00:01
Before moving on,
I think it's important to review
the resident glomerular cells.
00:05
So let's look at our schematic
over here to the right.
00:08
The glomerular endothelial
cell is represented in yellow
and it lines are
capillary lumen.
00:16
The masangial cell,
outlined in blue,
is what provides
structural support
and makes extracellular matrix.
00:23
The podocytes or glomerular
epithelial cell is represented in red,
and it lines the outer
aspect of the capillary loop
and I want to take just a moment
for you to really appreciate
where that podocyte is.
00:35
Is look at the cell body and how it's
really just hanging in the urinary space
and what's actually
attaching that podocyte
to the underlying
glomerular basement membrane
are those foot processes.
00:46
If you look now at my electron
micro graph over here,
you can see on the left
is our actual cell body
and then on the right
are those foot processes
and look how beautiful they are
and how they line up
just like a picket fence.
00:59
They actually interdigitate
with each other
and there's a slit
diaphragm between them
and that really is
critical to maintaining
that glomerular capillary wall
and that ability to
keep that filtrate
in macromolecules from escaping.
01:14
So the podocyte has a couple of
different jobs it maintains loop shape.
01:19
It provides the size and charge
barrier to filter protein.
01:24
And it synthesizes and maintains
glomerular basement membrane.
01:28
So what I have represented over here
is a scanning electron micrograph.
01:31
And what I want
you to appreciate
is how those foot processes
interdigitate with each other
and you can see how that's
so critically important
in order to be that
ultimate barrier
to keep those macromolecules
from filtering out.
01:45
Okay, so we've discussed
the resident cells
let's talk now a little bit
more about nephrotic syndrome
and what the ideologies are.
01:52
When we think about
that we can group them
into primary glomerular diseases
and secondary
glomerular diseases
and before moving on what
I'd like you to appreciate is
that anytime we're talking
about glomerular diseases
there's a couple of different
things that go into it.
02:06
Number 1,
our patients tend to have
a genetic predisposition
we know this because when we do
genome-wide association studies,
there are things about our patients
that are that predispose them.
02:15
Number 2,
there's some kind of environmental
trigger that happens.
02:19
In number three,
our patients have the
tendency towards autoimmunity
and then manifests with
these glomerular diseases.
02:25
So again, when I'm thinking about
primary glomerular diseases,
these are diseases
where there's an immune
mediated injury to the podocyte.
02:33
We also call them
immune podocytopathy.
02:35
So I want you to
think of it in a sense
that the podocyte really
is the star of the show.
02:40
These are diseases like
membranous nephropathy,
minimal change disease,
and focal segmental
glomerulosclerosis.
02:47
It's a mouthful.
So often times we just say FSGS.
02:50
Remember no proliferative
glomerularnephritis
this is also included
in this category.
02:55
When we think about
secondary systemic diseases,
This is where the podocyte
injury really is a consequence
to an old underlying
systemic disease.
03:03
So it's kind of an
innocent bystander
that gets injured
during this process
of other disease process.
03:09
This includes amyloidosis,
diabetic nephropathy,
and systemic lupus erythematosus
or lupus nephritis.
03:16
Now as you can see,
I've bolded both
membranoproliferative
glomerulonephritis and lupus nephritis.
03:21
And the reason being
is that these two
diseases can present
both with nephrotic syndrome
and with nephritic syndrome,
but because they have more
of an inflammatory etiology,
we're going to be talking about them
in the nephritic syndrome lecture.