Recombinant bacterial endotoxin testing: a proven solution

Anti-diabetic Biologicals: Exploring the Role of Different Analytical Techniques

Antidiabetic biologicals (ADBs) have revolutionized the treatment of diabetes mellitus, once considered incurable through conventional medicine. These biological products, derived from natural sources via extraction, semi-synthesis, or recombinant DNA technology, include insulin and its analogs, GLP-1 receptor agonists, amylin analogs, and the recently approved monoclonal antibody teplizumab. Regulatory authorities worldwide have established QC parameters outlined in pharmacopoeias, alongside analytical techniques to ensure their safety and efficacy. This review focuses on the analytical techniques used to assess QC parameters of ADBs, including chromatographic methods, spectroscopic techniques, capillary electrophoresis, immunoassays, and endotoxin testing. Key parameters such as identification, potency, purity, and impurity profiling are thoroughly examined. The paper provides a comprehensive and up-to-date compilation of QC requirements and methodologies, along with a detailed comparison of analytical techniques. In doing so, it highlights their advantages and limitations, offering valuable insights for researchers and regulatory professionals involved in selecting suitable methods for QC assessment and understanding the complexities of ADBs evaluation. Furthermore, the article discusses the paramount importance of QC and future perspectives, emphasizing the transition to advanced versions of current techniques driven by the need for efficiency and reliability in quality testing.

Evaluation for endotoxin in intraocular materials used during phacoemulsification surgery using a recombinant factor C assay

OBJECTIVE

Cataract surgery remains the sole method to resolve blindness secondary to cataract formation. One complication includes fibrin web formation post-operatively. This study aimed to investigate the presence of endotoxin within materials used during cataract surgery as a possible cause of fibrin web phenomenon.

METHODS

Preservative-free epinephrine, heparin, viscoelastic devices, and intraocular lenses were collected for evaluation. Various manufacturers and manufacturing lot numbers were used when available. Viscosity of viscoelastics was reduced by incubating samples with human recombinant hyaluronidase. Intraocular product (IOL) packaging fluid was collected and stored for testing. The IOLs were then washed with a sterile balanced salt solution, incubated at 37°C for 48 h, and then fluid was collected for testing to mimic intraocular placement. Samples were tested using a commercially available rFC kit. Fluorescence was measured at time zero and after 1 h using a fluorescence microplate reader. The change in fluorescence was corrected for blank fluorescence and plotted to a standard curve.

RESULTS

Endotoxin levels were below the limit of detection (0.05 EU/mL) in all samples. Incubation of IOLs at intraocular temperature did not increase extraction of endotoxin.

CONCLUSION

Endotoxin was not identified in any tested sample, including those used in cases of fibrin web formation post-phacoemulsification. As fibrin webs are often observed episodically, it is possible that endotoxin levels may vary between batches, or that endotoxin is not related to fibrin formation.

Recombinant Factor C as an In Vitro Assay for the Residual Pathogenicity Evaluation of Veterinary Autogenous Vaccines

BACKGROUND

Veterinary autogenous vaccines, similar to all injectable pharmaceutical products, must be tested to assess endotoxin concentrations. The Limulus Amebocyte Lysate Test (LAL test) is widely used in in vitro quality control assays for endotoxin detection, although it presents some ethical issues related to the production of reagents and is also characterized by a low specificity due to other contaminants that can activate the reaction. For all these reasons, a new recombinant factor C LAL test was developed.

AIM

In this study, we described the comparison between two LAL test methods for in vitro quality control of veterinary autogenous vaccines, with the aim of evaluating the most suitable method and establishing an endotoxin concentration range for two different matrices.

METHODS

Two hundred batches of two different vaccine matrices were tested using the kinetic chromogenic LAL test and recombinant factor C endotoxin detection assay commercial kits.

RESULTS AND CONCLUSIONS

Statistical analysis conducted after the validation of the recombinant factor C test exhibited a statistically significant correlation between the two methods and for both vaccine matrices, suggesting that the animal-free assay can be used as a routine quality control test for veterinary autogenous vaccines.

High-Lactate-Metabolizing Photosynthetic Bacteria Reprogram Tumor Immune Microenvironment

The elevated levels of lactate in tumor tissue play a pivotal role in fostering an immunosuppressive microenvironment. Therefore, efficiently reducing lactate levels to reprogram tumor immune microenvironment (TIM) is considered a crucial step for boosted immunotherapy. Here, a high-lactate-metabolizing photosynthetic bacteria (LAB-1) is selectively screened for TIM reprogramming, which then improves the efficacy of tumor immunotherapy. The culture medium for LAB-1 screening is initially developed through an orthogonal experiment, simulating the tumor microenvironment (TME) and utilizing lactate as the sole organic carbon source. As demonstrated in a murine 4T1 model, LAB-1 colonizes the TME selectively, resulting in a significant reduction in lactate levels and a subsequent increase in pH values within the tumor tissue. Furthermore, single-cell RNA sequencing analysis reveals that LAB-1 effectively reprograms the TIM, thereby enhancing the effectiveness of antitumor immune therapy. This approach of utilizing lactate-consuming bacteria represents a potent tool for augmenting tumor immunotherapy efficiency.

Ophthalmic viscoelastics commonly used in cataract surgery: A microbiota investigation

PURPOSE

To survey commonly used, sterile ophthalmic viscoelastic materials used during routine cataract surgery for the presence of bacterial DNA and/or viable bacteria and endotoxin quantification.

METHODS

Samples from three different ophthalmic viscoelastic manufacturers and three different production lots per manufacturer were collected for 16 S ribosomal ribonucleic acid (rRNA) sequencing and conventional aerobic and capnophilic bacterial culture. Other samples of viscoelastic material from the same three manufacturers were collected for endotoxin quantification using a commercially available Limulus amebocyte lysate (LAL) assay. Statistical analysis was performed using Sigma Plot 14.0, and R v4.0.2.0. Differences (p ≤ .05) between sample collection sites in total DNA concentration, microbial richness, mean intra-group distances, and endotoxin quantification alongside reagent controls were evaluated.

RESULTS

Culture yielded two isolates, identified as Staphylococcus epidermidis and Bacillus megaterium. 16 S rRNA sequencing revealed no differences between brands in richness or overall composition. The most common bacterial DNA detected across all brands was Staphylococcus sp., Cutibacterium sp., Flavobacterium sp., and Lactobacillus sp. A significant difference was found between the median endotoxin concentration between Anvision and Hyvisc® viscoelastic (Anvision: 0.171 EU/mL, Hyvisc®: 0.03 EU/mL; p < .001).

CONCLUSIONS

No brand-specific differences in bacterial DNA were detected in the viscoelastic materials. Staphylococcus, Cutibacterium, Flavobacterium, and Lactobacillus were the dominant contributors to the bacterial DNA detected. Although Anvision viscoelastic samples contained significantly more endotoxin than Hyvisc® viscoelastic samples, endotoxin concentrations were below the FDA limit of 0.2 EU/mL for both manufacturers. These data further the understanding of inflammatory outcomes following cataract surgery.

Advancing the protection of marine life through genomics

The rapid growth in genomic techniques provides the potential to transform how we protect, manage, and conserve marine life. Further, solutions to boost the resilience of marine species to climate change and other disturbances that characterize the Anthropocene require transformative approaches, made more effective if guided by genomic data. Although genetic techniques have been employed in marine conservation for decades and the availability of genomic data is rapidly expanding, widespread application still lags behind other data types. This Essay reviews how genetics and genomics have been utilized in management initiatives for ocean conservation and restoration, highlights success stories, and presents a pathway forward to enhance the uptake of genomic data for protecting our oceans.