Abstract Purpose There are no established criteria for discontinuing ex vivo normothermic limb perfusion (EVNLP) before irreversible damage occurs. This study evaluates weight gain as an indicator of injury during EVNLP. Methods Sixteen Yorkshire pig forelimbs were procured and preserved using EVNLP with a hemoglobin‐based oxygen carrier (HBOC‐201) or static cold storage. EVNLP continued until termination criteria were met: arterial pressure ≥ 115 mm Hg, compartment pressure > 30 mm Hg, or 20% reduction of oxygen saturation. Limb weight, contractility, hemodynamics, perfusate electrolytes, metabolites and gases were recorded. Muscles were biopsied 6‐h, and muscle injury scores (MIS) calculated. Forearm compartment pressures and indocyanine green (ICG) angiography were recorded at endpoint. Outcomes were compared at 2%, 5%, 10%, and 20% limb weight gain. Results EVNLP lasted 20 ± 3 h. Weight gain was observed after 13 ± 5 h (2%), 15 ± 6 h (5%), 16 ± 6 h (10%), and 19 ± 4 h (20%). Weight correlated positively with MIS (ρ = 0.92, p < 0.0001), potassium (ρ = −1.00, p < 0.0001), pressure (ρ = 0.78, p < 0.0001), and negatively with contractility (ρ = −0.96, p = 0.011). At 5% weight gain, MIS (p < 0.0001), potassium (p = 0.03), and lactate (p < 0.0001) were significantly higher than baseline. Median muscle contractility was 5 [3–5] at 2% weight gain, 4 [1–5] at 5%, 3 [0–4] and 2 [0–2] at 10% and 20%, respectively. At 20% weight gain, contractility was significantly lower than baseline (p = 0.003). Percent weight gain correlated negatively with endpoint ICG hoof fluorescence (r = −0.712, p = 0.047). Conclusions Weight gain correlated with microscopic muscle injury and was the earliest evidence of limb dysfunction. Weight gain may serve as a criterion for discontinuation of EVNLP.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/aor.14442

Weight gain is an early indicator of injury in ex vivo normothermic limb perfusion (EVNLP)

The applications of Vascularized composite allotransplantation (VCA) are increasing since the first successful hand transplantation in 1998. However, the abundance of muscle tissue makes VCA's vulnerable to ischemia-reperfusion injury (IRI), which has detrimental effects on the outcome of the procedure, restricting allowable donor-to-recipient time and limiting its widespread use. The current clinical method is Static cold storage (SCS) and this allows only 6 h before irreversible damage occurs upon reperfusion. In order to overcome this obstacle, the focus of research has been shifted towards the prospect of ex-vivo perfusion preservation which already has an established clinical role in solid organ transplants especially in the last decade. In this comprehensive qualitative review, we compile the literature on all VCA machine perfusion models and we aim to highlight the essentials of an ex vivo perfusion set-up, the different strategies, and their associated outcomes.

Review of machine perfusion studies in vascularized composite allotransplant preservation

Background: Vascularized composite allotransplantation has become a viable reconstructive option for selected patients, but preservation remains a major barrier to broader clinical application. Static cold storage is the current gold standard, yet ischemia reperfusion injury and limited preservation times restrict its effectiveness. Recent advances in machine perfusion and subzero non-freezing storage (or supercooling) have prompted renewed interest in optimizing graft viability. Methods: Following PRISMA guidelines, we systematically searched PubMed, EMBASE, and Cochrane, covering studies published from June 2022 through August 2025 for studies on ex vivo preservation of vascularized composite allotransplantations. Eligible articles included original studies in English evaluating postharvest, pretransplant preservation strategies. Data extracted were study design, preservation methods, perfusates, and primary outcomes. Risk of bias was assessed using SYRCLE for animal studies and JBI for human/cadaver studies. Results: Seventeen studies met inclusion criteria: one on static cold storage, thirteen on machine perfusion, and three on supercooling. Static cold storage research has declined, with the only recent study investigating sub-normothermic machine perfusion as a recovery adjunct. Machine perfusion studies focused on optimization of perfusion parameters, perfusate composition, and circuit design. Red blood cell-based perfusates remained common, but alternative oxygen carriers such as polymerized hemoglobin-based oxygen carrier-201 and dextran oxygen microcarriers showed promise despite edema-related challenges. Supercooling studies demonstrated feasibility of multi-day preservation in rodent and porcine models. Overall, risk of bias was high or unclear across animal studies, mainly due to selection and performance bias, whereas the single human ex vivo study showed low risk of bias. Conclusions: The field of vascularized composite allograft preservation is expanding rapidly, with machine perfusion and supercooling emerging as the most promising strategies to extend graft viability beyond the limits of static cold storage. However, translation to clinical setting remains limited by small preclinical studies, methodological heterogeneity, and the paucity of functional and immunologic endpoints. Standardized protocols, robust large-animal models, and eventual human feasibility trials are needed to establish clinically applicable preservation strategies. Level of evidence: IV 

Preservation Strategies for Vascularized Composite Allotransplantation: An Updated Systematic Review of a Rapidly Expanding Field

An injectable ‘biostasis’ drug that could slow organ injury by inducing a state of suspended animation through reversible slowing of metabolic processes would have great value for organ preservation and treatment of badly injured patients at the point-of-care. Using whole-organism screening of metabolism, mobility, and development in Xenopus, we identified an existing drug, SNC80, that rapidly and reversibly slows biochemical and metabolic activities while preserving cell and tissue viability, independently of its known delta opioid receptor modulating activity. Metabolic suppression was also achieved using SNC80 in cultured cells and microfluidic human organs-on-chips, as well as in explanted whole porcine hearts and limbs, demonstrating the cross-species relevance of this approach and potential clinical relevance for surgical transplantation. Thermal proteome profiling revealed that SNC80 targets the NCX1/EEAT1 membrane transport system and chemical modulation of NCX1 induces biostasis in non-hibernating Xenopus tadpoles. Molecular induction of biostasis may offer a new therapeutic approach for organ preservation, trauma management, and enhancing patient survival in remote and low-resource locations.

/pdf/identification-of-a-pharmaceutical-biostasis-inducer-that-1qs28p2b.pdf

Identification of a pharmaceutical biostasis inducer that slows metabolism in multiple vertebrates that do not hibernate

Ex-vivo limb perfusion using a novel portable closed perfusion system reduces edema, and efficiently delivers oxygen maintaining tissue integrity at ambient temperature compared to traditional ex-vivo open perfusion systems. BACKGROUND The two approaches to vascularized tissue machine perfusion use either the open (nonpressurized) or closed (pressurized) perfusion system. Most studies describing isolated limb perfusion preservation rely on open perfusion systems and report tissue edema exceeding 40% after 12 to 14 hours of preservation. A variant of machine perfusion places the limb and perfusate into a reservoir closed to atmosphere. It is hypothesized that the reservoir pressure, acting as a transmural pressure, has the advantage of reducing edema formation by counteracting the hydrostatic pressure gradient from the perfusion pressure. This proof-of-concept study aim was to demonstrate feasibility of the Universal Limb Stasis System for Extended Storage (ULiSSES) device (closed, vertical perfusion system) to preserve forelimbs of Sus scrofa swine for 24 hours of subnormothermic perfusion compared with an open, horizontal perfusion system. The ULiSSES is a compact, practical device that applies pulsatile, pressurized perfusion through the novel use of a diaphragm pump powered by compressed oxygen. METHODS Forelimbs from swine were preserved in ULiSSES device (closed perfusion system) (n = 9) and in an open perfusion system (n = 4) using subnormothermic modified Krebs-Henseleit solution. Physiological parameters were measured at the start and every 3 hours for 24 hours. Limbs were weighed before and after perfusion to compare weight gain. Edema and cellular integrity were evaluated using histopathology pre and post perfusion. RESULTS Closed perfusion system showed superiority compared with the open perfusion system in terms of oxygen consumption, reduction in vascular resistance, and overall tissue integrity. The closed perfusion system demonstrated a 21% reduction in weight gain compared with the open perfusion system and significantly reduced intracellular edema. CONCLUSION The ULiSSES closed, pressurized perfusion technology has translatable military applications with the potential to preserve porcine limbs for 24 hours with improved results compared with an open perfusion system.

Proof of concept study for a closed ex vivo limb perfusion system for 24-hour subnormothermic preservation using acellular perfusate

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

O. Parry

Author Tools

Chat about Author

Papers

Identification of a pharmaceutical biostasis inducer that slows metabolism in multiple vertebrates that do not hibernate

Proof of concept study for a closed ex vivo limb perfusion system for 24-hour subnormothermic preservation using acellular perfusate