Related Experiment Video
Updated: Jul 18, 2026
Normothermic Machine Perfusion of Rat Kidneys for Transplantation
Published on: January 27, 2026
Microscopic intrarenal particles after pulsatile machine preservation do not adversely affect outcomes after renal
J V Guarrera1, S H Nasr, C M Reverte
1Division of Abdominal Organ Transplantation, New York Presbyterian Hospital, New York, New York, USA.
Introduction:
Our center has recently observed foreign carbohydrate-appearing particles (FP) on transplant postreperfusion biopsy specimens: (PRBx).
Methods:
To further characterize FPs, we reviewed all renal transplant RBx (30-45 minutes) performed between September 1, 2004 and December 3, 2005. Donor, preservation, and outcome variables were collected among patients with FP.
Results:
A total of 135 PRBx were performed (45 deceased donors [DD] and 90 live donors [LD]). Fifteen PRBx demonstrated FP. All 15 cases were DD kidneys that underwent machine perfusion (MP) on the Waters RM3 (Waters Medical Systems, Rochester, Minn, United States) with Belzer MP solution (Trans Med, Elk River, Minn, United States). Donor age was 39.8 +/- 15.7 years. Terminal creatinine level was 1.45 +/- 0.8 mg/dL. Two of 15 were flushed in situ with HTK solution (no starch). Cold ischemia time was 28.8 +/- 9.1 hours with 14.3 +/- 5.1 hours of MP. In 13 of 15 patients, perfusion parameters were excellent (flow > 100 mL; resistance < .35). CHARACTERISTICS OF FP: Particles were 10-30 mu and globular in shape. FP were not visible on hematoxylin and eosin stain, but stained strongly periodic acid-Schiff-(PAS) positive and were refractile under polarized light. FP were seen segmentally within glomerular capillaries in all cases and in peritubular capillaries in 3. In 11 of the 15 cases with FP, focal glomerular fibrin thrombi or intracapillary neutrophil margination was seen. Ten of 15 patients with FP had a biopsy within the first week with no identifiable FP.
Outcomes:
Recipient age was 45.3 +/- 11.6 years. Eight patients (53.3%) had delayed graft function. Biopsy-proven rejection occurred in 3 patients (20%). Three-month creatinine level was 1.59 +/- 0.35 mg/dL. One graft was lost to early thrombosis in a patient with a hypercoagulable state and 1 patient died of sepsis at 2 months. All remaining 13 patients are alive with excellent graft function at a median follow-up of 6.7 months (range, 3-17 months).
Conclusions:
Microscopic intrarenal particles may be seen on DD kidney PRBx after MP. These FPs likely originate from surgical gloves. FPs are too small to be captured by standard filters but clear spontaneously and do not have deleterious effects on renal function or outcomes.
Insights
Foreign particles observed in kidney transplant biopsies after machine perfusion are likely from surgical gloves. These particles are microscopic, clear spontaneously, and do not impact transplant outcomes.
Area of Science:
- Nephrology
- Transplantation
- Pathology
Background:
- Foreign carbohydrate-appearing particles (FP) have been observed in postreperfusion biopsy (PRBx) specimens of kidney transplants.
- The origin and significance of these particles require further investigation.
Purpose of the Study:
- To characterize foreign particles (FP) found in renal transplant postreperfusion biopsies (PRBx).
- To determine the association of FP with donor type, preservation methods, and patient outcomes.
Main Methods:
- Retrospective review of 135 renal transplant PRBx performed between September 2004 and December 2005.
- Analysis of donor, preservation, and outcome variables in patients with identified FP.
- Characterization of FP morphology, staining properties (PAS, polarized light), and location within renal tissue.
Main Results:
- Fifteen of 135 PRBx (11.1%) demonstrated FP, exclusively in deceased donor (DD) kidneys subjected to machine perfusion (MP).
- FP were microscopic, PAS-positive, refractile, and located within glomerular and peritubular capillaries.
- Patients with FP showed a high incidence of delayed graft function (53.3%) and biopsy-proven rejection (20%), though graft function at 3 months was comparable to those without FP.
Conclusions:
- Microscopic foreign particles can be detected in DD kidney PRBx following machine perfusion.
- These particles are likely introduced from surgical gloves and are too small for standard filters.
- FP appear to clear spontaneously and do not adversely affect renal function or long-term transplant outcomes.
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