A Contemporary Risk Analysis of Iatrogenic Transmission of Creutzfeldt-Jakob Disease (CJD) via Corneal Transplantation in the United States

A Pilot Case Series on the Use of a Large Mushroom-Shaped Corneal Graft for the Surgical Management of Post-Penetrating Keratoplasty Ectasia and Endothelial Failure

Objective: The aim of this study was to evaluate the effect of a surgical technique for managing post-penetrating keratoplasty (PK) ectasia complicated by late endothelial failure (LEF). Methods: A single-center pilot case series was conducted regarding consecutive patients affected by post-PK ectasia with late graft failure. Using a microkeratome, a single donor cornea was dissected to prepare a two-piece graft, comprising a larger anterior lamella made up of anterior stroma and a smaller posterior lamella made up of posterior stroma, Descemet's membrane, and endothelium. The two lamellae were then positioned on the appropriately prepared recipient cornea. The technique was applied to 15 patients between 2022 and 2023, and data were retrospectively collected from preoperative evaluations and at 1, 6, and 12 months, post-operatively. At each visit, patients underwent standard clinical evaluation, corneal topography, and endothelial cell density evaluation, and visual acuity was measured using a LogMAR chart. Results: The technique restored normal corneal curvature and achieved a clear graft in all patients, leading to the resolution of preoperative ectasia and improved corneal pachymetry. At the one-year follow-up, the average K was reduced from 51.1 ± 4.5 D to 43.5 ± 1.1 D; the best corrected visual acuity (BCVA) was improved from 1.1 ± 0.4 to 0.3 ± 0.2 LogMAR; the central corneal thickness was reduced from 629 ± 39 μm to 532 ± 45 µm; and the endothelial cell density was 1926 ± 199 cells/mm2. None of the patients developed severe complications. Conclusions: The two-piece manual mushroom PK may represent an effective technique for managing complex post-PK ectasia cases combined with endothelial decompensation.

The burden of medical contraindications to corneal donation: Time for review

Corneal graft (keratoplasty) is the most common allograft in the world, but the imbalance between the number of donors and the number of patients waiting for transplants is abysmal on a global scale and varies enormously from one country to another. The risk of transmission of systemic diseases from donor to recipient is demonstrably low. In over 50 years and an estimated 2.5 million transplants, only 8 cases of rabies, 2 cases of hepatitis B and 2 cases of Creutzfeldt-Jakob disease (CJD) have been documented. Conversely, other cases of rabies, HIV, hep C, hep B and CJD have not been transmitted via keratoplasty. The list of medical contraindications (CI) to corneal donation also includes diseases for which no actual, only theoretical, risk has been identified, in particular, neurodegenerative diseases, hematological malignancies, melanomas, tumors of the central nervous system, neoplastic meningitis and lymphangitic carcinomatosis. Their contribution to the reduction in the potential donor pool has not previously been investigated. We analyzed 45 months of exhaustive data from the hospital coordination for organ and tissue procurement at St-Etienne University Hospital (01/01/2020 to 06/09/2023). Out of the 2349 consecutive potential donors' files analyzed by the coordination team,1346 (57%) had an CI to donation. The identification of a neurodegenerative disease was the most frequent, accounting for 16% of the files examined and 29% of CIs. Of these, 75% were related to cognitive disorders. The 5 diseases or families of diseases for which there is only theoretical risk of transmission equated to a loss of 712 potential donors, corresponding to 30% of the files examined and 53% of all CIs. Of the 1003 deceased without CI, 738 families (74%) were contacted. No objection to donation was received in 52% of cases, enabling 385 procurements to be carried out. Removing these 5 CIs would have increased the number of donors by 71% (658 instead of 385). The potential pool of corneal donors is significantly restricted by a group of CIs introduced decades ago in response to a theoretical transmission of disease. A substantive amount of evidence now suggests that many CIs now need to be reviewed, modified or discarded altogether. This approach will result in a highly significant worldwide increase in the availability of corneas for transplant and have an immediate and major impact in reducing corneal blindness across the globe. We propose that this reduction in CIs be accompanied by a prospective evaluation process, by allocating the corneas of these donors to patients aged 75 years and over, and by monitoring them for a minimum of 5 years.

Creutzfeldt-Jakob disease: A comprehensive review of current understanding and research

Creutzfeldt-Jakob Disease (CJD) is one of the sample prion diseases that have characteristic features of rapidly progressive neurodegenerative disease manifested by psychomotor changes, some of which include cognitive dysfunction, motor disorder, and behavioral abnormalities. In general, this brief review will assist in elucidating the clinical features and onset, causes, diagnostic challenges, and therapeutic possibilities of CJD. It is classified into sporadic, hereditary, and acquired forms, and affection is identified as linked to the different prion varieties and genetic profiles. The disease process of CJD consists of the deposition of misfolded prions in the brain that causes apoptosis and the subsequent morphological features in the form of spongiform changes. Diagnostic strategies have changed; presently, one can see imaging methods, diagnosis through CSF biomarkers, and genetic-based diagnosis. At this time, there is no cure for CJD; therefore, management and treatment aim at supporting the patient and alleviating the signs and symptoms of the disease. As per our discussion, this review sought to accustom the readers with recent studies conducted, diagnostic advancements, and probable therapeutic approaches, pointing to the general index that more research is needed to fight CJD.

Unveiling the Potential of Enzymatic Detergents to Deactivate Infectious Prions

When infectious misfolded proteins self-propagate, they cause transmissible spongiform encephalopathies (TSEs) or prion diseases. TSEs are rare, progressive neurodegenerative diseases with long incubation times and are always fatal. Iatrogenic transmission of these diseases is a major concern for human health, and existing methods of decontamination are either ineffective or require caustic chemical treatment followed by extended steam sterilization cycles. Research was undertaken to explore using enzymatic detergents to decontaminate prion-laden surgical devices, equipment, and stainless-steel tools using existing healthcare facility protocols, including cleaning followed by steam or low-temperature sterilization. Several formulations of enzymatic detergents were used to clean stainless steel wires contaminated with infected hamster brain homogenate. Buffering the solutions to achieve a final pH between 8.5 and 9 when diluted, followed by sonication at 45 to 60°C, was effective in rendering prions undetectable in Western blot images. Subsequent sterilization in an autoclave improved the results, causing further prion degradation. Protein misfolding cyclic amplification showed that adding a four-minute prevacuum auto-clave cycle produced a less than 5-log to 6-log reduction in infectious prion proteins using a multienzymatic detergent and a 6-log reduction using a protease enzyme detergent. Increasing the autoclave cycle to 18 minutes generated a consistent 6-log reduction for both formulations, which is the accepted benchmark for effective sterilization.

A Systematic Review of Sporadic Creutzfeldt-Jakob Disease: Pathogenesis, Diagnosis, and Therapeutic Attempts

Creutzfeldt-Jakob disease is a rare neurodegenerative and invariably fatal disease with a fulminant course once the first clinical symptoms emerge. Its incidence appears to be rising, although the increasing figures may be related to the improved diagnostic tools. Due to the highly variable clinical picture at onset, many specialty physicians should be aware of this disease and refer the patient to a neurologist for complete evaluation. The diagnostic criteria have been changed based on the considerable progress made in research on the pathogenesis and on the identification of reliable biomarkers. Moreover, accumulated knowledge on pathogenesis led to the identification of a series of possible therapeutic targets, although, given the low incidence and very rapid course, the evaluation of safety and efficacy of these therapeutic strategies is challenging.

National Consensus on Contraindications for Corneal Donation for Transplantation in Switzerland

PURPOSE

To establish a national consensus on contraindications for corneal donation for transplantation in Switzerland.

METHODS

Swisstransplant (SWT), the Swiss national foundation coordinating tissue and organ donations, convened a working group consisting of six national corneal surgeons and eye bankers and donation experts to create a contraindication list for corneal donation. The group reviewed available national and international guidelines and recommendations, while adhering to Swiss law and transplant regulations. In cases of opposing opinions, the group held follow-up meetings until a consensus was reached. A consensus was defined as agreement among all parties present.

RESULTS

From March 2021 to November 2021, the study group held six meetings and created a standardized minimal contraindication list for corneal donation in Switzerland. Thanks to this list, SWT has created a mandatory working and documentation file for donor coordinators to use when evaluating multiorgan donors for corneal harvesting. The authors agreed that while the national consensus list provides standardized minimal contraindication criteria, local eye banks may choose to introduce additional, more rigorous criteria.

CONCLUSION

Given that corneal transplantation is the most commonly performed transplantation, establishing a consensus on contraindications is crucial for recipient safety. The creation of a consensus on contraindications for corneal donation in Switzerland is an essential contribution to fulfil the legal requirements concerning quality assurance and provides sufficient high-quality donor tissue within the country. Therefore, periodic review and revision of the consensus is considered critical.

Risk assessment of variant Creutzfeldt-Jakob disease in corneal transplantation

Purpose

While corneal transplantation is known to have a potential risk of transmission of variant Creutzfeldt-Jacob Disease (vCJD), the magnitude of this risk has not been quantified.

Observations

A case report is presented of a 73 year-old man with a penetrating keratoplasty graft from corneal tissue that was recalled after transplantation due to risk of vCJD because it was later discovered that the donor had traveled to the United Kingdom (UK). Probabilities of vCJD transmission were extrapolated using Creutzfeldt-Jacob Disease (CJD) mortality (incidence) rate, all-cause death rate, and rate of recovery for intended transplantation.

Conclusions

An overestimate of the risk of transplanting a cornea infected with vCJD in 2018 was 1 in 940,000. The true risk of vCJD transmission would be even lower due to an incomplete infectivity rate. We conclude that the risk of transmission of latent vCJD by corneal transplantation from a donor who traveled to the UK from 1980 to 1996 is exceedingly low.

An Overview of Corneal Transplantation in the Past Decade

The cornea is a transparent avascular structure located in the front of the eye that refracts light entering the eyes and also serves as a barrier between the outside world and the internal contents of the eye. Like every other body part, the cornea may suffer insult from trauma, infection, and inflammation. In the case of trauma, a prior infection that left a scar, or conditions such as keratoconus that warrant the removal of all or part of the cornea (keratoplasty), it is important to use healthy donor corneal tissues and cells that can replace the damaged cornea. The types of cornea transplant techniques employed currently include: penetrating keratoplasty, endothelial keratoplasty (EK), and artificial cornea transplant. Postoperative failure acutely or after years can result after a cornea transplant and may require a repeat transplant. This minireview briefly examines the various types of corneal transplant methodologies, indications, contraindications, presurgical protocols, sources of cornea transplant material, wound healing after surgery complications, co-morbidities, and the effect of COVID-19 in corneal transplant surgery.

Human prion diseases and the prion protein - what is the current state of knowledge?

Prion diseases and the prion protein are only partially understood so far in many aspects. This explains the continued research on this topic, calling for an overview on the current state of knowledge. The main objective of the present review article is to provide a comprehensive up-to-date presentation of all major features of human prion diseases bridging the gap between basic research and clinical aspects. Starting with the prion protein, current insights concerning its physiological functions and the process of pathological conversion will be highlighted. Diagnostic, molecular, and clinical aspects of all human prion diseases will be discussed, including information concerning rare diseases like prion-associated amyloidoses and Huntington disease-like 1, as well as the question about a potential human threat due to the transmission of prions from prion diseases of other species such as chronic wasting disease. Finally, recent attempts to develop future therapeutic strategies will be addressed.