Biomedical subjects

Sandip Kapur

Publications and source records attributed to Sandip Kapur.

14 recordsLinked to original sources

PubMed2021

Detection of PKD1 and PKD2 Somatic Variants in Autosomal Dominant Polycystic Kidney Cyst Epithelial Cells by Whole-Genome Sequencing.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the development of multiple cysts in the kidneys. It is often caused by pathogenic mutations in PKD1 and PKD2 genes that encode polycystin proteins. Although the molecular mechanisms for cystogenesis are not established, concurrent inactivating germline and somatic mutations in PKD1 and PKD2 have been previously observed in renal tubular epithelium (RTE). METHODS: To further investigate the cellular recessive mechanism of cystogenesis in RTE, we conducted whole-genome DNA sequencing analysis to identify germline variants and somatic alterations in RTE of 90 unique kidney cysts obtained during nephrectomy from 24 unrelated participants. RESULTS: Kidney cysts were overall genomically stable, with low burdens of somatic short mutations or large-scale structural alterations. Pathogenic somatic "second hit" alterations disrupting PKD1 or PKD2 were identified in 93% of the cysts. Of these, 77% of cysts acquired short mutations in PKD1 or PKD2 ; specifically, 60% resulted in protein truncations (nonsense, frameshift, or splice site) and 17% caused non-truncating mutations (missense, in-frame insertions, or deletions). Another 18% of cysts acquired somatic chromosomal loss of heterozygosity (LOH) events encompassing PKD1 or PKD2 ranging from 2.6 to 81.3 Mb. 14% of these cysts harbored copy number neutral LOH events, while the other 3% had hemizygous chromosomal deletions. LOH events frequently occurred at chromosomal fragile sites, or in regions comprising chromosome microdeletion diseases/syndromes. Almost all somatic "second hit" alterations occurred at the same germline mutated PKD1/2 gene. CONCLUSIONS: These findings further support a cellular recessive mechanism for cystogenesis in ADPKD primarily caused by inactivating germline and somatic variants of PKD1 or PKD2 genes in kidney cyst epithelium.

Humans↗

PubMed2005

Retraction.

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Retraction Notice↗

PubMed2004

Pulsatile machine perfusion with Vasosol solution improves early graft function after cadaveric renal transplantation.

BACKGROUND: Cold storage is the most common method of preservation in renal transplantation, but pulsatile machine perfusion (MP) is increasingly used for purposes of ex vivo assessment and resuscitation of high risk allografts. Vasosol (VSL) MP solution (MPS) (Pike Laboratories Inc, Eagle, PA) is a novel perfusate with enhanced vasodilatory and antioxidant capacity. We report our experience with VSL in machine preservation of renal allografts. METHODS: Locally procured cadaver kidney pairs undergoing MP were randomized to VSL or control solution (Belzer MPS; Trans-Med, Elk River, MN). En bloc perfusion was performed according to standard MP procedures. Transplantation was performed at 1 of 12 local transplant centers. Donor and recipient data were collected prospectively. RESULTS: Data from 162 transplanted kidneys were analyzed. A total of 82 renal grafts were perfused with VSL, and 80 were perfused with control solution. No organs were lost secondary to the technique of MP. There was no difference in donor or recipient age between groups. Kidneys perfused with VSL exhibited significantly higher rates of immediate function and significantly less delayed graft function (12.2% vs. 21.2%). Discharge creatinine and length of stay were also significantly improved in the VSL group. One-year graft and patient survivals were equivalent (95%) in both groups. CONCLUSIONS: VSL improved early graft function and shortened the length of stay compared with Belzer MPS. Further improvement in preservation solutions in conjunction with pulsatile perfusion shows promise in improving early outcomes after renal transplantation, especially for extended criteria donor kidneys.

Adenosine↗

PubMed2004

Resection of an intravenous leiomyoma with intracardiac extension with use of endovascular techniques.

Intravenous leiomyoma with intracardiac extension is a rare entity that necessitates surgical excision to alleviate symptoms and prevent life-threatening complications. These procedures are generally performed under cardiopulmonary bypass, and review of the literature reveals an evolution in management of this disease from 2-stage to single-stage procedures. We report the case of a 45-year-old woman with an intravenous leiomyoma with intracardiac extension after presenting with syncopal symptoms. The intravenous tumor and its supradiaphragmatic extension were ultimately resected via laparotomy without the need for cardiopulmonary bypass. Distal control was achieved by passing an occluding balloon catheter above the tumor through a venotomy with fluoroscopic guidance and echocardiography, thus enabling protected tumor extraction through the intra-abdominal inferior vena cava. In selected patients, we believe use of endovascular techniques combined with proper preoperative imaging can safely permit single-stage resection of these tumors via laparotomy without cardiopulmonary bypass.

Angioplasty, Balloon↗

PubMed2004

Noninvasive detection of renal allograft inflammation by measurements of mRNA for IP-10 and CXCR3 in urine.

BACKGROUND: We explored the hypothesis that measurements of mRNA encoding interferon-inducible protein-10 (IP-10) or the chemokine receptor CXCR3 in urinary cells offer a noninvasive means of elucidating cellular traffic causing acute rejection of human renal allografts. METHODS: We obtained 63 urine specimens from 58 renal allograft recipients who underwent 63 allograft biopsies to resolve the basis for graft dysfunction, and 27 additional urine samples from 24 other patients with stable allograft function. Twenty-seven of the 63 biopsies were classified as acute rejection, 20 as other, and 16 as chronic allograft nephropathy. We measured the levels of transcripts for IP-10 and CXCR3, and a constitutively expressed gene 18S rRNA in the urine specimens and correlated transcript levels with renal allograft diagnosis. RESULTS: mRNA levels of IP-10 (P < 0.0001) or CXCR3 (P < 0.0001) but not the levels of 18S rRNA (P= 0.56) predicted intragraft cellular traffic causing acute rejection. Receiver-operating characteristic curve analysis demonstrated that acute rejection can be predicted with a sensitivity of 100% and a specificity of 78% using the (log-transformed) cutoff value of 9.11 copies of IP-10, and with a sensitivity of 63% and a specificity of 83% using the cutoff value of 11.59 copies of CXCR3. Immunohistologic analysis of allograft biopsies showed exuberant expression of IP-10 and CXCR3 during acute rejection whereas both were absent in grafts with stable function. CONCLUSION: Our investigation demonstrates that intragraft cellular events associated with acute rejection of human renal allografts can be noninvasively identified by measurements of mRNA for IP-10 and CXCR3 in urinary cells.

Adult↗

PubMed2003

Molecular signatures of urinary cells distinguish acute rejection of renal allografts from urinary tract infection.

Acute rejection (AR) and urinary tract infection (UTI) continue to plague renal transplantation. We tested the hypotheses that UTI does not increase granzyme B mRNA levels in urinary cells, and that the levels distinguish AR from UTI. We measured the levels of granzyme B mRNA in 15 urine specimens from renal allograft recipients with UTI, 29 specimens from patients with AR but without UTI, and 14 specimens from patients without AR and without UTI. We also measured transcript levels in urine specimens from 41 nontransplant individuals, 11 with UTI and 30 without UTI. UTI did not increase granzyme B mRNA levels. Granzyme B mRNA levels were lower in renal allograft recipients with UTI compared with those with AR (P<0.0001). We conclude that bacterial UTI is unlikely to confound AR diagnosis made by measurement of granzyme B mRNA levels in urinary cells.

Acute Disease↗

PubMed2003

Serine proteinase inhibitor-9, an endogenous blocker of granzyme B/perforin lytic pathway, is hyperexpressed during acute rejection of renal allografts.

BACKGROUND: Serine proteinase inhibitor (PI)-9 with a reactive center P1 (Glu)-P1' is a natural antagonist of granzyme B and is expressed in high levels in cytotoxic T lymphocytes (CTL). In view of the role of CTL in acute rejection, we explored the hypothesis that PI-9 would be hyperexpressed during acute rejection. Because PI-9 can protect CTL from its own fatal arsenal and potentially enhance the vitality of CTL, we examined whether PI-9 levels correlate with the severity of rejection as well as predict subsequent graft function. METHODS: We obtained 95 urine specimens from 87 renal allograft recipients. RNA was isolated from the urinary cells and mRNA encoding PI-9, granzyme B, or perforin and a constitutively expressed 18S rRNA was measured with the use of real-time quantitative polymerase chain reaction assay, and the level of expression was correlated with allograft status. RESULTS: The levels of PI-9 (P=0.001), granzyme B (P<0.0001), and perforin mRNAs (P<0.0001), but not the levels of 18S rRNA (P=0.54), were higher in the urinary cells from the 29 patients with a biopsy-confirmed acute rejection than in the 58 recipients without acute rejection. PI-9 levels were significantly higher in patients with type II or higher acute rejection changes compared with those with less than type II changes (P=0.01). Furthermore, PI-9 levels predicted subsequent graft function (r=0.43, P=0.01). CONCLUSIONS: PI-9 mRNA levels in urinary cells are diagnostic of acute rejection, predict renal allograft histology grade, and predict functional outcome following an acute rejection episode.

Acute Disease↗

PubMed2003

CD103 mRNA levels in urinary cells predict acute rejection of renal allografts.

BACKGROUND: CD103 is displayed on the cell surface of alloreactive CD8 cytotoxic T lymphocytes (CTLs) and is a critical component for the intraepithelial homing of T cells. Because intratubular localization of mononuclear cells is a feature of acute cellular rejection of renal allografts, we explored the hypothesis that CD103 messenger (m)RNA levels in urinary cells predict acute rejection. METHODS: We collected 89 urine specimens from 79 recipients of renal allografts. RNA was isolated from the urinary cells, and we measured CD103 mRNA levels and a constitutively expressed 18S ribosomal (r)RNA with the use of real-time quantitative polymerase chain reaction assay. RESULTS: CD103 mRNA levels, but not 18S rRNA levels, were higher in urinary cells from 30 patients with an episode of acute rejection (32 biopsies and 32 urine samples) compared with the levels in 12 patients with other findings on allograft biopsy (12 biopsies and 12 urine samples), 12 patients with biopsy evidence of chronic allograft nephropathy (12 biopsies and 12 urine samples), and 25 patients with stable graft function after renal transplantation (0 biopsies and 33 urine samples) (P = 0.001; one-way analysis of variance). Acute rejection was predicted with a sensitivity of 59% and a specificity of 75% using natural log-transformed value 8.16 CD103 copies per microgram as the cutoff value (P = 0.001). CONCLUSION: CD103 mRNA levels in urinary cells are diagnostic of acute rejection of renal allografts. Because CD103 is a cell surface marker of intratubular CD8 CTLs, a noninvasive assessment of cellular traffic into the allograft may be feasible by the measurement of CD103 mRNA levels in urinary cells.

Acute Disease↗

PubMed2003

Analysis of failure in living donor liver transplantation: differential outcomes in children and adults.

Over the past decade we have reported excellent outcomes in pediatric living-donor liver transplantation (LDLT) with recipient survival exceeding 90%. Principles established in these patients were extended to LDLT in adults. To compare outcomes in donors and recipients between adult and pediatric LDLT in a single center, we reviewed patient records of 45 LDLT performed between 1/98 and 2/01: 23 adult LDLT (54 +/- 6.5 yr) and 22 pediatric LDLT (33.7 +/- 53.5 months). Preoperative liver function was worse in adults (International Normalized Ratio [INR] 1.5 +/- 0.4 vs. INR 1.2 +/- 0.5; p = 0.032). 4 adults (17%) met criteria for status 1 or 2A. Only 1 child was transplanted urgently. Analysis included descriptive statistics and Kaplan-Meier estimation. Donor mortality was 0% with 1 re-exploration, 2.4%. Median hospital stay (LOS) was 6.0 days (range, 4-12 days). Donor morbidity and LOS did not differ by sex, extent of hepatectomy, or adult and pediatric LDLT ( p = 0.49). In contrast, recipient outcomes were worse for adults. Adult 1 year graft survival was 65% (3 retransplants [ReTx], 5 deaths) vs. 91% for children (1 ReTx, 1 death) p = 0.02. Graft losses in adults were due to sepsis (n = 3), small for size (n = 2), suicide, and hepatic artery thrombosis (HAT), whereas in children graft losses were due to portal thrombosis and total parenteral nutrition (TPN) liver failure. Biliary leaks occurred in 22% of adults and 9% of children. Hepatic vein obstruction occurred in 17% of adults and in none of the children. Median LOS was comparable (adult, 16.5 days (range, 7-149 days); child, 17 days (range, 10-56 days), p = 0.2). Graft function (total bilirubin (TBili) < 5mg/dl, INR < 1.2, aspartate aminotransferase (AST) < 100 U/l) normalizing by day 4 in children and by day 14 in adults. Adults fared worse, with an array of problems not seen in children, in particular, hepatic vein obstruction and small-for-size syndrome. Biliary leaks were diagnosed later in adults and were lethal in 3 cases; this was later avoided with biliary drainage in adult recipients. Finally, use of LDLT in decompensated adults led to death in 3 of 4 patients, and should be restricted to elective use.

Adolescent↗

PubMed2003

Outflow reconstruction in right hepatic live donor liver transplantation.

BACKGROUND: Inconstant venous anatomy increases the risk of outflow complications in right hepatic live donor liver transplantation (RH-LDT), but no consensus has emerged guiding optimal reconstruction for venous outflow. METHODS: We retrospectively analyzed surgical venous reconstruction using a flexible approach to anterior accessory veins in 48 RH-LDTs performed between April, 1998 and July, 2002. RESULTS: Actuarial recipient graft and patient survival was 79% and 85%, respectively. Single hepatic venous anastomosis was performed in 74% of the patients. Twelve patients underwent reconstruction of 20 accessory veins, including 7 posterior segment veins and 13 anterior segment veins. Anterior vein reconstruction techniques included end-to-end anastomosis to the middle hepatic vein, interposition conduit, venoplasty, or a combination of techniques. Documented complications related to the venous anastomosis occurred in only 1 patient (2%), with no patient having a documented venous thrombosis of either the main RHV or a reconstructed accessory vein. There were no differences in outcome based on single versus multiple venous reconstruction. Anteromedial congestion was noted in 3 patients in the absence of anatomic venous anastomotic complication, but the clinical significance of this finding is unclear. CONCLUSIONS: Despite variations in segmental venous drainage and a propensity for anteromedial congestion in right hepatic grafts, RH-LDT can be performed without outflow obstruction with close attention to a wide RHV anastomosis. In addition, anterior accessory vein reconstruction can be reserved for grafts of marginal size or quality where early postoperative venous congestion may impair early graft function. Routine extended hepatectomy incorporating the MHV with the graft is unnecessary.

Actuarial Analysis↗

PubMed2002

Proapoptotic Bax is hyperexpressed in isolated human islets compared with antiapoptotic Bcl-2.

BACKGROUND: Apoptosis is a well-documented pathway for islet cell death. One potential mechanism is overexpression of death-promoting Bax compared with antiapoptotic Bcl-2 in islets. METHODS: We isolated islets from 10 human pancreata and measured the expression of Bax mRNA and Bcl-2 mRNA by real-time quantitative polymerase chain reaction; islet and pancreas expression of Bax, Bcl-2, activated caspase-3, and cleaved poly (ADP-ribose) polymerase were also assessed by immunohistochemistry. Islet cell apoptosis was evaluated by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) assay and by flow cytometry. RESULTS: The mean (+/-SE) level of Bax mRNA was 336+/-79 copies per nanogram of total RNA, and the level of Bcl-2 mRNA was 36+/-10 (P=0.001). A positive correlation existed between islet expression of Bax mRNA and Bcl-2 mRNA (P=0.001). The islet Bax to Bcl-2 ratio was 10.8+/-1.3 and 1.71+/-0.3 for the spleens (P=0.0001). Bax mRNA (P=0.04), but not Bcl-2 mRNA, was expressed at a higher level in islets compared with spleens. Human islets contained large numbers of cells expressing Bax protein, whereas only infrequent islet cells expressed Bcl-2 protein, activated caspase-3, and poly (ADP-ribose) polymerase. The apoptotic index was 5% by TUNEL assay, and the percentage of apoptotic islet cells was 9.7+/-2.5% by flow cytometry. Sections of human pancreas before islet isolation showed islet staining for Bax but not Bcl-2. CONCLUSIONS: Our finding that isolated human islets express Bax at a higher level compared with Bcl-2 suggests a molecular mechanism for islet cell death by apoptosis. We hypothesize that reducing islet expression of Bax, or regulating its activation, will help preserve islet cell mass after islet transplantation.

Adult↗

PubMed2002

Enforced c-REL deficiency prolongs survival of islet allografts1.

BACKGROUND: The NF-kappaB/Rel family of transcription factors regulates biologic processes ranging from apoptosis to inflammation and innate immunity. Whether c-Rel, a lymphoid-predominant member of the NF-kappaB/Rel family, is essential for transplantation immunity is not known. METHODS: We explored the role of c-Rel in the anti-allograft repertory using mice with targeted disruption of the c-Rel gene (c-Rel-/-) as recipients of H-2 mismatched islet allografts. Allogeneic DBA/2 (H-2d) islets were transplanted into the renal subcapsular space of diabetic c-Rel-/- C57BL/6 (H-2b) mice or the c-Rel +/+ C57BL/6 wild-type mice. Islet graft survival, cellular traffic into the islet grafts and their phenotype, and intragraft expression of cytokines and cytotoxic attack molecules were determined at the protein (by immunohistochemistry) and mRNA (by real-time quantitative polymerase chain reaction) levels. RESULTS: We found superior islet graft survival in the c-Rel-/- recipients compared to c-Rel+/+ C57BL/6 recipients. Splenocytes from c-Rel-/- mice proliferated poorly compared to splenocytes from the c-Rel+/+ mice on stimulation with anti-CD3 mAbs or Con A. Peri-islet infiltration composed of T lymphocytes and macrophages was found in both c-Rel+/+ recipients and c-Rel-/- recipients, but intra-islet infiltration was observed only in c-Rel+/+ recipients. Immunohistologic and molecular studies showed impaired T helper-type 1 immunity and decreased intragraft expression of cytotoxic attack molecules perforin and granzyme B in c-Rel-/- recipients as compared to wild-type recipients. CONCLUSIONS: Our results demonstrate that c-Rel is essential for robust rejection of islet allografts and support the idea that strategies that impair c-Rel function may be of value for constraining alloimmunity and facilitating survival of allogafts.

Animals↗

PubMed2002

Analysis of donor risk in living-donor hepatectomy: the impact of resection type on clinical outcome.

The progressive shortage of liver donors has mandated investigation of living-donor transplantation (LDT). Concerns about increasing risk to the donor are evident, but the impact of the degree of parenchymal loss has not been quantified. We analyzed clinical and biological variables in 45 LDT performed by our team over 2years to assess risks faced in adult LDT. All donors are alive and well with complete follow-up through to February 2001. When the three operations were compared, right hepatectomy (RH) was significantly longer in terms of anesthesia time and blood loss compared with left hepatectomy (LH) and left lobectomy (LL). Donor remnant liver was significantly reduced after RH compared with LH and LL. There were significant functional differences as a consequence of the remnant size, measured by an increase in peak prothrombin time after RH. RH for adults represents a markedly different insult from pediatric donations in terms of parenchymal loss and early functional impairment. Left hepatectomy donation offers modest advantage over right lobes but seems to confer substantial technical risk for a small gain in graft size. Unless novel strategies are developed to enhance liver function of the LH graft in the adult recipient, right lobe donation will be necessary for adult LDT.

Adult↗

PubMed2002

Successful sequential liver and stem cell transplantation for hepatic failure due to primary AL amyloidosis.

We report on a patient with primary AL amyloidosis who presented with progressive liver failure secondary to hepatic infiltration in the absence of significant extrahepatic involvement. Orthotopic liver transplantation was performed successfully. After an uneventful postoperative course, the patient developed evidence of significant recurrent amyloidosis requiring treatment. He then underwent stem cell transplantation 10 and 14 months after liver transplantation. After 28 months of follow-up posttransplantation, the patient continues to do well, with no clinical evidence of recurrent disease. This is the first reported patient with primary amyloidosis to undergo sequential liver and stem cell transplantation leading to resolution of the disease and only the second to undergo successful liver transplantation for this disorder.

Aged↗