Silk Fibroin-Based Coatings for Pancreatin-Dependent Drug Delivery

Triggerable coatings, such as pH-responsive polymethacrylate copolymers, can be used to protect the active pharmaceutical ingredients contained within oral solid dosage forms from the acidic gastric environment and to facilitate drug delivery directly to the intestine. However, gastrointestinal pH can be highly variable, which can reduce delivery efficiency when using pH-responsive drug delivery technologies. We hypothesized that biomaterials susceptible to proteolysis could be used in combination with other triggerable polymers to develop novel enteric coatings. Bioinformatic analysis suggested that silk fibroin is selectively degradable by enzymes in the small intestine, including chymotrypsin, but resilient to gastric pepsin. Based on the analysis, we developed a silk fibroin-polymethacrylate copolymer coating for oral dosage forms. In vitro and in vivo studies demonstrated that capsules coated with this novel silk fibroin formulation enable pancreatin-dependent drug release. We believe that this novel formulation and extensions thereof have the potential to produce more effective and personalized oral drug delivery systems for vulnerable populations including patients that have impaired and highly variable intestinal physiology.

Sub-1.4 cm3 capsule for detecting labile inflammatory biomarkers in situ

Transient molecules in the gastrointestinal tract such as nitric oxide and hydrogen sulfide are key signals and mediators of inflammation. Owing to their highly reactive nature and extremely short lifetime in the body, these molecules are difficult to detect. Here we develop a miniaturized device that integrates genetically engineered probiotic biosensors with a custom-designed photodetector and readout chip to track these molecules in the gastrointestinal tract. Leveraging the molecular specificity of living sensors1, we genetically encoded bacteria to respond to inflammation-associated molecules by producing luminescence. Low-power electronic readout circuits2 integrated into the device convert the light emitted by the encapsulated bacteria to a wireless signal. We demonstrate in vivo biosensor monitoring in the gastrointestinal tract of small and large animal models and the integration of all components into a sub-1.4 cm3 form factor that is compatible with ingestion and capable of supporting wireless communication. With this device, diseases such as inflammatory bowel disease could be diagnosed earlier than is currently possible, and disease progression could be more accurately tracked. The wireless detection of short-lived, disease-associated molecules with our device could also support timely communication between patients and caregivers, as well as remote personalized care.

In Situ Detection of Gastrointestinal Inflammatory Biomarkers Using Electrochemical Gas Sensors

More than two decades ago it was discovered that nitric oxide (NO) concentrations in gas aspirated during colonoscopy were more than 100 times higher in patients diagnosed with Ulcerative Colitis (UC) than controls. While this provides a diagnostic opportunity, it has not been possible to perform in situ detection of NO via a non-invasive manner. This work presents the feasibility of in situ detection of NO by means of a capsule-like electrochemical gas sensor. Our in vivo results in a large animal model of intestinal inflammation show that NO can be directly detected at the site of inflammation and that it quickly dissipates to surrounding tissues, demonstrating the importance of in situ detection.

Delivery of therapeutic carbon monoxide by gas-entrapping materials

Carbon monoxide (CO) has long been considered a toxic gas but is now a recognized bioactive gasotransmitter with potent immunomodulatory effects. Although inhaled CO is currently under investigation for use in patients with lung disease, this mode of administration can present clinical challenges. The capacity to deliver CO directly and safely to the gastrointestinal (GI) tract could transform the management of diseases affecting the GI mucosa such as inflammatory bowel disease or radiation injury. To address this unmet need, inspired by molecular gastronomy techniques, we have developed a family of gas-entrapping materials (GEMs) for delivery of CO to the GI tract. We show highly tunable and potent delivery of CO, achieving clinically relevant CO concentrations in vivo in rodent and swine models. To support the potential range of applications of foam GEMs, we evaluated the system in three distinct disease models. We show that a GEM containing CO dose-dependently reduced acetaminophen-induced hepatocellular injury, dampened colitis-associated inflammation and oxidative tissue injury, and mitigated radiation-induced gut epithelial damage in rodents. Collectively, foam GEMs have potential paradigm-shifting implications for the safe therapeutic use of CO across a range of indications.

An automated all-in-one system for carbohydrate tracking, glucose monitoring, and insulin delivery

Glycemic control through titration of insulin dosing remains the mainstay of diabetes mellitus treatment. Insulin therapy is generally divided into dosing with long- and short-acting insulin, where long-acting insulin provides basal coverage and short-acting insulin supports glycemic excursions associated with eating. The dosing of short-acting insulin often involves several steps for the user including blood glucose measurement and integration of potential carbohydrate loads to inform safe and appropriate dosing. The significant burden placed on the user for blood glucose measurement and effective carbohydrate counting can manifest in substantial effects on adherence. Through the application of computer vision, we have developed a smartphone-based system that is able to detect the carbohydrate load of food by simply taking a single image of the food and converting that information into a required insulin dose by incorporating a blood glucose measurement. Moreover, we report the development of comprehensive all-in-one insulin delivery systems that streamline all operations that peripheral devices require for safe insulin administration, which in turn significantly reduces the complexity and time required for titration of insulin. The development of an autonomous system that supports maximum ease and accuracy of insulin dosing will transform our ability to more effectively support patients with diabetes.

Dynamic Monitoring of Systemic Biomarkers with Gastric Sensors

Continuous monitoring in the intensive care setting has transformed the capacity to rapidly respond with interventions for patients in extremis. Noninvasive monitoring has generally been limited to transdermal or intravascular systems coupled to transducers including oxygen saturation or pressure. Here it is hypothesized that gastric fluid (GF) and gases, accessible through nasogastric (NG) tubes, commonly found in intensive care settings, can provide continuous access to a broad range of biomarkers. A broad characterization of biomarkers in swine GF coupled to time-matched serum is conducted . The relationship and kinetics of GF-derived analyte level dynamics is established by correlating these to serum levels in an acute renal failure and an inducible stress model performed in swine. The ability to monitor ketone levels and an inhaled anaesthetic agent (isoflurane) in vivo is demonstrated with novel NG-compatible sensor systems in swine. Gastric access remains a main stay in the care of the critically ill patient, and here the potential is established to harness this establishes route for analyte evaluation for clinical management.

Historical Evolution and Provider Awareness of Inactive Ingredients in Oral Medications

PURPOSE

A multitude of different versions of the same medication with different inactive ingredients are currently available. It has not been quantified how this has evolved historically. Furthermore, it is unknown whether healthcare professionals consider the inactive ingredient portion when prescribing medications to patients.

METHODS

We used data mining to track the number of available formulations for the same medication over time and correlate the number of available versions in 2019 to the number of manufacturers, the years since first approval, and the number of prescriptions. A focused survey among healthcare professionals was conducted to query their consideration of the inactive ingredient portion of a medication when writing prescriptions.

RESULTS

The number of available versions of a single medication have dramatically increased in the last 40 years. The number of available, different versions of medications are largely determined by the number of manufacturers producing this medication. Healthcare providers commonly do not consider the inactive ingredient portion when prescribing a medication.

CONCLUSIONS

A multitude of available versions of the same medications provides a potentially under-recognized opportunity to prescribe the most suitable formulation to a patient as a step towards personalized medicine and mitigate potential adverse events from inactive ingredients.

Carbon monoxide improves haemodynamics during extracorporeal resuscitation in pigs

AIMS

Heart disease of different aetiology remains the leading cause of cardiac arrest (CA). Despite efforts to improve the quality of cardiopulmonary resuscitation (CPR), subsequent myocardial and systemic damage after CA still present a major long-term burden. Low-dose carbon monoxide (CO) is known to exert protective effects in cardiovascular pathophysiology but clinical applications are challenged by unfavourable delivery modes. We tested the hypothesis that extracorporeal resuscitation (E-CPR) in combination with controlled fast onset CO delivery results in improved cardiac physiology and haemodynamics. Damage-associated molecular pattern (DAMP) signalling may be part of the molecular mechanism.

METHODS AND RESULTS

In an established porcine model, E-CPR was performed. While E-CPR leads to similar results as compared to a conventional CPR strategy, CO delivery in combination with E-CPR demonstrated significant cardioprotection. Cardiac performance analysis using echocardiography and thermodilution techniques showed a CO-dependent improved cardiac function compared to severe myocardial dysfunction in CPR and E-CPR (left ventricular ejection fraction: Sham 49 ± 5; CPR 26 ± 2; E-CPR 25 ± 2; CO-E-CPR 31 ± 4; P < 0.05). While sublingual microcirculation was significantly compromised in CPR and E-CPR, CO delivery demonstrated a significant improvement in microvascular function (microvascular flow index: Sham 2.9 ± 0.1; CPR 2.2 ± 0.1; E-CPR 1.8 ± 0.1; CO-E-CPR 2.7 ± 0.1; P < 0.01). Histological and serological myocardial damage markers were significantly reduced (hsTroponin-T Sham 0.01 ± 0.001; CPR 1.9 ± 0.2; E-CPR 3.5 ± 1.2; CO-E-CPR 0.5 ± 0.2 ng/mL; P < 0.05). DAMP signalling was decreased ipse facto leading to influence of cardioprotective heat shock and cyclooxygenase response.

CONCLUSIONS

CO treatment restores myocardial function and improves systemic macro- and microhaemodynamics in E-CPR through a reduction in DAMPs.

Development of a long-acting direct-acting antiviral system for hepatitis C virus treatment in swine

Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis worldwide and kills more Americans than 59 other infections, including HIV and tuberculosis, combined. While direct-acting antiviral (DAA) treatments are effective, limited uptake of therapy, particularly in high-risk groups, remains a substantial barrier to eliminating HCV. We developed a long-acting DAA system (LA-DAAS) capable of prolonged dosing and explored its cost-effectiveness. We designed a retrievable coil-shaped LA-DAAS compatible with nasogastric tube administration and the capacity to encapsulate and release gram levels of drugs while resident in the stomach. We formulated DAAs in drug-polymer pills and studied the release kinetics for 1 mo in vitro and in vivo in a swine model. The LA-DAAS was equipped with ethanol and temperature sensors linked via Bluetooth to a phone application to provide patient engagement. We then performed a cost-effectiveness analysis comparing LA-DAAS to DAA alone in various patient groups, including people who inject drugs. Tunable release kinetics of DAAs was enabled for 1 mo with drug-polymer pills in vitro, and the LA-DAAS safely and successfully provided at least month-long release of sofosbuvir in vivo. Temperature and alcohol sensors could interface with external sources for at least 1 mo. The LA-DAAS was cost-effective compared to DAA therapy alone in all groups considered (base case incremental cost-effectiveness ratio $39,800). We believe that the LA-DAA system can provide a cost-effective and patient-centric method for HCV treatment, including in high-risk populations who are currently undertreated.

Carbon Monoxide Exerts Functional Neuroprotection After Cardiac Arrest Using Extracorporeal Resuscitation in Pigs

OBJECTIVES

Neurologic damage following cardiac arrest remains a major burden for modern resuscitation medicine. Cardiopulmonary resuscitation with extracorporeal circulatory support holds the potential to reduce morbidity and mortality. Furthermore, the endogenous gasotransmitter carbon monoxide attracts attention in reducing cerebral injury. We hypothesize that extracorporeal resuscitation with additional carbon monoxide application reduces neurologic damage.

DESIGN

Randomized, controlled animal study.

SETTING

University research laboratory.

SUBJECTS

Landrace-hybrid pigs.

INTERVENTIONS

In a porcine model, carbon monoxide was added using a novel extracorporeal releasing system after resuscitation from cardiac arrest.

MEASUREMENTS AND MAIN RESULTS

As markers of cerebral function, neuromonitoring modalities (somatosensory-evoked potentials, cerebral oximetry, and transcranial Doppler ultrasound) were used. Histopathologic damage and molecular markers (caspase-3 activity and heme oxygenase-1 expression) were analyzed. Cerebral oximetry showed fast rise in regional oxygen saturation after carbon monoxide treatment at 0.5 hours compared with extracorporeal resuscitation alone (regional cerebral oxygen saturation, 73% ± 3% vs 52% ± 8%; p < 0.05). Median nerve somatosensory-evoked potentials showed improved activity upon carbon monoxide treatment, whereas post-cardiac arrest cerebral perfusion differences were diminished. Histopathologic damage scores were reduced compared with customary resuscitation strategies (hippocampus: sham, 0.4 ± 0.2; cardiopulmonary resuscitation, 1.7 ± 0.4; extracorporeal cardiopulmonary resuscitation, 2.3 ± 0.2; extracorporeal cardiopulmonary resuscitation with carbon monoxide application [CO-E-CPR], 0.9 ± 0.3; p < 0.05). Furthermore, ionized calcium-binding adaptor molecule 1 staining revealed reduced damage patterns upon carbon monoxide treatment. Caspase-3 activity (cardiopulmonary resuscitation, 426 ± 169 pg/mL; extracorporeal cardiopulmonary resuscitation, 240 ± 61 pg/mL; CO-E-CPR, 89 ± 26 pg/mL; p < 0.05) and heme oxygenase-1 (sham, 1 ± 0.1; cardiopulmonary resuscitation, 2.5 ± 0.4; extracorporeal cardiopulmonary resuscitation, 2.4 ± 0.2; CO-E-CPR, 1.4 ± 0.2; p < 0.05) expression were reduced after carbon monoxide exposure.

CONCLUSIONS

Carbon monoxide application during extracorporeal resuscitation reduces injury patterns in neuromonitoring and decreases histopathologic cerebral damage by reducing apoptosis. This may lay the basis for further clinical translation of this highly salutary substance.

A gastric resident drug delivery system for prolonged gram-level dosing of tuberculosis treatment

Multigram drug depot systems for extended drug release could transform our capacity to effectively treat patients across a myriad of diseases. For example, tuberculosis (TB) requires multimonth courses of daily multigram doses for treatment. To address the challenge of prolonged dosing for regimens requiring multigram drug dosing, we developed a gastric resident system delivered through the nasogastric route that was capable of safely encapsulating and releasing grams of antibiotics over a period of weeks. Initial preclinical safety and drug release were demonstrated in a swine model with a panel of TB antibiotics. We anticipate multiple applications in the field of infectious diseases, as well as for other indications where multigram depots could impart meaningful benefits to patients, helping maximize adherence to their medication.

Our surgical technique to treat premature growth plate closure 7 years after toe-to-thumb transfer. A case report

In children, traumatic distal amputations of the thumb can be treated by partial first toe transfer. Growth is preserved by conserving a portion of the growth plate in the hallux distal phalanx. In the patient featured here, 7 years after such a distal thumb reconstruction, bone bridge resection was needed to restart growth and correct clinodactyly. When this patient was reviewed 4 years later, the thumb's longitudinal growth had been restored and continued.

Do teenagers return to normal physical activity levels after limb fractures? A longitudinal, accelerometry-based, activity monitoring study

PURPOSE

This study aimed to elucidate whether levels of physical activity (PA) return to normal after bone healing or whether long-term behavioural changes in PA are to be expected in children and teenagers who have sustained limb fractures.

METHODS

In all, 100 children and teenagers with a first episode of limb fracture and 100 sex- and age-matched healthy controls (CTRL) were recruited for a prospective study. PA in limb fracture patients was assessed at 18-month follow-up using accelerometer measurements, and values were compared with those of CTRL. Time spent in PA at different levels of intensity was determined for each participant and expressed in minutes and as a percentage of total validly measured time.

RESULTS

Mean levels of PA at different levels of intensity by previously injured children and teenagers were similar than CTRL (42 sets of paired data). However, time spent in moderate-to-vigorous PA (MVPA) was lower than 60 minutes among limb-fracture patients at 18-month follow-up.

CONCLUSION

The amount of skeletal loading in children and teenagers returns to normal values by 18 months after limb fracture. Even if time spent in MVPA is not significantly lower in children and teenagers with limb fractures, it no longer reached the international recommendations for school-aged children (MVPA > 60 minutes), which may be interpreted as a lifestyle modification or a behavioural change to avoid new trauma.

LEVEL OF EVIDENCE

II.

Extracorporeal resuscitation with carbon monoxide improves renal function by targeting inflammatory pathways in cardiac arrest in pigs

Deleterious consequences like acute kidney injury frequently occur upon successful resuscitation from cardiac arrest. Extracorporeal life support is increasingly used to overcome high cardiac arrest mortality. Carbon monoxide (CO) is an endogenous gasotransmitter, capable of reducing renal injury. In our study, we hypothesized that addition of CO to extracorporeal resuscitation hampers severity of renal injury in a porcine model of cardiac arrest. Hypoxic cardiac arrest was induced in pigs. Animals were resuscitated using a conventional [cardiopulmonary resuscitation (CPR)], an extracorporeal (E-CPR), or a CO-assisted extracorporeal (CO-E-CPR) protocol. CO was applied using a membrane-controlled releasing system. Markers of renal injury were measured, and histopathological analyses were carried out. We investigated renal pathways involving inflammation as well as apoptotic cell death. No differences in serum neutrophil gelatinase-associated lipocalin (NGAL) were detected after CO treatment compared with Sham animals (Sham 71 ± 7 and CO-E-CPR 95 ± 6 ng/mL), while NGAL was increased in CPR and E-CPR groups (CPR 135 ± 11 and E-CPR 124 ± 5 ng/mL; P < 0.05). Evidence for histopathological damage was abrogated after CO application. CO increased renal heat shock protein 70 expression and reduced inducible cyclooxygenase 2 (CPR: 60 ± 8; E-CPR 56 ± 8; CO-E-CPR 31 ± 3 µg/mL; P < 0.05). Caspase 3 activity was decreased (CPR 1,469 ± 276; E-CPR 1,670 ± 225; CO-E-CPR 755 ± 83 pg/mL; P < 0.05). Furthermore, we found a reduction in renal inflammatory signaling upon CO treatment. Our data demonstrate improved renal function by extracorporeal CO treatment in a porcine model of cardiac arrest. CO reduced proinflammatory and proapoptotic signaling, characterizing beneficial aspects of a novel treatment option to overcome high mortality.

"Inactive" ingredients in oral medications

Oral forms of medications contain "inactive" ingredients to enhance their physical properties. Using data analytics, we characterized the abundance and complexity of inactive ingredients in approved medications. A majority of medications contain ingredients that could cause adverse reactions, underscoring the need to maximize the tolerability and safety of medications and their inactive ingredients.

Ingestible hydrogel device

Devices that interact with living organisms are typically made of metals, silicon, ceramics, and plastics. Implantation of such devices for long-term monitoring or treatment generally requires invasive procedures. Hydrogels offer new opportunities for human-machine interactions due to their superior mechanical compliance and biocompatibility. Additionally, oral administration, coupled with gastric residency, serves as a non-invasive alternative to implantation. Achieving gastric residency with hydrogels requires the hydrogels to swell very rapidly and to withstand gastric mechanical forces over time. However, high swelling ratio, high swelling speed, and long-term robustness do not coexist in existing hydrogels. Here, we introduce a hydrogel device that can be ingested as a standard-sized pill, swell rapidly into a large soft sphere, and maintain robustness under repeated mechanical loads in the stomach for up to one month. Large animal tests support the exceptional performance of the ingestible hydrogel device for long-term gastric retention and physiological monitoring.

Phosphodiesterase-4 inhibition reduces ECLS-induced vascular permeability and improves microcirculation in a rodent model of extracorporeal resuscitation

Extracorporeal circulation can be accompanied by increased vascular permeability leading to pathological fluid balance and organ dysfunction. The second messenger cAMP is involved in capillary permeability and maintains endothelial integrity. The aim of the present study was to evaluate the effect of phosphodiesterase-4 (PDE4) inhibition with rolipram on extracorporeal circulation-induced capillary leakage, microcirculatory dysfunction, and organ injury in rodents. Rats were randomly allocated to the following groups: sham ( n = 5), venoarterial extracorporeal circulation [extracorporeal life support (ECLS), n = 7], ECLS + rolipram ( n = 7), extracorporeal resuscitation (ECPR; n = 7), and ECPR + rolipram ( n = 7). In the groups that underwent ECPR, ECLS-based cardiopulmonary resuscitation (ECPR) was performed after the induction of hypoxic cardiac arrest. Upon return of spontaneous circulation, rolipram was administered intravenously. The mesenteric microcirculation was studied using intravital microscopy, and organ specimens were harvested upon completion of the study. ECLS and ECPR induced a proinflammatory response (cytokines IL-1β, IL-6, and TNF-α). Although PDE4 expression was upregulated in vascular tissue, PDE4 inhibition abrogated impaired microcirculation and capillary leak (albumin extravasation of the sham group: 1 ± 0.03-fold, ECLS group: 1.2 ± 0.05-fold, ECLS + rolipram group: 0.99 ± 0.04-fold, ECPR group: 1.6 ± 0.04-fold, and ECPR + rolipram group: 1.06 ± 0.02-fold from the sham group, P < 0.05). PDE4 inhibition led to stabilization of vascular cAMP levels but did not affect cytokine levels. Capillary leak was reduced, as demonstrated by the decrease of the systemic biomarkers soluble vascular-endothelial cadherin and activated complement 3. Histological analysis revealed reduced injury to the lungs and kidneys after PDE4 inhibition, with a significant decrease in systemic renal damage markers. Our findings demonstrate that extracorporeal circulation causes an inflammatory reaction associated with decreased vascular cAMP levels, increased vascular permeability, and impaired microcirculation. PDE4 inhibition proved to be capable of reducing these side effects in ECLS and ECPR, leading to reduced microcirculatory, renal, and pulmonary injury. NEW & NOTEWORTHY Various complications are common after extracorporeal circulation. Among these, endothelial injury may cause impaired microcirculation and capillary leak. Here, we report that phosphodiesterase-4 inhibition targeting endothelial cAMP is capable of reducing microvascular complications in a rodent model of extracorporeal resuscitation. Microcirculation and vascular permeability are influenced without targeting extracorporeal circulation-induced inflammation. Thus, pulmonary and renal organ protection may be conferred.

Overcoming safety challenges in CO therapy - Extracorporeal CO delivery under precise feedback control of systemic carboxyhemoglobin levels

Carbon monoxide (CO) has demonstrated therapeutic potential in multiple inflammatory conditions including intensive care applications such as organ transplantation or sepsis. Approaches to translate these findings into future therapies, however, have been challenged by multiple hurdles including handling and toxicity issues associated with systemic CO delivery. Here, we describe a membrane-controlled Extracorporeal Carbon Monoxide Release System (ECCORS) for easy implementation into Extracorporeal Membrane Oxygenation (ECMO) setups, which are being used to treat cardiac and respiratory diseases in various intensive care applications. Functionalities of the ECCORS were investigated in a pig model of veno-arterial ECMO. By precisely controlling CO generation and delivery as a function of systemic carboxyhemoglobin levels, the system allows for an immediate onset of therapeutic CO-levels while preventing CO-toxicity. Systemic carboxyhemoglobin levels were profiled in real-time by monitoring exhaled CO levels as well as by pulse oximetry, enabling self-contained and automatic feedback control of CO generation within ECCORS. Machine learning based mathematical modeling was performed to increase the predictive power of this approach, laying foundation for high precision systemic CO delivery concepts of tomorrow.

Localized delivery of carbon monoxide

The heme oxygenase (HO)/carbon monoxide (CO) system is a physiological feedback loop orchestrating various cell-protective effects in response to cellular stress. The therapeutic use of CO is impeded by safety challenges as a result of high CO-Hemoglobin formation following non-targeted, systemic administration jeopardizing successful CO therapies as of this biological barrier. Another caveat is the use of CO-Releasing Molecules containing toxicologically critical transition metals. An emerging number of local delivery approaches addressing these issues have recently been introduced and provide exciting new starting points for translating the fascinating preclinical potential of CO into a clinical setting. This review will discuss these approaches and link to future delivery strategies aiming at establishing CO as a safe and effective medication of tomorrow.

Prevention of colitis by controlled oral drug delivery of carbon monoxide

Carbon monoxide (CO) is an endogenous signal transmitter involved in numerous physiological processes including the gastrointestinal (GI) homeostasis. CO has been recognized as potential new therapeutic agent for motility related and inflammatory disorders of the GI tract. A therapeutic use, however, is challenged by inappropriate drug delivery modes. Here we describe a micro scale Oral Carbon Monoxide Release System (M-OCORS) designed for localized and controlled exposure of the GI tract with in situ generated CO. M-OCORS allowed for controlled release profiles lasting for several minutes or up to almost one day. These in vitro release profiles translated into a large pharmacokinetic design space following oral administration in mice and measured as CO-hemoglobin (CO-Hb) formation. M-OCORS with a release profile featuring exposure of the intestine was profiled in two independently performed studies demonstrating preventive effects in chemically induced colitis. M-OCORS significantly reduced damage scores and prevented upregulation of colitis biomarkers.

Controlled therapeutic gas delivery systems for quality-improved transplants

Therapeutic gases enriched into perfusion solutions have been effectively used for the improvement of organ transplant quality. At present, the enrichment of perfusion solutions with gases requires complex machinery/containers and handling precautions. Alternatively, the gas is generated within the perfusion solution by supplemented carbonylated transition metal complexes with associated toxicological concerns when these metals contact the transplant. Therefore, we developed therapeutic gas releasing systems (TGRSs) allowing for the controlled generation and release of therapeutic gases (carbon monoxide and hydrogen sulfide) from otherwise hermetically sealed containers, such that the perfusion solution for the transplant is saturated with the gas but no other components from the TGRS are liberated in the solution. The release from the TGRS into the perfusion solution can be tailored as a function of the number and thickness of gas permeable membranes leading to release patterns having been linked to therapeutic success in previous trials. Furthermore, the surrogate biomarker HMGB1 was significantly downregulated in ischemic rat liver transplants perfused with enriched CO solution as compared to control. In conclusion, the TGRS allows for easy, reliable, and controlled generation and release of therapeutic gases while removing safety concerns of current approaches, thereby positively impacting the risk benefit profile of using therapeutic gases for transplant quality improvement in the future.

Cellular and complement-dependent cytotoxicity of Ep-CAM-specific monoclonal antibody MT201 against breast cancer cell lines

MT201 is a fully human monoclonal IgG1 antibody with moderate affinity for epithelial cell adhesion molecule (Ep-CAM) being clinically developed for the treatment of carcinomas. Like many other clinically validated IgG1 monoclonal antibodies, MT201 primarily acts by antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Here, we analysed ADCC and CDC induced by MT201 and, as reference, trastuzumab against a panel of nine human breast cancer cell lines expressing distinct surface levels of Ep-CAM and human epithelial growth factor receptor type 2 antigen. Maximal cell lysis by ADCC by MT201 and trastuzumab in the presence of peripheral mononuclear cells did not significantly differ when averaged over the nine cell lines, but showed marked differences with respect to individual cell lines. The extent of cell lysis at intermediate surface target density was highly variable, suggesting a dominant influence of other susceptibility factors. Only one breast cancer cell line was eliminated via CDC, but only by MT201. Resistance to CDC appeared to correlate with high expression levels of complement resistance factors. Our present data as well as recent data on the prevalence and prognostic relevance of Ep-CAM expression in metastatic breast cancer suggest that Ep-CAM-specific monoclonal IgG1 antibodies may have a significant therapeutic potential in the treatment of breast cancer.

Determinants of viral clearance and persistence during acute hepatitis C virus infection

The virological and immunological features of hepatitis C virus (HCV) infection were studied weekly for 6 months after accidental needlestick exposure in five health care workers, four of whom developed acute hepatitis that progressed to chronicity while one subject cleared the virus. In all subjects, viremia was first detectable within 1-2 weeks of inoculation, 1 month or more before the appearance of virus-specific T cells. The subject who cleared the virus experienced a prolonged episode of acute hepatitis that coincided with a CD38+ IFN-gamma- CD8+ T cell response to HCV and a small reduction in viremia. Subsequently, a strong CD4+ T cell response emerged and the CD8+ T cells became CD38- and started producing IFN-gamma in response to HCV, coinciding with a rapid 100,000-fold decrease in viremia that occurred without a corresponding surge of disease activity. Chronic infection developed in two subjects who failed to produce a significant T cell response and in two other subjects who initially mounted strong CD4+ T cell responses that ultimately waned. In all subjects, viremia was higher at the peak of acute hepatitis than it was when the disease began, and the disease improved during the viremia. These results provide the first insight into the host-virus relationship in humans during the incubation phase of acute HCV infection, and they provide the only insight to date into the virological and immunological characteristics of clinically asymptomatic acute HCV infection, the commonest manifestation of this disease. In addition, the results suggest that the vigor and quality of the antiviral T cell response determines the outcome of acute HCV infection, that the ability of HCV to outpace the T cell response may contribute to its tendency to persist; that the onset of hepatitis coincides with the onset of the CD8+ T cell response, that disease pathogenesis and viral clearance are mediated by different CD8+ T cell populations that control HCV by both cytolytic and noncytolytic mechanisms, and that there are different pathways to viral persistence in asymptomatic and symptomatic acute HCV infection.