Intramyocardial Cell Delivery: Observations in Murine Hearts

Previous studies showed that cell delivery promotes cardiac function amelioration by release of cytokines and factors that increase cardiac tissue revascularization and cell survival. In addition, further observations revealed that specific stem cells, such as cardiac stem cells, mesenchymal stem cells and cardiospheres have the ability to integrate within the surrounding myocardium by differentiating into cardiomyocytes, smooth muscle cells and endothelial cells.Here, we present the materials and methods to reliably deliver noncontractile cells into the left ventricular wall of immunodepleted mice. The salient steps of this microsurgical procedure involve anesthesia and analgesia injection, intratracheal intubation, incision to open the chest and expose the heart and delivery of cells by a sterile 30-gauge needle and a precision microliter syringe.Tissue processing consisting of heart harvesting, embedding, sectioning and histological staining showed that intramyocardial cell injection produced a small damage in the epicardial area, as well as in the ventricular wall. Noncontractile cells were retained into the myocardial wall of immunocompromised mice and were surrounded by a layer of fibrotic tissue, likely to protect from cardiac pressure and mechanical load.     

Gene transfer by biolistic process

Gene transfer into somatic tissues is a tool for both the study of gene function in the basic science laboratory and for gene therapy and genetic immunization in the clinic. Biolistic processes can be used to deliver both viral and nonviral vectors into somatic tissues. This review discusses the advantages and disadvantages of three biolistic processes: jet injection, microparticle bombardment, and needle and syringe injection. Jet injection and needle and syringe injection can be used to deliver both viral and nonviral vectors. Both jet injection and microparticle bombardment can be used to target a broad range of tissues. Needle and syringe injection has been most widely used in muscle tissue. The choice of which biolistic process to use is dependent on the specific application.     

Intracoronary delivery of autologous bone marrow mononuclear cells radiolabeled by 18F-fluoro-deoxy-glucose: tissue distribution and impact on post-infarct swine hearts

Intracoronary injection of the bone marrow-derived mononuclear cells (MNCs) is emerging as a potentially novel therapy for ischemic heart failure. This study was aimed at assessing the efficacy of intracoronary MNC delivery in the myocardium. The in vivo distribution and myocardial homing of intracoronarily delivered MNCs in experimental Chinese swine with acute myocardial infarction (AMI) created by occlusion of left anterior descending (LAD) coronary artery for 90 min. MNCs radiolabeled with 18F-fluoro-deoxy-glucose (18F-FDG) were delivered using a coronary catheter into the infarct-related coronary artery 1 week after AMI. Dual-nuclide single photon emission computed tomography (SPECT) revealed that 1 h after cell infusion, 6.8 +/- 1.8% of 18F-FDG-labeled MNCs occurred in the infarcted myocardium with the remaining activity found primarily in the liver and spleen. In the heart, MNCs were detected predominantly in the under-perfused myocardium. The infused cells retained in the hearts at a rate highly correlated with the under-perfused lesional sizes. Pathological examination further demonstrated that 6 weeks after infusion, compared to controls, the hearts receiving MNCs exhibited less fibrosis and inflammatory infiltrate, more viable tissue, and higher vascular density. Cardiac function was significantly improved in the MNC-infused hearts. Thus, 18F-FDG labeling and dual-nuclide SPECT imaging is capable of monitoring in vivo distribution and homing of MNCs after intracoronary infusion. MNC coronary delivery may improve cardiac function and positive ventricular remodeling in the heart with AMI.     

Transplantation of pancreatic islets into the kidney capsule of diabetic mice

Our protocol was developed to cleanly and easily deliver islets or cells under the kidney capsule of diabetic or normal mice. We found that it was easier to concentrate the islets or cells into pellets in the final delivery tubing (PE50) used to transplant the cells under the kidney capsule. This technique provides both speed and ease while reducing any undue stress to the cells or to the mouse. LOADING: Settled, hand picked, islets or pelleted cells are carefully aspirated off the bottom of a 1.5 mL microcentrifuge tube using a p200 pipetteman and a straight, thin-wall pipette tip. A length of PE50 tubing is attached to the pipette tip using a small silicone adapter tubing. Cells are allowed to settle, in the tip, and then are transferred to the PE50 tubing by slowly dialing the pipetteman. Once the cells are near the end of the PE50 tubing, a kink is made and the silicone adaptor tubing is placed over the kink. The PE50 tubing is transferred to a 15 mL conical containing a cut 5 mL pipet, and the PE50 tubing is taped over the side of the 5 mL pipet to prevent curling during centrifuging. Cells are allowed to reach 1,000 rpm and stopped. TRANSPLANTATION: Recipient mice are anesthetized, shaved, and cleaned. A small incision is made on the left flank of the mouse and the kidney is exposed. The kidney, fat, and tissue are kept moist with normal saline swab. The distal end of the PE50 is attached to a Hamilton screw drive syringe, containing a pipette tip, using the silicone adaptor tubing. A small nick is made on the right flank side of the kidney, not too large nor too deep. The beveled end of the PE50 tubing, nearest the cells, is carefully placed under the capsule, the tubing is moved around gently to make space while swabbing normal saline; a dry capsule can tear easily. A small air bubble is delivered under the capsule by slowly dialing the syringe screw drive. Islets are then slowly delivered behind the air bubble. Once the islets have been delivered kidney homeostasis is maintained and the knick is cauterized with low heat. The kidney is placed back into the cavity and the peritoneum and skin are sutured and stapled. Mice are immediately treated with Flunixin and Buprenorphine s.q. and placed in a cage on a heating pad.     

An Air-Drying Procedure for Mammalian Male Meiotic Chromosomes, Following Softening in Gluconic Acid and Cell Separation by An Ethanol-Acetic Mixture

A I cm³ sample of tubules from testes is placed in 5 ml of 0.7% Na-citrate for 20-30 min, then 5 ml of glacial acetic acid is added, mixed well, and allowed to stand for 30 min. The mixture is centrifuged, the supernatant removed, and 3 ml of 3 M gluconic acid is mixed with the tissue and allowed to act for 3 hr. The gluconic acid is removed with a pipette and the tissue is suspended in 5 ml of a freshly made 1:1 absolute ethanol-glacial acetic acid mixture. The tissue is drawn into and discharged from a syringe several times through an 18, a 20, and finally a 22 gauge needle to separate and suspend the cells. The cells are centrifuged and resuspended several times in fresh fixative to remove the gluconic acid. Finally, the cells are suspended in sufficient fixative to give a smear of suitable density, and air-dried preparations are made, or the suspension may be stored at 0-5 C for several days. The cells can be stained by any of the usual stains for chromosomes. This technique results in the improved spreading produced by the air-drying technique and permits recovery of all stages of meiosis and mitosis present.     

Intravitreous injection for establishing ocular diseases model

Intravitreous injection is a widely used technique in visual sciences research. It can be used to establish animal models with ocular diseases or as direct application of local treatment. This video introduces how to use simple and inexpensive tools to finish the intravitreous injection procedure. Use of a 1 ml syringe, instead of a Hamilton syringe, is used. Practical tips for how to make appropriate injection needles using glass pipettes with perfect tips, and how to easily connect the syringe needle with the glass pipette tightly together, are given. To conduct a good intravitreous injection, there are three aspects to be observed: 1) injection site should not disrupt retina structure; 2) bleeding should be avoided to reduce the risk of infection; 3) lens should be untouched to avoid traumatic cataract. In brief, the most important point is to reduce the interruption of normal ocular structure. To avoid interruption of retina, the superior nasal region of rat eye was chosen. Also, the puncture point of the needle was at the par planar, which was about 1.5 mm from the limbal region of the rat eye. A small amount of vitreous is gently pushed out through the puncture hole to reduce the intraocular pressure before injection. With the 45 degrees injection angle, it is less likely to cause traumatic cataract in the rat eye, thus avoiding related complications and influence from lenticular factors. In this operation, there was no cutting of the conjunctiva and ocular muscle, no bleeding. With quick and minor injury, a successful intravitreous injection can be done in minutes. The injection set outlined in this particular protocol is specific for intravitreous injection. However, the methods and materials presented here can also be used for other injection procedures in drug delivery to the brain, spinal cord or other organs in small mammals.     

Closed-chest cell injections into mouse myocardium guided by high-resolution echocardiography

The mouse is an important model for the development of therapeutic stem cell/bone marrow cell implantation to treat ischemic myocardium. However, its small heart size hampers accurate implantation into the left ventricular (LV) wall. Precise injections have required surgical visualization of the heart, which is subject to complications and is impractical for delayed or repeated injections. Furthermore, the thickness of the myocardium is comparable to the length of a needle bevel, so surgical exposure does not prevent inadvertent injection into the LV cavity. We describe the use of high-resolution echocardiography to guide nonsurgical injections accurately into the mouse myocardial wall. We optimized this system by using a mixture of ultrasound contrast and fluorescent microspheres injected into the myocardium, which enabled us to interpret the ultrasound image of the needle during injection. Quantitative dye injection studies demonstrated that guided closed-chest injections and open-chest injections deliver comparable amounts of injectate to the myocardium. We successfully used this system in a mouse myocardial infarction model to target the injection of labeled cells to a region adjacent to the infarct. Intentional injection of tracer into the LV cavity resulted in a small accumulation in the myocardium, suggesting that non-guided cell injections into mouse hearts may appear to be successful even if the majority of the injectate is lost in the chamber. The use of this system will allow more precise cellular implantation into the mouse myocardium by accurately guiding injections to desired locations, confirming successful implantation of cells, in a clinically relevant time frame.     

Improved method of studying the blood for sterility

The technique used for the inoculation and subculturing of blood samples in testing them for sterility is described. This technique eliminates the possibility of contaminating the culture medium and the blood sample under test with extraneous bacterial flora. Blood samples were inoculated without opening the containers with the culture medium. Inoculation was made with the syringe and the needle used for taking the blood sample through the punctured rubber stopper closing the container. Subculturing on solid culture media was also carried out without opening the containers: the rubber stopper was punctured and the contents of the container withdrawn with a pipette needle. The use of this new technique made it possible to detect bacteremia in 12.8% of cases, only in persons with purulent and septic diseases, whereas by using the existing technique bacteremia was detected both in sick and healthy persons, in 38.6% and 26.6% of cases, respectively.     

Automated Needle‐free Injection Method for Delivery of Bacterial Suspensions into Citrus Leaf Tissues

A prototype needle‐free device was evaluated for delivery of Xanthomonas citri subsp. citri bacteria into the leaves of cultivars susceptible and resistant to citrus canker. The device delivered a precisely controlled volume of bacterial suspension through infiltration of stomata by injection with pressurized gas. The device produced a uniform inoculation of bacteria into the leaves as measured by the volume of infiltration and diameter of the infiltrated area. No damage to the leaves was observed after inoculation with the automated device, even though a higher number of canker lesions developed compared to a hand‐held needleless syringe injection method. The level of practice needed for operation of the automated device was minimal compared to considerable skill required to perform the hand‐held injection. Results from inoculations with the automated device are in accord with the results with the hand‐held syringe method that demonstrated kumquats are highly resistant to citrus canker while rough lemon and ‘Hamlin’ sweet orange are susceptible.     

Immune responses to hepatitis B surface antigen following epidermal powder immunization

Langerhans cells in the epidermis of skin are potent antigen-presenting cells that trigger the immune system to respond to invading microorganisms. We have previously shown that epidermal powder immunization with a powdered inactivated influenza virus vaccine, by targeting the Langerhans cell-rich epidermis, was more efficacious than deeper tissue injection using a needle and syringe. We now report enhanced humoral and cellular immune responses to recombinant hepatitis B surface antigen following epidermal powder immunization. We observed that epidermal powder immunization with unadjuvanted hepatitis B surface antigen elicited an antibody titre equivalent to that induced by the alum-adjuvanted vaccine delivered by intramuscular injection, suggesting that epidermal powder immunization can overcome the need for adjuvantation. We demonstrated that synthetic CpG oligonucleotides (CpG DNA) could be coformulated with hepatitis B surface antigen and delivered by epidermal powder immunization to further augment the antibody response and modulate T helper cell activities. Epidermal powder immunization of hepatitis B surface antigen formulated with CpG DNA formulations resulted in 1.5-2.0 logs higher IgG antibody titres than alum-adjuvanted commercial vaccines administered by intramuscular injection. Formulation of hepatitis B surface antigen with CpG DNA elicited an augmented IgG2a antibody response and increased frequency of IFN-gamma secreting cells. In addition, CpG DNA was found to activate epidermal Langerhans cells and stimulate the production of TNF-alpha and IL-12 cytokines by epidermal cells, explaining its strong adjuvant activity following epidermal powder immunization. These results show that epidermal powder immunization is a safe and effective method to deliver hepatitis B surface antigen and the addition of new adjuvants, such as CpG DNA, may further enhance the efficacy of this vaccine.     

Skin vaccination against cervical cancer associated human papillomavirus with a novel micro-projection array in a mouse model

Background

Better delivery systems are needed for routinely used vaccines, to improve vaccine uptake. Many vaccines contain alum or alum based adjuvants. Here we investigate a novel dry-coated densely-packed micro-projection array skin patch (Nanopatch™) as an alternate delivery system to intramuscular injection for delivering an alum adjuvanted human papillomavirus (HPV) vaccine (Gardasil®) commonly used as a prophylactic vaccine against cervical cancer.

Methodology/Principal Findings

Micro-projection arrays dry-coated with vaccine material (Gardasil®) delivered to C57BL/6 mouse ear skin released vaccine within 5 minutes. To assess vaccine immunogenicity, doses of corresponding to HPV-16 component of the vaccine between 0.43±0.084 ng and 300±120 ng (mean ± SD) were administered to mice at day 0 and day 14. A dose of 55±6.0 ng delivered intracutaneously by micro-projection array was sufficient to produce a maximal virus neutralizing serum antibody response at day 28 post vaccination. Neutralizing antibody titres were sustained out to 16 weeks post vaccination, and, for comparable doses of vaccine, somewhat higher titres were observed with intracutaneous patch delivery than with intramuscular delivery with the needle and syringe at this time point.

Conclusions/Significance

Use of dry micro-projection arrays (Nanopatch™) has the potential to overcome the need for a vaccine cold chain for common vaccines currently delivered by needle and syringe, and to reduce risk of needle-stick injury and vaccine avoidance due to the fear of the needle especially among children.     

Finite Element Model to Reproduce the Effect of Pre-Stress and Needle Insertion Velocity During Infusions into Brain Phantom Gel

Convection-enhanced delivery (CED) is a technique to bypass the blood-brain barrier and deliver therapeutic agents into the brain. However, animal studies and preliminary clinical trials have reported reduced efficacy to transport drugs in specific regions, attributed mainly to backflow, in which an annular zone is formed outside the catheter and the fluid preferentially flows toward the surface of the brain rather than through the tissue toward the targeted area. In this study, a finite element model of backflow was updated by implementing the pre-stress generated during needle insertion, which allows considering the effect of needle insertion velocity during CED infusions in agarose gel. The nonlinear mechanical properties of the agarose solutions were obtained by fitting experimental data from stress-relaxation tests. Additional experimental measurements of backflow lengths were used to adjust the pre-stress model. The developed model was able to reproduce changes of backflow length under different insertions velocities and flow rates. These findings reveal the relevance of considering the pre-stress in the tissue located around the needle surface during CED infusions into the brain.     

Transdermal delivery of scopolamine by natural submicron injectors: in-vivo study in pig

Transdermal drug delivery has made a notable contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. While transdermal delivery systems would appear to provide an attractive solution for local and systemic drug delivery, only a limited number of drugs can be delivered through the outer layer of the skin. The most difficult to deliver in this way are hydrophilic drugs. The aquatic phylum Cnidaria, which includes sea anemones, corals, jellyfish and hydra, is one of the most ancient multicellular phyla that possess stinging cells containing organelles (cnidocysts), comprising a sophisticated injection system. The apparatus is folded within collagenous microcapsules and upon activation injects a thin tubule that immediately penetrates the prey and delivers its contents. Here we show that this natural microscopic injection system can be adapted for systemic transdermal drug delivery once it is isolated from the cells and uploaded with the drug. Using a topically applied gel containing isolated natural sea anemone injectors and the muscarinic receptor antagonist scopolamine, we found that the formulated injectors could penetrate porcine skin and immediately deliver this hydrophilic drug. An in-vivo study in pigs demonstrated, for the first time, rapid systemic delivery of scopolamine, with T(max) of 30 minutes and C(max) 5 times higher than in controls treated topically with a scopolamine-containing gel without cnidocysts. The ability of the formulated natural injection system to penetrate a barrier as thick as the skin and systemically deliver an exogenous compound presents an intriguing and attractive alternative for hydrophilic transdermal drug delivery.     

Prestress as an optimal biomechanical parameter for needle penetration

Drug delivery requires precise intradermal and subcutaneous injections of formulations to clinically relevant penetration depths. However, penetration depth is confounded by skin deflection, which occurs prior to and during penetration as the skin surface deforms axially with the needle, and which varies profoundly due to differing intrinsic mechanical (e.g. viscoelastic) tissue properties, disease state, aging, and ethnicity. Herein, an ex vivo model was utilized to study factors that affect skin deflection and the efficacy of injection, including prestress applied at the tissue surface, needle gauge, velocity, and actuation depth. The application of prestress minimized skin deflection during needle penetration and allowed for needle actuation to the targeted penetration depths with minimum variability. The force required to achieve target penetration depths was found to increase with prestress and decrease with needle gauge. Our findings emphasize the need for prestress applied to the skin surface to minimize variation in skin properties and administer formulations for intradermal and subcutaneous treatments with maximum precision.     

Multiple insulin injections with the help of a subcutaneous catheter or metered syringe (Pen)]

Multiple, daily injections of insulin in intensified insulin therapy of diabetes mellitus has many important advantages. From the technical point of view however it requires new instruments, which could further limit the trauma of injection and facilitate the necessary manipulations. For these reasons a combination of typical insulin syringe (Novo-Noraisk Pen) and a special subcutaneous insulin catheter (Vigo-Spectramed Insuflon) was examined in a systematic way. Insuflon was inserted for 7 days. Insulin injection was made with a syringe through the head of the Insuflon. The needle of a syringe easily penetrated the membrane inside the Insuflon 4 times daily for 7 days without any damage. The acceptance of this method was high. It increased the compliance in general. The parameters of diabetes mellitus control changed positively. No side-effects of such procedure were noted.     

DNA integrity and transgene expression after passage through the NOGA needle catheter used for therapeutic myocardial angiogenesis

BACKGROUND: The NOGA (Biosense Webster, Markham, ON, Canada) injection catheter is an innovative navigational device that provides an ideal platform for intra-myocardial injection material. However, injection through a long (1.91 m), narrow (27G) nitinol needle could result in deterioration in the integrity and functionality of DNA. METHODS: To test this possibility, DNA in plasmid form (pcDNA3.1) containing the Lac Z transgene (250 micro l) was passed through the NOGA needle using a hand-held 1 cc syringe at a gentle hand injection pressure (43 +/- 3 PSI, 3.0 +/- 0.2 kg/cm(2)) or at maximal manual pressure (90 +/- 6 PSI, 6.3 +/- 0.4 kg/cm(2)), either once or 20 times. This DNA, compared to DNA not passed through the NOGA needle (control), was then used to transfect primary cultures of rat skin fibroblasts (FB) from Fisher 344 rats and the cells were subsequently stained for beta galactosidase (betagal). RESULTS: Transfection efficiency was significantly reduced by passing the DNA through the needle at both 43 +/- 3 PSI (78 +/- 4% of control, n = 10, P < 0.05 versus control) and 90 +/- 6 PSI (66 +/- 4 % of control, n = 10, P < 0.01 versus control, P < 0.02 versus 43 +/- 3 PSI). Passage of the DNA through the NOGA needle 20 times resulted in a transfection efficiency of only 5 +/- 1% of control (n = 20, P < 0.1 x 10(-11) versus control). Capillary Electrophoresis revealed that the reduction in transfection efficiency was due to a conformational change in the DNA from predominantly supercoiled to nicked and linearized DNA. Transfection efficiency as compared with control decreased as the concentration of the DNA solution which was passed through the needle was increased from 0.3 micro g/ micro l to 2.4 micro g/ micro l. Recovery experiments confirmed that the reduction in transfection efficiency was not due to loss of DNA by binding to the NOGA needle. CONCLUSION: These results suggest that DNA is susceptible to shear forces when injected through the NOGA needle even at nominal clinical injection pressures, suggesting that careful and controlled injections will be required to achieve optimal gene integrity and expression.     

Delivery and long-term expression of a 135 kb LDLR genomic DNA locus in vivo by hydrodynamic tail vein injection

BACKGROUND: The delivery of a complete genomic DNA locus in vivo may prove advantageous for complementation gene therapy, especially when physiological regulation of gene expression is desirable. Hydrodynamic tail vein injection has been shown to be a highly efficient means of non-viral delivery of plasmid DNA to the liver. Here, we apply hydrodynamic tail vein injection to deliver and express large genomic DNA inserts > 100 kb in vivo. METHODS: Firstly, a size series (12-172 kb) of bacterial artificial chromosome (BAC) plasmids, carrying human genomic DNA inserts, episomal retention elements, and the enhanced green fluorescent protein (EGFP) reporter gene, was delivered to mice by hydrodynamic tail vein injection. Secondly, an episomal BAC vector carrying the whole genomic DNA locus of the human low-density lipoprotein receptor (LDLR) gene, and an expression cassette for the LacZ reporter gene, was delivered by the same method. RESULTS: We show that the efficiency of delivery is independent of vector size, when an equal number of plasmid molecules are used. We also show, by LacZ reporter gene analysis, that BAC delivery within the liver is widespread. Finally, BAC-end PCR, RT-PCR and immunohistochemistry demonstrate plasmid retention and long-term expression (4 months) of human LDLR in transfected hepatocytes. CONCLUSION: This is the first demonstration of somatic delivery and long-term expression of a genomic DNA transgene > 100 kb in vivo and shows that hydrodynamic tail vein injection can be used to deliver and express large genomic DNA transgenes in the liver.     

Potent Immunity to Low Doses of Influenza Vaccine by Probabilistic Guided Micro-Targeted Skin Delivery in a Mouse Model

Background

Over 14 million people die each year from infectious diseases despite extensive vaccine use [1]. The needle and syringe—first invented in 1853—is still the primary delivery device, injecting liquid vaccine into muscle. Vaccines could be far more effective if they were precisely delivered into the narrow layer just beneath the skin surface that contains a much higher density of potent antigen-presenting cells (APCs) essential to generate a protective immune response. We hypothesized that successful vaccination could be achieved this way with far lower antigen doses than required by the needle and syringe.

Methodology/Principal Findings

To meet this objective, using a probability-based theoretical analysis for targeting skin APCs, we designed the Nanopatch™, which contains an array of densely packed projections (21025/cm²) invisible to the human eye (110 µm in length, tapering to tips with a sharpness of <1000 nm), that are dry-coated with vaccine and applied to the skin for two minutes. Here we show that the Nanopatches deliver a seasonal influenza vaccine (Fluvax® 2008) to directly contact thousands of APCs, in excellent agreement with theoretical prediction. By physically targeting vaccine directly to these cells we induced protective levels of functional antibody responses in mice and also protection against an influenza virus challenge that are comparable to the vaccine delivered intramuscularly with the needle and syringe—but with less than 1/100^th of the delivered antigen.

Conclusions/Significance

Our results represent a marked improvement—an order of magnitude greater than reported by others—for injected doses administered by other delivery methods, without reliance on an added adjuvant, and with only a single vaccination. This study provides a proven mathematical/engineering delivery device template for extension into human studies—and we speculate that successful translation of these findings into humans could uniquely assist with problems of vaccine shortages and distribution—together with alleviating fear of the needle and the need for trained practitioners to administer vaccine, e.g., during an influenza pandemic.     

A practical device for pinpoint delivery of molecules into multiple neurons in culture

We have developed a device for pinpoint delivery of chemicals, proteins, and nucleic acids into cultured cells. The principle underlying the technique is the flow of molecules from the culture medium into cells through a rupture in the plasma membrane made by a needle puncture. DNA transfection is achieved by stabbing the needle tip into the nucleus. The CellBee device can be attached to any inverted microscope, and molecular delivery can be coupled with conventional live cell imaging. Because the position of the needle relative to the targeted cultured cells is computer-controlled, efficient delivery of molecules such as rhodamine into as many as 100 HeLa cells can be completed in 10 min. Moreover, specific target cells within a single dish can be transfected with multiple DNA constructs by simple changes of culture medium containing different plasmids. In addition, the nano-sized needle tip enables gentle molecular delivery, minimizing cell damage. This method permits DNA transfection into specific hippocampal neurons without disturbing neuronal circuitry established in culture.