. We summarize a variety of analytical methods that can be used to calculate bEV dose for preparations made from diverse bacterial sources (including sterility testing, total protein concentration, particle concentration, and lipopolysaccharide concentration). We also describe basic methodology for intravenous administration of bEV preparations via tail vein injection in laboratory mice. Throughout the description of methodology, we highlight potential pitfalls and alternatives to further equip the reader for troubleshooting should challenges arise. Robust and reproducible characterization is a prerequisite of bEV preparation quality control and consistent dosing during preclinical development. This will allow for more streamlined testing of candidate therapeutic bEVs within a given research laboratory, and furthermore facilitate reproducibility of findings across laboratories.

There are few reports of poisoning caused by high-dose intravenous injection of mercury. Its clinical manifestations are diverse and the risk of mortality is high. Currently, the pathogenesis is not clear and the treatment experience is insufficient, leading to difficulties in clinical diagnosis and treatment. In this article, the data of a case of mercury poisoning caused by intravenous self-administration was analyzed and summarized. The patient developed multiple organ dysfunction syndrome after intravenous injection of high-dose mercury. After comprehensive treatment, such as mercury removal, organ support, and infection prevention, the condition was improved. This case suggests that intravenous injection of mercury can cause damage to the functions of multiple organs, such as the heart, lungs, and kidneys. Early treatment and intervention can bring benefits.
一次性静脉注射大剂量汞引起中毒的报道很少，患者临床表现多样且汞致死风险高，目前存在发病机制不明确、治疗经验不足等问题，为临床诊疗及救治工作带来困难。本文对1例静脉注射大剂量汞引起中毒的病例资料进行整理。患者静脉注射大剂量汞后出现多器官功能障碍综合征，经过驱汞治疗、器官支持治疗、防治感染等综合救治后病情好转。提示静脉注射汞会对心脏、肺、肾等多器官功能造成损伤，早期系统干预治疗可以带来获益。.

Injection of mercury into the upper limb is a rare method of self-harm. We report two patients with varied clinical presentations - a 19-year-old male student who injected himself with mercury extracted from a sphygmomanometer bulb and reported to our emergency department 24 hours after the event and a 34-year-old industry worker who presented 2 years after injecting himself with elemental mercury. The management of mercury poisoning is described along with a brief review of literature. Mercury is a toxic element and adequate safety precautions must be taken by the surgical team in the management of such patients. Level of Evidence: Level V (Therapeutic).

BACKGROUND: Sudden sensorineural hearing loss (SSNHL), characterized by a rapid and unexplained loss of hearing, particularly at moderate to high frequencies, presents a significant clinical challenge. The therapeutic use of methylprednisolone sodium succinate (MPSS) via different administration routes, in combination with conventional medications, remains a topic of interest.
OBJECTIVE: To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid- to high-frequency SSNHL.
METHODS: The medical records of 109 patients with mid- to high-frequency SSNHL were analyzed. The patients were divided into three groups based on the route of administration: Group A [intratympanic (IT) injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection], Group B (intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection), and Group C (single IT injection of MPSS). The intervention effects were compared and analyzed.
RESULTS: The posttreatment auditory thresholds in Group A (21.23 ± 3 .34) were significantly lower than those in Groups B (28.52 ± 3.36) and C (30.23 ± 4.21; P < 0.05). Group A also exhibited a significantly greater speech recognition rate (92.23 ± 5.34) than Groups B and C. The disappearance time of tinnitus, time to hearing recovery, and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C (P < 0.05). The total effective rate in Group A (97.56%) was significantly greater than that in Groups B and C (77.14% and 78.79%, χ 2 = 7.898, P = 0.019). Moreover, the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B (4.88%, 3.03% vs 2.57%, χ 2 = 11.443, P = 0.003), and the recurrence rate in Group A was significantly lower than that in Groups B and C (2.44% vs 20.00% vs 21.21%, χ 2 = 7.120, P = 0.028).
CONCLUSIONS: IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS. This approach effectively improves patients\' hearing and reduces the risk of disease recurrence.

Intravenous infusion has been used as the method of cell delivery in many preclinical studies as well as in some early clinical trials. Among its advantages are broad distribution, ability to handle a large-volume infusion, and ease of access. Progenitor cells used in cell-based therapy act through their secretomes, rather than their ability to differentiate into lineage-specific cell type. Since not all progenitor cells have similar secretome potency, the innate abilities of the secretome of cells used in clinical trials will obviously dictate their effectiveness. We previously found that cardiac neonatal mesenchymal stromal cells (nMSCs) are more effective in repairing the infarcted myocardium compared to adult mesenchymal stromal cells (aMSCs) due to their robust secretome (Sharma et al Circulation Research 120:816-834, 2017). In this study, we explored the efficacy of intravenous (IV) delivery of nMSCs for myocardial recovery. Six-week-old male Brown Norway rats underwent acute MI by ligation of the left anterior descending artery, followed by IV infusion of cell dose 5 × 106 nMSCs/rat body weight (kg) or saline on days 0 and 5. We found that cardiac parameters in the rodent ischemia model improved 1 month after nMSCs infusion, and the result is comparable with the intramyocardial injection of nMSCs. Tracking the infused cells in target organ revealed that their movement after IV delivery was mediated by the cell surface receptor CD44. Systemic injection of nMSCs stimulated immunomodulatory responses specifically by increasing FoxP3+ T-regulatory cell influenced anti-inflammatory macrophages (M2) in heart. These data demonstrate that nMSCs promote immunogenic tolerance via CD44-driven T-reg/M2 stimulation that helps nMSCs for longer viability in the injured myocardium for better functional recovery. Our data also demonstrate a rationale for a clinical trial of IV infusion of nMSCs to promote cardiac function improvement in the ischemic patients.

BACKGROUND: Although umbilical cord mesenchymal stem cell (UCMSC) infusion has been proposed as a promising strategy for the treatment of acute lung injury (ALI), the parameters of UCMSC transplantation, such as infusion routes and doses, need to be further optimized.
METHODS: In this study, we compared the therapeutic effects of UCMSCs transplanted via intravenous injection and intratracheal instillation on lipopolysaccharide-induced ALI using a rat model. Following transplantation, levels of inflammatory factors in serum; neutrophils, total white blood cells, and lymphocytes in bronchoalveolar lavage fluid (BALF); and lung damage levels were analyzed.
RESULTS: The results indicated that UCMSCs administered via both intravenous and intratracheal routes were effective in alleviating ALI, as determined by analyses of arterial blood gas, lung histopathology, BALF contents, and levels of inflammatory factors. Comparatively, the intratracheal instillation of UCMSCs was found to result in lower levels of lymphocytes and total proteins in BALF, whereas greater reductions in the serum levels of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were detected in rats receiving intravenously injected stem cells.
CONCLUSIONS: Our findings in this study provide convincing evidence to indicate the efficacy of UCMSC therapy in the treatment of ALI mediated via different delivery routes, thereby providing a reliable theoretical basis for further clinical studies. Moreover, these findings imply that the effects obtained using the two assessed delivery routes for UCMSC transplantation are mediated via different mechanisms, which could be attributable to different cellular or molecular targets.

Adeno-associated virus (AAV) vectors have emerged as a promising tool in the development of gene therapies for various neurological diseases, including Alzheimer\'s disease and Parkinson\'s disease. However, the blood-brain barrier (BBB) poses a significant challenge to successfully delivering AAV vectors to the brain. Strategies that can overcome the BBB to improve the AAV delivery efficiency to the brain are essential to successful brain-targeted gene therapy. This review provides an overview of existing strategies employed for AAV delivery to the brain, including direct intraparenchymal injection, intra-cerebral spinal fluid injection, intranasal delivery, and intravenous injection of BBB-permeable AAVs. Focused ultrasound has emerged as a promising technology for the noninvasive and spatially targeted delivery of AAV administered by intravenous injection. This review also summarizes each strategy\'s current preclinical and clinical applications in treating neurological diseases. Moreover, this review includes a detailed discussion of the recent advances in the emerging focused ultrasound-mediated AAV delivery. Understanding the state-of-the-art of these gene delivery approaches is critical for future technology development to fulfill the great promise of AAV in neurological disease treatment.

OBJECTIVE: The intravenous administration of adipose tissue-derived mesenchymal stem cells (AdMSCs) in veterinary medicine is an attractive treatment option. On the other hand, it can result in severe complications, including pulmonary thromboembolism (PTE).
OBJECTIVE: The present study assessed the occurrence of PTE after the intravenous infusion of canine AdMSCs (cAdMSCs) into experimental animals.
METHODS: Five-week-old male BALB/c hairless mice were categorized into groups labeled A to G. In the control group (A), fluorescently stained 2 × 106 cAdMSCs were diluted in 200 μL of suspension and injected into the tail vein as a single bolus. The remaining groups included the following: group B with 5 × 106 cells, group C with 3 × 106 cells, group D with 1 × 106 cells, group E with 1 × 106 cells injected twice with a one-day interval, group F with 2 × 106 cells in 100 μL of suspension, and group G with 2 × 106 cells in 300 μL of suspension.
RESULTS: Group D achieved a 100% survival rate, while none of the subjects in groups B and C survived (p = 0.002). Blood tests revealed a tendency for the D-dimer levels to increase as the cell dose increased (p = 0.006). The platelet count was higher in the low cell concentration groups and lower in the high cell concentration groups (p = 0.028). A histological examination revealed PTE in most deceased subjects (96.30%).
CONCLUSIONS: PTE was verified, and various variables were identified as potential contributing factors, including the cell dose, injection frequency, and suspension volume.

UNASSIGNED: To determine the differences in improvement in cardiac function by intramyocardial (IM) vs. intravenous (IV) injection of human bone mesenchymal stem cell-derived extracellular vesicles (HBMSC-EV) after acute MI.
UNASSIGNED: FVB mice underwent acute MI via left anterior descending coronary artery ligation and subsequent injection of: (1) IM saline control; (2) IM HBMSC-EV; (3) IV saline control; and (4) IV HBMSC-EV. Cardiac function was evaluated with weekly postoperative echocardiography. On postoperative day 28, the mice were euthanized, and the heart, lungs, liver, spleen, and kidneys were harvested. Given previous studies showing HBMSC-EV hepatic uptake after IV injection, the liver was evaluated for changes in inflammation, fibrosis, and proliferation.
UNASSIGNED: On postoperative day 28, there were no significant differences in left ventricular ejection fraction (P = 0.6151), fractional shortening (P = 0.1135), or anterior border zone fibrosis (P = 0.6333) in any of the experimental groups. Interestingly, there was a strong trend demonstrating improvement in infarct size on fibrosis staining, which did not reach significance (P = 0.05620). There were no differences in hepatic inflammation, fibrosis, and proliferation.
UNASSIGNED: Although there was a trend in the improvement in infarct size, a single-dose administration of neither IM nor IV injection of HBMSC-EV resulted in significant improvement in post-MI cardiac function. A major limitation of this study is the lack of trials determining the optimal dose of HBMSC-EV needed in this model. However, the current study demonstrates that future studies are required to either optimize administration or bioengineer HBMSC-EV with cardiac-homing properties.

OBJECTIVE: To assess the safety and tolerability of subcutaneous (SC) trastuzumab (Herceptin) administered either with a single-use injection device (SID) or manually from a vial using a hand-held syringe.
METHODS: The ESCAPE trial (NCT02194166) included 90 women aged 18 years or older with HER2-positive early breast cancer who underwent surgical treatment and completed (neo) adjuvant chemotherapy and radiotherapy (if indicated). Patients enrolled in the study were first subjected to 4 cycles of trastuzumab IV (8 mg/kg loading dose followed by 6 mg/kg maintenance dose, q3w) prior to being randomized into groups: [A] SC trastuzumab (fixed dose 600 mg, q3w) administered through a hand-held syringe followed by 7 cycles of SC trastuzumab administered with an SID or [B] the reverse sequence.
RESULTS: Patient-reported outcomes revealed that 78 (94.0 % [95 % CI: 90.4-99.0]) out of 83 patients preferred SC trastuzumab over IV trastuzumab, among whom 28 patients indicated a strong preference. Sixteen out of 17 HCPs (94.1 %) were very satisfied with the use of SC trastuzumab, while 1/17 (5.9 %) remained uncertain. The mean time spent for IV vs. SC trastuzumab administration, including pre- and postinjection procedures, was 93.8 and 22 min, respectively. A total of 49 (54.4 %) patients reported 164 AEs.
CONCLUSIONS: In this trial, SC trastuzumab was preferred over IV trastuzumab. The duration of SC trastuzumab administration was significantly shorter than that of IV trastuzumab, saving patients and HCPs time. Safety and efficacy results were consistent with other published trials and were not associated with any new safety signal.