Another Uworld FA discrepancy. Help?

[voicesinmyhead]

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Uworld qid 383 says charge selectivity provided by endothelium and gbm, size selectivity by podocyte and GBM.

Fa says charge by podocyte and GBM, size by endothelium and GBM. Pg 533 2016.

Who's correct?

 

[zhopv10]

I would be tempted to say uworld is right here. The charge is I believe largely established by the GBM and I would imagine podocytes are big in size since minimal change disease allows albumin (big molecule ) to get through and it is a dz of the podocytes. That being said though I think all 3 could contribute to size to some degree since they are all barriers to some extent


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[moisne]

I don't see how endothelium selects for charges... I thought charges are determined most by the GBM by heparin sulfate

 

[AZ7]

I think FA is correct here. Think of it this way, in Minimal change as the defect is at the level of podocytes you've got a loss of the charge barrier and resultant albuminuria. Another thing I've thought of is that ( Not sure though ) in diseases where the endothelium is affected too like DM, you get microalbuminuria initially, which later progresses to full blown albuminuria, i.e the size barrier lost gradually and so it first allows the smaller albumin to pass through and then the larger.

 

[zeevee]

UW is correct in saying that charge barrier is provided by the negativity of the endothelium and the BM .Pododcytes help make the slit diaphragm so they make a size barrier.

 

[voicesinmyhead]

calling any one of the greats! how do you answer this for boards? @tasar1898 @Phloston @Transposony

 

[chillaxbro]

@chillaxbro

 

[Phloston]

An example is non-enzymatic glycosylation of the GBM in diabetes leads to albumin passing through, both due to alteration in size and charge. Boards won't get OCD about whether size or charge is lost where, and if they do they will give enough information so you can make the inference.

 

[worldbeater]

I thought it was mainly due to charge 0f heparin sulfate as a poster above said, so I would go in that direction if asked.